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Author Topic: The flight plan, magnetic course, headwinds.  (Read 453126 times)

Irvine John Donald

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Re: The flight plan, magnetic course, headwinds.
« Reply #285 on: January 31, 2012, 07:42:18 PM »

Jeff H. Please tell me there would be more!  LOL!
Respectfully Submitted;

Irv
 
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Gary LaPook

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Re: The flight plan, magnetic course, headwinds.
« Reply #286 on: February 01, 2012, 12:44:37 AM »



The closest we humans can probably get to that is something like the Monte Carlo analysis.  Maybe that's what Gary has in mind.  He didn't agree with much of the assumption used in the well-known one done for TIGHAR so maybe he'll do his own with inputs that suit his beliefs better.



LTM -
After examining the diagram, I now agree with TIGHAR, the Monte Carlo simulation produces the most accurate estimate of the position of the aircraft at 1912 Z. Of course this means that they couldn't have landed on Gardner.  ....

gl

Is this then your theory on what happened to AE and FN?  "Of course this means that they couldn't have landed on Gardner.".  Why " of course"? There are many possibilities as to what happened.
I should have added "by using dead reckoning as Ric agrees was the only method they had to navigate to Gardner" making the complete statement: "Of course this means that they couldn't have landed on Gardner by using dead reckoning as Ric agrees was the only method they had to navigate to Gardner"


Ric said, "Unfortunately, Gary has a gross misunderstanding of TIGHAR's hypothesis.  We are not suggesting that Earhart or Noonan navigated down the line using celestial navigation to stay on course.  As Gary points out, again and again, there is no way to do that.  It is TIGHAR's hypothesis that, upon reaching the LOP calculated to fall through Howland Island, and not seeing Howland Island, AE and FN turned and flew first northwestward, then southeastward along the line by means of the the only navigation method available to to them at that time - dead reckoning.   As Lindbergh once said, "The only thing wrong with dead reckoning is the name."  He used it to cross 1,700 miles of trackless ocean from St. John's Newfoundland and hit Dingle Bay, Ireland on the button.  To suggest that a navigator of Noonan's caliber could not dead reckon a few hundred miles - perhaps as few as 150 miles - with decent accuracy is, frankly, nonsense."

Rics idea is premised on the plane starting from a position somewhere on the 157° -  337° LOP that ran trough Howland, and from such a starting position he might be right. But if WOULD NOT HAVE WORKED FROM ANY OTHER STARTING POSITION, such as the position predicted by the Monte Carlo simulation. If you don't know where you are starting from then you can't navigate by dead reckoning, see "What is dead reckoning"? Noonan would have had no reason to believe he was starting from the Monte Carlo position so could not have plotted a course to take them to Gardner from there and just flying a heading to maintain the 157° course line would not take them to Gardner, they would fly parallel to the LOP with a minimum of a 55 SM offset to the west as I showed in my prior post and attached diagram.



gl
« Last Edit: February 01, 2012, 12:50:08 AM by Gary LaPook »
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Gary LaPook

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Re: The flight plan, magnetic course, headwinds.
« Reply #287 on: February 01, 2012, 01:00:38 AM »


I respect Gary's knowledge … all the calculations can only carry you so far in figuring out what happened to the flight. ...discard the ones that don't work...

The closest we humans can probably get … the Monte Carlo analysis.  Maybe that's what Gary has in mind.  He didn't agree with much of the assumption used in the well-known one done for TIGHAR so maybe he'll do his own …

LTM -
I have finally been able to decipher the Monte Carlo simulation printout, ... "H" and the "B" in the two squares representing Howland and Baker. Based on the spacing of these two squares and the fact that these islands are about 36 NM apart makes it clear that each square represents 6 NM, ...

… I now agree with TIGHAR, the Monte Carlo simulation produces the most accurate estimate of the position of the aircraft at 1912 Z. Of course this means that they couldn't have landed on Gardner. ...I drew the 157° line through Howland that goes to Gardner but the simulation shows that they were unlikely to be closer than at a 55 SM offset from there with a higher probability …more than at a 100 SM offset. ... … very difficult for them to see the island.

gl


Then nothing from AE for another 43 minutes, despite numerous attempts by Itasca to raise her, this at 2013Z -

" TIMEBZ: 2013
LITERAL: KHAQQ TO ITASCA WE ARE ON THE LINE 157 337 WL REPT MSG WE WILL REPT THIS ON 6210 KCS WAIT,
3105/A3 S5 (?/KHAQQ XMISION WE ARE RUNNING ON N ES S LINE
TRANSLATION: EARHART TO ITASCA: WE ARE ON THE LINE 157 337. WE WILL REPEAT THIS MESSAGE WE WILL REPEAT
THIS ON 6210 KCS; WAIT; SIGNALS HEARD ON 3105 KHZ WITH VOICE AND SIGNAL STRENGTH 5…  SOURCE: BELLARTS RECORD NO.: 851"


Besides, who else left all that stuff on Gardner?

LTM -

WE ARE RUNNING ON N ES S LINE or WE ARE RUNNING ON LINE N ES S sounds a whole lot more like a description of some sort of a search pattern than a statement that they are flying to the Phoenix Islands.
gl
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Heath Smith

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Re: The flight plan, magnetic course, headwinds.
« Reply #288 on: February 01, 2012, 03:36:06 AM »

The problem that I have with the theory that they took a shot at the Phoenix Islands is that they would have had a heading more like 135 rather than 157, aiming for the center of the 5 islands. Even if you did not know exactly where you were around Howland, the islands would have created a 130 mile wide (not including visibility ranges) target that would be difficult to miss.

If you did want to reach the closest possible island while climbing for maximum visibility, you would probably go for McKean. That would be a risky target if you had no idea where you were. Your chances were not much better than sticking around Howland to find Howland or Baker.

Quote
If FN was able to gain a more reliable position as the sun rose higher in that last 43 minutes to an hour of searching, then the direction of the search might logically have been improved – eastward.  I believe that is likely, and that placement well could have improved toward the east by the time of the 2013Z call ('on the line') – and therefore closer to the LOP we think of as through Howland / Gardner vicinity.

If not, then we could well be stuck with a discouraging westward placement, as Gary suggests.

Other than the MC simulation, the logic behind we do not have access to, what evidence is there of falling short of Howland? Is there any? So far I have yet to see any compelling evidence that this is the case.
« Last Edit: February 01, 2012, 03:53:32 AM by Heath Smith »
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Irvine John Donald

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Re: The flight plan, magnetic course, headwinds.
« Reply #289 on: February 01, 2012, 06:34:57 AM »

Heath, I agree with you that there is no evidence to suggest they did not know where they were at all times. When AE said "We must be on you" I'm sure that AE and FN had consulted before she made that radio call. I believe they just didn't see Howland or did see it and didn't recognize it for what it was. They then spent some time searching then headed for the Phoenix islands. Not specifically for Gardner.  If you do a search pattern then FN would have been talking with AE and noting the various course changes. As Jeff N so slearly writes, "never stop navigating.". When the decision to head south was made then FN would have continued to dead reckon and headed to the Phoenix group. Where that turn point would be is unknown. Perhaps once they spotted an island in this group and confirmed their dead reckoning position they then discussed what to do next. For all we know they chose Gardiner for its size and lush vegetation as well as reef edge landing strip so as not to lose the valuable Electra in a ditching.  And Gary....If you don't think they landed at Gardner then what happened? Crashed and sank or landed somewhere else?  That's the only choices available. I really don't think you subscribe to the alien abduction thing. But I shouldn't guess for you.
Respectfully Submitted;

Irv
 
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John Ousterhout

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Re: The flight plan, magnetic course, headwinds.
« Reply #290 on: February 01, 2012, 08:17:08 AM »

If you can’t find Howland, and aren’t sure where you are, then you can’t “dead reckon” to the Phoenix group.  If you know where you are with enough accuracy to be certain you’re near Howland, then why fly 300 miles (short of gas) towards the Phoenix group, when you know there’s a landing strip and ship and radios and people to help you nearby?  Why wouldn’t you keep searching for Howland?  That’s the argument against landing on Gardner.
Radio transmissions after they must have stopped flying indicate they were on land.  That’s the argument against splash and sank.
Reconcile those conclusions for me, and I’ll tell you what I think happened.  There is no requirement for me or Gary or anyone else to say “what I believe”.  What’s wrong with “I don’t know”?  The facts will hopefully tell us the eventual story of what happened, but they take a long time to find and sort out and verify, and we just don't have enough facts to draw a conclusion yet.
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JohnO
 
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JNev

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Re: The flight plan, magnetic course, headwinds.
« Reply #291 on: February 01, 2012, 08:40:21 AM »


WE ARE RUNNING ON N ES S LINE or WE ARE RUNNING ON LINE N ES S sounds a whole lot more like a description of some sort of a search pattern than a statement that they are flying to the Phoenix Islands.
gl

I agree, Gary.  In fact, I believe that flying a LOP is by definition part of a search pattern.  The only question I have is 'what part of the search pattern was it?'

AE's last call suggests to me, because it came at the end of an hour's effort of what was logically a searching effort, a description of the last line being run, so to speak, in the box or in whatever pattern they were using.  That's of course just an impression - I can't know for certain that they did not continue a pattern - unless it is proven that NR16020 did arrive at Gardner some day.  But at some point, with dwindling fuel in a land plane, you should consider whether to cut and run for land if you don't find your island.  The Phoenix group was the next best choice. 

The call's description also suggest to me that they had either arrived at, or returned to, what they believed was a line of position that should have passed through Howland, established at some point by a sun observation and then kept later by pilotage.  Of course which way they were running at that time we do not know - and I agree - AE did not say anything about bugging out for the Phoenix group, etc. at that time.  Of course NR16020 went mute again right after that last call for whatever reason - similar to the preceding 43 minutes.

I realize the LOP may have actually been offset in error without FN realizing it (I guess that's obvious) - and how that could wreck the plan.  But my own understanding from all this is fairly simple:

- IF NR16020 DID make it to Gardner, she would have had to have been flying on or close to a line of 157 - 337 - and would have had to do so by flying down to the SE on that line (by pilotage, once the LOP had been established by observation previously)
- IF the MC IS 'correct' and the flight WAS placed to the SW at 1912Z as it indicates, then FN would have had to eventually find his way further east by more observations
- Coming finally to what he believed was 'THE' line of position through Howland (at least by 2013Z), the flight proceeded north by some distance (but not far enough to reach Baker or Howland), thence, not finding the island(s), finally continued SE hoping for landfall among the Phoenix group.

From this you can see there is a 'N-S challenge' bias in my thinking:
- The LOP seems elementary enough for FN as the sun rose higher - (I don't think sunrise was a reliable time for the shot but correct me if I'm wrong);
- WHICH WAY to proceed along the line and HOW FAR seem to issues to me - hence the bias: for whatever reason I am struggling with how FN might have been able to bound himself as to north and south; I believe this may have been crucial - but correct me if I'm wrong in this belief.

This is the picture I have been able to gain.  Among that, again, is that I agree that a search pattern was very likely flown in that hour or so of effort prior to the 2013Z call - it was a given tool in FN's box.  I also agree that flying the LOP as stated was at least a part of that search pattern effort.  The 'cut and run' part at the end is still a mystery - but I believe Gardner is indicated as a very possible outcome for reasons I've stated. 

Thanks for your response above and for considering my thoughts on this.

LTM -
- Jeff Neville

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Irvine John Donald

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Re: The flight plan, magnetic course, headwinds.
« Reply #292 on: February 01, 2012, 09:06:21 AM »

Okay John.  Good points

"we must be on you" suggests they believe they are on very near Howland and they think Howland should be visible from where they are sending the message.  FN isnt a total loss as a navigator so FN likely realizes that they missed Howland "for whatever reason" but couldn't have missed it by a lot (insert MC simulation info here).  He therefore really doesnt know his exact position because he thought he knew he was in sight of Howland and wasn't so he is probably puzzled how he could miss but he did.  I believe they would have done some form of searching for Howland but keeping in mind the limit on their fuel and the known group of islands to the south.  FN likely did the calculation and told AE they had XX minutes to search for Howland before heading south to other known land.  Self preservation would likely be a strong feeling about now.  They would be calm as they searched and become more anxious as time passed and no Howland in sight.  But they wouldnt keep flying in a search pattern until gas runs out.  Why would they when they can go south to the Phoenix group.  Once FN realized they missed Howland he likely spent at least a few minutes reviewing his sightings and navigation from Lae to find his mistake, if there was one.  If there was he would have told AE and recalculated as best he could and given her a new course to head for Howland. 

Gary is a great resource but is trying in every way he can to show the TIGHAR hypothesis doesn't work.  He can try attacking it 18 ways from Sunday because TIGHAR posts its research, evidence, findings, etc for all to see.  Perhaps for Gary to move from "I don't know" to "perhaps there is something to this TIGHAR theory" he should state what he believes happened and we can help him with the logic of his approach.  If TIGHAR just said the other theories aren't right but we wont tell you ours then how much credibility would TIGHAR have?   Is it possible for someone who knows so much about the events of that day, and has queried in the fine detail that Gary brings to the table, that he hasn't formed an opinion on what he thinks happened?  He just knows of all the facts as he sees them but doesn't put them together and say "This is what I believe happened."  You really think he doesn't have his own theory?  Marty thinks Gary is a crashed and sank guy.  The more this thread goes on the more I believe that too.  I think thats helpful in understanding where Gary is coming from in his logic but shouldnt it come from Gary and not us putting words in his mouth?  Does Gary have to state it?  No.  As you point out John there is no requirement to state your opinion.  And rightly so in a democracy.  Many people read this forum without ever posting or stating their opinion.  But if youre going to attack TIGHAR's opinion I think its not enough to just naysay.  I think you should say what you believe happened instead.  As alway this is my unlearned opinion and my comments are not meant to be disrespectful.

Jeff N.  Just read your post and agree with all comments.  You said it much better than I did.  (As usual)
Respectfully Submitted;

Irv
 
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JNev

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Re: The flight plan, magnetic course, headwinds.
« Reply #293 on: February 01, 2012, 09:10:06 AM »

If you can’t find Howland, and aren’t sure where you are, then you can’t “dead reckon” to the Phoenix group.  If you know where you are with enough accuracy to be certain you’re near Howland, then why fly 300 miles (short of gas) towards the Phoenix group, when you know there’s a landing strip and ship and radios and people to help you nearby?  Why wouldn’t you keep searching for Howland?  That’s the argument against landing on Gardner.
Radio transmissions after they must have stopped flying indicate they were on land.  That’s the argument against splash and sank.
Reconcile those conclusions for me, and I’ll tell you what I think happened.  There is no requirement for me or Gary or anyone else to say “what I believe”.  What’s wrong with “I don’t know”?  The facts will hopefully tell us the eventual story of what happened, but they take a long time to find and sort out and verify, and we just don't have enough facts to draw a conclusion yet.

"If you can’t find Howland, and aren’t sure where you are, then you can’t “dead reckon” to the Phoenix group." -

Actually, yes you can - IF you are fortunate enough to be on a line of position (but not knowing how far north or south along that line you are).

"If you know where you are with enough accuracy to be certain you’re near Howland, then why fly 300 miles (short of gas) towards the Phoenix group..." -

Because you may not 'know where you are' with regard to how far north or south you are from Howland.  You may THINK you are south, so you fly north for a given search period; if that fails you turn back and hope you're actually north after all - but if you don't find Howland flying south, you eventually do find landfall.

That's the idea anyway.

"There is no requirement for me or Gary or anyone else to say “what I believe”." -

No, there's not.  But Gary had graciously offered that he was working on an idea - and some of us have goaded him on that.  It's a lively forum and Gary contributes a lot of knowledge and good ideas - and challenges.  It's just part of the dialogue and I'm grateful that he did put up more about his own theory.  He has challenged TIGHAR's ideas - that's fair - and now has put up more of his own for consideration.  I like that and admire him for it.

"What’s wrong with “I don’t know”?  The facts will hopefully tell us the eventual story of what happened, but they take a long time to find and sort out..." -

Nothing is wrong with it - and the fact is not one of us can know with any certainty at this point what happened.  But to find out what happened takes a search; to mount a search takes a theory or idea - and one that gets people motivated to support the effort.  THEN we can know, one day, maybe.  It does take a long time and lots of effort.

Thanks John - very thoughtful post - just my thoughts in reply, of course.

LTM -
- Jeff Neville

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JNev

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Re: The flight plan, magnetic course, headwinds.
« Reply #294 on: February 01, 2012, 09:14:36 AM »

Other than the MC simulation, the logic behind we do not have access to, what evidence is there of falling short of Howland? Is there any? So far I have yet to see any compelling evidence that this is the case.

They didn't make it to Howland - that's pretty compelling.

Whether they fell short, overflew, or flew by we can still wonder.  But it seems odd that they might have not only missed it themselves, but not been detected by those watching if they ever overshot or flew by within 10 miles or so anyway.
- Jeff Neville

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Heath Smith

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Re: The flight plan, magnetic course, headwinds.
« Reply #295 on: February 01, 2012, 04:17:59 PM »

Quote
Quote
Other than the MC simulation, the logic behind we do not have access to, what evidence is there of falling short of Howland? Is there any? So far I have yet to see any compelling evidence that this is the case.

They didn't make it to Howland - that's pretty compelling.

Whether they fell short, overflew, or flew by we can still wonder.  But it seems odd that they might have not only missed it themselves, but not been detected by those watching if they ever overshot or flew by within 10 miles or so anyway.

The fact that they did not make it does not translate in to they were short of the island. There are many other possibilities as well.

The way I see it, if they were in one of these green areas (see picture) they had a pretty good chance of finding Howland assuming that they had some clue where they were when they began an improvised search. On the other hand, if they really had no clue if they were North or South, short or long, they could have easily missed the island while searching.

For example let's say the were on the West edge of the box to the North and searched to the North on the first leg of their search. If they then traveled further West, they would have missed the island when searching South. The room for error was slim if they chose the wrong direction to search, North-South or East-West depending where they really were at 19:12 GMT.

If they were short of the yellow line, or long on the blue line, their odds of finding Howland get slim unless you were to get lucky in search.

The yellow line is about 48 SM West of Howland, the Blue is about 33 SM East of Howland. The large red circle is about 128 miles in diameter and would represent the DR error if they had not had a fix since the Ontario.
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Irvine John Donald

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Re: The flight plan, magnetic course, headwinds.
« Reply #296 on: February 01, 2012, 08:22:48 PM »

Interesting graphic Heath. As I have said in previous posts, there was nothing in the messages received to suggest they did not know where they were. Right up to and including the "we must be on you" message they transmitted as though they knew exactly where they were. I think not finding Howland likely was a surprise to both AE and FN.  There would have been a lot of discussion back and forth and an alternate plan created.  Regardless of where they were they just knew they weren't seeing (finding) Howland.  So make a new plan.
Respectfully Submitted;

Irv
 
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JNev

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Re: The flight plan, magnetic course, headwinds.
« Reply #297 on: February 01, 2012, 11:43:05 PM »

Quote
Quote
Other than the MC simulation, the logic behind we do not have access to, what evidence is there of falling short of Howland? Is there any? So far I have yet to see any compelling evidence that this is the case.

They didn't make it to Howland - that's pretty compelling.

Whether they fell short, overflew, or flew by we can still wonder.  But it seems odd that they might have not only missed it themselves, but not been detected by those watching if they ever overshot or flew by within 10 miles or so anyway.

The fact that they did not make it does not translate in to they were short of the island. There are many other possibilities as well.

The way I see it, if they were in one of these green areas (see picture) they had a pretty good chance of finding Howland assuming that they had some clue where they were when they began an improvised search. On the other hand, if they really had no clue if they were North or South, short or long, they could have easily missed the island while searching.

For example let's say the were on the West edge of the box to the North and searched to the North on the first leg of their search. If they then traveled further West, they would have missed the island when searching South. The room for error was slim if they chose the wrong direction to search, North-South or East-West depending where they really were at 19:12 GMT.

If they were short of the yellow line, or long on the blue line, their odds of finding Howland get slim unless you were to get lucky in search.

The yellow line is about 48 SM West of Howland, the Blue is about 33 SM East of Howland. The large red circle is about 128 miles in diameter and would represent the DR error if they had not had a fix since the Ontario.

"The fact that they did not make it does not translate in to they were short of the island." -

My meaning was that they 'fell short' of arriving, actually - I covered the other points (overshot / etc.).  I am rather convinced they covered the 'distance' - just not in the right direction or at the right latitude.

"There are many other possibilities as well." -

Yes there are!  And I am not particularly interested in cutting them off (and I guess that's what irks me about forceful debunkers and makes me want to press them for their ideas).  But only so many fit the facts and possibilities well enough to become probabilities.  It is a puzzle.

And speaking of puzzles, I'm glad you put up your illustration and discussed it - I look forward to studying it more - good stuff.

LTM -
- Jeff Neville

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Gary LaPook

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Re: The flight plan, magnetic course, headwinds.
« Reply #298 on: February 02, 2012, 12:12:50 AM »

If you can’t find Howland, and aren’t sure where you are, then you can’t “dead reckon” to the Phoenix group.  If you know where you are with enough accuracy to be certain you’re near Howland, then why fly 300 miles (short of gas) towards the Phoenix group, when you know there’s a landing strip and ship and radios and people to help you nearby?  Why wouldn’t you keep searching for Howland?  That’s the argument against landing on Gardner.
Radio transmissions after they must have stopped flying indicate they were on land.  That’s the argument against splash and sank.
Reconcile those conclusions for me, and I’ll tell you what I think happened.  There is no requirement for me or Gary or anyone else to say “what I believe”.  What’s wrong with “I don’t know”?  The facts will hopefully tell us the eventual story of what happened, but they take a long time to find and sort out and verify, and we just don't have enough facts to draw a conclusion yet.

"If you can’t find Howland, and aren’t sure where you are, then you can’t “dead reckon” to the Phoenix group." -

Actually, yes you can - IF you are fortunate enough to be on a line of position (but not knowing how far north or south along that line you are).
But if they knew they were on the LOP then they could just follow it to Howland which is much closer and that is where all the goodies are.
Quote

"If you know where you are with enough accuracy to be certain you’re near Howland, then why fly 300 miles (short of gas) towards the Phoenix group..." -

Because you may not 'know where you are' with regard to how far north or south you are from Howland.  You may THINK you are south, so you fly north for a given search period; if that fails you turn back and hope you're actually north after all - but if you don't find Howland flying south, you eventually do find landfall.
I've said this many times before and people either don't get it or are purposefully avoiding dealing with this fly in the Gardner ointment. This time I will draw you a picture. Contrary to the  "don't know how far north or south they are" argument, Noonan certainly did, just by dead reckoning, to a level that would keep them from flying down to Gardner. Even using the unrealistic assumption that they dead reckoned all the way from the Ontario, then the maximum expected D.R. error is 110 NM (128 SM), 10% of the 1100 NM from Ontario to Howland, so they would not have proceeded more than 110 NM south from the D.R. position of Howland before turning around and going back to the north, searching for Howland. However, it is much more likely that they got a fix around 1623 Z, or even later, making the maximum D.R. error only 46 NM, see Landfall procedure navigation to Howland Island. But the plane was not being flown by an automaton, Noonan knew how far they had flown since the last fix and would have allowed the appropriate offset for the intercept point on the sunline LOP. So, even if it was just dead reckoning all the way from the Ontario, then Noonan would have aimed 110 NM, at least, to the north-northwest of Howland which would ensure that they did not end up south of Howland at the point of intercept. They would then fly 220 NM south-southeast along the LOP looking for Howland so, worst case, if they missed the island and if they had been at the maximum D.R. error to the right point of interception, they would still not proceed more than 110 NM further to the south-southeast before turning back to the north to execute a search pattern. But what if there were actually a much larger error in the DR than expected, wouldn't they have ended up much further south? Well that brings in Baker, 38 NM south of Howland. In order to miss seeing both Howland and Baker, and with 20 NM visibility, they would have had to have been an additional 58 NM off to the right of the DR course in order to pass so far south of Baker so as to not be able to see it. This would be a total DR error of 168 NM, 15% of the distance flown from Ontario and 26% of the distance flown from a 1623 Z fix. It is highly unlikely to have such large DR errors. Based on the statistics of navigation, (appendix Q in the 1977 edition of the American Practical Navigator) there is only one chance in 370 of being 15% off course and only one chance in ten-million of being 26% off course! And, as is likely, if Noonan added an additional safety margin to his offset then missing both Howland and Baker is an even more remote possibility.

Now, the second point. If the DR accuracy doesn't convince you then let's shoot the moon. I have pointed out many times that the moon was positioned to provide an LOP that would tell Noonan whether he was north or south of Howland and so would also prevent flying down to Gardner. Looking at 1912 Z, the height of the moon was 74° 26' at Howland and its azimuth was 328° which produced an LOP running 058° -238° T. (We know that Noonan could take observations at least as high as 75° since he did so on the leg to Hawaii.) Using this LOP, Noonan would have known how far he was north or south along the 157° -337° sun line LOP. I have attached a chart showing a fix using the sun (the 157° -337° sun line LOP is the white line) and the moon at 1912 Z. (I am not saying that they were at this fix position, this is just an example of a fix that Noonan could have obtained at 1912 Z.) So, looking at the moon LOP running from the lower left to the upper right (yellow line,) you can see that Noonan could have determined how far they were south of Howland and so would have let them know that they had to turn around to go back to the north to search for Howland. The yellow moon LOP was calculated from an observation of the moon of 73° 22' placing the LOP, and the observer (Noonan)  64 NM south-southeast of Howland. If Noonan had measured the height of the moon to be greater than 73° 22' then he would know he was actually closer to the Moon' position over the earth and would know he had to be north of the yellow moon LOP line. If he measured a lower altitude then he would know he was south of that line. The white sunline LOP was calculated from an observation of 17° 13' placing this LOP and Noonan 109 NM west-southwest of Howland. If Noonan measured the sun's altitude to be greater than  17° 13' then he had to be east of the white sunline LOP and if he measured a lower altitude then he would know he was west of that line. That is how celestial navigation works. From the plotted example fix it is 153 NM on a course of 032° T to Howland. The weather conditions south of Howland were conducive to celestial observation of both the sun and the moon.

gl
« Last Edit: February 09, 2012, 08:48:58 PM by Gary LaPook »
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Gary LaPook

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Re: The flight plan, magnetic course, headwinds.
« Reply #299 on: February 02, 2012, 02:23:57 AM »

Interesting argument about diverting to Nauru.  I don't buy it.

Too much construct, too little motive for AE and FN to have done it when I look at the whole context.  Why would FN drive extra complexity into the effort?  As 'simple' as it is for the navigator making a pure case here, it also would drive many more opportunities into the flight for error.

Is that the sum of your point, Gary?  That FN  pressed an exercise into the flight which compounded opportunties for error - and that the pair finally got caught in that web somehow? 
Can you describe how Noonan's taking the normal celestial sights, that were already part of the plan, only this time taking some of those  sights over a brightly lit island that they could find just by ("go to the light, Luke" ) following the lights in from 150 miles out, which provided a reliable visual checkpoint, provided compounded opportunties for error ?

gl

Yes -

Just as you seem to see that it somehow adds assurance, it also distinctly adds more variables than just following the lubber and verifying along the way with celestial - more heading changes, more points for AE to process, etc.  There's also the not so minor point of needing to consider if one really wants to trash their night vision over the sea by approaching that flame of light at Nauru, like a moth - not to mention what it might do to FN's ability to take clear shots for some time.  I believe you helped describe the mining lights yourself earlier - or if not, think about it.  Not good.

Not that I think I need to defend the idea - I think it's more logical for someone floating these variation theories to put up strong reasons, not just possibilities, if they expect them to stand.


"Thrash their night vision," I put that in the category of "grasping at straws." Have you ever flown over lights at night, say over a large city? Oh, I guess not, because if you had you would have "trashed your night vision", lost control of the plane and crashed and died and wouldn't be posting on the TIGHAR Forum. I'm still laughing about this one. :D

I did give good navigational reasons to confirm their position and their navigational methods and equipment by a slight deviation off the straight line (which they hadn't been following up to that point, anyway) adding only about 10 NM to the flight distance. To me, your counter-arguments seem contrived and not compelling, but YMMV ;)

Keep up the good work, I like these discussions.

gl

The word was 'trash' - and yes, I've flown at night - and navigated on the surface at night - and had my night vision 'trashed' by other vessels and landmarks, and have avoided it for good reason.  The latter case is better.  Crash and burn really wasn't the concern, so your comment is a bit highhat - although it's happened to some; I had more in mind ability to get clear shot of heavens, other lights that may appear on the ocean (I find your skepticism on spotting ships highly questionable, and a need to deviate toward Nauru weak), and AE being able to stay on the ball over a dark sea.
If you are concerned with the lights interfering with Noonan's night vision making it more difficult to shoot stars then he could hunker down in the back on the plane and so shield his eyes from the lights while still allowing him to look upwards through the window and take star sights. If your concern is for Earhart's vision then she can do what we all do, close one eye until leaving the lighted area and she could also put the plane on auto-pilot since the auto-pilot didn't have any eyes to be bothered by the light.

Maybe you didn't understand how flying over Nauru would allow checking his navigation and the accuracy of his octant. All celsetial navigation involves picking a position on the ground and calculating what altitude of a celestial body would be measured from that spot, that is what those tables are used for. The normal way to check the accuracy of your sextant or octant is to go to a position for which  you know the accurate coordinates, do the normal calculation and then compare what you measured with your sextant with the computed altitude, they should be exactly the same. Any difference is called the "index error" of the instrument and you apply that as a correction to subsequent observation. The index error determined can only be as accurate as the accuracy of the known position used for the test. This is why he couldn't do the same type of check over the Ontario because he couldn't know the location of the Ontario to the necessary level of accuracy (in fact, the navigator on the Ontario also could not know his position accurately enough to do this test.)

There are additional reasons to fly over Nauru. One is to determine the winds at their cruising altitude. You were trained to compute a wind correction angle using a wind vector diagram on your E-6B but few instructors teach the next computation, calculating the winds encountered in flight by using the same vector diagram. I always taught my students how to do this on the first cross country flight. Technically this is known as "wind between fixes" and it can also be done between celestial fixes, Noonan mentioned this in his letter to Weems. What you do is you plot your "no-wind position," just the DR position from your prior fix based on heading and airspeed. You then plot your new fix and the difference between the "no-wind position" and the fix was caused by the wind. Say your fix is 15 NM straight south of the no-wind and you have been flying for one hour, you then know the wind has pushed you 15 NM straight south in one hour so you know that the wind is 15 knots from the north. However, the accuracy of this method is no better than the accuracy of the fixes which, for celestial fixes, is taken to be 10 NM. Since the starting fix could be anywhere within a 10 NM circle around the plotted position and the same is true of the second fix, the wind determined this way, on a one hour leg, has an uncertainty of 20 knots and the direction of the wind, determined from a 130 knot plane, could be off by 17 degrees. But doing the same computation using visual fixes over terrestrial landmarks, that have only a one or two mile uncertainty, reduces the possible error in the measured wind to 4 knots and 3 degrees. This was also much more accurate than using drift measurements. Looking forward to the next leg, from Ontario or from Nauru to Howland, having an accurate wind would be very important to Noonan and flying over Nauru could provide this. Using the Ontario for the visual checkpoint would not allow the same accuracy because of the uncertainty in the position of the ship.

Yet another reason why flying over Nauru was desirable is that it would provide an accurate starting point for the dead reckoning to Howland. The accuracy of dead reckoning can never be any better than the accuracy of the starting position. DRing from a celestial fix starts with the 10 NM uncertainty inherent in the celestial fix itself. Starting from Nauru would cut this down to one or two NM. And using the Ontario as a starting position has even more uncertainty than a celestial fix because Noonan could not know, for certain, the actual position of the ship. And, he had to be aware of the possibility of another ship being in the area that, if misidentified as the Ontario, could make the visual fix, and the subsequent DR, off by possibly 50 NM or more.

Navigators are expected to use all information available to them for safely conducting the flight. In trans-oceanic navigation it is unusual to be able to take visual bearings on terrestrial landmarks but when they are available, navigators take advantage of them. I'll bet that any WW2 Air Force navigator that flew over the western Pacific would tell you the same thing, that he used every opportunity that presented itself to take a visual observation of islands to confirm and to improve his navigation.

So, compared to the slight cost of less than an additional 10 NM, it was well worth going over Nauru.

gl
« Last Edit: February 09, 2012, 08:49:48 PM by Gary LaPook »
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