NavList:

Howard thanks for the Occum's razor style of explanation. I believe that I now have a satisfying explanation of what happened to Earhart. It does not matter to me if the shadow on the ocean floor is an aircraft or not.

Question....if Chichester had disappeared would there have been a similar fuss or would he have become a footnote in history?  Of course, he was successful.............

The southern ocean is in stark contrast to the north Atlantic. During the off-peak there are none or at most one aircraft between south america and Austalia and NZ. In the peak maybe four. I follow planes flying between Santiago and Sydney because their route is obviously weather dependant. The vertex of the great circle  is 61 degS. Most plane head up to near this latitude. However some go up to 70 deg. The other day one reached 73 deg. (I am using the term up to refer up to the pole). I believe that abve 75 deg grid navigation would be used.  On the other hand one or two aeroplanes have crossed the Pacific W to E at 33 deg - approxinately the rumb line.

As an aside a ship could steam from Sydney to near Santiago but it cannot follow the rumb line - NZ gets in the way.

In contrast to Earhart the planes  are at 35-40,000 feet at hundreds of knots ground speed.

I started  watching the southern ocean after I wondered if any planes flew near Elephant Island (lat 61 deg S). So far I have not seen any. The other reason was to sudy loxodromes, otrhodromes, meridional parts and the Gudormannian  function. FWIIW meridional parts measure distance on a mercator chart, not on the earth.

I recomend https://www.movable-type.co.uk/scripts/latlong.html. The site provides code snippets for computer programmers. Because of the way it is writted I find it useful for GC/Rumb calculations on my PC with a keybourse and mouse. I do not like touch screen phone apps.

After that ramble I repeat that thanks to Howard I now know the Occum's Razor explanation of what happened to Earhart. That is all I need to know.

David C