Colin-
An interesting piece. thx for sharing. I had a few thoughts:
1) there is some not-very-reliable information about weather over the North Atlantic on May 9, 1927, which suggests:
a) icing conditions west of Iceland;
b) precipitation along the entire route, suggesting overcast conditions (altitude and ceiling unavailable)
c) cross winds east of Greenland, tail winds west of Greenland;
2) This suggests (to me) that under zero wind conditions and accurate navigation, Nungesser & Coli should have arrived at Belle Isle circa 0500 GMT with tail winds, or 0700 GMT at zero winds. Instead, they turn up at Harbor Grace, 285 nm SE of Belle Isle, at 1300 GMT (9:30 am local).
3) If they flew direct to Belle Isle, then direct to Harbor Grace, they are still four hours late. Whatever the exact status of the winds, something bad happened with the navigation, and as a consequence, they now have a looming fuel supply problem. I would guess this is too much missing time to attribute just to drift. I suspect they went to some wrong place, and then had to search or return from there.
5) Given all the lighthouses, buoys, roads chimney smoke, and other traces of civilization in the Harbor Grace area, I am inclined to suspect they had discovered their approximate location by 1300 GMT, but who knows?
6) Note your map shows a course from Trinity Bay to Placentia Bay, while the more probable sightings suggest a course from Conception Bay to St Mary's Bay. The destination of this course is a puzzle. If they were a little farther west, I would have bet on French territory--St Pierre & Miquelon, where one could get decent wine and a proper meal. But they don't appear to have been heading to St Pierre.
7) There were sightings over Nova Scotia, St Pierre, and Maine, though the reported sightings were not especially persuasive. Nor do they seem to have been heading there.
Note that because the magnetic deviation close to the north magnetic pole is so large and variable as one approaches Newfoundland, an error in calculating one's position will also cause an error in heading, which is sort the definition of going from bad to worse. In particular, the declination at Belle Isle is 34 degrees west of north, while Harbor Grace is 30 degrees west of north, so, if one thinks one is at Belle Isle, one's actual course will be 4 degrees off the course one thinks one is flying.
9) There have been at least two errors of this sort--the German/Irish "Bremen" whose crew attempted to fly Ireland-Newfoundland in 1928. They had a celestial navigator on board, but couldn't get a fix for 13 hours, and apparently didn't update their declination. When they got out of the fog, they found themselves flying above snow-covered lakes and mountains, all unrecognizable. They headed south and eventually made a forced landing adjacent to a lighthouse on the north shore of the Gulf of St Lawrence. The other was Korean Airlines Flight 902, in 1978.
hope this helps,
adr
