# TIGHAR

## Amelia Earhart Search Forum => Celestial choir => Topic started by: Irvine John Donald on September 03, 2011, 09:20:29 PM

Title: Working the Flight backwards
Post by: Irvine John Donald on September 03, 2011, 09:20:29 PM
There has been a lot of discussion in this forum as to whether or not AE and FN made it to Gardner. Lots of theories, ideas, gas calculations, etc. with several people even suggesting that navigating to Gardner may have been plan B.  How about this?  AE and FN have navigated through the night and cant find Howland. Noonan has a chart showing the Phoenix island group and knows if he heads south on the LOP then he will "likely" find an island. He has AE head the aircraft on south leg of LOP on 157. They watch for land. I can't for one minute believe they found other islands first and chose to keep flying until they got to Gardner. Therefore, if Gardner was the first island they found you can plot backwards on the LOP and determine where (approximately) they were when they headed south. Gardner is the western most island in the group. I believe there has been much discussion on where they were when they headed south but there is lots of debate over where that point is. Having at least an approximation would help with gas calculations, signal strength at Howland, and may help explain somewhat why they couldnt see Howland. Has anyone done this plot before?  If not can one of our forums navigation wizards give it a try. Yes there are tons of variables and approximations but I think everyone agrees AE and FN missed Howland.  But FN did his part and got close to Howland.  With no Howland AE and FN were probably now super conscious of their navigating because their lives depended on it. The leg from where they turned south until Gardner island was probably the best navigated of the entire trip!
Title: Re: Working the Flight backwards
Post by: Ric Gillespie on September 04, 2011, 08:50:01 AM
Funny you should bring this up.  Bob Brandenburg and I have been spending a great deal of time doing exactly what you're talking about.
There are three ways to gauge where the airplane was on the LOP when the last in-flight transmission was received by Itasca.  That time, btw, was not 08:43 or 08:44 Itasca time as is commonly supposed.  As explained in the Research Bulletin, "Last Words," (http://tighar.org/Projects/Earhart/Archives/Research/Bulletins/49_LastWords/49_LastWords.html) the best estimate is 08:55 - or, as we prefer, 2025Z.

1.  The last transmission was heard loud and clear - logged by the radio operator aboard Itasca as "Strength 5" (the maximum).  Where on the LOP was the aircraft most likely to be at 2025Z for Itasca to hear a Strength 5 signal?

2.  During the morning hours of July 2nd, the tide at Gardner Island was rising.  Where on the LOP would the airplane need to be at 2025Z in order for it to reach Gardner in time to land on the reef before the water level at the apparent landing site reached 6 inches - the estimated maximum height permissible for a safe landing?

3. The credible post-loss radio signals could only have been sent if the airplane landed with enough fuel to run the generator-equipped engine long enough to provide the necessary electrical power.   Where on the LOP would the airplane need to be at 2025Z in order for it to reach Gardner and land with enough remaining fuel to meet that requirement?

As you can see, the three methods approach the question from completely different directions.  If the answers to all three questions overlap to some degree there is a high probability that the correct answer is within that area.

We have almost all the information we need to answer the three questions and I fully expect to be able to lay it all out in the TIGHAR Journal 2011 paper entitled "The Last Week of NR16020."

The last pieces of information we need are the reasonable variables for her speed and fuel consumption during the run down the LOP.  On the final run-in toward Howland, Earhart reported she was flying at 1,000 feet (probably to stay under the bases of the scattered cumulus clouds). She was down there for at least an hour prior to the last radio message heard by Itasca. We're assuming that she stayed low while running on the line.  We, of course, don't know what power settings and airspeed she was maintaining during that portion of the flight or how much fuel she was burning.  We need to define the reasonable possibilities.

In "Last Flight" she writes that at the end of the Oakland/Honolulu flight, to kill some time and let the sun come up, she backed off to 120 mph burning only 20 gallons per hour - but that was at 10,000 feet.

Let's say she's down at 1,000 feet and decides to maintain her cruising TAS of 150 mph.  How much power does she need to carry to do that and what does that do to her fuel consumption in gph? (answer: nothing good)

What happens if she backs off to, say, 140 mph?  130 mph?  120 mph? Or even 110 mph?  We don't think she'd go slower than that.

Any help will be appreciated but it needs to be based on hard data, not seat-of-the-pants hunches.
Title: Re: Working the Flight backwards
Post by: Ric Gillespie on September 04, 2011, 08:58:43 AM
Forgot to provide a link to Last Words (http://tighar.org/Projects/Earhart/Archives/Research/Bulletins/49_LastWords/49_LastWords.html).
Title: Re: Working the Flight backwards
Post by: Martin X. Moleski, SJ on September 04, 2011, 09:50:34 AM
Forgot to provide a link to Last Words (http://tighar.org/Projects/Earhart/Archives/Research/Bulletins/49_LastWords/49_LastWords.html).

Any member of the Forum (including idiots like Gillespie ;D ) may modify their own posts (http://tighar.org/smf/index.php/topic,453.msg5492.html#msg5492) as needed.

Moderators may modify member's posts (as I have often done ) to make corrections in them.

This posting has been modified by moderator Gillespie.
Title: Re: Working the Flight backwards
Post by: h.a.c. van asten on September 04, 2011, 02:05:25 PM
A/c was not very sensible for fuel expenditure @ different altitudes (Report LH 487) .Usual consumption was 310 lb/hr (letter Feb 3 , 1937 /Earhart ; wire Putnam Feb 3 , 1937) . For wind zero to moderate , Beaufort 2..4
TAS1   to    TAS2     factor     (factor)^3                  lb / hr       galls / hr

150             150       1.00         1.00                         310             52
150             140       0.93         0.80                         248             41
150             130       0.87         0.66                         205             34
150             120       0.80         0.50                         155             26
150             110       0.73         0.39                         121             20

The lower row figure  20   matches Earhart´s  for 10,000 ft figure . Outcomes based on relative speed increment  dV/V  gives additional chemical energy needed
(dV/V)^3  . At lower altitudes due to higher air density wing´s  attack angle slightly smaller than @ high altitude with low density , for same lift @ lower speed , therefore low alt. air resistance higher , but CL/CD better ; this explains moderate sensibilty for altitude versus fuel consumption ratio .

Title: Re: Working the Flight backwards
Post by: Irvine John Donald on September 04, 2011, 10:55:57 PM
Thanks Ric.  I look forward to the paper being published.

Unfortunately there is no hard data on this part of the flight as our intrepid aviators never reported it by radio nor had the decency to leave a castaway's diary.  At least not that has been found or we know of. Not being an aviator or navigator I can only presume that on failing to find Howland both AE and FN would navigate and fly very carefully for the next few hours. If it was me i would have reduced gas consumption as much as possible to stretch the remaining reserves. However i also think i would be transmitting everything i was doing.  Just because nothing was heard doesn't mean she wasn't transmitting but its hard to imagine that Itasca wouldn't hear her signal fading away as she moved south.

However we believe she had a broken antenna.  Could the signal from the broken antenna be picked up when flying west to east but not well, or at all, when she turned the aircraft to fly south?  Did you and Bob consider that the flight changing direction may have caused the lack of reception?  I know nothing of radio signals but know that the early radios were affected by many factors. Thats just enough to ask silly questions.

I believe that AE and FN probably started into survival mode when they made the decision to turn south. When choices are presented in what "could" have happened I think we should lean to what someone in survival mode would do.

Thanks for your detailed answers Ric. Not only do you "fill in the blanks" but you often add variables, concepts or info I hadn't thought of.
Title: Re: Working the Flight backwards
Post by: h.a.c. van asten on September 05, 2011, 12:23:20 AM
Additionally :  @ 1,000 ft the air density (0.964 kg/m^3) is 27% higher than @ 1,000 ft (1.225 kg/m^3) , but the speed 110 is 27% lower than 150 , making break-even .
Title: Re: Working the Flight backwards
Post by: h.a.c. van asten on September 05, 2011, 01:03:17 AM
Oops , @ 10,000 ft the air density is 27% lower ...
Title: Re: Working the Flight backwards
Post by: Tom Swearengen on September 05, 2011, 11:49:26 AM
Ok---I'll ask the question of our navigator friends. IF the weather was cloudy during the nighttime part of the flight, Fred would NOT have been able to shoot a celestrial plot. So, when he was able to shoot the 157/337 sunline, how would he have known where along the sunline he was? He wouldnt have been able to guage their drift, so they actually "could" have been south of Gardner. AT 1000 feet, they may not have been able to see Howland, which "could" have been a few miles over the horizon from their position.

So--as they flew south along the sunline, they came across Gardner.
Does this make any sense to anyone??
Title: Re: Working the Flight backwards
Post by: h.a.c. van asten on September 05, 2011, 01:46:45 PM
If they had gone astray they would have announced it , radio transmission from aboard to Itasca was excellent for a number of hours . From 1,000 ft the natural horizon was 61 km , 38 mls away . You btw never know where you are on a sun line when reaching it , therefore an island is usually approached by a dog leg operation . It was indeed possible to set course for Gardner from a guessed position near Howland , and reach it easily by DR terrestrial triangulation without following any sun line . A drift of several hundred miles , incurred by an experienced navigator is improbable :  5 to 10% deviation to L/R of a by DR only distance made good is the historical limit due to observation error . That mr.Noonan lost insight of A/c´s latitude is improbable : between Nukumanu and the twilight zone off Howland , every 20 minutes a star ( d-Ophiuchi , Antares no.42 to Al Naír no.55) was flown in A/c´s meridian and when then shot the latitude was immediately known from the star´s ephemeries . Stars head-on delivered course position lines by which A/c´s progression in longitude could be established .
Title: Re: Working the Flight backwards
Post by: Harry Howe, Jr. on September 05, 2011, 09:21:29 PM

By Jove, I believe we have made a believer out of Mr, Van Esten.  Welcome Friend.
Title: Re: Working the Flight backwards
Post by: Harry Howe, Jr. on September 05, 2011, 09:24:06 PM

Mr. Van Easten (sp) sorry friend.
Title: Re: Working the Flight backwards
Post by: Irvine John Donald on September 05, 2011, 09:57:06 PM
Ok---I'll ask the question of our navigator friends. IF the weather was cloudy during the nighttime part of the flight, Fred would NOT have been able to shoot a celestrial plot. So, when he was able to shoot the 157/337 sunline, how would he have known where along the sunline he was? He wouldnt have been able to guage their drift, so they actually "could" have been south of Gardner. AT 1000 feet, they may not have been able to see Howland, which "could" have been a few miles over the horizon from their position.

So--as they flew south along the sunline, they came across Gardner.

Does this make any sense to anyone??

Why the sunline Tom?  Wasn't sunrise before Howland?  Why turn south at sunrise when he was supposed to continue to Howland?  I believe at sunrise they didn't know they were lost yet.  Or is "sunline" not the same as sunrise?

Non navigators like me must bug the heck out of real navigators but sometimes the non tech guys can see the forest and the trees.

I think one of the best methods of trying to work this out is to drop the tech stuff for a minute, figure out what someone who is worried and scared would do, then apply the tech theories to see if it fits. Fear is a powerful behaviour modifier.
Title: Re: Working the Flight backwards
Post by: h.a.c. van asten on September 05, 2011, 11:52:02 PM
Up to GMT 1912 the voice communication records show the crew to be completely at ease . The sun line has been probably advanced from a sunrise line , although it was also possible to plot such line from the already risen sun when its elevation enabled for a reliable observation annex time and distance-off check . The turn for Howland may have been from a dog leg operation northwards of the island , upon which , when flying along the sun line over the supposed position of destination , it did unexpectedly not run in sight . From then an emergency situation was incurred .
Title: Re: Working the Flight backwards
Post by: Tom Swearengen on September 06, 2011, 05:24:36 AM
I thought the sunline represented the first real "position" that Fred had after flying through the night. If he had been able to get a position earlier, Amelia would have radioed it. So, I was assuming that he could not get a celestrial position, and was flying on compass only. Assuming that they had a tailwind, then the winds could have put them anywhere along the courseline towards Howland, if Fred did not do a course correction.
We dont know the power settings she was using, so we also dont know the fuel burn per hour. So IF she did have a tailwind, it could have increased her range to easily make Niku, or possibly somewhere else.
I think we need to look at this from 1937 technology---not 2011. How would YOU have done this? From what I see, she had enough fuel to make Niku, and still be able use the engines to power the radio. What we dont know is where and HOW she landed. Given the evidence, I think Rics reef landing theory is correct, and the Electra is down there.
Title: Re: Working the Flight backwards
Post by: Martin X. Moleski, SJ on September 06, 2011, 05:50:58 AM
... IF she did have a tailwind, it could have increased her range ...

If wishes were horses, then beggars would ride.

If my grandmother had wheels, she would be a bicycle.

The ETA for the flight was eighteen hours after takeoff:

"Finally, just before 8:00 PM aboard Itasca, official notification of Earhart’s departure arrived from Lae, via Samoa: 'Urgent, Black, Itasca . . . Amelia Earhart left Lae at 10 AM local time July 2nd. Due Howland Island 18 hours time.' This information presented a new picture. The plane had left Lae two hours earlier than previously reported, and the eighteen-hour time-en-route estimate indicated that Earhart anticipated lighter headwinds than predicted in the most recent forecast. Itasca should now expect the plane to arrive at around 6:30 AM" (Finding Amelia, p. 85).

The actual arrival in the vicinity of Howland took nineteen hours ("We must be on you" at 1912 GMT) (http://tighar.org/wiki/Transmission_timeline).  That suggests headwinds rather than tailwinds.
Title: Re: Working the Flight backwards
Post by: Ric Gillespie on September 06, 2011, 06:47:37 AM
There is still confusion about the LOP.
1. Credible reports of overcast conditions during the night mean that Fred was not able to maintain an accurate course for Howland using celestial navigation.
2. After sunrise Fred takes his observation.  He already knows that the sun will come at 67° True so he knows that his Line of Position will be 157° - 337°.  His after-sunrise observation lets him draw that line on his map and shows him how far along he is in an east-west sense.  He has no way knowing where he is in a north-south sense.
3. Having drawn his 157-337 line on the chart ("I'm somewhere on this line.") he draws another 157-337 line that passes through Howland.  He then measures the distance between the two parallel lines.  Now he knows how far it is from the line he is on to the line that passes through Howland.
4. Next question: How long will it take to cover that distance?  For that he needs to know the airplane's ground speed and that means getting an accurate handle on what the wind is doing (something he has not been able to do all night).  Now that it's daylight he can estimate the wind by watching the wave tops on the ocean or using his drift meter.
5. Now he can estimate at what time they will reach the line that passes through Howland. That time turns out to be 19:00 Greenwich.  He tells AE (probably with a note)  "ETA 1900."  He, of course, means that they'll reach the line at 19:00.  If they're bang on course they'll also reach Howland at 19:00, but Fred has been DRing all night without a celestial fix. He knows it would be amazing if they are still exactly on course.   Amelia doesn't understand the nuance.  All she knows is that Fred says ETA 1900.
6.  Amelia tries repeatedly to get Itasca to take a bearing on her but gets no reply.
7. 19:00 comes but Howland is not there and, at 19:12, Amelia radios, "We must be on you but cannot see you."  Fred knows that it's not true that "we must be on you" but he's not the one on the radio.  He knows that what they have to do now is DR their way up and down the line to find Howland.
8. He has Amelia fly northwest first and at 20:00 she tries to use her loop antenna, but no luck.  Fred has her turn around and they retrace their steps, DRing southeast and still hoping that they'll find Howland.
9.  Amelia finally understands what they're doing and why and at 20:13 radios "We are on the line 157 -337" and says she'll repeat this on her other frequency, but before she does she decides to explain further and at 20:25 radios, "We are running on line north and south."  Then she changes frequencies and nothing more is heard.
10. Noonan knows that all of the other islands on or near the LOP are southeast of Howland.  That's why he goes northwest first. But everything they do is in hopes of finding Howland.  At no point do they decide to "go for" some other island.
Title: Re: Working the Flight backwards
Post by: Martin X. Moleski, SJ on September 06, 2011, 07:13:56 AM
There is still confusion about the LOP.  ...

As long as there are newcomers to this one-room schoolhouse, there will be confusion.

Thanks for the narrative.  I've added it to the Ameliapedia article about the last transmission (http://tighar.org/wiki/%22We_are_on_the_line_157_337%22).
Title: Re: Working the Flight backwards
Post by: Irvine John Donald on September 06, 2011, 07:50:39 AM
I thought the sunline represented the first real "position" that Fred had after flying through the night. If he had been able to get a position earlier, Amelia would have radioed it. So, I was assuming that he could not get a celestrial position, and was flying on compass only. Assuming that they ..............  landed. Given the evidence, I think Rics reef landing theory is correct, and the Electra is down there.

Thanks Tom.  I also believe the TIGHAR theory and expect the Electra to be found off the reef.
Youre right that we should be thinking in 1937 terms which is why I also say let's put our mindset into terms of being in survivor mode.

The navigation used has so many variables and so many opinions that I thoughtbto look at it from a non technical way. IF, and many will say its a big IF, we assume the theory is correct then they landed on Gardner.  IMHO they did not make the decision to fly to Gardner.  Once they realized they could not find Howland they had to also realize they were lost. If Fred's navigation was right then Howland had to be nearby.  What would the conversation in the Electra have been?  I think AE would have listened to Fred and thats why they flew south on the LOP. The best chance of hitting an island.  In survivor mode, and knowing Howland was the best site, then any island would suffice. So they head south on the 157 LOP.  Its likely that Gardner was the first.  They land.  No matter what all the theories say, if we believe the theory then we must believe Gardner WAS the final stop.  How the got there from the route to Howland is the question everyone seems to be asking. I believe we draw a straight line on the recipricol course to 157. Thats the 337 line back to where it intersects the course to Howland.  Thats where they were when they decided to fly south.  Its just not as clean and simple as that I know but it might be.
Would they have found a different island first and decided not to land but find somewhere better?  Not likely. They are in survivor mode with ever lower gas supply. If they were further east when they turned south on the LOP then they would have potentially reached other islands first.  Look at the Gardner group on the map.  Fred was probably expecting to see other islands before seeing Gardner.  They would have been watching their gas supply dwindle away.  Then Gardner pops up. They likely didn't know it was Gardner at first but Fred should have been able to get that figured out in short order. They land, believing the US Coastguard and navy will find them.
All this means is that no matter what all the theories are you should just draw the line backwards north from Gardner along 337. Thats the "likely" intersection point where they turned.
No further flying east. No further flying around looking for Howland. No more discussion in the cockpit. For all we know AE and FN were blaming each other over the failure to find Howland and they weren't thinking rationally. We just don't know. Our belief in the theory is they landed on Gardner. It doesn't matter what else we "think" happened. They obviously had the gas, the charts and the determination to find land. Any land at this point.
Now we just work it backwards. We find that point where they turned south and ask "so why couldn't they find Howland? Why are they here when they turn south?"
Of course this is only if you believe in the TIGHAR theory.  :)

I just read Ric's latest post.  Ric's points are well made and I agree that all of them probably transpired. The main point is his point number 10.  At no point did they decide to ""go for" some other island". I think he means "going for" a "specific" island by name. I believe they were looking for "any" island once they turned south. At some point in that cockpit they knew they were lost and Ric's description of likely actions is tame compared to the "panic" I would have been in. Don't forget the radio message "suggested" AE's voice had some "anxiety" showing.
I still don't understand why they weren't blasting the entire Pacific with radio transmissions?  In survivor mode wouldn't they be trying to get any contact?  Knowing they are headed away from Howland wouldn't they be trying to tell Itasca they decided to head south so please come that way to pick them up?  Wouldn't they (AE) be using the radio to try to raise a ship or land based radio? To raise anybody?  Why no messages?  That doesn't fit the survivor mode. Unless the radio had issues.
Title: Re: Working the Flight backwards
Post by: Irvine John Donald on September 06, 2011, 08:08:19 AM
There is still confusion about the LOP.
1. Credible reports of overcast conditions during the night.........
10. Noonan knows that all of the other islands on or near the LOP are southeast of Howland.  That's why he goes northwest first. But everything they do is in hopes of finding Howland.  At no point do they decide to "go for" some other island.

I also believe that Ric's point ten would lead to a point 11.

11.  After a reasonable period of flying south looking for Howland, FN would have told AE they were now looking for any island.  The gas supply would have backed that up.

But still thinking they were looking for Howland three hours after turning south?  I'm thinking no.
Title: Re: Working the Flight backwards
Post by: Martin X. Moleski, SJ on September 06, 2011, 08:11:18 AM
... We find that point where they turned south ...

Randy Jacobson's Monte Carlo Simulation (http://tighar.org/wiki/Monte_carlo) put that location SSW of Howland.

Quote
I still don't understand why they weren't blasting the entire Pacific with radio transmissions?

What makes you think that they weren't?

Title: Re: Working the Flight backwards
Post by: Irvine John Donald on September 06, 2011, 08:49:51 AM
I believe they were Marty. My "survivor mode theory" suggests they would be using the radio extensively while frantically scanning for land or ships. Adrenaline would be pumping. FN would be taking fixes. But we "suspect" a broken antennae and poor planning prevented them from connecting with Itasca.

But Itasca could hear them. Why then wouldn't Itasca hear them while headed south on the LOP. Other than the one message that says they were on the LOP we have silence?  Meaning they didn't use the radio again?  That doesn't fit. So assuming they were transmitting why didn't anyone hear them?  Further radio problems?  Lack of radios being monitored? (no scanning mode in those days). As I asked in a previous post, is it possible that by turning south the broken antenna is transmitting differently than when travelling west to east?  If the radio wasn't working then how were the post loss signals made?  Repairs by AE and FN?  If FN was hurt could AE do it?  We think FN was hurt based on signals from a radio with a broken antenna that is mounted on the belly of the aircraft (unless she switched to her upper body loop antenna) which is on the ground and not 10,000 feet in the air.  If those messages could be heard then why not in the air travelling south on the LOP from 1,000 foot altitude?  Landed and on her wheels the highest antenna is no more than 30' off the ground and we heard from that position.

We have signals before turning south and after landing but nothing in between when its the most critical for them to get info out?
Title: Re: Working the Flight backwards
Post by: Martin X. Moleski, SJ on September 06, 2011, 09:25:49 AM
... we "suspect" a broken antennae and poor planning prevented them from connecting with Itasca.

The (theoretically) "lost antenna" (http://tighar.org/wiki/The_Lost_Antenna) would explain the inability of AE and FN to receive messages.  It does not explain the failure of the Itasca to hear any more messages after AE switched to her daytime frequency.

The assertion that planning for the flight was fatally flawed is more than a suspicion.  It is demonstrable that AE did not understand or communicate the limits of her equipment and the limits of the Itasca's equipment (http://tighar.org/wiki/Failure_to_communicate).

Quote
But Itasca could hear them. Why then wouldn't Itasca hear them while headed south on the LOP.

Please look up in this thread.  I've already given you a link to answer that question.  AE changed frequencies.  There are problems with radio propagation at different times of day on different frequencies.  You may not like that answer, but it would be a courtesy to recognize that an answer has been given to your question.

Quote
... is it possible that by turning south the broken antenna is transmitting differently than when traveling west to east?

The antenna that seems to have broken on takeoff was for RECEIVING, not transmitting.

Quote
If the radio wasn't working then how were the post loss signals made?

We know that the transmitter was working.

Transmitters SEND signals.

They are two different parts of the radio system.

One part was broken (receiving).  One part was not (transmitting).
Title: Re: Working the Flight backwards
Post by: Ric Gillespie on September 06, 2011, 09:52:07 AM
Knowing they are headed away from Howland wouldn't they be trying to tell Itasca they decided to head south so please come that way to pick them up?

At what point would they know that they were headed away from Howland, and how would they know that?

Wouldn't they (AE) be using the radio to try to raise a ship or land based radio? To raise anybody?  Why no messages?  That doesn't fit the survivor mode. Unless the radio had issues.

The issue was frequencies.  The airplane's radio had the ability to transmit on only three frequencies - 3105 KhZ, 6210 KHz, and 500 KHz.
All ships monitored 500 Khz as a "calling" and emergency frequency, but 500 kHz was code-only and AE and FN did  not know Morse code and the aircraft had insufficient antenna to put out a meaningful signal on 500 kHz.
The other two frequencies were aviation-only voice frequencies and, at that time, no one but Itasca was listening on those frequencies anywhere in the central Pacific.
Title: Re: Working the Flight backwards
Post by: Irvine John Donald on September 06, 2011, 10:17:46 AM
Thanks Marty for those clarifications. I apologize for not formally acknowledging your answer.

I respectfully submit that I do not necessarily "accept" all answers given as being unquestionably correct. If I do then I am mentally dead.

I accept your response to the radio regarding transmitter working but receiving isn't. Glad you clarified that for me.

Question Marty.  Can AE tell if she is transmitting correctly?  A light or gauge to indicate she is transmitting?
Title: Re: Working the Flight backwards
Post by: Erik on September 06, 2011, 10:20:45 AM
With all the arguments and speculation over the accuracy needed to be able to find Gardner from LOP , I have not really seen any mention of the 'vertical height' being a benefit.   This is especially true for the navigational accuracy (or inaccuracy) that would be needed to reliably find Gardner.  From looking below, it doesn't appear that a whole lot of science would be needed!

Here's food for thought...

If I am not mistaken, the elevation of NW end of the island combined with the height of the buka trees would put a total vertical height of 100' feet or so.  Combine that with a horizontal width of 1/4 - 1/2 mile profile from the NW end.  This gives you an object sticking up from the horizon with dimensions approximately 100' x 2500' in size.    It's not a ship blowing smoke, but it would seem hard to miss an object that size.

I am assuming that they had binoculars, but even if not, I would guess that an object of that size on the horizon would be fairly noticable even from far distances.  With or without cloud cover.  Does anyone by chance have any real pictures of a similar island from open ocean?

Just for kicks, I created a vertical object 100' x 2500' in google earth, drew an approximate line from Gardner to Howland, and then estimated flying altitude that might seem reasonable.  Here is what it might look like from a sampling of several different pespectives.  Of course this is just a simulation, but you get the idea.

Gardner from 50 miles out on LOP at 3000' altitude
(http://farm7.static.flickr.com/6083/6109007179_82f20fe6cc.jpg)

Gardner from 25 miles out on LOP at 1500' altitude
(http://farm7.static.flickr.com/6198/6109007113_aa14a150c4.jpg)

Gardner from 10 miles out on LOP at 1000' altitude
(http://farm7.static.flickr.com/6065/6109557388_d0134ae3c5.jpg)

It would seem to me that Gardner would be fairly easy to spot, even with crude DR techniques.

Title: Re: Working the Flight backwards
Post by: Irvine John Donald on September 06, 2011, 10:39:59 AM
Very interesting. If you leave the altitude at 1,000 feet then what can you see from 50 miles and 25 miles out.

I believe they were not specifically trying to find Gardner.  Ric believes they were looking still for Howland. My theory is that after flying three hours south they, at some point Ric, must have realized that they weren't anywhere near Howland and needed someplace to land.  But both those theories would have the two travellers scanning the water for land or ships. Is it best to do so from 1,000 feet or 10,000 feet? Keeping in mind the trade off of elevation over aircraft performance (endurance).  I believe opinion in this forum is to choose 1,000 feet.
Title: Re: Working the Flight backwards
Post by: Ric Gillespie on September 06, 2011, 10:42:33 AM
Question Marty.  Can AE tell if she is transmitting correctly?  A light or gauge to indicate she is transmitting?

Interesting question. In flight? Probably not unless the ammeter flickers.  On the ground?  She should hear the dynamotor kick in when she transmits.  But all those things tell her is that the power is going to the transmitter.  I don't know how she'd be able to confirm that the antenna was radiating.
Title: Re: Working the Flight backwards
Post by: Irvine John Donald on September 06, 2011, 11:02:53 AM
Knowing they are headed away from Howland wouldn't they be trying to tell Itasca they decided to head south so please come that way to pick them up?

At what point would they know that they were headed away from Howland, and how would they know that? ..........

Thanks Ric.

How would they know the were headed away from Howland?  Hmm.  Good point and i believe the answer is that they didn't. Your description says that FN told AE to first fly north but, finding no Howland, FN then instructed her to fly south. We don't know this for sure, but if the entire TIGHAR theory is right then they got to Gardner somehow.  But you're surmissing Ric that at a point while travelling NW he tells her to turn around and head SE. (See section 8 of previous post).  Based on what facts would he tell her to turn?  They fly NW from 19:12 to 20:00.  Approximately 45 mins. Then they head south. They know they didn't see Howland while flying 45 minutes NW so its not likely they expected to see Howland until at least minute 46 on thr trip back.  Unless of course they missed it. I'm not suggesting they wouldnt be looking during that first 45 minutes on SE route.  But now we fly for three hours south?  Still looking for Howland??  I respectfully suggest that at about an hour after turning SE on the LOP that they came to the realization that they missed Howland and now it was time to find any island or ship.
Title: Re: Working the Flight backwards
Post by: Ric Gillespie on September 06, 2011, 11:12:10 AM
Is it best to do so from 1,000 feet or 10,000 feet?

The issue is clouds.  The Itasca deck log that morning recorded scattered cumulus clouds.  A noon observation on Howland recorded the bases at 2,650 feet.  That's a very typical central Pacific morning.  Some wisps of cloud appear at ballpark 1,200 feet just as dawn first begins to color the sky.  By the time the sun is up there's a well-defined scattered cumulus deck.  By mid-day the clouds have grown and bases have risen to about 2,500 feet.  By late afternoon there may or may not be some isolated squalls around.

If you're flying above a scattered deck everything except what is directly beneath you is hidden.  If you're looking for an airport (or an island) you have to stay below the bases.
Title: Re: Working the Flight backwards
Post by: Erik on September 06, 2011, 11:13:58 AM
Very interesting. If you leave the altitude at 1,000 feet then what can you see from 50 miles and 25 miles out.
Gardner from 50 miles out on LOP at 1000' altitude
(http://farm7.static.flickr.com/6205/6120471877_fdddd2f3f6.jpg)
Note - how the model indicates the island is not yet viewable and still below the horizon.

Gardner from 25 miles out on LOP at 1000' altitude
(http://farm7.static.flickr.com/6072/6121013454_ddaf3d26bd.jpg)

Is it best to do so from 1,000 feet or 10,000 feet? Keeping in mind the trade off of elevation over aircraft performance (endurance).  I believe opinion in this forum is to choose 1,000 feet.

From a low wing aircraft, much more 'real estate' is blocked from the wings the higher you fly.  From low altitudes, your wings block less 'real estate', but you compromise distant viewing.  In open ocean, it would seem preferable to be at a lower altitude.  This way the effect you get from spotting an object on the horizon would be much more apparent.
Title: Re: Working the Flight backwards
Post by: Martin X. Moleski, SJ on September 06, 2011, 11:16:11 AM
Thanks Marty for those clarifications. I apologize for not formally acknowledging your answer.

Much appreciated.

Quote
I respectfully submit that I do not necessarily "accept" all answers given as being unquestionably correct. If I do then I am mentally dead.

If you "doubt everything," then please stop posting to the Forum.  Under your standard, you must doubt that we exist, that the Forum connects you to other people, and that posting makes any difference.  Unreasonable doubt causes mental death just as much as unreasonable faith.

If you are willing to operate under the criterion of "reasonable doubt," then you should be able to accept some testimony as reliable (e.g., that the plane never landed on Howland, that no parts of it were found in the 1937 search, that the radio logs exist, etc.).

Quote
Question Marty.  Can AE tell if she is transmitting correctly?  A light or gauge to indicate she is transmitting?

I have never seen or operated a Western Electric Model 13C (http://tighar.org/wiki/Radio_equipment_on_NR16020#Western_Electric_Model_20B).  The schematic (http://tighar.org/testhtml/Projects/Earhart/Archives/Research/ResearchPapers/ElectraRadios/FigureB.html) shows where a meter could be connected to report the load on the antenna, but it doesn't reveal whether such a meter was installed on this model.
Title: Re: Working the Flight backwards
Post by: Irvine John Donald on September 06, 2011, 11:26:57 AM
Question Marty.  Can AE tell if she is transmitting correctly?  A light or gauge to indicate she is transmitting?
Interesting question. In flight? Probably not unless the ammeter flickers.  On the ground?  She should hear the dynamotor kick in when she transmits.  But all those things tell her is that the power is going to the transmitter.  I don't know how she'd be able to confirm that the antenna was radiating.

If she is transmitting successfully and not receiving for the entire trip to Howland then why would she stop transmitting on her trip SE towards the Phoenix islands?  If she has no way to know if she is transmitting then the lack of receiving didn't stop her from transmitting.  She was transmitting without getting any reception but she kept transmitting. If she has no method of knowing she can transmit from inside the aircraft but continues to transmit then why did she stop or why did Itasca not hear? The radio is her ONLY means of telling people (Itasca) where she is.

So, Marty and Ric ( and anyone else), the radio transmits but doesn't receive.  It has two frequencies being monitored by Itasca.  Itasca hears her.  She doesn't hear Itasca but continues to transmit. They decided to fly NW then SE but sends only one message about flying the LOP. Nothing more is heard until the post loss signals when she is on the ground. Why no messages?  Did she decide, near Howland, that she had a radio problem and stopped transmitting only to decide on the ground she would try again?  I'm stumped.  I know we don't know for sure what happened but what is "likely"?

Title: Re: Working the Flight backwards
Post by: Ric Gillespie on September 06, 2011, 11:32:57 AM
But you're surmissing Ric that at a point while travelling NW he tells her to turn around and head SE. (See section 8 of previous post).  Based on what facts would he tell her to turn?

The fact that their fuel supply is limited and all of the possible alternate islands are southeast of Howland.  Whichever direction they search first and how ever far they go, they will have to backtrack that far if they do not find Howland in order to continue their search.  No way to avoid that.  The only thing that makes sense is to go northwest as far as you dare first, then turn around and head southeast and just keep going.  The question then becomes - how far do you dare search to the NW before you turn around, knowing that the farther you go, the more fuel you'll waste back tracking?  You are 20 hours into your 24 hours of fuel - well into your 20% reserve.  Go NW for half an hour and, if no Howland, back track half an hour.  Now you're back where you started from with only 3 hours left.  Go NW for 45 minutes and now you'll have burned an hour and a half of fuel getting back to square one - and you still don't know which way it is to Howland.  But you do know that all of the other islands are southeast of Howland so you had better just keep going SE, hoping to find Howland but knowing that even if you're headed away from Howland you're headed toward land.

I respectfully suggest that at about an hour after turning SE on the LOP that they came to the realization that they missed Howland and now it was time to find any island or ship.

We'll never know.
Title: Re: Working the Flight backwards
Post by: Irvine John Donald on September 06, 2011, 11:42:07 AM
Thanks Marty for those clarifications. I apologize for not formally acknowledging your answer.

I respectfully submit that I do not necessarily "accept" all answers given as being unquestionably correct. If I do ........

Thanks to Ric and Erik for their posts. Thank you Marty for your post. I should clarify that I believe in "reasonable doubt".  I thought by saying I do not "necessarily" accept all answers as being "unquestionably" correct that I was saying I "do" accept some answers as being correct.  And I have known some answers to be incorrect.

Nowhere in any of my posts have I, knowingly, said or suggested that I "doubt everything".
Title: Re: Working the Flight backwards
Post by: Irvine John Donald on September 06, 2011, 11:49:53 AM
But you're surmissing Ric that at a point while travelling NW he tells her to turn around and head SE. (See section 8 of previous post).  Based on what facts would he tell her to turn?

The fact that their fuel supply is limited and all .........

We'll never know.

Thanks Ric

The detail in your answer makes a lot of sense and your second answer is spot on. Unless a diary is found that would explain all of this we will never know.

Title: Re: Working the Flight backwards
Post by: Ric Gillespie on September 06, 2011, 11:53:12 AM
If she is transmitting successfully and not receiving for the entire trip to Howland then why would she stop transmitting on her trip SE towards the Phoenix islands?
We don't know that she did stop transmitting.  All we know is that Itasca stopped hearing her. Why would that be?  What changed?  Earhart told us what changed.  She said she was going to try her other frequency, 6210 KHz - her "daytime" frequency. After all, it was now daylight and she had heard nothing from Itasca on her "nighttime" frequency, 3105 KHz.  So why didn't Itasca hear her on 6210?  Perhaps for the same reason Lae didn't hear the day before on 6210 until five hours after departure.

The peculiarities of her transmitting antenna, the way radio waves interacted with the fuselage of her airplane, and the propagation properties of that frequency meant that she could only be heard if she was much farther away than she was.  3105 was almost as weird.  Itasca stood the best chance of hearing her at maximum strength if she about 150 nautical miles away.  Under about 40 nm there was virtually no chance they would hear her.  These counter-intuitive conditions are not a matter of speculation but of detailed computer modeling of the aircraft and the antenna system.
Title: Re: Working the Flight backwards
Post by: Irvine John Donald on September 06, 2011, 11:59:30 AM
Erik,  if you "flew" the route from SW of Howland on Google Earth at 1,000 feet and did a 360 degree search, as you fly, is it possible to see any other land?  I don't think so but it would be nice to have more info. As pointed out in previous posts we should not rely on the accuracy of Google Earth as it is only a software program that has some issues.  Perhaps the new X Flight simulator will give a more accurate representation.
Title: Re: Working the Flight backwards
Post by: Irvine John Donald on September 06, 2011, 12:12:16 PM
Thanks yet again Ric.  So when the radio signals reported by Itasca are strength 5 and they believe she must be almost overhead, she is in fact 150 miles away?  This would mean that if the Monte Carlo simulation is correct then the distance they report her away is accurate also?
Title: Re: Working the Flight backwards
Post by: Irvine John Donald on September 06, 2011, 12:19:40 PM
Ric, when you say the radio information is from detailed computer modelling of the aircraft and antenna systems.  Is this new information to be released or existing on the forum?
Title: Re: Working the Flight backwards
Post by: Ric Gillespie on September 06, 2011, 12:20:02 PM
Thanks yet again Ric.  So when the radio signals reported by Itasca are strength 5 and they believe she must be almost overhead, she is in fact 150 miles away?  This would mean that if the Monte Carlo simulation is correct then the distance they report her away is accurate also?

Yyyyyyep.
Title: Re: Working the Flight backwards
Post by: Ric Gillespie on September 06, 2011, 12:44:37 PM
Ric, when you say the radio information is from detailed computer modelling of the aircraft and antenna systems.  Is this new information to be released or existing on the forum?

Bob Brandenburg, who has done most of the radio propagation work, has a number of papers on the TIGHAR website but this latest work has not yet been published.  I'll be covering much of it in the TIGHAR Journal 2011 to be sent to TIGHAR members in October.
Title: Re: Working the Flight backwards
Post by: Irvine John Donald on September 06, 2011, 01:15:35 PM
Thank you Ric and Bob

I will enjoy reading both Bob's historical work and the new journal when released.
Title: Re: Working the Flight backwards
Post by: Erik on September 06, 2011, 01:33:51 PM
Erik,  if you "flew" the route from SW of Howland on Google Earth at 1,000 feet and did a 360 degree search, as you fly, is it possible to see any other land?

Not really.  The only other 'land' is McKean, which is more of a reef/atoll environment more so than it is real land.  Even McKean would have been approximately ~50 miles away from a SW Howland-Gardner route, and difficult, if not impossible to see.  Without any vertical elevation McKean would have been way over the horizon.  It would have been doubtful it was visible unless flying at higher altitudes such as 6,000 thousand feet or greater.

The other possible visible features (at 1,000 feet) may have been the chain of reefs enroute.  They look like islands in the map below, but they are not.  Although not land per se, these reefs may have provided visible whitecaps if the tide was just right.

(http://farm7.static.flickr.com/6185/6120791489_11f3d6f7bb.jpg)

I don't think so but it would be nice to have more info. As pointed out in previous posts we should not rely on the accuracy of Google Earth as it is only a software program that has some issues.  Perhaps the new X Flight simulator will give a more accurate representation.

Google Earth's accuracy is horrible for some things and nearly perfect for others.  As with anything, it's a tool that needs to be used correctly within reason.  For example, it's accuracy in terms of precise topography, up-to-date imagery, and street networks may be in question.  On the other hand, measurements such as the entire length of Gardner island are very precise to the extent that you could measure it with an accuracy within a a few yards if you really wanted to

Using Google Earth as a model to generate simulations and provide graphics to back up verbal and written concepts is where it is very powerful tool!  It's mathematical coordinate precision for inputing your own data is accurate to 6 decimal places of a degree, which is roughly about 4 inches.  So, in other words, it is not Google Earth itself that is in question, but rather the originating source that is being used.

To derive the height of the island, I mainly used maps on TIGHAR's own website and recounts of the of the buka trees height to generate the dimensions of the models used here.  After researching, I found these figures were fairly accurate with Google Earth coincidently.  If I didn't have both sources, you are correct, I would have abandoned Google Earth's accuracy and sought additional information.  But in this case, they all matched.
Title: Re: Working the Flight backwards
Post by: Harry Howe, Jr. on September 06, 2011, 01:47:18 PM

With respect to radio communications, They (AE and Itasca) were successful in comunicating with each other on 7500 kHz.  Why didn't they continue on that frequency?  Why change to 3105 and then to 6210? Because it's daytime? or nighttime?  I mean. really, accept success and get on with flying alternate plan B to Gardner.  And by all means tell the folks on Itasca where you are going so that the Cavalry can steam full speed ahead and rescue you.

Anyway, at some moment in time they (AE/FN) probably realized that they had a radio problem and the first order of business after successfully landing on Gardner would have been to fix the radio, thus the post loss transmissions at low tides.
Title: Re: Working the Flight backwards
Post by: Irvine John Donald on September 06, 2011, 02:00:31 PM
Hi Harry

In the video of the Lae take off you see the little sort of dust that is thought to be the antenna snapping?  Would the broken piece still be attached so the two broken ends could be repaired?  Did anyone at Lae examine the runway after takeoff or even see what we did?
Title: Re: Working the Flight backwards
Post by: Martin X. Moleski, SJ on September 06, 2011, 02:00:51 PM

With respect to radio communications, They (AE and Itasca) were successful in communicating with each other on 7500 kHz.  Why didn't they continue on that frequency?

The Itasca could only transmit in Morse Code (CW) on 7500 kcs.

AE and FN had refused to learn Morse Code (http://tighar.org/wiki/Failure_to_communicate#Abandonment_of_CW_.28Morse_Code.29) and planned on doing everything with telephony.
Title: Re: Working the Flight backwards
Post by: Martin X. Moleski, SJ on September 06, 2011, 02:05:27 PM
... Did anyone at Lae examine the runway after takeoff or even see what we did?

This is the second time I am posting the link to a short article on the Lost Antenna (http://tighar.org/wiki/Lost_antenna) in this thread.

You should be able to tell that it is a link, Irvine, because it is in a different color from the rest of this post.

If you run your cursor over the link, then click on it, it will open up the article in the wiki.

There you should be able to read the following:

R.E. Fullenwider (TIGHAR #0126) "spent some time in Lae during World War Two courtesy of Uncle Sam." As he remembers it, the old-timers there often said they hadn’t been surprised when Earhart was lost because "she left part of her trailing wire antenna laying on the runway" (TIGHAR Tracks, December 31, 1993). (http://www.tighar.org/Publications/TTracks/1993Vol_9/0904.pdf)

TIGHAR has not been able to verify that anecdote.
Title: Re: Working the Flight backwards
Post by: Harry Howe, Jr. on September 06, 2011, 02:16:38 PM

Erik:
How would Howland have looked from 1000 feet for three cases A. approaching Howland from about 270 degrees, 50 miles out, 20 miles out, 5 miles out?   B. Same parameters (sp?) but approaching from SSE (157 to 337) and C. Approaching from NNW (337 to 157?
Title: Re: Working the Flight backwards
Post by: Irvine John Donald on September 06, 2011, 02:21:16 PM
Marty, I thank you for that post and the link.

I apologize for using an ipad as a computer. Great device but it has shortcomings especially in this editor. Very difficult to edit as the ipad doesnt let me scroll in the text window. Therefore if i hit "quote" the quoted text disappears off into the bottom of the text window and i cant getbto the bottom to edit. This is no fault of the editor as it happens with many forums i am part of.

Using the ipad however is no excuse for me not seeing that quoted article. I had not seen that one and look forward to reading it.

As you say it wasn't verified so can't be accepted as fact. Thats unfortunate. It still seems to me that so many coincidental anecdotes, scientific facts and hard evidence collected by TIGHAR over the years isn't yet enough to say the theory has been proven.
Title: Re: Working the Flight backwards
Post by: Gary LaPook on September 06, 2011, 03:03:22 PM
With all the arguments and speculation over the accuracy needed to be able to find Gardner from LOP , I have not really seen any mention of the 'vertical height' being a benefit.   This is especially true for the navigational accuracy (or inaccuracy) that would be needed to reliably find Gardner.  From looking below, it doesn't appear that a whole lot of science would be needed!

Here's food for thought...

If I am not mistaken, the elevation of NW end of the island combined with the height of the buka trees would put a total vertical height of 100' feet or so.  Combine that with a horizontal width of 1/4 - 1/2 mile profile from the NW end.  This gives you an object sticking up from the horizon with dimensions approximately 100' x 2500' in size.    It's not a ship blowing smoke, but it would seem hard to miss an object that size.

I am assuming that they had binoculars, but even if not, I would guess that an object of that size on the horizon would be fairly noticable even from far distances.  With or without cloud cover.  Does anyone by chance have any real pictures of a similar island from open ocean?

Just for kicks, I created a vertical object 100' x 2500' in google earth, drew an approximate line from Gardner to Howland, and then estimated flying altitude that might seem reasonable. Here is what it might look like from a sampling of several different pespectives.  Of course this is just a simulation, but you get the idea.

Gardner from 50 miles out on LOP at 3000' altitude
(http://farm7.static.flickr.com/6083/6109007179_82f20fe6cc.jpg)

Gardner from 25 miles out on LOP at 1500' altitude
(http://farm7.static.flickr.com/6198/6109007113_aa14a150c4.jpg)

Gardner from 10 miles out on LOP at 1000' altitude
(http://farm7.static.flickr.com/6065/6109557388_d0134ae3c5.jpg)

It would seem to me that Gardner would be fairly easy to spot, even with crude DR techniques.

-----------------------------------

Seeing a tree 100 feet high from 50 NM away would be like seeing a dime laying in  the end zone from the 59 yard line. (If you are using statute miles then it would be like seeing that dime from the 52 yard line. )

We have no weather observations at Gardner for July 2, 1937 but we have another source we can use to evaluate the ability of Earhart to spot that island. According to the U.S. Navy Climatic Atlas of the World, Volume V, South Pacific Ocean (1979), page 183, in July in the vicinity of Gardner, 90% of time the visibility is less than 25 NM; 60% of the time less than 20 NM; 45% of the time less than 15 NM; and 32% of the time less than 10 NM.

So their views of Gardner from 25 and 50 miles away are much more likely to be as depicted in the attached photo than in your simulations.

The clouds depicted are scattered, about one octa (1/8th coverage). According to the same source, the cloud coverage in the vicinity of Gardner in July is greater than two octas 60% of the time and greater than one octa 80% of the time!

Still think it would have been easy for them to spot the island from far away?

(BTW, this photo also illustrates why you can't determine an LOP at sunrise. For you to time an accurate sunrise you must be able to see the actual blue sea horizon edge of the earth to measure the edge of the sun against and to take an accurate time. A one minute error in timing of a celestial observation results in a fifteen nautical mile error in the resulting computed longitude. This photo was taken on a day with really good weather but the clouds are obstructing the sea horizon so a sunrise observation would not have been possible and there is reason to believe that the weather was worse north and west of Howland on July 2nd. See: https://sites.google.com/site/fredienoonan/discussions/the-myth-of-the-sunrise-lop )
gl
Title: Re: Working the Flight backwards
Post by: Mark Petersen on September 06, 2011, 04:03:34 PM
As you can see, the three methods approach the question from completely different directions.  If the answers to all three questions overlap to some degree there is a high probability that the correct answer is within that area.

My apologies for posting so late, but I just came across this thread and found the premise very intriguing.  Working backwards obviously won't prove the Niku theory to skeptics, but if one assumes that the theory is correct, then working backwards may yield some interesting location/time information if the theory is correct.  What's intriguing is that this is information that, by its very nature, is something that can't be answered by any other means.

The overlap is the key.  If there is a lot of overlap, then then the location and time information is too loose and won't help to tie down the specifics.  If there is no overlap, then it points to an accuracy problem with one or more of the 3 questions.  But if there is a small degree of overlap, then bingo, I would think that this would allow us to be able to narrow down the time/location datum considerably.

There is still confusion about the LOP.
.
.
8. He has Amelia fly northwest first and at 20:00 she tries to use her loop antenna, but no luck.  Fred has her turn around and they retrace their steps, DRing southeast and still hoping that they'll find Howland.

Do we know for certain that FN had AE fly NW?  I realize that it fits the theory and is the logical thing to do, but are there other scenarios that might have FN and AE flying SE along the LOP without having traveled NW first?  I have an idea about this, but I don't want to derail this thread so I'll post it in another thread.

Thanks yet again Ric.  So when the radio signals reported by Itasca are strength 5 and they believe she must be almost overhead, she is in fact 150 miles away?  This would mean that if the Monte Carlo simulation is correct then the distance they report her away is accurate also?

Yyyyyyep.

One thing that I never understood about the Monte Carlo simulation (https://tighar.org/smf/index.php/topic,169.msg1051.html#msg1051) is why it puts the 10E so far off of the LOP.  My meager knowledge of navigation (gleaned only from this forum) tells me that one would assume that FN would be able to measure the dawnline with a high degree of accuracy.  After dawn, he would also be able to measure and account for wind drift fairly accurately.  So his DRing to get to the LOP should be fairly accurate and with a high probability, even though his location on that line might be very inaccurate.  The Monte Carlo simulation would imply that this isn't the case though.   From the other thread (in my link above), I don't think that the Monte Carlo simulation incorporates the recent 3105 donut information, so it could be freshened up if someone were so inclined.

Note, this doesn't change the radio propogation numbers and therefore the received signal strength that is being discussed.  But might it not be possible that the 10E were actually further south of Howland and therefore closer to Gardner?  This would give them more fuel reserves to reach the island, and also more fuel to run the radio after a possible landing.

Title: Re: Working the Flight backwards
Post by: Martin X. Moleski, SJ on September 06, 2011, 05:42:12 PM
Do we know for certain that FN had AE fly NW?  I realize that it fits the theory and is the logical thing to do, but are there other scenarios that might have FN and AE flying SE along the LOP without having traveled NW first?

As Tonto is said to have said to the Lone Ranger, "What you mean 'we,' white man?"

I believe this is the natural reading of the last transmission (http://tighar.org/wiki/Last_transmission): "We are flying north and south on the line 157-337."  337 is NNW; 157 is SSE.  She said "north" before "south."  Did she mean what she said?  Or was she just indicating a general plan to search the line both ways?

You get to make up your own mind whether the last transmission satisfies your own standards of certitude.

Quote
One thing that I never understood about the Monte Carlo simulation (https://tighar.org/smf/index.php/topic,169.msg1051.html#msg1051 (https://tighar.org/smf/index.php/topic,169.msg1051.html#msg1051)) is why it puts the 10E so far off of the LOP.

Wild guess: it puts the 10E so far off the LOP because if the aircraft had reached the broad band of LOPs that pass within visible range of Howland, they would have landed safely.  I don't know whether Randy coded it that way or whether it is the consequence of other assumptions he made.

It seems to me that any reconstruction has to incorporate some "zone of exclusion": the area that the plane must not have reached because, if it had gotten inside that zone, AE and FN would have seen Howland or Baker.  Calculating the size of the zone involves many imponderables:
• Fred's skill as a navigator.
• The quality of FN's instruments and chronometer.
• AE's pilotage--how well did she follow Fred's directions?
• Visibility on that morning at 1000' feet ASL.
• Visibility of Itasca's smoke signal (hotly disputed).
• Accuracy of charts.
• Accuracy of compasses.
• Field of vision.
• Visual acuity after a night at high altitude without oxygen.
Whether you come up with a large zone or a small one, we must agree that they didn't enter that region--for whatever reason.

Quote
Note, this doesn't change the radio propagation numbers and therefore the received signal strength that is being discussed.  But might it not be possible that the 10E were actually further south of Howland and therefore closer to Gardner?  This would give them more fuel reserves to reach the island, and also more fuel to run the radio after a possible landing.

The Monte Carlo simulation is an estimate of probabilities based on millions of variations in the variables.  It does not say that the couldn't have been somewhere other than in the most probable region.  All it says is that the further you get away from the mass of particular instances that clump together, the less likely that outcome seems from the standpoint of the assumptions made in construction of the simulation.  Strange things do happen.  People do get royal flushes in poker every now and again.  The longest of long shots occasionally wins a race and pays off ridiculously huge amounts of money.

Which is a long-winded way of saying, "Yes, it's possible that they hit the band of LOPs that pass through the neighborhood of Howland and Baker well south of those too islands instead of west of the band of LOPs."

On this drawing, the letter "A" represents the whole cloud of possible routes that would have brought them close to Howland and Baker, but just a little too far west to catch sight of them, while still placing them on a LOP that comes close enough to Niku for them to find it.  "B" represents the whole cloud of possible routes that are within the Howland-Baker zone in terms of longitude (East-West location) but too far south in terms of latitude to find Howland and Baker after searching northward for a length of time that is unknown to us.

It seems to me that these are the two most likely scenarios.  In either case, we have to judge that Fred's navigation was off (east-west or north-south).

(http://tighar.org/aw/mediawiki/images/9/90/How-close.png)
Title: Re: Working the Flight backwards
Post by: Chuck Varney on September 06, 2011, 06:00:18 PM

With respect to radio communications, They (AE and Itasca) were successful in communicating with each other on 7500 kHz.  Why didn't they continue on that frequency?

The Itasca could only transmit in Morse Code (CW) on 7500 kcs.

AE and FN had refused to learn Morse Code (http://tighar.org/wiki/Failure_to_communicate#Abandonment_of_CW_.28Morse_Code.29) and planned on doing everything with telephony.

Two-way communication between Itasca and the Electra was not possible on 7500 kHz--regardless of transmission mode--because AE's Western Electric 13C transmitter could not transmit on 7500 kHz.

Chuck
Title: Re: Working the Flight backwards
Post by: Martin X. Moleski, SJ on September 06, 2011, 06:04:35 PM

With respect to radio communications, They (AE and Itasca) were successful in communicating with each other on 7500 kHz.  Why didn't they continue on that frequency?

The Itasca could only transmit in Morse Code (CW) on 7500 kcs.

AE and FN had refused to learn Morse Code (http://tighar.org/wiki/Failure_to_communicate#Abandonment_of_CW_.28Morse_Code.29) and planned on doing everything with telephony.

Two-way communication between Itasca and the Electra was not possible on 7500 kHz--regardless of transmission mode--because AE's Western Electric 13C transmitter could not transmit on 7500 kHz.

Technically, you are correct in your narrow definition of "on 7500 kHz."

But she could have transmitted on 3105 kHz and listened on 7500 kHz, enabling two-way communication, if she had known Morse Code or if they had their 7500 kHz transmitter set up for voice operations.
Title: Re: Working the Flight backwards
Post by: Ric Gillespie on September 06, 2011, 06:16:05 PM
With respect to radio communications, They (AE and Itasca) were successful in comunicating with each other on 7500 kHz.

No they weren't.  Earhart asked for a "long count" on 7500.  A long count, as you probably know, is counting from 1 to 10 and back to 1 slowly by voice.  Itasca could not send voice on 7500. They had told Earhart that in a communication several days previous. She apparently was not paying attention.  They did what they could.  They sent the Morse code letter "A" (dit dah) - the pre-arranged letter for signals for Itasca.  (The USS Ontario was supposed to send the letter "N.") Earhart hear the "A"s but could not reply in Morse and didn't even try.  In short, Earhart heard the signals but there was no communication.
Title: Re: Working the Flight backwards
Post by: Erik on September 06, 2011, 07:05:23 PM

Erik:
How would Howland have looked from 1000 feet for three cases A. approaching Howland from about 270 degrees, 50 miles out, 20 miles out, 5 miles out?   B. Same parameters (sp?) but approaching from SSE (157 to 337) and C. Approaching from NNW (337 to 157?

Good point.

Howland's vertical profile (15' or so max.) would be so minimal that it wouldn't be high enough to distrupt the natural horizon's profile.

It appears it would take being as close as 1 mile and as low as 100' feet before the height of the island would even be a factor.

More likely, one would need to be in a rowboat a hundred yards offshore before the natural horizon would be disrupted by Howland's vertical height.

Title: Re: Working the Flight backwards
Post by: Mark Petersen on September 06, 2011, 07:17:41 PM
As Tonto is said to have said to the Lone Ranger, "What you mean 'we,' white man?"

We as in Tighar members.  I know who the Lone Ranger is, but I won't speculate on the identity of Tonto.   ;D

Quote
I believe this is the natural reading of the last transmission (http://tighar.org/wiki/Last_transmission): "We are flying north and south on the line 157-337."  337 is NNW; 157 is SSE.  She said "north" before "south."  Did she mean what she said?  Or was she just indicating a general plan to search the line both ways?

Ahh, okay I can see how one can interpret that.  She apparently also used the word 'AND' indicating that both directions had been traveled.  I used the word apparently, because as mentioned in Tighar Tracks, the radio logs are a bit of a mess and the exact wording might not have been recorded properly.

Quote
Wild guess: it puts the 10E so far off the LOP because if the aircraft had reached the broad band of LOPs that pass within visible range of Howland, they would have landed safely.  I don't know whether Randy coded it that way or whether it is the consequence of other assumptions he made.

It would be interesting to see what probability the Monte Carlo Simulation assigned to the accuracy of the dawnline measurement vs the probability of the dead reckoning needed to hit the north-south LOP position.  As a fairly new Tighar member, I'm not aware of the early discussions that took place at the time that the Simulation was generated.  But there have been a large number of relatively new forum discussions about the LOP that all lead to the premise that navigating to the LOP itself with a morning dawnline should be easy, but hitting a north-south point on the LOP is difficult.

This isn't to say that the Monte Carlo Simulation is wrong.  It might be the case that the simulation took into account the high accuracy of a dawnline measurement and the combined weight of all of the other factors still end up giving us the probability that we have (of hitting well SW of the target).  It might be the case then that the Simulation is telling us some important clues, such as FN might have made a simple mistake or was using the inaccurate charts that have been much discussed.  Also as you have pointed out the Monte Carlo Simulation is only giving us the probability of various outcomes, not necessarily the outcome that actually occurred.

Quote
The Monte Carlo simulation is an estimate of probabilities based on millions of variations in the variables.  It does not say that the couldn't have been somewhere other than in the most probable region.  All it says is that the further you get away from the mass of particular instances that clump together, the less likely that outcome seems from the standpoint of the assumptions made in construction of the simulation.  Strange things do happen.  People do get royal flushes in poker every now and again.  The longest of long shots occasionally wins a race and pays off ridiculously huge amounts of money.

Exactly.  The thought has also occurred to me that this whole discussion of working backwards from our 3 assumptions, could in itself be food for another Monte Carlo Simulation.  It shouldn't be that difficult for someone to drum up a simulation in Matlab.  Even MS Excel has a Monte Carlo Simulation option I believe.

Incidentally, one other thing about Monte Carlo Simulations.  They are very useful in "what-if" scenarios whereby various parameters are changed to gauge their impacts.   From that standpoint it becomes a living mathematical model that can be used for endless "what-if" scenarios.  Perhaps Tighar should revisit this tool and perhaps use it on an ongoing basis as new data is found.

Quote
Which is a long-winded way of saying, "Yes, it's possible that they hit the band of LOPs that pass through the neighborhood of Howland and Baker well south of those too islands instead of west of the band of LOPs."

On this drawing, the letter "A" represents the whole cloud of possible routes that would have brought them close to Howland and Baker, but just a little too far west to catch sight of them, while still placing them on a LOP that comes close enough to Niku for them to find it.  "B" represents the whole cloud of possible routes that are within the Howland-Baker zone in terms of longitude (East-West location) but too far south in terms of latitude to find Howland and Baker after searching northward for a length of time that is unknown to us.

It seems to me that these are the two most likely scenarios.  In either case, we have to judge that Fred's navigation was off (east-west or north-south).

Nice graphic.  This is the crux of the error isn't it?  Speaking as a novice, it's easy for me to believe that Fred's navigation was well off in a north-south direction because of the overcast that likely prohibited the course corrections needed for the overnight flight.  Simultaneously, it's more difficult to believe that Fred would have blown the dawnline measurement.  So both of those together seem to strengthen the notion that the flight was on the LOP probably well south (probably 150 miles south per the Strength 5 radio reception and 3105 donut discussions).   But most of the Tighar assumptions seem to be that the flight was actually much further west, which is what has me puzzled.
Title: Re: Working the Flight backwards
Post by: Erik on September 06, 2011, 07:32:32 PM
Still think it would have been easy for them to spot the island from far away?

I guess I should have been more clear in the original intent of my posting.  Perhaps using the word 'easier' as opposed to 'easy' would have been a better choice.

The point was that any vertical obstruction on an otherwise featureless horizon would be a benefit to any observer, regardless of visibility, cloud cover, fatigue, etc.  The greater magnitude of that vertical disturbance, the greater the benefit.

The larger and taller the object is would only increase the ability for naked eye to detect it when scanning the natural, unobstructed horizon.  Gardner certainly fits that category.  Its vertical profile (from the NW) is approximately 100' high by nearly 1/2 mile wide.

That was the intent of the simulation was to demonstrate the 'trigonometry' that would affect the visual cues while scanning the horizon's naturally flat profile.  It would certainly benefit the observer vs. a situation with no vertical obstructions at all.

Title: Re: Working the Flight backwards
Post by: Irvine John Donald on September 06, 2011, 07:44:50 PM
The navigation issue is part of what hurt their chances to find Howland. Another question for our navigators and experts. If a navigator flies long enough with one pilot does the navigator make allowances for that pilots flying habits?  For instance when flying a long distance without distinct land marks would a pilot tend to veer a bit more to the right or left.  At the end of a long leg would they have to fly 50 miles toward the target due to that pilots natural "drift"?  Would a navigator ever factor that in?  Would an aircraft have a tendency to "pull" in one direction more than another?  Without celestial shots and at night can you tell what you're drift is?
Title: Re: Working the Flight backwards
Post by: Erik on September 06, 2011, 08:01:38 PM
The navigation issue is part of what hurt their chances to find Howland. Another question for our navigators and experts. If a navigator flies long enough with one pilot does the navigator make allowances for that pilots flying habits?  For instance when flying a long distance without distinct land marks would a pilot tend to veer a bit more to the right or left.  At the end of a long leg would they have to fly 50 miles toward the target due to that pilots natural "drift"?  Would a navigator ever factor that in?  Would an aircraft have a tendency to "pull" in one direction more than another?  Without celestial shots and at night can you tell what you're drift is?

What an interesting question.  Puts a whole new twist on wind correction angle i.e. "pilot correction" angle - huh?.  Perhaps a trim-tab setting for individual pilots?  :o

Seriously though, that would be a good question to see if AE had a historical tendancy to be left or right of her target.  Any way to figure that out?

Title: Re: Working the Flight backwards
Post by: Gary LaPook on September 06, 2011, 08:17:06 PM
The navigation issue is part of what hurt their chances to find Howland. Another question for our navigators and experts. If a navigator flies long enough with one pilot does the navigator make allowances for that pilots flying habits?  For instance when flying a long distance without distinct land marks would a pilot tend to veer a bit more to the right or left.  At the end of a long leg would they have to fly 50 miles toward the target due to that pilots natural "drift"?  Would a navigator ever factor that in?  Would an aircraft have a tendency to "pull" in one direction more than another?  Without celestial shots and at night can you tell what you're drift is?

-----------------------------------------------------

If the directional gyro was drifting, and they all do, then the autopilot or the human pilot will follow it and steer off course. An example will help. Earhart sets the DG to agree with the compass and then  sets the autopilot to fly a true heading of 157°. (I am simplifying this by leaving out the complication of variation, deviation and wind correction angle.) The pilot or autopilot controls the plane so that 157° stays under the lubber line (the heading index line). After ten minutes the pilot checks the compass and finds that the plane is now heading 147° even though the DG still shows 157°. The DG has drifted ten degrees. The pilot then resets the DG to 147° and then turns the plane back to 157° on the DG (or the autopilot makes the turn back to 157° on the DG.) However, during that ten minute period the plane was making a gradual turn to the left so the average heading actually flown was 152° so the plane has drifted 5° off course to the left. Most likely the DG will continue to drift at the same rate so if the pilot continues to just reset the DG as described then the plane will actually fly 152° not 157° over time. A 5° deviation will place the plane 29 NM (33 SM) off course on a leg of 350 NM from Howland to Gardner.

gl
Title: Re: Working the Flight backwards
Post by: Gary LaPook on September 06, 2011, 08:26:07 PM
Still think it would have been easy for them to spot the island from far away?

I guess I should have been more clear in the original intent of my posting.  Perhaps using the word 'easier' as opposed to 'easy' would have been a better choice.

The point was that any vertical obstruction on an otherwise featureless horizon would be a benefit to any observer, regardless of visibility, cloud cover, fatigue, etc.  The greater magnitude of that vertical disturbance, the greater the benefit.

The larger and taller the object is would only increase the ability for naked eye to detect it when scanning the natural, unobstructed horizon.  Gardner certainly fits that category.  Its vertical profile (from the NW) is approximately 100' high by nearly 1/2 mile wide.

That was the intent of the simulation was to demonstrate the 'trigonometry' that would affect the visual cues while scanning the horizon's naturally flat profile.  It would certainly benefit the observer vs. a situation with no vertical obstructions at all.
---------------------------------------------

You could be standing across the street from the Empire State Building and if the fog limited visibility to 20 feet then you would never see the building. It doesn't matter how big an object is or how high the plane is you still will be limited by the prevailing visibility. If the visibility was 20 NM or less, which seems quite likely, then the furthest they could possibly see Gardner was 20 NM or less. And, as you can see from the photo I posted, if flying above them, even scattered clouds will restrict the distance you can see to a lower limit than the prevailing visibility below the clouds. (Oh, and what about cloud shadows?)

gl
Title: Re: Working the Flight backwards
Post by: Ric Gillespie on September 06, 2011, 08:37:50 PM
If the directional was drifting, and they all do, then the autopilot or the human pilot will follow it and steer off course.

Yes, that's why you periodically reset the DG.  It's as basic to cross-country flying as switching fuel tanks or leaning the mixture at altitude.  AE and FN were both highly experienced long-distance flyers, much of it by DR.  If they couldn't fly competently when they were tired they wouldn't have lived as long as they did.
Title: Re: Working the Flight backwards
Post by: Ric Gillespie on September 06, 2011, 08:43:30 PM
If the visibility was 20 NM or less, which seems quite likely, then the furthest they could possibly see Gardner was 20 NM or less.

Why would you think the visibility was 20 nm or less?  According to Itasca's deck log, visibility that whole morning was "9" - the maximum on the scale, defined as "Prominent objects visible above 20 miles."
Title: Re: Working the Flight backwards
Post by: Erik on September 06, 2011, 09:02:04 PM
You could be standing across the street from the Empire State Building and if the fog limited visibility to 20 feet then you would never see the building. It doesn't matter how big an object is or how high the plane is you still will be limited by the prevailing visibility.

Correct.  I should have been more clear (no pun intended) and excluded IFR conditions in the analysis.  I also should've mentioned that AE was not current in her CAT III certification either.  ???  Good grief...

And, as you can see from the photo I posted, if flying above them, even scattered clouds will restrict the distance you can see to a lower limit than the prevailing visibility below the clouds. (Oh, and what about cloud shadows?)

Lost, looking for islands in a sea of nothingness, above the clouds?  Even for AE = Doubtful!
Title: Re: Working the Flight backwards
Post by: Martin X. Moleski, SJ on September 06, 2011, 10:32:50 PM
Ahh, okay I can see how one can interpret that.  She apparently also used the word 'AND' indicating that both directions had been traveled.  I used the word apparently, because as mentioned in Tighar Tracks, the radio logs are a bit of a mess and the exact wording might not have been recorded properly.

The website is chock-full of information to help you decide what is and is not reliable.

I've got a small page on the last transmission (http://tighar.org/wiki/Last_transmission).  On it, you will find a scan of the last transmission from one of the logs:

(http://tighar.org/aw/mediawiki/images/3/3f/Lastwords_fig5.gif)

At the end of the article are ten links to material elsewhere on the site.  The first five links are:
• "The Radio Logs of the USCG Itasca: Introduction and Index." (http://tighar.org/Projects/Earhart/Archives/Research/Bulletins/37_ItascaLogs/Itascalog.html)
• "The Radio Logs of the USCG Itasca: Analysis of the 0843 Message." (http://tighar.org/Projects/Earhart/Archives/Research/Bulletins/37_ItascaLogs/analysis.html)
• "Last Words." (http://tighar.org/Projects/Earhart/Archives/Research/Bulletins/49_LastWords/49_LastWords.html)
• "What is the significance of Earhart's statement, 'We are on the line 157 337'?" (http://tighar.org/Projects/Earhart/Archives/Forum/FAQs/navigation.html)
• "Log Jam." (http://www.tighar.org/Publications/TTracks/12_2/logjam.html)
Yes, of course, it is not necessarily the "exact wording."  Maybe she really said "South and North" and the operator wrote "North and South."

I'm satisfied that it is probably sufficiently accurate to tell us what they were doing.  YMMV.

Quote
Exactly.  The thought has also occurred to me that this whole discussion of working backwards from our 3 assumptions, could in itself be food for another Monte Carlo Simulation.  It shouldn't be that difficult for someone to drum up a simulation in Matlab.  Even MS Excel has a Monte Carlo Simulation option I believe.

Don't just talk about it.  Do it and let us know how it turns out.

Quote
Incidentally, one other thing about Monte Carlo Simulations.  They are very useful in "what-if" scenarios whereby various parameters are changed to gauge their impacts.   From that standpoint it becomes a living mathematical model that can be used for endless "what-if" scenarios.  Perhaps TIGHAR should revisit this tool and perhaps use it on an ongoing basis as new data is found.

TIGHAR is up to its neck in funding the interpretation of the last expedition and designing the next.  The organization is sold on the Niku Hypothesis (http://tighar.org/wiki/Niku_hypothesis).  All you get from the simulation is a sense of how the aircraft may have ended up at Niku; knowing the exact path is of no use whatsoever in searching for the wreckage or other telltale material from AE and FN.  The whole question is moot (http://tighar.org/wiki/Moot): something about which reasonable people may reasonably disagree; something that can be argued endlessly; something that makes no difference to the next steps that need to be taken.

Quote
Nice graphic.  This is the crux of the error isn't it?  Speaking as a novice, it's easy for me to believe that Fred's navigation was well off in a north-south direction because of the overcast that likely prohibited the course corrections needed for the overnight flight.  Simultaneously, it's more difficult to believe that Fred would have blown the dawnline measurement.  So both of those together seem to strengthen the notion that the flight was on the LOP probably well south (probably 150 miles south per the Strength 5 radio reception and 3105 donut discussions).   But most of the TIGHAR assumptions seem to be that the flight was actually much further west, which is what has me puzzled.

The assumption that counts is that the flight ended at Niku with sufficient fuel to account for the post-loss radio messages that seem to be credible (http://tighar.org/wiki/PLRM).  Any number of flight paths from Lae to Niku can lead to that result.
Title: Re: Working the Flight backwards
Post by: Gary LaPook on September 06, 2011, 10:36:18 PM
If the visibility was 20 NM or less, which seems quite likely, then the furthest they could possibly see Gardner was 20 NM or less.

Why would you think the visibility was 20 nm or less?  According to Itasca's deck log, visibility that whole morning was "9" - the maximum on the scale, defined as "Prominent objects visible above 20 miles."
---------------------------------

O.K., 21 miles based on Itasca's deck log. ;)

You don't think it was a 100 NM, do you? Visibilities over the ocean are never that great which is why the scales max out at 25 NM in the Climatic Atlas and at 20 NM in the Navy reporting scheme. They may exceed 25 NM but never by much.

60% probability = "quite likely" in my dictionary.

But Itasca was 350 NM from Gardner and there was no reported weather observation taken at Gardner that day so my basis, as I stated, is the U.S. Navy's Climatic Atlas for the Gardner area for any day in the month of July of any year. Do you have any other information that is more authoritative as to the conditions at Gardner on that date?

We can also compare the visibility as observed at Howland with the expected conditions at Gardner. Based on the Navy Climatic Atlas, in the vicinity of Howland in July, you can expect visibility less than 25 NM 70% of the time; less than 20 NM 60%; less than 15 NM 50% and less than 10 NM 39% of the time. So 40% of the time the visibility will equal or exceed 20 NM. Itasca logged at least 20 NM so there is a 10 % chance that it was more than 20 NM but less than 25 NM and only a 30% chance that it exceeded 25 NM and probably not by a lot more than 25 NM. Comparing this with the data for the vicinity of Gardner shows a three times higher likelihood that the visibility was more than 25 NM at Howland than at Gardner (30% compared to only 10%.) Based on this comparison, the visibility I stated for the Gardner area is quite reasonable and has more support than any other speculation about it.

gl
Title: Re: Working the Flight backwards
Post by: Gary LaPook on September 06, 2011, 10:39:29 PM
You could be standing across the street from the Empire State Building and if the fog limited visibility to 20 feet then you would never see the building. It doesn't matter how big an object is or how high the plane is you still will be limited by the prevailing visibility.

Correct.  I should have been more clear (no pun intended) and excluded IFR conditions in the analysis.  I also should've mentioned that AE was not current in her CAT III certification either.  ???  Good grief...

And, as you can see from the photo I posted, if flying above them, even scattered clouds will restrict the distance you can see to a lower limit than the prevailing visibility below the clouds. (Oh, and what about cloud shadows?)

Lost, looking for islands in a sea of nothingness, above the clouds?  Even for AE = Doubtful!
--------------------------------------------------

O.K., below the clouds, visibility limited only by the prevailing visibility, 90% probability it was less than 25 NM and 60% probability that it was less than 20 NM.

gl
Title: Re: Working the Flight backwards
Post by: Gary LaPook on September 06, 2011, 11:17:25 PM
You could be standing across the street from the Empire State Building and if the fog limited visibility to 20 feet then you would never see the building. It doesn't matter how big an object is or how high the plane is you still will be limited by the prevailing visibility.

Correct.  I should have been more clear (no pun intended) and excluded IFR conditions in the analysis.  I also should've mentioned that AE was not current in her CAT III certification either.  ???  Good grief...

And, as you can see from the photo I posted, if flying above them, even scattered clouds will restrict the distance you can see to a lower limit than the prevailing visibility below the clouds. (Oh, and what about cloud shadows?)

Lost, looking for islands in a sea of nothingness, above the clouds?  Even for AE = Doubtful!
-------------------------

She didn't complete her instrument rating so she could not have qualified for CAT 3 authorization. And the Electra didn't have a radar altimeter so it couldn't even qualify for CAT 2 approaches.

But you are trying to avoid my point, that the distance that they could have seen Gardner was limited by the prevailing visibility and that the size of the island doesn't change that one bit.

gl
Title: Re: Working the Flight backwards
Post by: Mark Petersen on September 07, 2011, 12:10:41 AM
Don't just talk about it.  Do it and let us know how it turns out.

To be honest this is something that I've mulled over for awhile now.  I have a modest background in numeric methods and have worked on mathematical modeling before (finite differencing models used to predict the behavior of solid-state devices).   It used to be the case that custom software was needed in order to do this sort of work, but this is the era of Matlab and heavy duty MS Excel scripts and plug-ins.  The only problem is getting the free time necessary.  After attending the Tighar Field School, I've started to put a lot of my free time into wreck chasing, for example I will be hiking to the summit of Mt. Whitney this weekend to check out the pair of F6F Hellcat's that crashed back in '46.  If others in Tighar were to feel that a new MC Simulation has value though, I would be more inclined to put the time into it.

Quote
TIGHAR is up to its neck in funding the interpretation of the last expedition and designing the next.  The organization is sold on the Niku Hypothesis (http://tighar.org/wiki/Niku_hypothesis).  All you get from the simulation is a sense of how the aircraft may have ended up at Niku; knowing the exact path is of no use whatsoever in searching for the wreckage or other telltale material from AE and FN.  The whole question is moot (http://tighar.org/wiki/Moot): something about which reasonable people may reasonably disagree; something that can be argued endlessly; something that makes no difference to the next steps that need to be taken.

That may be true, but isn't that the whole point of this thread?

Quote
The assumption that counts is that the flight ended at Niku with sufficient fuel to account for the post-loss radio messages that seem to be credible (http://tighar.org/wiki/PLRM).  Any number of flight paths from Lae to Niku can lead to that result.

Yes, but the point is that if we accept the Niku hypothesis and work backwards, we might be able to rule out some of those flight paths and perhaps have a better understanding of what happened and perhaps even what went wrong.  This seems to be a reasonable goal and something that could also benefit from a MC simulation.

LTM,  Mark  #2850
Title: Re: Working the Flight backwards
Post by: Gary LaPook on September 07, 2011, 12:35:41 AM
Still think it would have been easy for them to spot the island from far away?

I guess I should have been more clear in the original intent of my posting.  Perhaps using the word 'easier' as opposed to 'easy' would have been a better choice.

The point was that any vertical obstruction on an otherwise featureless horizon would be a benefit to any observer, regardless of visibility, cloud cover, fatigue, etc.  The greater magnitude of that vertical disturbance, the greater the benefit.

The larger and taller the object is would only increase the ability for naked eye to detect it when scanning the natural, unobstructed horizon.  Gardner certainly fits that category.  Its vertical profile (from the NW) is approximately 100' high by nearly 1/2 mile wide.

That was the intent of the simulation was to demonstrate the 'trigonometry' that would affect the visual cues while scanning the horizon's naturally flat profile.  It would certainly benefit the observer vs. a situation with no vertical obstructions at all.

-------------------------------
Unfortunately for your simulation, the trees on Gardner would not be silhouetted above the horizon. From 3,000 feet the horizon is 72.1 SM away (I assume that you are using statute miles.) This is from Table 9 of Bowditch or by formula: distance to the horizon (SM) = 1.317 times the square root of the height in feet. The 100 foot high trees are only 1.3  minutes of arc (1/60 of a degree) tall at that distance.  Because your diagram is for 50 SM, the island and its trees would appear about a quarter of a degree (16 minutes of arc) below the horizon,  so the 100 foot tall trees would not pierce the horizon. To be tall enough to break the horizon the trees would have to have been more than 1200 feet tall!

Looking at your second example, 25 SM, the same situation applies. From 1500 feet the horizon is 51.0 SM away and your island is only 25 SM away so is also well short of the horizon At this distance the trees are 2.6 minutes of arc tall. The island, only 25 SM away, is also more than a quarter of a degree below the horizon (19 minutes of arc) so, again, the trees would not pierce the horizon. To be tall enough to break the horizon the trees would have to have been more than 700 feet tall!

Your last example, 10 SM at 1,000 feet, puts the horizon is 41.6 SM away. The island, only 10 SM away, is 23 minutes of arc below the horizon and the 100 foot high trees are only 6 minutes tall so the tops of the trees will be 17 minutes below the horizon so also will not be silhouetted against the sky. To be tall enough to break the horizon the trees would have to have been more than 350 feet tall!

Don't rely on Google earth, do the trig yourself.

gl
Title: Re: Working the Flight backwards
Post by: Gary LaPook on September 07, 2011, 12:58:11 AM
Erik,  if you "flew" the route from SW of Howland on Google Earth at 1,000 feet and did a 360 degree search, as you fly, is it possible to see any other land?

Not really.  The only other 'land' is McKean, which is more of a reef/atoll environment more so than it is real land.  Even McKean would have been approximately ~50 miles away from a SW Howland-Gardner route, and difficult, if not impossible to see.  Without any vertical elevation McKean would have been way over the horizon.  It would have been doubtful it was visible unless flying at higher altitudes such as 6,000 thousand feet or greater.

The other possible visible features (at 1,000 feet) may have been the chain of reefs enroute.  They look like islands in the map below, but they are not.  Although not land per se, these reefs may have provided visible whitecaps if the tide was just right.

(http://farm7.static.flickr.com/6185/6120791489_11f3d6f7bb.jpg)

I don't think so but it would be nice to have more info. As pointed out in previous posts we should not rely on the accuracy of Google Earth as it is only a software program that has some issues.  Perhaps the new X Flight simulator will give a more accurate representation.

Google Earth's accuracy is horrible for some things and nearly perfect for others.  As with anything, it's a tool that needs to be used correctly within reason.  For example, it's accuracy in terms of precise topography, up-to-date imagery, and street networks may be in question.  On the other hand, measurements such as the entire length of Gardner island are very precise to the extent that you could measure it with an accuracy within a a few yards if you really wanted to

Using Google Earth as a model to generate simulations and provide graphics to back up verbal and written concepts is where it is very powerful tool!  It's mathematical coordinate precision for inputing your own data is accurate to 6 decimal places of a degree, which is roughly about 4 inches.  So, in other words, it is not Google Earth itself that is in question, but rather the originating source that is being used.

To derive the height of the island, I mainly used maps on TIGHAR's own website and recounts of the of the buka trees height to generate the dimensions of the models used here.  After researching, I found these figures were fairly accurate with Google Earth coincidently.  If I didn't have both sources, you are correct, I would have abandoned Google Earth's accuracy and sought additional information.  But in this case, they all matched.
--------------------------------------------

I decided to do some checking on the accuracy of Google Earth coordinates to make sure they were accurate in the Pacific. I found the published coordinates of Mili airport, 6º 05' N, 171º 44'E;  Mujuro airport, 7º  03' 44'' N, 171º 16' 19" E; and Kosrae airport, 5º 21' 25" N, 162º 53' 30"E since these were the closest to Howland. Then going to them with Google Earth I found that the Google Earth coordinates were exactly right, correct to the accuracy of the positions given in the airport database. Mili was only given to the nearest minute but the others were to the second. ( A second is only 100 feet!) You can check for yourself, just go to Google Earth with those coordinates which you will see fall on the runways.

gl
Title: Re: Working the Flight backwards
Post by: Gary LaPook on September 07, 2011, 03:56:41 AM
Ok---I'll ask the question of our navigator friends. IF the weather was cloudy during the nighttime part of the flight, Fred would NOT have been able to shoot a celestrial plot. So, when he was able to shoot the 157/337 sunline, how would he have known where along the sunline he was? He wouldnt have been able to guage their drift, so they actually "could" have been south of Gardner. AT 1000 feet, they may not have been able to see Howland, which "could" have been a few miles over the horizon from their position.

So--as they flew south along the sunline, they came across Gardner.
Does this make any sense to anyone??
----------------------------------------------
﻿There is no reason to think that Noonan had not been able to get celestial fixes. Earhart wrote
that “Noonan must have star sights” so they would not have just changed their minds about this
requirement.
The “Point of No Return” is a standard calculation done by flight navigators, taking into account
air speed, wind speed and endurance, to determine the point along the planned course at which
the plane could reverse its course and return safely to the departure airport.

If Noonan thought he had a 24 hour endurance, using the 23 knot wind component that he measured in flight then he would have calculated the PNR as 1407 Z at 1511 NM from Lae, just five hours and 710 NM short of Howland.
Using a 15 knot wind component then he would have gotten 1323 Z at 1539 NM and with a 25
knot wind he would have gotten 1418 Z and 1502 NM.

It also turns out that there was an airport at Rabaul, 344 NM along the course line to Howland.
Noonan could have calculated a PNR for a departure from Lae with a return to Rabaul. Since
Rabaul was closer to Howland then this PNR would also be closer to Howland. Doing this
calculation we find the PNR occurs at 1526 Z, 1653 NM from Lae, only four hours and 570 NM
short of Howland. So if Noonan had not been able to get fixes they could have turned around and
returned safely to Lae or Rabaul and try again another day.

Air Force Manual 51-40 states the uncertainty of dead reckoning as 10% of the distance flown
from the prior fix.

So contrary to what many people believe, “that they had no idea where they were north and
south" when they intercepted the sunline LOP, we can expect that any error or uncertainty would
be limited to 10 miles for every 100 miles that they had flown since their last fix.

Sunrise at Howland was 1745 Z and civil twilight occurred 22 minutes
earlier at 1724 Z at which point the sky would have been too bright to
see the stars and to obtain a fix. Sunrise and civil twilight would have
occurred even later at their position west of Howland by an additional
one minute for each 15 miles that they were west of Howland. We can
assume that they had arrived close to Howland at 1912 Z when they
reported "must be on you." This is 1 hour and 48 minutes after civil
twilight at Howland and the Electra would have flown 235 nautical miles
in this time at 130 knots. Civil twilight occurred 16 minutes later 235
NM west of Howland so they could have obtained a fix slightly later than
1724 Z at 1740 Z. We can assume that Noonan was busy right up to the
time of civil twilight so that they would have the latest and most
accurate fix to use in locating Howland.

From 1740 Z to 1912 Z NR16020 would have flown 199 nautical miles at 130
knots so the accuracy of their position would only have deteriorated 20
nautical miles based on 10% of the distance flown in that period, If you add this 20 nautical miles
to the uncertainty of the original fix, 10 nautical  miles according to
navigation textbooks, Federal Aviation Regulations, and also based on what
Noonan himself reported to Weems in a letter published at Weem, page 423 page 424 & 425, (see:
https://sites.google.com/site/fredienoonan/resources/weems/weems-422-423.JPG?attredirects=0 (https://sites.google.com/site/fredienoonan/resources/weems/weems-422-423.JPG?attredirects=0) and https://sites.google.com/site/fredienoonan/resources/weems/weems-424-425.JPG?attredirects=0 (https://sites.google.com/site/fredienoonan/resources/weems/weems-424-425.JPG?attredirects=0)  ) they should have known their position within 30 nautical miles.  Although we do not know the time
of his last fix, Noonan did know and would have used that knowledge
in planning his approach and in figuring the possible uncertainty and
how far to aim off.

Looking at this uncertainty in the north-south direction you end up with a 30 nautical mile north-south uncertainty. Noonan would have made the same calculations based on his previous experience, maybe he even rounded this value up for extra safety.

There has been concern expressed that clouds could have prevented Noonan from taking star
sights that late (1940 Z). They had reported flying at 12,000 feet, which normally is above most
clouds. Even if some clouds where higher than 12,000 feet it is unlikely that they blocked the
entire sky for hundreds of miles along the flight path. It has been claimed that Earhart reported at
1415 Z and again at 1515 Z "cloudy and overcast" but these words are not found in either radio
log so there is no support for the claim that Noonan had been prevented from shooting stars. But
what is actually recorded in the radio log, more than an hour after this 1515 Z possible report of
"overcast" conditions, is at 1623 Z Earhart reported "partly cloudy." There are no reports after
this "partly cloudy" report so it is the most current report, in both time and location, so there is no
actual evidence that the weather deteriorated later so as to prevent celestial observations. Earhart
did not report descending to 1,000 feet until almost two hours later at 1818 Z.

Based on this last report of in-flight weather conditions, we can be almost certain that Noonan was able
to take sights at 1623 Z, only two hours and forty-nine minutes before the "must be on you"
transmission at 1912 Z. So looking at this as the worst case scenario, we can do the same
computations as before about the uncertainty of the D.R. position at 1912 Z. In two hours and
forty-nine minutes the plane would have covered 366 NM at 130 knots so the uncertainty caused
by dead reckoning for 366 NM is 37 NM for the 10% estimate of DR accuracy. We have to add
to these estimates the original 10 NM uncertainty in a fix obtained at 1623 Z so the totals is 47
NM of uncertainty at 1912 Z. Noonan knew the time that he obtained his last celestial fix and
would have used the right amount of offset to allow for the possible uncertainty.

So these two cases mark the bounds of the possible uncertainty in the north and south direction, 47 NM if the last fix was obtained at 1623 Z and 30 NM if the last fix was obtained as late as possible (clouds permitting) at 1740 Z. Either way they would not have flown for hours southward still expecting to find Howland.

Also see:
gl

Title: Re: Working the Flight backwards
Post by: Martin X. Moleski, SJ on September 07, 2011, 05:43:35 AM
... If others in TIGHAR were to feel that a new MC Simulation has value though, I would be more inclined to put the time into it.

Perform to self-set standards.  If it interests you, working on it would be worthwhile.

If not, not.

Quote
Quote
The whole question is moot (http://tighar.org/wiki/Moot): something about which reasonable people may reasonably disagree; something that can be argued endlessly; something that makes no difference to the next steps that need to be taken.

That may be true, but isn't that the whole point of this thread?

Understanding the 157-337 message is part of the backstory for TIGHAR's searches on Niku.

Getting a general sense of the challenges faced by AE and FN in using celestial navigation is helpful in assessing the odds of their ending up at Niku with enough fuel to transmit the post-loss radio messages that seem credible.

Calculating with the greatest precision what route or set of routes have the highest probability under some untestable assumptions goes beyond those modest goals.  I predict that if you do the exercise, you will find (as Randy did) many routes that work and some that leave them in the ocean.

Quote
Quote
The assumption that counts is that the flight ended at Niku with sufficient fuel to account for the post-loss radio messages that seem to be credible (http://tighar.org/wiki/PLRM).  Any number of flight paths from Lae to Niku can lead to that result.

Yes, but the point is that if we accept the Niku hypothesis and work backwards, we might be able to rule out some of those flight paths and perhaps have a better understanding of what happened and perhaps even what went wrong.  This seems to be a reasonable goal and something that could also benefit from a MC simulation.

OK.  Go for it.  I'm sure you will find lots of people here willing to offer you peer review after you've built your model.   :)
Title: Re: Working the Flight backwards
Post by: Irvine John Donald on September 07, 2011, 06:38:08 AM
... If others in TIGHAR were to feel that a new MC Simulation has value though, ........
The whole question is moot (http://tighar.org/wiki/Moot): something about which reasonable people may reasonably disagree; something that can be argued endlessly; something that makes no difference to the next steps that need to be taken

Marty, I think a theory needs to be able to withstand questioning from all angles to test its validity. That becomes the strength of the theory. I have talked with many people about the different theories and the TIGHAR Niku theory is the only one that has strength due to the nature of the science and the evidence that exists. However this theory is not accepted as the final answer in the puzzle. Someone has decided a smoking gun is required. The Electra or some other hard evidence as yet unfound. In the current absence of that smoking gun I believe it is productive and healthy to prod at the theory to determine if there is something that was missed, overlooked or that can be learned to add additional strength.  I, too, believe this forum is an excellent tool for playing "what if" scenarios. Your "moot point" comment suggests something different. Are we to only test the theory in certain ways?  I believe this forum works exceptionally well BECAUSE it allows freedom to ask questions and get answers from like minded individuals. Even off the wall or seemingly time wasting points. They all deserve attention because one of them may help the theory become reality.  My 2 cents.
Title: Re: Working the Flight backwards
Post by: h.a.c. van asten on September 07, 2011, 07:07:25 AM
GMT (1912 - 1740) = 1h32m @ 130 kts = 200 nm off Howland , for direct approach . GMT (1912 -1815) = 0h57m @ 130 kts = 134 nm (neither 100 nm nor 100 sm) . Does anybody know what distance unit Noonan (ex-sea navigator , said to have accounted for nm & kts) used for his in flight on paper messages to Earhart ? (did he p.e. measure nm and first multiply by 1.153 before sending the paper off ?) .
Title: Re: Working the Flight backwards
Post by: Martin X. Moleski, SJ on September 07, 2011, 08:34:56 AM
I think a theory needs to be able to withstand questioning from all angles to test its validity. That becomes the strength of the theory.

That is a great theory.

In practice, "questioning from all angles" costs time and money.

Given limited resources, the TIGHAR board and its agents decide what projects are worth funding.

Right now, the exploration of Niku has a higher priority in TIGHAR's approach than developing another flight simulation.

No one is stopping you from creating your own models and offering your own conclusions.

I have no doubt about what the exercise will show: the probabilities of various flight paths approximating the real path taken by the aircraft will vary with the assumptions made in the construction of the model.  Different conclusions flow from different premises; if we had more data, we wouldn't have to guess about the premises of any one model; in the absence of data, many models can be built that lead to different conclusions.

Quote
I have talked with many people about the different theories and the TIGHAR Niku theory is the only one that has strength due to the nature of the science and the evidence that exists. However this theory is not accepted as the final answer in the puzzle. Someone has decided a smoking gun is required. The Electra or some other hard evidence as yet unfound. In the current absence of that smoking gun I believe it is productive and healthy to prod at the theory to determine if there is something that was missed, overlooked or that can be learned to add additional strength.

Poke and prod away.  I have explained why I won't try to code another simulation and why I think it is unlikely that TIGHAR will code another one, either.  You are a free agent and may do as you please with your time and money.

Quote
I, too, believe this forum is an excellent tool for playing "what if" scenarios. Your "moot point" comment suggests something different. Are we to only test the theory in certain ways?  I believe this forum works exceptionally well BECAUSE it allows freedom to ask questions and get answers from like minded individuals.

You can't have it both ways.  I am evidently not like-minded to you.  I express my conviction that there is a limit to the value of playing "what-if" games; you disagree with me.  When you question me, you see it as exhibition of the glorious freedom of skeptical inquirers to ask questions; when I disagree with you, you portray it as close-mindedness.

Quote
Even off the wall or seemingly time wasting points. They all deserve attention because one of them may help the theory become reality.  My 2 cents.

I respectfully disagree.  I question your evaluation.  Here is my argument against your view: We do not have an unlimited budget to play with.  We have to select certain lines of inquiry that seem fruitful and neglect others that we think are less likely to produce results.
Title: Re: Working the Flight backwards
Post by: Ric Gillespie on September 07, 2011, 09:10:15 AM
﻿There is no reason to think that Noonan had not been able to get celestial fixes.

I disagree.  It is true that at 02:45-48 Bellarts logged, "HEARD EARHART PLANE / BUT UNREADABLE THROUGH STATIC (http://tighar.org/Projects/Earhart/Archives/Research/Bulletins/37_ItascaLogs/pos2page1.pdf)" but that is not the only primary source documentation of what occurred. Associated Press reporter James Carey was in the radio room. His rough notes (http://tighar.org/Publications/TTracks/2007Vol_23/discovery.pdf), taken at the time, and his diary (http://tighar.org/Projects/Earhart/Archives/Documents/Carey_Diary/Careydiary.html) document that he heard Earhart say "sky overcast."

In an article (http://tighar.org/Projects/Earhart/Archives/Documents/Carey_Article/Careyarticle5.htmll) he wrote a few days later, Carey described the scene:

Friday, July 2---“Quiet everybody,” yelled one of the radiomen at 2:48 AM, “I think I’ve contacted the plane.” A pin-drop silence ensued. With my ears to the phones, I could hear the voice of Amelia Earhart, somewhere out in the South Pacific, speaking on the voice phones. “KHAQQ calling Itasca; KHAQQ calling Itasca,” she said and then the static drowned out a part of the message. “Sky overcast,” she continued somewhat audibly, and that was all for the rest of the message was lost in noisy rumblings of static interference.

Why does Carey contradict Bellarts?  Note that Bellarts says the transmission began at 02:45 and ended at 02:48.  Carey's references are all at 02:48.  They're listening on headphones, not a speaker.  I suspect that what happened is that Bellarts heard something over his headphones that convinced him that he was hearing Earhart but he couldn't make out the words. He yelled, "Quiet everybody" as Carey says and then he either passed his headphones to Carey or Carey plugged in another set.  In any event, Carey heard what he heard.  You can choose to believe him or not, but his notes stand as a contemporary primary source document.

Earhart wrote that “Noonan must have star sights” so they would not have just changed their minds about this
requirement.
The “Point of No Return” is a standard calculation done by flight navigators, taking into account
air speed, wind speed and endurance, to determine the point along the planned course at which
the plane could reverse its course and return safely to the departure airport.

If Noonan thought he had a 24 hour endurance, using the 23 knot wind component that he measured in flight then he would have calculated the PNR as 1407 Z at 1511 NM from Lae, just five hours and 710 NM short of Howland.

"Would have" is a guess masquerading as fact. Chater (http://tighar.org/Projects/Earhart/Archives/Documents/Chater_Report.html) reported that at 5:18 pm Lae time, Earhart was heard to say "POSITION 4.33 SOUTH 159.7 EAST HEIGHT 8000 FEET OVER CUMULUS CLOUDS WIND 23 KNOTS."  She did not say whether the wind was a headwind, tailwind or crosswind.  By your own reasoning, if it was a headwind they should have turned back.

It also turns out that there was an airport at Rabaul, 344 NM along the course line to Howland.
Noonan could have calculated a PNR for a departure from Lae with a return to Rabaul. ... So if Noonan had not been able to get fixes they could have turned around and
returned safely to Lae or Rabaul and try again another day.

What evidence do you have to support your claim that there was an airfield at Rabaul in 1937? The Wikipedia page on The Bombing of Rabaul (http://en.wikipedia.org/wiki/Bombing_of_Rabaul_(November_1943)) says there were two "pre-war Australian strips" on Rabaul - Lakunai and Vunakanau - but does not say when they were constructed.  The Wikipedia pages for Lakunai (http://en.wikipedia.org/wiki/Lakunai_Airfield) and Vunakanau (http://en.wikipedia.org/wiki/Vunakanau_Airfield) say they were constructed by the Royal Australian Air Force.  To my knowledge, the RAAF was not building airfields in the region in 1937.

You seem to have gone to great lengths to try to prove that Earhart and Noonan should have reached Howland and shouldn't have reached Gardner, and yet there is abundant evidence that they didn't reach Howland and did reach Gardner.
Title: Re: Working the Flight backwards
Post by: Irvine John Donald on September 07, 2011, 10:45:25 AM
I think a theory needs to be able to withstand questioning from all angles to test its validity. That becomes the strength of the theory.

That is a great theory.

In practice, "questioning from all angles" costs time and money.

Given limited resources, the TIGHAR board and its agents decide what projects are worth funding.

Right now, the exploration of Niku has a higher priority in TIGHAR's approach than developing another flight simulation.

No one is stopping you from creating your own models and offering your own conclusions.

I have no doubt about what the exercise will show: the probabilities of various flight paths approximating the real path taken by the aircraft will vary with the assumptions made in the construction of the model.  Different conclusions flow from different premises; if we had more data, we wouldn't have to guess about the premises of any one model; in the absence of data, many models can be built that lead to different conclusions.

Quote
I have talked with many people about the different theories and the TIGHAR Niku theory is the only one that has strength due to the nature of the science and the evidence that exists. However this theory is not accepted as the final answer in the puzzle. Someone has decided a smoking gun is required. The Electra or some other hard evidence as yet unfound. In the current absence of that smoking gun I believe it is productive and healthy to prod at the theory to determine if there is something that was missed, overlooked or that can be learned to add additional strength.

Poke and prod away.  I have explained why I won't try to code another simulation and why I think it is unlikely that TIGHAR will code another one, either.  You are a free agent and may do as you please with your time and money.

Quote
I, too, believe this forum is an excellent tool for playing "what if" scenarios. Your "moot point" comment suggests something different. Are we to only test the theory in certain ways?  I believe this forum works exceptionally well BECAUSE it allows freedom to ask questions and get answers from like minded individuals.

You can't have it both ways.  I am evidently not like-minded to you.  I express my conviction that there is a limit to the value of playing "what-if" games; you disagree with me.  When you question me, you see it as exhibition of the glorious freedom of skeptical inquirers to ask questions; when I disagree with you, you portray it as close-mindedness.

Quote
Even off the wall or seemingly time wasting points. They all deserve attention because one of them may help the theory become reality.  My 2 cents.

I respectfully disagree.  I question your evaluation.  Here is my argument against your view: We do not have an unlimited budget to play with.  We have to select certain lines of inquiry that seem fruitful and neglect others that we think are less likely to produce results.

Thanks Marty.  I appreciate you taking the time to respond.  One of the great points in this forum is that we get to read about how others think.  Too often however the interepretation of what is said is either mistaken or just isn't clear.

You made the comment to Mark Petersen; "TIGHAR is up to its neck in funding the interpretation of the last expedition and designing the next.  The organization is sold on the Niku Hypothesis.  All you get from the simulation is a sense of how the aircraft may have ended up at Niku; knowing the exact path is of no use whatsoever in searching for the wreckage or other telltale material from AE and FN.  The whole question is moot: something about which reasonable people may reasonably disagree; something that can be argued endlessly; something that makes no difference to the next steps that need to be taken."

It was the sentence "The whole question is moot: something about which reasonable people may reasonably disagree; something that can be argued endlessly; something that makes no difference to the next steps that need to be taken." that threw me off.  It seemed to suggest that we shouldn't waste any time thinking about the past work only to think to the future work on the entire Niku theory.

Your response clarifies what you mean and it was in reference to doing studies that have been previously done, amongst other work.  Good point.  I also believe that TIGHAR and its advisory council must decide where to spend scarce and valuable resources.  I believe I am priviledged to be able to access this forum and participate but would NEVER presume to suggest or instruct what direction it should take or how to spend its money.  Sorry but thats for the advisory council and members like yourself who have vast amounts of history and experience in this matter.  I see the forum only as a mechanism for discussion.  From these discussions I hope the advisory council may see threads of direction.  Sure a lot of ground gets repeated.  Even in my short time in this forum I see repetition that even I might be able to answer but there are many experts who also participate and the answers are usually pretty quick and complete.

Those same experts may also enjoy the challenge of creating a new Monte Carlo simulation or graphic as some people enjoy doing this.  But you're right that if we want to see something like that and have the time to "waste" then go for it.  That's a fair comment.

I enjoy reading posts from a number of people on this forum and you are one of them.  I just want to clarify this comment you made. "I am evidently not like-minded to you.  I express my conviction that there is a limit to the value of playing "what-if" games; you disagree with me.  When you question me, you see it as exhibition of the glorious freedom of skeptical inquirers to ask questions; when I disagree with you, you portray it as close-mindedness."     Questioning someone can also mean you are trying to understand their point more clearly.  I don't disagree with you.  I never said I disagreed with you. But my questions to you elicited an answer that clarified your point.  We can always agree to disagree on some points and agree on others.  That's the beauty of free speech and a respectful forum.  But questioning someone's opinion is not always disagreement nor close mindedness.

For the future please understand that I have the utmost respect for Ric, yourself, and all the many forum participants who venture to share their thoughts, comments, opinions, experience, anecdotes and ,yes, even the jokes.
Title: Re: Working the Flight backwards
Post by: Irvine John Donald on September 07, 2011, 11:15:10 AM
Re: Gary LaPook's post -

"...So these two cases mark the bounds of the possible uncertainty in the north and south direction, 47 NM if the last fix was obtained at 1623 Z and 30 NM if the last fix was obtained as late as possible (clouds permitting) at 1740 Z. Either way they would not have flown for hours southward still expecting to find Howland.

Also see:
gl
..."

I looked at this "FreddieNoonan" site and some of the stuff in it (mainly from another string on Noonan's "errors") -

Wonder how come it's chock-full of the kind of arguments we're seeing here from Gary, but there's no forum there???  Or did I miss something...

I am glad we have a forum here at TIGHAR.

If I could see where anyone else had done a credible job of back-tracking the flight, etc. and come up with something more reasonable than a Niku landing possibility it would be more interesting to follow.  So far, however, TIGHAR is the only outfit I've found that has exhausted the tedious details available to us and come up with anything reasonable.  Sad, but conjecture to the contrary for the sake of trying to tear-down a good theory (which is backed by a growing body of evidence) just doesn't seem worth the read after a point; I only have so much time.

As I think about it, I could start coming up with reasons why we never really went to the moon... and never mind those pictures NASA now has of man's foot trails and trash up there (http://www.cbsnews.com/stories/2011/09/06/scitech/main20102114.shtml).  Gee, if NASA can get pix like that for a few billion bucks, then me thinks the 7 site artifacts are well worth the scrutiny and personal investment on my part - so far it's the best AE trail anyone has found.

And to think that trail turned-up on Niku... what a co-inky-dink  ;D

LTM -

Hi Jeffrey

Couldn't agree more.  You would think that with the money spent by the military in the Pacific alone they would consider a complete water search off Niku as an excellent training exercise if nothing else.

I was born in 1954, only 17 years after AE and FN went missing.  My father had told me about AE when I was very young.  The information of the day was completely flawed and incomplete.  I had no idea AE had a navigator with her until many years later.  In fact I was told, and believed, the crash at sea story and believed it as there was no alternative presented.  A year ago I discovered the TIGHAR site and plowed through many of the research papers and documents.  (Sorry Marty but I have forgotten so many points that I will go back and read them again so I can link properly.)   I believe the Niku theory IS true.  Too much circumstantial evidence to be wrong.  However thats why I suggested with this thread that we think backwards and see if we can bring any new ideas to bear.  Any new leads in finding a smoking gun would help, while Ric and crew find funding for the really hard parts.

Perhaps we should suggest to Google that mapping the land surfaces are done so lets go map the ocean floor.  Perhaps that view would reveal something?
Title: Re: Working the Flight backwards
Post by: Tom Swearengen on September 07, 2011, 02:10:50 PM
mapping the ocean floor is an extremely difficult task. It  isnt like a satelite orbiting above, taking endless pictures. But, oh boy, the possibilities of mapping the ocean, and reefs. Lets have them start----At Niku!
Tom
Title: Re: Working the Flight backwards
Post by: Irvine John Donald on September 07, 2011, 02:15:04 PM
mapping the ocean floor is an extremely difficult task. It  isnt like a satelite orbiting above, taking endless pictures. But, oh boy, the possibilities of mapping the ocean, and reefs. Lets have them start----At Niku!
Tom

Wouldn't they just have a bunch of little one man subs with cameras mounted on them?  :D
Title: Re: Working the Flight backwards
Post by: Mark Petersen on September 07, 2011, 05:34:02 PM
For the future please understand that I have the utmost respect for Ric, yourself, and all the many forum participants who venture to share their thoughts, comments, opinions, experience, anecdotes and ,yes, even the jokes.

Well said and this represents my perspective as well.  The problem with forum posts, email and written correspondence in general is that nuances are lost and it's possible for people to misread the intentions of the writer.  Just to clarify, I don't think that anyone is raising doubts about the Tighar Niku theory.  It is and continues to be the best theory of what happened back in 1937.  When I've asked questions of Ric or others in this thread its not been to cast doubt on what is being said, but rather to learn more about something and in particular to learn why our Tighar members feel the way that they do.  Ric and the other Tighar EPAC members are recognized experts in the Earhart field and have a wealth of knowledge in this area, so it doesn't seem unreasonable that members would frequently ask questions of them.

In fact one of the things that I most like about Tighar is that there is an open forum where people can ask questions.   There is a give and take spirit on this forum whereby members can learn more about the Earhart disappearance.  It should be realized though that these questions, at least in my case, aren't an indictment of what is being said, but truly a desire to learn more.

As far as Tighar funded research goes, I heartily agree that any funds should go where needed.  The beauty of a mathematical model though is that there is no cost involved, only the time of the person who volunteers to construct it.   I don't think that the inputs to the model can hope to be accurate without feedback from the Tighar EPAC group though, therefore I doubt that the results will be accurate if done as a solo effort.  At least that's my current thinking.  If Ric and the other EPAC members don't have the time to devote to it, that's understandable though.

One last point, I seem to have dredged up a sore point by bringing up the Monte Carlo Simulation (actually it was someone else who brought it up, but I was the one who asked questions about it).  My questions about it were based on a desire to learn more about it (engineers brains are wired that way), so again I hope that people don't get the wrong impression about the spirit in which these questions were asked.  It should also be pointed out that working backwards by calculating the probability of 3 key constraints and then determining the intersection between them, as was the topic of this thread, is essentially a simple Monte Carlo Simulation, even if done on pad and pencil.  I thought that the idea was a good one and continue to feel this way.
Title: Re: Working the Flight backwards
Post by: Gary LaPook on September 07, 2011, 05:53:39 PM
﻿There is no reason to think that Noonan had not been able to get celestial fixes.

I disagree.  It is true that at 02:45-48 Bellarts logged, "HEARD EARHART PLANE / BUT UNREADABLE THROUGH STATIC (http://tighar.org/Projects/Earhart/Archives/Research/Bulletins/37_ItascaLogs/pos2page1.pdf)" but that is not the only primary source documentation of what occurred. Associated Press reporter James Carey was in the radio room. His rough notes (http://tighar.org/Publications/TTracks/2007Vol_23/discovery.pdf), taken at the time, and his diary (http://tighar.org/Projects/Earhart/Archives/Documents/Carey_Diary/Careydiary.html) document that he heard Earhart say "sky overcast."

In an article (http://tighar.org/Projects/Earhart/Archives/Documents/Carey_Article/Careyarticle5.htmll) he wrote a few days later, Carey described the scene:

Friday, July 2---“Quiet everybody,” yelled one of the radiomen at 2:48 AM, “I think I’ve contacted the plane.” A pin-drop silence ensued. With my ears to the phones, I could hear the voice of Amelia Earhart, somewhere out in the South Pacific, speaking on the voice phones. “KHAQQ calling Itasca; KHAQQ calling Itasca,” she said and then the static drowned out a part of the message. “Sky overcast,” she continued somewhat audibly, and that was all for the rest of the message was lost in noisy rumblings of static interference.

Why does Carey contradict Bellarts?  Note that Bellarts says the transmission began at 02:45 and ended at 02:48.  Carey's references are all at 02:48.  They're listening on headphones, not a speaker.  I suspect that what happened is that Bellarts heard something over his headphones that convinced him that he was hearing Earhart but he couldn't make out the words. He yelled, "Quiet everybody" as Carey says and then he either passed his headphones to Carey or Carey plugged in another set.  In any event, Carey heard what he heard.  You can choose to believe him or not, but his notes stand as a contemporary primary source document.

Earhart wrote that “Noonan must have star sights” so they would not have just changed their minds about this
requirement.
The “Point of No Return” is a standard calculation done by flight navigators, taking into account
air speed, wind speed and endurance, to determine the point along the planned course at which
the plane could reverse its course and return safely to the departure airport.

If Noonan thought he had a 24 hour endurance, using the 23 knot wind component that he measured in flight then he would have calculated the PNR as 1407 Z at 1511 NM from Lae, just five hours and 710 NM short of Howland.

"Would have" is a guess masquerading as fact. Chater (http://tighar.org/Projects/Earhart/Archives/Documents/Chater_Report.html) reported that at 5:18 pm Lae time, Earhart was heard to say "POSITION 4.33 SOUTH 159.7 EAST HEIGHT 8000 FEET OVER CUMULUS CLOUDS WIND 23 KNOTS."  She did not say whether the wind was a headwind, tailwind or crosswind.  By your own reasoning, if it was a headwind they should have turned back.

It also turns out that there was an airport at Rabaul, 344 NM along the course line to Howland.
Noonan could have calculated a PNR for a departure from Lae with a return to Rabaul. ... So if Noonan had not been able to get fixes they could have turned around and
returned safely to Lae or Rabaul and try again another day.

What evidence do you have to support your claim that there was an airfield at Rabaul in 1937? The Wikipedia page on The Bombing of Rabaul (http://en.wikipedia.org/wiki/Bombing_of_Rabaul_(November_1943)) says there were two "pre-war Australian strips" on Rabaul - Lakunai and Vunakanau - but does not say when they were constructed.  The Wikipedia pages for Lakunai (http://en.wikipedia.org/wiki/Lakunai_Airfield) and Vunakanau (http://en.wikipedia.org/wiki/Vunakanau_Airfield) say they were constructed by the Royal Australian Air Force.  To my knowledge, the RAAF was not building airfields in the region in 1937.

You seem to have gone to great lengths to try to prove that Earhart and Noonan should have reached Howland and shouldn't have reached Gardner, and yet there is abundant evidence that they didn't reach Howland and did reach Gardner.
---------------------------------

I have an unimpeachable source for my statement.

" At quarter to three he [Bellarts] listened for her scheduled broadcast and heard a voice. It was barely discernable against the background noise, but Bellarts was sure he was hearing Earhart. The transmission lasted three minutes, and he could not make out a word of what she was saying. He typed: 'Heard Eahart plane but unreadable thru static' and notified the bridge that first contact had been made.

"Commander Thompson, in his official report, later claimed that at this time 'Bellarts caught Earhart's voice and it came through loudspeaker, very low monotone 'cloudy overcast.' Mr. Carey, Associated Press representative, was present. also Mr. Hanzlik [sic] of United Press, both gentlemen recognized the voice from previous flights to and from Hawaii. There was no question as to hearing Earhart.' Overcast conditions would have prevented Fred Noonan from using star sightings to track the flight's progress. But the ship's radio logs do not support Thompson's allegations. Asked about the discrepancy many years later, Bellarts vehemently denied that he had heard Earhart say 'cloudy, overcast' and explained that, at that time the loudspeaker was not in use: 'That static was something terrific, you know, just crashing in on your ears. And I'll guarantee you that Hanzlick and that other joker never heard that. Oh. I would definitely be on the phones. Absolutely. Not on loudspeaker.'"

- Ric Gillespie, Finding Amelia, page 87.

You can't get any better source than that!

gl
Title: Re: Working the Flight backwards
Post by: Ric Gillespie on September 07, 2011, 08:13:28 PM
You can't get any better source than that!

Sure you can.  When I wrote Finding Amelia, Bellart's log was the only contemporary written source we had from someone who was in the radio room. I was correct in siding against Commander Thompson's later claim that Earhart said "cloudy overcast" because there was no support for it. Finding Amelia was published in September 2006.  We got out first clue to the possible existence of the Carey's notes and diary the very next month but it was February 2007 before we had them in hand.   New documented information changed the picture.

Bellart's recollections many years later may or may not be correct but if he passed the headphones to Carey as I suspect, he may have been absolutely correct in saying he never heard Earhart say that - but Carey's contemporary written notes trump Bellarts memory.
Title: Re: Working the Flight backwards
Post by: Gary LaPook on September 07, 2011, 10:38:24 PM
You can't get any better source than that!

Sure you can.  When I wrote Finding Amelia, Bellart's log was the only contemporary written source we had from someone who was in the radio room. I was correct in siding against Commander Thompson's later claim that Earhart said "cloudy overcast" because there was no support for it. Finding Amelia was published in September 2006.  We got out first clue to the possible existence of the Carey's notes and diary the very next month but it was February 2007 before we had them in hand.   New documented information changed the picture.

Bellart's recollections many years later may or may not be correct but if he passed the headphones to Carey as I suspect, he may have been absolutely correct in saying he never heard Earhart say that - but Carey's contemporary written notes trump Bellarts memory.
----------------------------------------

That's interesting. Not to quibble about this point, but reporting an overcast at the time of a radio broadcast doesn't tell us about the conditions during the rest of the hour. Obviously they were satisfied with the accuracy of the navigation or they could have turned around and returned to Lae at the time of that first report and could have made it back to Rabaul up to the time of the second report as I showed with the point of no return calculation.

But putting those two reports behind us, there is no dispute about the logged report of "partially cloudy" at 1623 Z, conditions that allowed Noonan to get a fix even if he had not been able to get one in the prior two hour period. Based on the normally accepted level of uncertainty for dead reckoning of 10% of the distance flown, from that point to 1912 Z it is very unlikely that their DR position would be more than 47 NM in error. You wrote in an earlier post that Earhart could DR to Gardner with only a 7% uncertainty, which is better than the standard, so would improve the accuracy of the DR position. So using your number, any error in the DR at 1912 Z is very unlikely to exceed 36 NM so they were not going to be far south of Howland, in fact, they would not have ended up south of Baker even with your maximum error, which is unlikely, since you are normally closer to the DR position than near the edge of the possible error band.

These types of navigational errors have been extensively analyzed statistically. The most complete treatment of the statistics of navigational errors is in the American Practical Navigator, commonly known as "Bowditch," U.S. Navy Hydrographic Office Publication number 9 (H.O. 9) which is the standard navigational authority  in the United States and has been since the first edition in 1802.  Appendix Q of the 1977 edition is a 33 page discussion of this topic. There is only one chance in twenty of being outside the 10% DR error band and the probabilities drop off very quickly after that. The chance of being at twice that distance away from the DR position  (94 NM in this case) is only one chance in 15,800 and being three times as far away is only one chance in five hundred and six million, eight hundred thousand, 1/506,800,000!

So based on the science of navigation Noonan would never have gotten so far south of Howland so that it would have made any sense to abandon their efforts to find Howland and instead to fly off to far away Gardner.
gl
Title: Re: Working the Flight backwards
Post by: Gary LaPook on September 08, 2011, 02:41:11 AM
﻿There is no reason to think that Noonan had not been able to get celestial fixes.

I disagree.  It is true that at 02:45-48 Bellarts logged, "HEARD EARHART PLANE / BUT UNREADABLE THROUGH STATIC (http://tighar.org/Projects/Earhart/Archives/Research/Bulletins/37_ItascaLogs/pos2page1.pdf)" but that is not the only primary source documentation of what occurred. Associated Press reporter James Carey was in the radio room. His rough notes (http://tighar.org/Publications/TTracks/2007Vol_23/discovery.pdf), taken at the time, and his diary (http://tighar.org/Projects/Earhart/Archives/Documents/Carey_Diary/Careydiary.html) document that he heard Earhart say "sky overcast."

In an article (http://tighar.org/Projects/Earhart/Archives/Documents/Carey_Article/Careyarticle5.htmll) he wrote a few days later, Carey described the scene:

Friday, July 2---“Quiet everybody,” yelled one of the radiomen at 2:48 AM, “I think I’ve contacted the plane.” A pin-drop silence ensued. With my ears to the phones, I could hear the voice of Amelia Earhart, somewhere out in the South Pacific, speaking on the voice phones. “KHAQQ calling Itasca; KHAQQ calling Itasca,” she said and then the static drowned out a part of the message. “Sky overcast,” she continued somewhat audibly, and that was all for the rest of the message was lost in noisy rumblings of static interference.

Why does Carey contradict Bellarts?  Note that Bellarts says the transmission began at 02:45 and ended at 02:48.  Carey's references are all at 02:48.  They're listening on headphones, not a speaker.  I suspect that what happened is that Bellarts heard something over his headphones that convinced him that he was hearing Earhart but he couldn't make out the words. He yelled, "Quiet everybody" as Carey says and then he either passed his headphones to Carey or Carey plugged in another set.  In any event, Carey heard what he heard.  You can choose to believe him or not, but his notes stand as a contemporary primary source document.

Earhart wrote that “Noonan must have star sights” so they would not have just changed their minds about this
requirement.
The “Point of No Return” is a standard calculation done by flight navigators, taking into account
air speed, wind speed and endurance, to determine the point along the planned course at which
the plane could reverse its course and return safely to the departure airport.

If Noonan thought he had a 24 hour endurance, using the 23 knot wind component that he measured in flight then he would have calculated the PNR as 1407 Z at 1511 NM from Lae, just five hours and 710 NM short of Howland.

"Would have" is a guess masquerading as fact. Chater (http://tighar.org/Projects/Earhart/Archives/Documents/Chater_Report.html) reported that at 5:18 pm Lae time, Earhart was heard to say "POSITION 4.33 SOUTH 159.7 EAST HEIGHT 8000 FEET OVER CUMULUS CLOUDS WIND 23 KNOTS." She did not say whether the wind was a headwind, tailwind or crosswind.  By your own reasoning, if it was a headwind they should have turned back.

It also turns out that there was an airport at Rabaul, 344 NM along the course line to Howland.
Noonan could have calculated a PNR for a departure from Lae with a return to Rabaul. ... So if Noonan had not been able to get fixes they could have turned around and
returned safely to Lae or Rabaul and try again another day.

What evidence do you have to support your claim that there was an airfield at Rabaul in 1937? The Wikipedia page on The Bombing of Rabaul (http://en.wikipedia.org/wiki/Bombing_of_Rabaul_(November_1943)) says there were two "pre-war Australian strips" on Rabaul - Lakunai and Vunakanau - but does not say when they were constructed.  The Wikipedia pages for Lakunai (http://en.wikipedia.org/wiki/Lakunai_Airfield) and Vunakanau (http://en.wikipedia.org/wiki/Vunakanau_Airfield) say they were constructed by the Royal Australian Air Force.  To my knowledge, the RAAF was not building airfields in the region in 1937.

You seem to have gone to great lengths to try to prove that Earhart and Noonan should have reached Howland and shouldn't have reached Gardner, and yet there is abundant evidence that they didn't reach Howland and did reach Gardner.

--------------------------------

gl
Title: Re: Working the Flight backwards
Post by: Gary LaPook on September 08, 2011, 03:38:15 AM
﻿There is no reason to think that Noonan had not been able to get celestial fixes.

I disagree.  It is true that at 02:45-48 Bellarts logged, "HEARD EARHART PLANE / BUT UNREADABLE THROUGH STATIC (http://tighar.org/Projects/Earhart/Archives/Research/Bulletins/37_ItascaLogs/pos2page1.pdf)" but that is not the only primary source documentation of what occurred. Associated Press reporter James Carey was in the radio room. His rough notes (http://tighar.org/Publications/TTracks/2007Vol_23/discovery.pdf), taken at the time, and his diary (http://tighar.org/Projects/Earhart/Archives/Documents/Carey_Diary/Careydiary.html) document that he heard Earhart say "sky overcast."

In an article (http://tighar.org/Projects/Earhart/Archives/Documents/Carey_Article/Careyarticle5.htmll) he wrote a few days later, Carey described the scene:

Friday, July 2---“Quiet everybody,” yelled one of the radiomen at 2:48 AM, “I think I’ve contacted the plane.” A pin-drop silence ensued. With my ears to the phones, I could hear the voice of Amelia Earhart, somewhere out in the South Pacific, speaking on the voice phones. “KHAQQ calling Itasca; KHAQQ calling Itasca,” she said and then the static drowned out a part of the message. “Sky overcast,” she continued somewhat audibly, and that was all for the rest of the message was lost in noisy rumblings of static interference.

Why does Carey contradict Bellarts?  Note that Bellarts says the transmission began at 02:45 and ended at 02:48.  Carey's references are all at 02:48.  They're listening on headphones, not a speaker.  I suspect that what happened is that Bellarts heard something over his headphones that convinced him that he was hearing Earhart but he couldn't make out the words. He yelled, "Quiet everybody" as Carey says and then he either passed his headphones to Carey or Carey plugged in another set.  In any event, Carey heard what he heard.  You can choose to believe him or not, but his notes stand as a contemporary primary source document.

Earhart wrote that “Noonan must have star sights” so they would not have just changed their minds about this
requirement.
The “Point of No Return” is a standard calculation done by flight navigators, taking into account
air speed, wind speed and endurance, to determine the point along the planned course at which
the plane could reverse its course and return safely to the departure airport.

If Noonan thought he had a 24 hour endurance, using the 23 knot wind component that he measured in flight then he would have calculated the PNR as 1407 Z at 1511 NM from Lae, just five hours and 710 NM short of Howland.

"Would have" is a guess masquerading as fact. Chater (http://tighar.org/Projects/Earhart/Archives/Documents/Chater_Report.html) reported that at 5:18 pm Lae time, Earhart was heard to say "POSITION 4.33 SOUTH 159.7 EAST HEIGHT 8000 FEET OVER CUMULUS CLOUDS WIND 23 KNOTS."  She did not say whether the wind was a headwind, tailwind or crosswind.  By your own reasoning, if it was a headwind they should have turned back.

It also turns out that there was an airport at Rabaul, 344 NM along the course line to Howland.
Noonan could have calculated a PNR for a departure from Lae with a return to Rabaul. ... So if Noonan had not been able to get fixes they could have turned around and
returned safely to Lae or Rabaul and try again another day.

What evidence do you have to support your claim that there was an airfield at Rabaul in 1937? The Wikipedia page on The Bombing of Rabaul (http://en.wikipedia.org/wiki/Bombing_of_Rabaul_(November_1943)) says there were two "pre-war Australian strips" on Rabaul - Lakunai and Vunakanau - but does not say when they were constructed.  The Wikipedia pages for Lakunai (http://en.wikipedia.org/wiki/Lakunai_Airfield) and Vunakanau (http://en.wikipedia.org/wiki/Vunakanau_Airfield) say they were constructed by the Royal Australian Air Force.  To my knowledge, the RAAF was not building airfields in the region in 1937.

You seem to have gone to great lengths to try to prove that Earhart and Noonan should have reached Howland and shouldn't have reached Gardner, and yet there is abundant evidence that they didn't reach Howland and did reach Gardner.
----------------------------------------

Don't believe everything you read on Wikipedia.

"After arrival at Rabaul, G-AUAA was fitted with an extra fuel tank, which enabled pilot ‘Pard’ Mustar to fly it to Lae on 31 March 1927 (some 720km, mostly over open sea). On 19 April, it became the first aircraft to land at Wau, the aerodrome for the goldfields (flown by ‘Pard’ Mustar, with a miner, named Taylor, as a passenger, probably to help him find Wau - it was Mustar’s 4th attempt to locate Wau and the flight took 45 minutes)."

http://www.airwaysmuseum.com/DH37%20G-AUAA%20p2.htm

There were three airport at Rabaul in 1937 and the first one was built in 1927. The third airport was Kokopo.

Here is a link to a newspaper article published on June 7, 1937 showing aerial pictures of the volcano at Rabaul and a photo of the plane that took them after it landed in Rabaul.

http://www.montevideomaru.info/Montevideo/images/1937/Plane_L_G.jpg
http://www.montevideomaru.info/Montevideo/images/1937/McNicoll_L_g.jpg

http://www.montevideomaru.info/Montevideo/html/Rabaul_1937.htm

So they could have returned to Rabaul after getting very close to Howland if they had not been satisfied with the accuracy of their navigation.

It also make me wonder why they didn't depart from Rabaul instead of Lae since it was several hours flying time closer to Howland. Rabaul was also the administrative capitol of New Guinea so would have had better services and the permissions she had obtained would have been valid there also.
gl
Title: Re: Working the Flight backwards
Post by: h.a.c. van asten on September 08, 2011, 05:25:10 AM
Rabaul Takua airport is from Oct 1928 with asphalt runway.
Title: Re: Working the Flight backwards
Post by: h.a.c. van asten on September 08, 2011, 05:43:30 AM
R.Conyers Nesbit found that wind from forecast 12 mph SE was actually 25 mph E @ medium altitudes (by which 45 min delay was incurred). [N.Met.Archive , Bracknell , Gr.Br.) . The mean equivalent headwind from 25 mph , 12 mph , 18 mph , 15 mph (last 3 from forecast) over 4 equal 639 mls tracks (to level transitional stages) was 16 mph , 26 kmh , 7 m/s , Bf. 4 .
Title: Re: Working the Flight backwards
Post by: Ric Gillespie on September 08, 2011, 08:11:09 AM
Obviously they were satisfied with the accuracy of the navigation or they could have turned around and returned to Lae at the time of that first report and could have made it back to Rabaul up to the time of the second report as I showed with the point of no return calculation.

Supposition after supposition.  The fact that they didn't turn around tells us nothing other than that they didn't turn around. Earhart planned to find Howland by Radio Direction Finding. How much en route navigational accuracy did Earhart consider necessary for continuing the flight?  I don't know and you don't know. When did Earhart, on any of her long distance flights, ever turn around? On both the Oakland/Honolulu and Brazil/Senegal flights the aircraft was significantly off course for much of the flight.

You have shown that there were airfields on Rabaul in 1937. Okay, good. Did Earhart know about them?  They don't appear on the strip maps that Clarence Williams prepared for her.  There's no reference to Rabaul in any of the pre-flight correspondence.  We don't know what charts Noonan used.

But putting those two reports behind us, there is no dispute about the logged  report of "partially cloudy" at 1623 Z, conditions that allowed Noonan to get a fix even if he had not been able to get one in the prior two hour period.

Supposition.  The log entry says only "HEARD EARHART (PART CLOUDY)."  The "(PART CLOUDY)" is typed over a dashed line and so was apparently added later. You interpret that entry to mean that Noonan could get a fix, but that is pure supposition.

Based on the normally accepted level of uncertainty for dead reckoning of 10% of the distance flown, from that point to 1912 Z it is very unlikely that their DR position would be more than 47 NM in error.

More supposition.

You wrote in an earlier post that Earhart could DR to Gardner with only a 7% uncertainty, which is better than the standard, so would improve the accuracy of the DR position.

I don't recall ever saying that.  I don't know what I would have based it on.

These types of navigational errors have been extensively analyzed statistically.
So based on the science of navigation Noonan would never have gotten so far south of Howland so that it would have made any sense to abandon their efforts to find Howland and instead to fly off to far away Gardner.

Don't confuse statistics with science.  Science relies on evidence and the evidence says they reached Gardner.
Title: Re: Working the Flight backwards
Post by: Gary LaPook on September 08, 2011, 11:49:54 AM
Obviously they were satisfied with the accuracy of the navigation or they could have turned around and returned to Lae at the time of that first report and could have made it back to Rabaul up to the time of the second report as I showed with the point of no return calculation.

Supposition after supposition.  The fact that they didn't turn around tells us nothing other than that they didn't turn around. Earhart planned to find Howland by Radio Direction Finding. How much en route navigational accuracy did Earhart consider necessary for continuing the flight?  I don't know and you don't know. When did Earhart, on any of her long distance flights, ever turn around? On both the Oakland/Honolulu and Brazil/Senegal flights the aircraft was significantly off course for much of the flight.

You have shown that there were airfields on Rabaul in 1937. Okay, good. Did Earhart know about them?  They don't appear on the strip maps that Clarence Williams prepared for her.  There's no reference to Rabaul in any of the pre-flight correspondence.  We don't know what charts Noonan used.

But putting those two reports behind us, there is no dispute about the logged  report of "partially cloudy" at 1623 Z, conditions that allowed Noonan to get a fix even if he had not been able to get one in the prior two hour period.

Supposition.  The log entry says only "HEARD EARHART (PART CLOUDY)."  The "(PART CLOUDY)" is typed over a dashed line and so was apparently added later. You interpret that entry to mean that Noonan could get a fix, but that is pure supposition.

Based on the normally accepted level of uncertainty for dead reckoning of 10% of the distance flown, from that point to 1912 Z it is very unlikely that their DR position would be more than 47 NM in error.

More supposition.

You wrote in an earlier post that Earhart could DR to Gardner with only a 7% uncertainty, which is better than the standard, so would improve the accuracy of the DR position.

I don't recall ever saying that.  I don't know what I would have based it on.

These types of navigational errors have been extensively analyzed statistically.
So based on the science of navigation Noonan would never have gotten so far south of Howland so that it would have made any sense to abandon their efforts to find Howland and instead to fly off to far away Gardner.

Don't confuse statistics with science.  Science relies on evidence and the evidence says they reached Gardner.
-----------------

Sure you did Ric. On August 31st your wrote:

"Amelia Earhart played the same game.  She was no Charles Lindbergh and she hit Ireland about 120 nautical miles off course. So, let's see .... if we use that as a measure of her ability to maintain a DR course (without any help from a navigator) it looks like she's about .07 nm off for every mile she flies by DR.  Worst case: If she DRed the entire distance between Howland and Gardner (about 350 nm) with no help from Noonan she should be off by roughly 24 miles.  That's hardly a scientific assessment but it's an interesting exercise."

".07 nm off for every mile she flies" is a 7% accuracy.

See:
https://tighar.org/smf/index.php/topic,447.0.html

gl
Title: Re: Working the Flight backwards
Post by: Ric Gillespie on September 08, 2011, 12:11:40 PM
Sure you did Ric. On August 31st your wrote:

"Amelia Earhart played the same game.  She was no Charles Lindbergh and she hit Ireland about 120 nautical miles off course. So, let's see .... if we use that as a measure of her ability to maintain a DR course (without any help from a navigator) it looks like she's about .07 nm off for every mile she flies by DR.  Worst case: If she DRed the entire distance between Howland and Gardner (about 350 nm) with no help from Noonan she should be off by roughly 24 miles.  That's hardly a scientific assessment but it's an interesting exercise."

0.07 nm off for each mile she flies is a 7% uncertainty.

For crying out loud  ...  I said it was hardly a scientific assessment but it's an interesting exercise.  You're playing games.  I don't have time for games.
Title: Re: Working the Flight backwards
Post by: h.a.c. van asten on September 08, 2011, 01:16:28 PM
Having not actually turned back , or communicating plans thereof says that the crew was convinced to have their train on the rails to destination .
Title: Re: Working the Flight backwards
Post by: Harry Howe, Jr. on September 08, 2011, 02:09:04 PM

As Ric said "For crying out loud..."
I say... It's not Rocket or Nuclear Science.

They didn't fly  a direct route and arrive near Howland and not know which way to turn (N or S), or keep going East, or turn back West.  They flew an offset to the SSE, arrived at the LOP and knew exactly which way to turn  (NNW) and how far to fly (the length of the offset).  Arriving  at where they expected to see Howland but not spotting it, they continued NNW for some time miles, fuel, pick a number) then turned around ( radio message  "Circling...") and flew SSE,  again not spotting Howland, so they continued SSE in accordance with their Alternate Pplan B, i.e. fly to Gardner.
Title: Re: Working the Flight backwards
Post by: Gary LaPook on September 08, 2011, 02:18:11 PM
Sure you did Ric. On August 31st your wrote:

"Amelia Earhart played the same game.  She was no Charles Lindbergh and she hit Ireland about 120 nautical miles off course. So, let's see .... if we use that as a measure of her ability to maintain a DR course (without any help from a navigator) it looks like she's about .07 nm off for every mile she flies by DR.  Worst case: If she DRed the entire distance between Howland and Gardner (about 350 nm) with no help from Noonan she should be off by roughly 24 miles.  That's hardly a scientific assessment but it's an interesting exercise."

0.07 nm off for each mile she flies is a 7% uncertainty.

For crying out loud  ...  I said it was hardly a scientific assessment but it's an interesting exercise.  You're playing games.  I don't have time for games.
--------------------------------------------------------

This is not a game, just normal navigational analysis. You show that she had been able to come within 7% of her destination on a much longer flight but now, on the much shorter leg from a 1627 Z fix, you claim that she can't DR within 50%, (a seven times larger error) which would have been the necessary error for them to end up closer to Gardner than to Howland. In prior discussions you used this 7% accuracy to claim that she could have easily DRed to Gardner but if she DRed as inaccurately as you are now saying that she did on this short leg then she would have missed Gardner by 175 NM.

If you don't like a 1627 Z fix then go all the way back to the takeoff at Lae. If Earhart and Noonan flew all the way from
Lae to Howland, 2222 NM, inside solid clouds without the opportunity to see any visual landmarks or to take any celestial sights, then it is highly unlikely that they were more than 222.2 NM away from Howland at 1912 Z. (Of course this is not a real scenario since Earhart wrote that "Noonan must have star sights" so they would have turned around if they could not see the stars.)

But wait, we know that they had a fix at 0718 Z near Nikumanu Island and it is only 1480 NM from there to Howland so the expected uncertainty would only be 148 NM if that was the last time they were able to get a fix. And then they saw the Ontario at 1030 Z which was only 1100 NM from Howland making the uncertainty at 1912 Z only 110 NM. Then they passed Nauru at about 1130 Z and it is only 990 NM from there to Howland, the uncertainty became 99 NM. Then they flew over Tabituea which is only 530 NM from Howland, further reducing the dead reckoning uncertainty to only 53 NM. And these numbers are based on using the standard 10% uncertainty, simply multiply these values by 0.7 to find the likely error using Earhart's 7% measurement. For example, using your 7% number for Earhart's DR acuracy they would have come within 155 NM of Howland even if they had to DR all the way from Lae.

So take your pick, normal DR should have brought them much closer to Holwand than to Gardner when they hit the sun line LOP. This is the same kind of analysis any flight navigator, including Noonan, makes and would have convinced Noonan that they were close to Howland so they would not have decided to give up searching for Howland and instead flown off to the far away Gardner.

gl

gl
Title: Re: Working the Flight backwards
Post by: Gary LaPook on September 08, 2011, 02:29:01 PM

As Ric said "For crying out loud..."
I say... It's not Rocket or Nuclear Science.

They didn't fly  a direct route and arrive near Howland and not know which way to turn (N or S), or keep going East, or turn back West.  They flew an offset to the SSE, arrived at the LOP and knew exactly which way to turn  (NNW) and how far to fly (the length of the offset).  Arriving  at where they expected to see Howland but not spotting it, they continued NNW for some time miles, fuel, pick a number) then turned around ( radio message  "Circling...") and flew SSE,  again not spotting Howland, so they continued SSE in accordance with their Alternate Pplan B, i.e. fly to Gardner.
-------------------------
Because of the relationship of the approach course to Howland and the azimuth of the sun line LOP, it was a shorter diversion to intercept to the NNW than to the SSE so that is the way any flight navigator, including Noonan, would have flown the approach, from the NNW. In addition, due to the unique relationship of Baker to Howland, making the approach from the NNW provides additional safety since Baker would act as a backstop, in effect making the offset longer so less likely to be insufficient. Aiming to the SSE looses this advantage.

(Harry, if you don't want to actually draw the diagram then you can figure it out with trig using the law of cosines, but you knew that already.)

and further discussion here:

gl
Title: Re: Working the Flight backwards
Post by: Harry Howe, Jr. on September 08, 2011, 02:59:45 PM

The difference in dstance flown, for the  same length offset, with a SSE offset is slightly shorter than with a NNW offset, but not significantly so. The main advantage of the SSE to NNW approach is that the bright rising sun is at your back not in your face (eyes) when flying the LOP and  when trying to spot that little sliver of land called Howland..  Arriving from the SSE (a SSE offset) Baker would be encountered  some time ( a known time, about 20 minutes or so) before Howland, however it is even smaller than Howland and presumably harder to spot.
Title: Re: Working the Flight backwards
Post by: Harry Howe, Jr. on September 08, 2011, 03:45:57 PM

Gary
Baker as a backstop?  Backstop to what?  It's smaller than Howland,  merely a dimple on the surface of the ocean, and certainly no place to land a plane.  However, if one were to  be rquired to "ditch" the aircraft at sea it would make sense to get as close as possible  to the nearest point of land and hope that the plane's momentum could get its nose against that land.
Title: Re: Working the Flight backwards
Post by: Gary LaPook on September 08, 2011, 03:47:05 PM

The difference in dstance flown, for the  same length offset, with a SSE offset is slightly shorter than with a NNW offset, but not significantly so. The main advantage of the SSE to NNW approach is that the bright rising sun is at your back not in your face (eyes) when flying the LOP and  when trying to spot that little sliver of land called Howland..  Arriving from the SSE (a SSE offset) Baker would be encountered  some time ( a known time, about 20 minutes or so) before Howland, however it is even smaller than Howland and presumably harder to spot.

--------------------------------

I'm sorry Harry, but you just don't seem to get how the offset (landfall) approach is done. As to the first part of your statement is is LONGER if intercepting to the SSE than to the NNW. Perhaps you should get out a piece of paper and  your plotter and draw it out. Make a dot in the center of your paper that represents Howland. Draw a line from that dot at 258° which is the approach course from Lae. Next draw a line extending 157-337° through the Howland dot and extending the same length in both directions.  Now pick any arbitrary point on the 258° approach course and measure the distance from that chosen spot to both ends of the 157-337° LOP line and you will see that it is further to the SSE end than it is to the NNW end.

As to the second part of your statement, approaching the LOP the sun will be almost directly in front of you depending on the offset you have chosen. After you intercept the LOP and turn to follow it, the sun will be on your wingtip since the azimuth to the sun is at right angles to the LOP that you are following. If you intercept to the SSE then the sun will be on the right wingtip. If you intercept to the NNW then the sun will be on the left wing tip. The sun will not be behind you if following the LOP from the SSE.

In addition to the two previous reasons I listed that favored the NNW intercept there are two more. A special, optically flat, window had only been installed on the left side of the aircraft for taking celestial observations so as to minimize any error caused by refraction. Using the normal landfall procedure that Noonan would have been using, you continue to take additional observations of the sun after the interception to ensure accurately tracking the LOP. Putting the sun out on the left wingtip, so that the better celestial viewing window was available, would maximize the accuracy of those critical observations.

The second additional reason to intercept to the NNW is that as the day goes on the azimuth of the sun rotates counter-clockwise which moves the LOP closer to one performing a NNW intercept and further away from one if attempting an intercept to the SSE. So if running late, and low on fuel, the NNW intercept will allow a shorter flight and more of a fuel reserve. You can draw this out on your diagram. If they were running even later, say starting the approach two hours later at 2112 Z, at that time the azimuth of the sun had changed to 058° true making the resulting LOP run 148-328°. Draw in this new LOP and make the same measurements and you will see that is is now a much shorter run into Howland from the NNW than from the SSE.

See:

gl
Title: The broken page
Post by: Gary LaPook on September 08, 2011, 04:02:48 PM

Gary
Baker as a backstop? Backstop to what?  It's smaller than Howland,  merely a dimple on the surface of the ocean, and certainly no place to land a plane.  However, if one were to  be rquired to "ditch" the aircraft at sea it would make sense to get as close as possible  to the nearest point of land and hope that the plane's momentum could get its nose against that land.
-----------------------------

Let's say, for example, that Noonan had figured that his maximum error in his DR, since the last fix, was 60 NM and so then he had aimed 60 NM north- northwest of Howland, Baker then provided an even larger safety margin, they would have to have been more than 98 NM off course to the south at the point of intercepting the LOP to actually pass south of Baker and so turn the wrong way, away from Howland because Baker is 38 NM SSE of Howland. In fact, with 20 NM visibility, they would have had to pass 20 NM south of Baker to miss seeing it, making the safety margin even greater since they would have had to have been more than 118 NM, (almost double Noonan's estimate of maximum DR error in this example) off course to miss seeing Baker. Once you see Baker it is trivial to DR 38 NM to Howland.

gl
Title: Re: The broken page
Post by: Irvine John Donald on September 08, 2011, 05:15:04 PM
Gentlemen...

In tne absence of any information from AE and FN on the events of that trip all we actually know, right now, is that they did not make it to Howland. Period. Full stop.  The Niku theory says they perished on Gardner after landing there and transmitting for a few nights. TIGHAR has spent many years and many dollars trying to prove this theory. Others have spent many years and many dollars to prove their theory and discredit TIGHAR.
We can only "theorize" as to the events of that night. There are so many variables to consider that we sometimes blur the difference between hard evidence and other people's theories.

Ric and others (Marty gets a lot of credit here) really spend a great deal of time trying to keep fact from fiction. This must be a difficult task.  For example... This thread. People keep insisting that the duo coulda, woulda, shoulda DR'd right to Gardner after missing Howland. Some threads even suggest the DR'ing (?) was done from Howland.  How is it possible to suggest this as fact?  If they missed Howland then where were they? How can they DR from a position that must be suspect by FN?  No where does it say they planned to travel to Gardner as plan b. We don't even know if there was a plan b.

The purpose behind this thread was to suggest an alternate methodology to the standard approach in thinking about what "might" have transpired after takeoff from Lae.  And to work backwards from the TIGHAR Niku theory that they ended their journey on Gardner in the hope we might learn something new or stimulate some more thought.

I think we have so much evidence pointing to the Niku theory as being right that we have forgotten the basic fact that they left Lau never to be seen again.
Title: Re: The broken page
Post by: Irvine John Donald on September 08, 2011, 10:40:57 PM
I do have one question I would like to ask Mr. LaPook.  In reading your website it is clear that you disagree with the TIGHAR theory. My question is simple.  What do you believe happened to AE and FN?  I couldn't find that info on your website.
Title: Re: The broken page
Post by: Gary LaPook on September 09, 2011, 12:47:58 AM
Obviously they were satisfied with the accuracy of the navigation or they could have turned around and returned to Lae at the time of that first report and could have made it back to Rabaul up to the time of the second report as I showed with the point of no return calculation.

Supposition after supposition.  The fact that they didn't turn around tells us nothing other than that they didn't turn around. Earhart planned to find Howland by Radio Direction Finding. How much en route navigational accuracy did Earhart consider necessary for continuing the flight?  I don't know and you don't know. When did Earhart, on any of her long distance flights, ever turn around? On both the Oakland/Honolulu and Brazil/Senegal flights the aircraft was significantly off course for much of the flight.

You have shown that there were airfields on Rabaul in 1937. Okay, good. Did Earhart know about them?  They don't appear on the strip maps that Clarence Williams prepared for her.  There's no reference to Rabaul in any of the pre-flight correspondence.  We don't know what charts Noonan used.

But putting those two reports behind us, there is no dispute about the logged  report of "partially cloudy" at 1623 Z, conditions that allowed Noonan to get a fix even if he had not been able to get one in the prior two hour period.

Supposition.  The log entry says only "HEARD EARHART (PART CLOUDY)."  The "(PART CLOUDY)" is typed over a dashed line and so was apparently added later. You interpret that entry to mean that Noonan could get a fix, but that is pure supposition.

Based on the normally accepted level of uncertainty for dead reckoning of 10% of the distance flown, from that point to 1912 Z it is very unlikely that their DR position would be more than 47 NM in error.

More supposition.

You wrote in an earlier post that Earhart could DR to Gardner with only a 7% uncertainty, which is better than the standard, so would improve the accuracy of the DR position.

I don't recall ever saying that.  I don't know what I would have based it on.

These types of navigational errors have been extensively analyzed statistically.
So based on the science of navigation Noonan would never have gotten so far south of Howland so that it would have made any sense to abandon their efforts to find Howland and instead to fly off to far away Gardner.

Don't confuse statistics with science.  Science relies on evidence and the evidence says they reached Gardner.
-----------------------------------------------

So it appears that your position regarding the Rabaul airport is that, if it is not depicted on the Williams chart, then neither Earhart nor Noonan whould know of its existence.

So I take it now, that to be consistent, that you are now also taking the position that neither Earhart nor Noonan knew of the existence of the Phoenix Islands since they are not depicted on the Williams chart either. So we can now agree that they could not have flown down the LOP to those islands since they did not know of their existence.

Agreed!

gl
Title: Re: The broken page
Post by: Ric Gillespie on September 09, 2011, 05:37:49 AM
So it appears that your position regarding the Rabaul airport is that, if it is not depicted on the Williams chart, then neither Earhart nor Noonan whould know of its existence.

So I take it now, that to be consistent, that you are now also taking the position that neither Earhart nor Noonan knew of the existence of the Phoenix Islands since they are not depicted on the Williams chart either. So we can now agree that they could not have flown down the LOP to those islands since they did not know of their existence.

Agreed!

gl

I don't take positions. I follow the evidence.  I don't know whether AE and FN knew about the airfields on Rabaul or not.  All I know is that there seems to be no evidence that they did.  Similarly, I do not know whether AE and FN had a chart that showed the Phoenix Islands but there seems to be abundant archival and physical evidence to suggest that they went there - whether by intention or accident.  As I've said many times, they don't need to be searching for Gardner to get to Gardner.  All they need to do is what AE said they were doing - running on the line north and south.

You are drawing conclusions based on supposition.  You can't do that.   You can't say "He wouldn't have done XYZ so he didn't do it."  By the same token, you can't say (as you did above) that because we have no evidence that someone knew something we can conclude that they didn't know it.

If you want to investigate something you gather facts, form a hypothesis, and then you test it.  You have gathered lots of facts but I can't see that you have formed a hypothesis, let alone attempted to test it - unless your hypothesis is that the airplane did not reach Gardner.  The only way to prove that is to find the airplane someplace else.  Where do you plan to look?
Title: Re: The broken page
Post by: Irvine John Donald on September 09, 2011, 05:58:02 AM
Ric, I am anxiously awaiting an answer from Mr. LaPook on that very question. His site sets out to "debunk" TIGHAR's theory and also has information where he says they couldn't have been on a Japanese spy mission.  It doesn't say what he believes happened to AE and FN. Since he agrees they did not get to Howland and he says its impossible to get to Gardner then I must assume he believes they went into the ocean near Howland.  He says if you are close to your destination standard practice would be to fly a search pattern. He says FN couldn't have been far from Howland so presumably Mr. LaPook is an advocate of the crashed at sea theory.  But I would prefer to hear that from him rather than me putting two and two together by stringing bits and pieces of evidence together and getting it wrong.
Title: Re: The broken page
Post by: h.a.c. van asten on September 09, 2011, 03:30:31 PM
The discussion up to now gives clearence for the conclusion that the sunline flown along was not the line over actual Howland in its (false) coordinates ....
Title: Re: The broken page
Post by: Irvine John Donald on September 09, 2011, 05:20:29 PM
Thanks Jeff for the reply and the links. I will look at each one as I do for the majority of links presented in this forum.

I am a Niku Theory believer. There is, IMHO, enough evidence that I would be really shocked for the outcome to be anything but.  My recent post on reminding people that AE and FN were last seen at Lae was to remind everyone that there is no written diary of events of that fateful flight. There is evidence to support the Niku Theory but this is like a diary with many missing pages.  Painfully slowly however, the pages are being put back together as they are found and validated with facts. I am intrigued by the many directions forum contributors go in as it leads to even more discussion.  Mr. LaPook should be thankful that he can post his dissenting opinion here.  This says a lot for the faith TIGHAR members have in the Niku Theory. But I still think he should share his thoughts on their fate and not just offer "debunking" theories.  Fair is fair.

You're so right Jeff about what will happen if (when) the smoking gun is found.  Many will claim they knew it all along and others will be naysayers. Your comment about how it may be stated that the aircraft crashed at sea and the currents moved it made me laugh out loud until I realized you're probably right. But I'm sure Ric and gang are ready for the onslaught.

Anyway we need to keep thought process and creative ideas flowing. Perhaps one will lead to another and that will help strengthen the theory. More reading this weekend for sure. Thanks again Jeff for the links and your reply.
Title: Re: The broken page
Post by: Harry Howe, Jr. on September 09, 2011, 08:20:00 PM

Jeff
You mentioned an error being discussed.  I don't have a link but I remember it being said that some charts of the area had  the location of Howland mislocated by 5 nm west of its "true" position.  Hence the relative location of Gardner to Howland would have been incorrect and the course connecting them would be more like the line 158/338 rather than 157/337.  Whether the additional error, 5 nm,would have affected the spotting of Gardner or not, who knows.  Nor do we know whether FN had one of those charts or not.  Maybe the charts he flew by are still on the plane.
Title: Re: The broken page
Post by: Gary LaPook on September 10, 2011, 12:29:33 AM
Ric, I am anxiously awaiting an answer from Mr. LaPook on that very question. His site sets out to "debunk" TIGHAR's theory and also has information where he says they couldn't have been on a Japanese spy mission.  It doesn't say what he believes happened to AE and FN. Since he agrees they did not get to Howland and he says its impossible to get to Gardner then I must assume he believes they went into the ocean near Howland.  He says if you are close to your destination standard practice would be to fly a search pattern. He says FN couldn't have been far from Howland so presumably Mr. LaPook is an advocate of the crashed at sea theory. But I would prefer to hear that from him rather than me putting two and two together by stringing bits and pieces of evidence together and getting it wrong.

https://tighar.org/smf/index.php/topic,383.95.html

gl
Title: Re: The broken page
Post by: Martin X. Moleski, SJ on September 10, 2011, 06:23:27 AM
N.B. This post is from Gary LaPook.  It seems to have been the one that was causing some problems with the thread.

Quote from: Harry Howe, Jr. on September 09, 2011, 10:20:00 PM (http://tighar.org/smf/index.php/topic,452.msg5677.html#msg5677)<blockquote>
Jeff
You mentioned an error being discussed.  I don't have a link but I remember it being said that some charts of the area had  the location of Howland mislocated by 5 nm west of its "true" position.  Hence the relative location of Gardner to Howland would have been incorrect and the course connecting them would be more like the line 158/338 rather than 157/337.  Whether the additional error, 5 nm,would have affected the spotting of Gardner or not, who knows.  Nor do we know whether FN had one of those charts or not.  Maybe the charts he flew by are still on the plane.
</blockquote>--------------------------------------------------------------------
This question is always coming up, hopefully this will be the final answer to this question.

Clarence Williams was hired by Earhart to plan the flight legs for her. His planning was for a westbound circumnavigation but he also included information for an eastbound flight. As part of this navigation planning he drew "strip charts" covering the legs and extending a reasonable distance on each side of the planned course line. One of these strip charts covered the leg between Lae and Howland and Mr. Williams completed this chart on February 9, 1937. A copy of this chart is now in the archives of Purdue University. I am attaching a scan of this chart. You will notice near the northeast corner of the chart that the coordinates for Howland that he used for his planning which are 0° 49' north latitude, 176° 43' west longitude.

But this is not the end of the story. Sometime before Earhart departed on her second attempt, Itasca, on its normal resupply cruise, determined more accurate coordinates for Howland and Itasca did this by using the most accurate navigation system available, celestial navigation.  The new coordinates for Howland are 0° 48' north latitude, 176° 38' west longitude. These coordinates were published in navigation manuals starting at least as early as 1938 and possibly in some earlier sources. These are still the coordinates published in official government manuals. Although there is no proof that these more accurate coordinates were communicated to Earhart, it is a reasonable assumption that they were based on the high government support for this flight; building an airport on the island for her use; sending several naval ships, in addition to the Itasca, on two cruises in support of the Earhart flight; Earhart's personal relationship with the White House (she gave flight lessons to Eleanor Roosevelt); and the obvious danger to Earhart if she was not provided with the most up to date coordinates would be apparent to everybody in possession of the new coordinates. The new coordinates are one nautical mile south and five nautical east of the old coordinates.

But if Earhart did not have the updated coordinates, would have made any difference?

Noonan was using the coordinates that he had for doing his celestial calculations. He calculated what the altitude (the height above horizontal) of the sun would be as viewed from those coordinates. The sun's altitude changes constantly as the earth turns during the day so Noonan had to do these calculations for the times that he took observations with his sextant. Most likely he did these calculations in advance, either at Lae or early in the flight, to cover the period that he expected to be approaching Howland, say for the period from 1815 Z (the time that the sun would first be high enough for accurate observations) to 2400 Z. This sounds complicated, but using the tables that he was using, H.O. 208, it would have taken only about one hour for all the calculations to cover this five hour and forty-five minute period. (See: https://sites.google.com/site/fredienoonan/resources/dreisonstock-h-o-208 (https://sites.google.com/site/fredienoonan/resources/dreisonstock-h-o-208) and https://sites.google.com/site/fredienoonan/topics/precomputed-altitude-curves (https://sites.google.com/site/fredienoonan/topics/precomputed-altitude-curves) ) Then, when Noonan took observations of the sun, he simply compared his measured observation atitude with the calculated altitude for the same time at the coordinates for Howland, the difference instantly tells him if he is on the LOP (line of position) that runs through the coordinates or how many miles he must correct to get onto the LOP. One degree difference in the altitudes means a 60 NM space between him and the LOP. A one minute of arc difference (1/60th of a degree) means a one nautical mile difference. If he was using incorrect coordinates then his calculation would show his distance from the LOP running through those incorrect coordinates and not his distance from the correct LOP that actually runs through Howland. Noonan would follow the erroneous LOP to the incorrect coordinates and end up one nautical mile north and five nautical miles west of the corrected coordinates for Howland. So with twenty NM visibility they would have been able to see Howland from there.

But is gets a little more complicated. I have attached a map of Howland with the these two sets of coordinates plotted. You will notice that the newer, more accurate coordinates, are actually located 0.75 NM west of the west shore of Howland. Itasca's navigator had calculated the wrong coordinates (but these are still the published official coordinates) and this 0.75 NM error is most likely due to the Itasca's chronometer running three seconds slow. But is Google Earth more accurate than Itasca's navigator? Yes, I have checked the accuracy of Google Earth in this area, see my prior reply #72 on this thread. So even if Noonan was using the updated coordinates, the LOP that passes through those coordinates would have taken them 0.75 NM west of the island. This also means that the older coordinates are actually a little further from Howland, 6.6 NM straight west from the western shore of Howland. But the LOP did not run straight north and south but at an angle, 157°-337°. So plotting this LOP through to old coordinates shows that it passes just 5.0 NM from the nearest part of Howland and only 4.1 NM from the new coordinates.

So does it make a difference which set of coordinates that Noonan was using? No, they would have seen the island from five nautical miles away. Even allowing for the maximum likely error in a sextant observation of seven NM they would still have passed within 12 NM of the island and should have seen it with the visibility existing at the time. In addition, the smoke trail produced by Itasca blew further west than 12 NM so the plane should have passed directly over the smoke trail even if Nnonan's observation had the maximum likely error at the time.

gl
Title: Re: The broken page
Post by: Gary LaPook on September 10, 2011, 05:38:26 PM
N.B. This post is from Gary LaPook.  It seems to have been the one that was causing some problems with the thread.

Quote from: Harry Howe, Jr. on September 09, 2011, 10:20:00 PM (http://tighar.org/smf/index.php/topic,452.msg5677.html#msg5677)<blockquote>
Jeff
You mentioned an error being discussed.  I don't have a link but I remember it being said that some charts of the area had  the location of Howland mislocated by 5 nm west of its "true" position.  Hence the relative location of Gardner to Howland would have been incorrect and the course connecting them would be more like the line 158/338 rather than 157/337.  Whether the additional error, 5 nm,would have affected the spotting of Gardner or not, who knows.  Nor do we know whether FN had one of those charts or not.  Maybe the charts he flew by are still on the plane.
</blockquote>--------------------------------------------------------------------
This question is always coming up, hopefully this will be the final answer to this question.

Clarence Williams was hired by Earhart to plan the flight legs for her. His planning was for a westbound circumnavigation but he also included information for an eastbound flight. As part of this navigation planning he drew "strip charts" covering the legs and extending a reasonable distance on each side of the planned course line. One of these strip charts covered the leg between Lae and Howland and Mr. Williams completed this chart on February 9, 1937. A copy of this chart is now in the archives of Purdue University. I am attaching a scan of this chart. You will notice near the northeast corner of the chart that the coordinates for Howland that he used for his planning which are 0° 49' north latitude, 176° 43' west longitude.

But this is not the end of the story. Sometime before Earhart departed on her second attempt, Itasca, on its normal resupply cruise, determined more accurate coordinates for Howland and Itasca did this by using the most accurate navigation system available, celestial navigation.  The new coordinates for Howland are 0° 48' north latitude, 176° 38' west longitude. These coordinates were published in navigation manuals starting at least as early as 1938 and possibly in some earlier sources. These are still the coordinates published in official government manuals. Although there is no proof that these more accurate coordinates were communicated to Earhart, it is a reasonable assumption that they were based on the high government support for this flight; building an airport on the island for her use; sending several naval ships, in addition to the Itasca, on two cruises in support of the Earhart flight; Earhart's personal relationship with the White House (she gave flight lessons to Eleanor Roosevelt); and the obvious danger to Earhart if she was not provided with the most up to date coordinates would be apparent to everybody in possession of the new coordinates. The new coordinates are one nautical mile south and five nautical east of the old coordinates.

But if Earhart did not have the updated coordinates, would have made any difference?

Noonan was using the coordinates that he had for doing his celestial calculations. He calculated what the altitude (the height above horizontal) of the sun would be as viewed from those coordinates. The sun's altitude changes constantly as the earth turns during the day so Noonan had to do these calculations for the times that he took observations with his sextant. Most likely he did these calculations in advance, either at Lae or early in the flight, to cover the period that he expected to be approaching Howland, say for the period from 1815 Z (the time that the sun would first be high enough for accurate observations) to 2400 Z. This sounds complicated, but using the tables that he was using, H.O. 208, it would have taken only about one hour for all the calculations to cover this five hour and forty-five minute period. (See: https://sites.google.com/site/fredienoonan/resources/dreisonstock-h-o-208 (https://sites.google.com/site/fredienoonan/resources/dreisonstock-h-o-208) and https://sites.google.com/site/fredienoonan/topics/precomputed-altitude-curves (https://sites.google.com/site/fredienoonan/topics/precomputed-altitude-curves) ) Then, when Noonan took observations of the sun, he simply compared his measured observation atitude with the calculated altitude for the same time at the coordinates for Howland, the difference instantly tells him if he is on the LOP (line of position) that runs through the coordinates or how many miles he must correct to get onto the LOP. One degree difference in the altitudes means a 60 NM space between him and the LOP. A one minute of arc difference (1/60th of a degree) means a one nautical mile difference. If he was using incorrect coordinates then his calculation would show his distance from the LOP running through those incorrect coordinates and not his distance from the correct LOP that actually runs through Howland. Noonan would follow the erroneous LOP to the incorrect coordinates and end up one nautical mile north and five nautical miles west of the corrected coordinates for Howland. So with twenty NM visibility they would have been able to see Howland from there.

But is gets a little more complicated. I have attached a map of Howland with the these two sets of coordinates plotted. You will notice that the newer, more accurate coordinates, are actually located 0.75 NM west of the west shore of Howland. Itasca's navigator had calculated the wrong coordinates (but these are still the published official coordinates) and this 0.75 NM error is most likely due to the Itasca's chronometer running three seconds slow. But is Google Earth more accurate than Itasca's navigator? Yes, I have checked the accuracy of Google Earth in this area, see my prior reply #72 on this thread. So even if Noonan was using the updated coordinates, the LOP that passes through those coordinates would have taken them 0.75 NM west of the island. This also means that the older coordinates are actually a little further from Howland, 6.6 NM straight west from the western shore of Howland. But the LOP did not run straight north and south but at an angle, 157°-337°. So plotting this LOP through to old coordinates shows that it passes just 5.0 NM from the nearest part of Howland and only 4.1 NM from the new coordinates.

So does it make a difference which set of coordinates that Noonan was using? No, they would have seen the island from five nautical miles away. Even allowing for the maximum likely error in a sextant observation of seven NM they would still have passed within 12 NM of the island and should have seen it with the visibility existing at the time. In addition, the smoke trail produced by Itasca blew further west than 12 NM so the plane should have passed directly over the smoke trail even if Noonan's observation had the maximum likely error at the time.

gl

-------------------------------------
Unfortunately I couldn't upload the Williams chart, it caused the site to crash. I have, however, now uploaded it to my site so you can view it here:

I am attaching the chart I created on Google Earth showing the relationship of he Williams coordinates point and the resulting LOP, to Howland and to the newer coordinates.

gl
Title: Re: Working the Flight backwards
Post by: Martin X. Moleski, SJ on September 10, 2011, 07:33:11 PM
Here is the image that caused the system to hang up (for reasons as yet undetermined):

(http://tighar.org/aw/mediawiki/images/8/8b/Williams_Stripchart.jpg)

It's a beautiful chart.
Title: Re: Working the Flight backwards
Post by: Irvine John Donald on September 10, 2011, 08:48:23 PM
Oh oh!  This is a scan of the Howland to Lae strip chart that may have been used by FN.  If it broke the forum, and AE and FN never found Howland with it, then I would say there is definitely something wrong with this chart. LOL!!!
Title: Re: Working the Flight backwards
Post by: h.a.c. van asten on September 11, 2011, 12:45:56 AM
Differences of William´s coordinates with coordinates computed from theory and with calculator are of a few arcmin magnitude , trivial since in the era logarithmic calculations were in use . Remarkable is that about GMT 0720 the communicated fix 159-07-E / 04-33-30 -S  is 8.5 nm south of the latitude as computed for 159-07 from William´s figures . With the coordinates from calculator and formulae the difference is 7.5 nm south . It probably says that mr.Noonan worked out his own plan for the leg since the fix coordinates exactly match for the rhumb line between coordinates of Lae and Gagan on Buka Island .
Title: Re: Working the Flight backwards
Post by: h.a.c. van asten on September 11, 2011, 02:33:40 AM
Not in discussion now , but you recently asked me to provide one air navigation manual handling the sunise-sunrise fixes as in the EJN 2008-2011 treatises which you considered false at these items . Go to Navigator´s Information File , NIF revised October 1944 , approved 2-28-44 , Section 3 , § 7. 2 , where LOP´s and fixes @ sunrise , sunset are described inclusive handling for horizon dip from higher then sea level altitudes . A moderate degree of accuracy is involved in case of relative emergency . Such situation mr. Noonan was in since he incurred 45 minutes delay on the Lae-Nukumanu leg , by which the duration of flight trespassed 18 hrs as a result of which arrival near Howland would be too late for establishing a stars fix .
Title: Re: Working the Flight backwards
Post by: Gary LaPook on September 11, 2011, 04:23:57 AM
Not in discussion now , but you recently asked me to provide one air navigation manual handling the sunise-sunrise fixes as in the EJN 2008-2011 treatises which you considered false at these items . Go to Navigator´s Information File , NIF revised October 1944 , approved 2-28-44 , Section 3 , § 7. 2 , where LOP´s and fixes @ sunrise , sunset are described inclusive handling for horizon dip from higher then sea level altitudes . A moderate degree of accuracy is involved in case of relative emergency . Such situation mr. Noonan was in since he incurred 45 minutes delay on the Lae-Nukumanu leg , by which the duration of flight trespassed 18 hrs as a result of which arrival near Howland would be too late for establishing a stars fix .

-----------------------------------------------------------
see attached
gl
Title: Re: Working the Flight backwards
Post by: Martin X. Moleski, SJ on September 11, 2011, 06:31:53 AM
Oh oh!  This is a scan of the Howland to Lae strip chart that may have been used by FN.  If it broke the forum, and AE and FN never found Howland with it, then I would say there is definitely something wrong with this chart. LOL!!!

The hassles were all worthwhile.

I've never seen a strip chart.

I believe that someone in this documentary (http://www.nzonscreen.com/title/jean-batten---the-garbo-of-the-skies-1988) about Jean Batten mentions how proud she was of doing all of the strip charts she needed for her record-setting flights.  It's clearly not a trivial task!
Title: Re: Working the Flight backwards
Post by: h.a.c. van asten on September 11, 2011, 06:50:36 AM
1. Noonan did not read NIF-1944 , but he had read earlier books , see R.Conyers Nesbit (professional navigator) "Missing Believed Killed" , he says (ex-) sea navigators were cenversant with the sunrise method. 2 . NIF paragraph is not only for LOP , the belonging example derives logitudes . 3 . For altitude correction / dip Noonan had H.O.208 , dip 31´ for 1,000 ft alt. 4 . Agreed , moderate accuracy ; this may have added to reasons why island was not found . 5 . Unobstructed sea horizon .  Article EJN 2008 shows precomputation for the sunrise fix probably planned by Noonan , if he executed the program is second item , but visibility about Howland was good as recorded . 6 . The method described in EJN 2008 is exactly the one as by NIF-1944 , the latter stating the observation with unarmed eye is sufficient , the first assuming a marine sextant preset for dip has been used , be it for the green filter only , anyone can check this by download .

Noonan (as recorded by P.Mantz , see Hollywood Pilot by Dwiggins) let the offset track fly by time-distance DR on the ETA via direct course to destination , that may have been the reason , or an additional feature ,  for breakdown of the attempt .

Title: Re: Working the Flight backwards
Post by: Ric Gillespie on September 11, 2011, 08:34:18 AM
Noonan (as recorded by P.Mantz , see Hollywood Pilot by Dwiggins) let the offset track fly by time-distance DR on the ETA via direct course to destination...

I have no idea what that sentence means.  On page 100 of Hollywood Pilot, Dwiggins relates Mantz's of the flight from Oakland to Honolulu.  With guidance from Manning, Noonan and Mantz, Earhart used the Bendix loop to fly a straight-in course.  "For the first time, AE had a chance to try out the Bendix loop antenna direction finder. Noonan asked her to hold Makapu beacon 'ten degrees on the starboard bow' - a heading of 252 degrees.  She went about it calmly, professionally, rotating the antenna loop on top of the cockpit until the compass needle swung over to 10 degrees - ten degrees to the right of where the electra was pointed.  This, she knew, was a wind drift correction Noonan had figured out."

Dwiggins had that last bit screwed up.  The procedure he describes would be correct if Earhart had an Automatic Direction Finder (ADF) but the read-out for the Bendix RDF was a simple left-right needle.  Dwiggins had a lot of things screwed up.  He has Manning annoying Earhart by coming forward to take star sightings through the hatch above her head. There is no way the cockpit hatch could be opened in flight without it tearing off the airplane.
Title: Re: Working the Flight backwards
Post by: h.a.c. van asten on September 11, 2011, 11:56:41 AM
Mantz interrogated Noonan about the risks of flying to Howland Island . Noonan replied using the One Line Approach (calling it "deliberate error" , the term used by Chichester , 1931) by offset from an on course point , established by an LOP ("from a series of sun observations"), this to be advanced over destination . The offset should be , he said , " e.g. left or right 10 or 20 degrees" and then : "When your time comes turn left or right and fly until you find your  destination" .  Thence , so to see , he (usually ?) planned to fly the offset lane by DR to the turn off point without further celnav . (Hollywood Pilot , 1967 , p. 105) . If he so did in the road of Howland he may have easily hit a line westwards of the over Howland (erroneous position) line , if his offset lane initial point was actually further west than precomputed , having the island on the starboard now @ ETA , in lieu of running it in sight below the Aircraft Progression Line . This does btw not affect the possibility to eventually fly to the Phoenix Group by setting course from a point of the position line by terrestrial triangulation and compass .
Title: Re: Working the Flight backwards
Post by: Ric Gillespie on September 11, 2011, 12:44:48 PM
The offset should be , he said , " e.g. left or right 10 or 20 degrees" and then : "When your time comes turn left or right and fly until you find your  destination" .  Thence , so to see , he (usually ?) planned to fly the offset lane by DR to the turn off point without further celnav . (Hollywood Pilot , 1967 , p. 105)

In my copy of Hollywood Pilot (first edition) the conversation you describe is on page 118-119. According to Dwiggins, according to Mantz's recollection, Noonan did describe the offset method as the way to find your destination "when you only have one star, or only the sun, and you can't get a second line of position to intersect the first on and give you a fix."  That, of course, does not describe the situation Noonan expected to face on the flight to Howland.  The "second line of position to intersect the first one" was expected to be a radio bearing provided either by Itasca or by the aircraft's own radio direction finder.

Let's say, for the sake of argument, that Noonan used an offset to the left (north) just to be safe.  They hit the advanced LOP, turn right and fly until AE says "We must be on you but cannot see you."  An hour later, having still failed to get any help from RDF, she says, "We are on the line 157 337 ... we are running on line north and south."
The whole point of using an offset is to be sure which way you need to fly on the line to reach your destination. If they used an offset why were they flying north and south on the line?
Title: Re: Working the Flight backwards
Post by: h.a.c. van asten on September 11, 2011, 02:01:01 PM
I have the Dwiggins paperback . Assume that about sunrise the latitude error was expected 5% of 300 mls , and the longitude error was expected 7% (both figures for experienced navigator) , then the combined possible error was the square root of the sum of the squares : (25 + 49)^1/2 =  8.6% of 300 mls = 26 mls . The circle of uncertainty @ the position fix has a 26 miles radius . For a northwards offset you should take the southernmost turn off point within visibility range of destination , say 10 miles . Thence , the northernmost turn off point will be (10 mls + 2 x 26 mls) = 62 mls off your island on the position line , to acquire a secure approach operation . If consequently , your latitude @ fix was more than 26 mls northwards w.r.t. your DR , say 40 mls , then you will not see the island @ ETA , and you continue southwards . When no result you turn northwards to look if you were more than 26 mls southwards of DR latitude @ fix , which case you have left the island behind you when turning off . You can continue flying north and south as far as your fuel permits , or , alternatively , 2 evasion operations remain : 1. Fly a search pattern , 2 . Divert to another defined landpoint in your chart , both if fuel permits . If fuel is low : stay one the line so that rescue parties have a first target to find you .
Title: Re: Working the Flight backwards
Post by: Gary LaPook on September 11, 2011, 09:43:53 PM
Noonan (as recorded by P.Mantz , see Hollywood Pilot by Dwiggins) let the offset track fly by time-distance DR on the ETA via direct course to destination...

I have no idea what that sentence means.  On page 100 of Hollywood Pilot, Dwiggins relates Mantz's of the flight from Oakland to Honolulu.  With guidance from Manning, Noonan and Mantz, Earhart used the Bendix loop to fly a straight-in course.  "For the first time, AE had a chance to try out the Bendix loop antenna direction finder. Noonan asked her to hold Makapu beacon 'ten degrees on the starboard bow' - a heading of 252 degrees.  She went about it calmly, professionally, rotating the antenna loop on top of the cockpit until the compass needle swung over to 10 degrees - ten degrees to the right of where the electra was pointed.  This, she knew, was a wind drift correction Noonan had figured out."

Dwiggins had that last bit screwed up.  The procedure he describes would be correct if Earhart had an Automatic Direction Finder (ADF) but the read-out for the Bendix RDF was a simple left-right needle.  Dwiggins had a lot of things screwed up.  He has Manning annoying Earhart by coming forward to take star sightings through the hatch above her head. There is no way the cockpit hatch could be opened in flight without it tearing off the airplane.
---------------------------

Are you sure about that Ric, I thought she had to listen for the null?

I have attached a copy of the 1941 Bendix catalog page that shows pictures of the components of the MN-13 Bendix RDF system, I don't see any left-right needle. It appears that this would have been the system installed in Earhart's plane since it could be used with the already installed radio receiver. There are other RDFs shown in this catalog that do have left- right indicators but those also have dedicated RDF radio receivers with outputs to drive the left-right indicator.

From the picture of Earhart mugging with the RDF loop, is is clear that she had the lower sensitivity nine inch loop, a poor choice for this flight.

I also notice that this RDF had provision for an input from a sense antenna to eliminate the 180 degree ambiguity. It is possible that the belly antenna was this sense antenna.

Hmmm, as I am typing this it just occurred to me that perhaps the loss of the belly sense antenna could have caused AE's RDF problem. The MN-13 has a frequency range up to 1500 kcs but that is probably a limit on the MN-13 loop amplifier but it apparently did work with the 7500 kcs signal but was only able to send a weaker signal to the radio receiver due to that signal being above the designed frequency range of the MN-13 loop amplifier.  Earhart's radio apparently was able to receive the 7500 kcs signal but she couldn't get a null. It is just possible, that although not optimized for 7500 kcs, that this loop might have had enough directivity to have provided a bearing to Itasca. The MN-13 has a switch which selects the sense antenna or leaves it out of the process. With the sense antenna connected and the selector switch set in the uni-directional position, this equipment eliminates the 180 degree ambiguity and produces only one null instead of the usual two nulls, spaced 180 degrees apart.

So what happens if Earhart sets the switch to the uni-directional position but there is no signal coming in on the sense antenna terminal because the antenna was lost? What would Earhart hear in her headphones? No null?  Two nulls? I don't know the answer to this question. I do know, that with an ADF, that without the sense antenna the needle just spins around and around, never settling on a bearing. I wonder now if Earhart could have been saved if only she had placed that switch back into the bi-directional position and used the normal procedure to manually eliminate the 180 degree ambiguity.

Ric, has Brandenburg looked into this?

gl
Title: Re: Working the Flight backwards
Post by: h.a.c. van asten on September 12, 2011, 12:07:40 AM
If the sense aerial is lost the RDF operator  "hears a null" , but ambiguity is not locked out and it can not be determined if the transmitting station is ahead of you , or behind , resp. to port or starboard . In WW II a B24 aircraft (Lady Be Good) ended up 600 mls in the North African Desert by the same failure . Earhart said to hear no null at all which thence must be attributed to other circumstances (transmitter too close , no sharply tuned receiver etc.) .
Title: Re: Working the Flight backwards
Post by: Gary LaPook on September 12, 2011, 01:24:53 AM
Noonan (as recorded by P.Mantz , see Hollywood Pilot by Dwiggins) let the offset track fly by time-distance DR on the ETA via direct course to destination...

I have no idea what that sentence means.  On page 100 of Hollywood Pilot, Dwiggins relates Mantz's of the flight from Oakland to Honolulu.  With guidance from Manning, Noonan and Mantz, Earhart used the Bendix loop to fly a straight-in course.  "For the first time, AE had a chance to try out the Bendix loop antenna direction finder. Noonan asked her to hold Makapu beacon 'ten degrees on the starboard bow' - a heading of 252 degrees.  She went about it calmly, professionally, rotating the antenna loop on top of the cockpit until the compass needle swung over to 10 degrees - ten degrees to the right of where the electra was pointed.  This, she knew, was a wind drift correction Noonan had figured out."

Dwiggins had that last bit screwed up.  The procedure he describes would be correct if Earhart had an Automatic Direction Finder (ADF) but the read-out for the Bendix RDF was a simple left-right needle.  Dwiggins had a lot of things screwed up.  He has Manning annoying Earhart by coming forward to take star sightings through the hatch above her head. There is no way the cockpit hatch could be opened in flight without it tearing off the airplane.

----------------------------------

Certainly one, and possibly three sextant observation were taken from the cockpit, if not through the hatch then through the windshield. The relative bearings of these shots were 320° (40° left of the nose, 341° (19° left of the nose,) and 36° right of the nose. These relative bearing are based on the azimuth of the stars shot and the track on the plane. They may very a  bit based on any wind correction angle being used.  The 341° relative bearing observation certainly was taken from the cockpit and the other two would have been easier from the cockpit than from the nav station aft.

I have attached a table showing the bearings of the fourteen celestial observations taken on the flight to Hawaii.

gl
Title: Re: Working the Flight backwards
Post by: Gary LaPook on September 12, 2011, 01:53:10 AM
The offset should be , he said , " e.g. left or right 10 or 20 degrees" and then : "When your time comes turn left or right and fly until you find your  destination" .  Thence , so to see , he (usually ?) planned to fly the offset lane by DR to the turn off point without further celnav . (Hollywood Pilot , 1967 , p. 105)

In my copy of Hollywood Pilot (first edition) the conversation you describe is on page 118-119. According to Dwiggins, according to Mantz's recollection, Noonan did describe the offset method as the way to find your destination "when you only have one star, or only the sun, and you can't get a second line of position to intersect the first on and give you a fix."  That, of course, does not describe the situation Noonan expected to face on the flight to Howland.  The "second line of position to intersect the first one" was expected to be a radio bearing provided either by Itasca or by the aircraft's own radio direction finder.

Let's say, for the sake of argument, that Noonan used an offset to the left (north) just to be safe.  They hit the advanced LOP, turn right and fly until AE says "We must be on you but cannot see you."  An hour later, having still failed to get any help from RDF, she says, "We are on the line 157 337 ... we are running on line north and south."
The whole point of using an offset is to be sure which way you need to fly on the line to reach your destination. If they used an offset why were they flying north and south on the line?

------------------------

Here are two links to illustrations of how celnav is actually done in fight. The first one ilustrates the landfall (offset) procedure and the second general in flight celnav also showing how wind is determined between two fixes.

gl
Title: Re: Working the Flight backwards
Post by: h.a.c. van asten on September 12, 2011, 02:41:40 AM
You can not , btw , eliminate the ambiguity by manual intervention , that was why the B 24 went astray , the navigator made the wrong guess having his air base behind him north  instead of ahead south . The sense aerial together with the loop quenches signals from one direction by the interferention of two different electromagnetic field graphs .
Title: Re: Working the Flight backwards
Post by: Ric Gillespie on September 12, 2011, 08:01:10 AM
Are you sure about that Ric, I thought she had to listen for the null?

Yes, she had to listen for the null.  That's what she meant when she said "unable to get a minimum."

I have attached a copy of the 1941 Bendix catalog page that shows pictures of the components of the MN-13 Bendix RDF system, I don't see any left-right needle.

In the "Radio" section of the August 1937 issue of Aero Digest magazine - "Newest Developments in the Field of Aircraft Radio" - is an article entitled "Bendix D-Fs." I'll send you a PDF.  The article begins, " Proven in several years of service in military aeronautics, Bendix aircraft radio direction finders have recently been made available commercially, in four models - MN-1, MN-3, MN-5 and MN-7."  Earhart's appears to have been an MN-5.
Unfortunately, there is no known photo of the instrument panel at the time of the second world flight attempt.  In The Miami Cockpit Photo (http://tighar.org/Projects/Earhart/Archives/Research/Bulletins/53_MiamiPhoto/53_MiamiPhoto.htm) I showed that the photo Elgen Long claimed was taken in Miami - wasn't.  It was probably taken in Burbank early in February or March 1937. There was a Bendix left-right needle on the panel at that time (immediately in front of the pilot and directly over the turn & bank).

I also notice that this RDF had provision for an input from a sense antenna to eliminate the 180 degree ambiguity. It is possible that the belly antenna was this sense antenna.

This dead horse has been flogged a hundred times. The starboard side belly antenna was on the airplane when it was delivered in July 1936 - long before it had any kind of direction finding system.  When the Hooven Radio Compass was installed in October 1936 a parallel second belly antenna appeared on the port side - almost certainly a sense antenna for the Hooven unit.  When the Bendix MN-5 replaced the Hooven Radio Compass immediately prior to the first world flight attempt, the port side belly antenna remained in place -possibly as a sense antenna for the new Bendix unit.  After the airplane was repaired following the Luke Field accident it had only the original starboard side antenna.

Title: Re: Working the Flight backwards
Post by: Bob Brandenburg on September 12, 2011, 09:11:38 AM
LF/MF loop systems don't do well with skywave HF signals, which can have a high degree of horizontal polarization.

As for directional ambiguity, that would be an issue only if the navigator didn't know the general direction of the signal source.  That would  not have been the case on the approach to Howland from the west -- before hitting the LOP.   Howland was somewhere forward of the aircraft.

Bob

Title: Re: Working the Flight backwards
Post by: Gary LaPook on September 12, 2011, 02:49:23 PM
LF/MF loop systems don't do well with skywave HF signals, which can have a high degree of horizontal polarization.

As for directional ambiguity, that would be an issue only if the navigator didn't know the general direction of the signal source.  That would  not have been the case on the approach to Howland from the west -- before hitting the LOP.   Howland was somewhere forward of the aircraft.

Bob
----------------------
Ric sent me that magazine article and it makes very interesting reading. To use the uni-directional feature the pilot must tune the loop amplifier in such a way that the loop output is equal to the sense antenna output which might be a complication beyond Earhart's abilities, Manning did this tuning for her on the approach to Hawaii. It is also possible, that because the 7500 kcs was so much higher than the design frequency band for the loop amplifier, than it would not even have been possible to equalize the two signals.

So Bob, my question is, what would she have heard in her earphones if she had the RDF set to uni-directional and :
1) she had not been able to equalize the two signals; 2) if the sense antenna was inoperative due to some damage or due to not being installed (any idea where the sense antenna is on the plane? I originally assumed that there was no sense antenna since they are not needed with a manual RDF.)

Same question if she switched it to bi-directional?  No signal received? we know this isn't the case since she reported receiving the signal. Equal signal all around the dial? one null? two nulls? one strong null and one weak null?

Any ideas?

gl

If she had the RDF set to uni-directional

-
Title: Re: Working the Flight backwards
Post by: Bob Brandenburg on September 12, 2011, 03:33:14 PM
If she was hearing 7500, which would be a skywave signal, the horizontal polarization component of the downcoming field could dominate, preventing her from getting a null.   She could hear the signal regardless of what sense mode she selected, but would be unable to get a null.  There's a reason why loop direction finder bands were in the low- and medium-frequency regions  -- signals there are vertically polarized, and tend to be that way when received within groundwave range.

Another possibility is that the signal duration was too short for her to get a null.

Bob

Title: Re: Working the Flight backwards
Post by: Gary LaPook on September 15, 2011, 12:35:11 AM
If she was hearing 7500, which would be a skywave signal, the horizontal polarization component of the downcoming field could dominate, preventing her from getting a null.   She could hear the signal regardless of what sense mode she selected, but would be unable to get a null.  There's a reason why loop direction finder bands were in the low- and medium-frequency regions  -- signals there are vertically polarized, and tend to be that way when received within groundwave range.

Another possibility is that the signal duration was too short for her to get a null.

Bob
------------------------------
Hooven criticizes the Bendix equipment and claims that Earhart was lost because of the 180 degree ambiguity. Either he didn't realize that the Bendix equipment incorporated a sense antenna or he knew, that even though the Bendix could be equipped with a sense antenna, that this particular installation didn't.

Did the plane have a sense antenna installed for the RDF?

gl
Title: Re: Working the Flight backwards
Post by: Ric Gillespie on September 15, 2011, 07:56:52 AM
Did the plane have a sense antenna installed for the RDF?

There was only one belly antenna on the airplane during the second world flight attempt and it looks like the same antenna that had been on the airplane since it was delivered in 1936 - so no, I don't think there was a sense antenna for the RDF at the time of the Lae/Howland flight.
Title: Re: Working the Flight backwards
Post by: Gary LaPook on September 15, 2011, 04:09:57 PM
If she was hearing 7500, which would be a skywave signal, the horizontal polarization component of the downcoming field could dominate, preventing her from getting a null.   She could hear the signal regardless of what sense mode she selected, but would be unable to get a null.  There's a reason why loop direction finder bands were in the low- and medium-frequency regions  -- signals there are vertically polarized, and tend to be that way when received within groundwave range.

Another possibility is that the signal duration was too short for her to get a null.

Bob

------------------------

Ric points out that there was no sense antenna on the plane. Bob, assume that she was within the 40 NM circle where you said she could get ground wave reception, my question is, what would she have heard in her earphones if she had the RDF set to uni-directional and  same question if she switched it to bi-directional?  No signal received?, equal signal all around the dial? one null? two nulls? one strong null and one weak null?

Any ideas?

gl
Title: Re: Working the Flight backwards
Post by: Ric Gillespie on September 26, 2011, 09:04:50 AM
The latest propagation analysis for the best chance of Itasca hearing a "Strength 5" signal from NR16020 on 3105 kHz puts the airplane a whole lot farther away than 5 or 40 miles.  At 40 nautical miles there was a 1% chance.  At 60 nm there was a 5% chance.  At 80 nm a 10% chance.  Itasca had the best chance (50%) of hearing a Strength 5 signal if the airplane was between about 150 and 260 nautical miles away.
Title: Re: Working the Flight backwards
Post by: Gary LaPook on September 27, 2011, 01:50:20 AM
The latest propagation analysis for the best chance of Itasca hearing a "Strength 5" signal from NR16020 on 3105 kHz puts the airplane a whole lot farther away than 5 or 40 miles.  At 40 nautical miles there was a 1% chance.  At 60 nm there was a 5% chance.  At 80 nm a 10% chance.  Itasca had the best chance (50%) of hearing a Strength 5 signal if the airplane was between about 150 and 260 nautical miles away.
---------------------------------
Ric,
Bob wrote on the "3105 donut" thread:

"It's possible that there was direct path propagation at short distances, due to excitation of the airframe, but ICEPAC only calculates path loss for an ionospheric path.   However, at 1,000 feet altitude (where Earhart said she was flying then), the horizon distance is about 38 miles.  So outside about 40  miles, there wouldn't be any direct path, and skywave would govern. "

So I was asking him about the operation of the RDF within the 40 miles that he said was possible with the direct wave, a signal that would be much stronger than the "near vertical incidence" skywave signals that create the donut. Those sky waves that create the donut travel at least 400 miles and suffer path losses one hundred times greater, 20 db, than the direct wave traveling only 40 miles. Plus, the signal strength of the signal emitted horizontally was much stronger, about 9 db, than at the takeoff angle of the skywaves that form the donut, according to Varney, so the direct signals would be about 29 db stronger than the skywaves in the donut so should have been easily received.

So I am still curious what Bob thinks would be heard on the RDF.

gl

Title: Re: Working the Flight backwards
Post by: Bob Brandenburg on September 27, 2011, 08:46:20 AM
Gary,

In the scenario you describe, who is listening to what on which RDF?

Bob
Title: Re: Working the Flight backwards
Post by: Gary LaPook on September 27, 2011, 09:16:42 AM
Gary,

In the scenario you describe, who is listening to what on which RDF?

Bob
--------------------------

Earhart is listening on her RDF for the 7500 signal from Itasca.

gl