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### AuthorTopic: Working the Flight backwards  (Read 172700 times)

#### Irvine John Donald

• T5
• Posts: 597
##### Working the Flight backwards
« 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!
Respectfully Submitted;

Irv

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#### Ric Gillespie

• Executive Director
• Posts: 6101
• "Do not try. Do or do not. There is no try" Yoda
##### Re: Working the Flight backwards
« Reply #1 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," 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.
« Last Edit: September 04, 2011, 09:38:06 AM by Martin X. Moleski, SJ »
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#### Ric Gillespie

• Executive Director
• Posts: 6101
• "Do not try. Do or do not. There is no try" Yoda
##### Re: Working the Flight backwards
« Reply #2 on: September 04, 2011, 08:58:43 AM »

Forgot to provide a link to Last Words.
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#### Martin X. Moleski, SJ

• Posts: 3006
##### Re: Working the Flight backwards
« Reply #3 on: September 04, 2011, 09:50:34 AM »

Forgot to provide a link to Last Words.

Any member of the Forum (including idiots like Gillespie ) may modify their own posts 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.
LTM,

Marty
TIGHAR #2359A

« Last Edit: September 04, 2011, 11:20:44 AM by Ric Gillespie »
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#### h.a.c. van asten

• T4
• Posts: 322
##### Re: Working the Flight backwards
« Reply #4 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 .

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#### Irvine John Donald

• T5
• Posts: 597
##### Re: Working the Flight backwards
« Reply #5 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.
Respectfully Submitted;

Irv

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#### h.a.c. van asten

• T4
• Posts: 322
##### Re: Working the Flight backwards
« Reply #6 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 .
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#### h.a.c. van asten

• T4
• Posts: 322
##### Re: Working the Flight backwards
« Reply #7 on: September 05, 2011, 01:03:17 AM »

Oops , @ 10,000 ft the air density is 27% lower ...
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#### Tom Swearengen

• T5
• Posts: 818
• earhart monument, Hawaii
##### Re: Working the Flight backwards
« Reply #8 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??
Tom Swearengen TIGHAR # 3297

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#### h.a.c. van asten

• T4
• Posts: 322
##### Re: Working the Flight backwards
« Reply #9 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 .
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#### Harry Howe, Jr.

• T5
• Posts: 576
• Nuclear Physicist(Ret) Pilot(Ret) Scuba(Ret)
##### Re: Working the Flight backwards
« Reply #10 on: September 05, 2011, 09:21:29 PM »

By Jove, I believe we have made a believer out of Mr, Van Esten.  Welcome Friend.
No Worries Mates
LTM   Harry (TIGHAR #3244R)

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#### Harry Howe, Jr.

• T5
• Posts: 576
• Nuclear Physicist(Ret) Pilot(Ret) Scuba(Ret)
##### Re: Working the Flight backwards
« Reply #11 on: September 05, 2011, 09:24:06 PM »

Mr. Van Easten (sp) sorry friend.
No Worries Mates
LTM   Harry (TIGHAR #3244R)

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#### Irvine John Donald

• T5
• Posts: 597
##### Re: Working the Flight backwards
« Reply #12 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.
Respectfully Submitted;

Irv

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#### h.a.c. van asten

• T4
• Posts: 322
##### Re: Working the Flight backwards
« Reply #13 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 .
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#### Tom Swearengen

• T5
• Posts: 818
• earhart monument, Hawaii
##### Re: Working the Flight backwards
« Reply #14 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.
Tom Swearengen TIGHAR # 3297

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