NavList:

I have been investigating Fred Noonan's navigation of the Amelia Earhart flight. On March 18, 1937 the plane flew from Oakland to Hawaii on the first leg of what was supposed to be a westbound around the world flight. But when they were taking off for the next leg from Hawaii to Howland, Earhart lost control of the aircraft and it crashed, never having lifted off of the runway on Ford Island in the middle of Pearl Harbor. The plane was crated up and sent back aboard a ship to California for repairs. After the repairs Earhart flew the route eastbound and disappeared flying from Lae to Howland on July 2, 1937.

The charts used for the Oakland to Hawaii leg as well as charts for the earlier legs of the eastbound flight are kept in the archives of Purdue University. I paid the archivist to scan several of these charts for me (not cheap) so that I could examine Noonan's chart work. I am attaching one of his charts showing a portion of the Oakland to Hawaii leg.

There is a mystery on this chart and I am hoping that the knowledgeable members of this group can solve this mystery since I haven't been able to. You will see on the chart a 0446 Z fix at approximately 34° north, 132° west. This fix was made up of a 0432 Z Alphecca line advanced to cross the 0446 Z Polaris line. (The 0442 arrow is a radio bearing, not a part of the mystery.) We have no more information than this chart, not Noonan's work sheet, nor his actual sextant readings. I have been able to check his work by computing the altitudes and azimuths for the stars he used for his fixes. I don't have his altitudes to compare with my computations but I have been able to compare the plotted azimuths with my work and his azimuths agree with mine. I think this shows that he probably computed his altitudes correctly since, when using H.O. 208, the azimuths are computed after the altitudes they would probably not be correct if the altitudes were not also correct.

For the 0446 Z fix, the azimuth of Polaris (not surprisingly) is 360°. I measured the azimuth of his 0432 Z Alphecca line and I get 082° true. We can see that he re-started his DR from this fix so he must have considered it to have been a good fix. There is one little problem, however. Alphecca would not have been visible at that time and would not rise in that location for another hour. So what star did Noonan shoot? I haven't been able to find any other stars that would have had an azimuth of about 082° at that time and place. I note tha Menkar would have amost a reciprocal azimuth but the azimuth arrow definitely points to the east.

(There is also a question in my mind, is this actually Noonan's chart work? On that first leg Manning was the chief navigator so it may be Manning's chart work. Looking at Noonan's methodology on the Natal to Dakar chart (only Noonan was on that flight) he doesn't plot the azimuth arrows. But the hand writing on both charts looks to be the same. Another mystery. I have previously posted the Natal to Dakar chart.)
Any ideas?

http://www.fer3.com/arc/imgx/North-Atlantic--5.jpg

http://fer3.com/arc/m2.aspx?i=112864

gl
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