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[h.a.c. van asten]

A Fixed Square Search is the in first line evasion from getting astray , as soon as destination does not run in sight at ETA . Such searches (also if circular) are very waisteful on fuel so , if you are low your risk to run out on one of the first search legs is too geat . Generally it is in the manuals prescribed not to leave a position line once you are on it for the sake of rescuers having a guideline .

[h.a.c. van asten]

Possibly if not probably , Chater´s watch was a few minutes off Zone Time . If precomputed a navigator can immediately see , even shortly before point of time , if his observation covers , or not . Can anybody explain with figures how the 0720 fix was established , with the sun only available , for the same given coordinates ?

[h.a.c. van asten]

I think the comment considered the LOP by its extension to compass point 157 , not the line itself but one estimated last point of it from which a 157 compass course , corrected or not , cold be set .

[Mona Kendrick]

. Generally it is in the manuals prescribed not to leave a position line once you are on it for the sake of rescuers having a guideline .

     A very interesting point that hasn't been brought up before on the forum.

Mona

[Irvine John Donald]

A Fixed Square Search is the in first line evasion from getting astray , as soon as destination does not run in sight at ETA . Such searches (also if circular) are very waisteful on fuel so , if you are low your risk to run out on one of the first search legs is too geat . Generally it is in the manuals prescribed not to leave a position line once you are on it for the sake of rescuers having a guideline .

Doesn't that point argue that FN did the right thing by staying on the LOP?  Didn't the US Navy and Coastguard also use the LOP as the place to search?  Itasca heading NW to search while other US navy officials suggested the Phoenix group as southern end of the LOP to be searched?

What manual recommends this procedure Mr. Van Asten? It would likely make interesting reading.

[h.a.c. van asten]

Navigator´s Information File NIF , 1944 April imprint , Section 3 , § 17 . 1 . "Landfalls" . Mr.Lapook has on this forum given a link to this manual , if you do not possess it .

[Gary LaPook]

Navigator´s Information File NIF , 1944 April imprint , Section 3 , § 17 . 1 . "Landfalls" . Mr.Lapook has on this forum given a link to this manual , if you do not possess it .

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Well there is nothing in this manual that supports Mr. van Asten's statement nor in any of the other manual excerpts that I put on my website. Here is a link to that document on my web site, see if you can find any mention of "rescuers" as van Asten claims.
https://sites.google.com/site/fredienoonan/resources/navigator-s-information-file-1944

But as long as we are looking at the "Landfall" section of the Navigator's Information File, I just want to point out the very first words in that section:

"Landfalls - The safest way to get to destination"

gl

[h.a.c. van asten]

pt. 4 of the paragraph : "Stay on this line of position until another line of position shows you to be off course . pt. 5 . Then repeat the process . But stay on a line of position through destination . There is no ETA in a landfall other than your best known groundspeed" .

[Gary LaPook]

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The LOP passed near Gardner only near the time of sunrise and moved quite far away by the time the plane could have been approaching that island. You seem to have missed the whole point of that web page.

gl

I didn't miss the point, but I think you missed mine:

Your site includes authoritative information on the use of sun lines on the "page 157" link.  Despite the example used in that text being nearly verbatim the same case AE and FN would have faced, you continue to discount that approach for some reason beyond my understanding.

As to sun lines, LOPs and movement -

Once established, the LOP does not "move" with the sun.  Think about it - if they did, they would be useless. 

A LOP could easily have been established by offset - FN would have known how far east or west he was at sunrise by the time.  From that shot he also would have had a good idea of speed.  Therefore it would have been a simple matter for him to project by offset a LOP for Howland: then it would be a matter of elapsed time by which to judge arrival at the LOP.

Once at the LOP it is a matter of track - simple enough and the obvious outcome would have been 157 - 337.

Simple indeed - and foundationally sound.  Given the nature of able humans like FN when confronted with a need to solve a problem, I suspect FN would have done about what Occam says is rational - and LOP is about as foundational as it gets in the case he was facing.  I think that's where I'll keep my money... 

Cool link between FN and the author of that material - thanks for sharing that.  Small world!

LTM -

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O.K.?

You did get the point that the LOP is perpendicular to the azimuth of the sun at the time that each observation is taken, right?

And if you haven't lived your whole life in a cave you have probably noticed that the azimuth of the sun changes during the day, rising in the east, passing through south at noon, and setting in the west, right?

So since the sun's azimuth changes during the day and the LOP is always perpendicular to the sun's azimuth then you do see that the azimuth of the LOP changes at the same rate as the sun's azimuth, right?

Then how can you say that "the LOP does not "move" with the sun"?

gl

[h.a.c. van asten]

Mr.Neville probably intended to say that the given 157-337 sun line as an original did not move with the sun , thereby supposing that it was possible to set course for Gardner from a point on the original sun line , which it was .

[h.a.c. van asten]

I do not claim "rescuers" , but it is clear , qualitate qua , and separating details from headlines , that searching along a line is more productive than searching at random , so if on a line and in distress : stay where you are is the word .

[Ric Gillespie]

There are standard search patterns to fly,

Please tell us which of these standard search patterns were standard search patterns in 1937 and how you know that Noonan knew them.

[Ric Gillespie]

. Generally it is in the manuals prescribed not to leave a position line once you are on it for the sake of rescuers having a guideline .

     A very interesting point that hasn't been brought up before on the forum.

Mona

And meaningless without a citation for what manuals he's talking about it. 

[h.a.c. van asten]

Navigator´s Information File , Section 3 , § 7 - 1 .

[Ric Gillespie]

Navigator´s Information File , Section 3 , § 7 - 1 .

So it's just one manual, not "the manuals."  When published?  If you're suggesting that it is something that may have influenced Noonan on July 2, 1937 it has to be published prior to that date.