NAVIGATION ANALYSIS OF THE CRASH OF AIRPLANE
#45-21768 ON THE 21ST OF FEBRUARY 1947

The last positive position of Aircraft 768 was obtained at 0150 AST by celestial means. It can be assumed that this position was accurate. At this position the airplane was left of course and Lt. Cowan altered heading to get back on course. Dead reckoning was carried on from this point throughout the rest of the mission until land was first encountered at approximately 0500 AST. It is of interest to note that only two celestial fixes were obtained during the entire mission, the first at 2008 ½ AST and the second at 0150 AST. It was possible to get celestial fixes at various times during the flight as is evidenced by Lt. Lesman’s ability to get true headings by celestial means right up until 0240 AST.

There were several factors which aggravated the situation in which the crew found themselves at 0501 AST:

(1) The C-1 autopilot had been retrimmed and reset after the climb to 24,000 feet at 0420 AST. A precession rate on the auto- pilot gyro had been determined on the previous autopilot setting, and the navigators were forced to use the past pre- cession with the new setting.

(2) The navigators, before take-off, had got the maps on which their course was plotted until they covered only that area adjacent to the path of expected flight. They had neglected to take the emergency map kit provided by Project 5. This emergency map kit contains all available maps of Siberia, Alaska, Canada, Greenland, and the Canadian Archipelago. Consequently, they had map coverage extending east as far only as the eastern shores of Borden and Melville Islands, west as far as 180 degrees, and south as far as 74 degrees on a VSO-XPE, and a strip map extending from Fairbanks to Point Barrow.

(3) Perhaps if they had climbed instead of continuing on for one hour and forty minutes under the overcast it would have been possible to obtain one or more celestial fixes and get a further check on gyro precessions.

Regardless of these facts, the navigators, upon finding themselves over land, should have immediately eliminated certain possible land masses and accepted the plausibility of others, for example:

Siberia: (1) Too far from the lst known position. (2) The sun could not be seen at all if the airplane were over Siberia. Since Siberia would be in total darkness at that time. The navigators had celestial tables with them which would give this information.

Alaska:

(1) Point Barrow and a vicinity within several hundred miles could be eliminated because it is a flat, level region. It was stated in reports, both verbal and written, that the land encountered had mountains which ran into the water. These were seen on the radar scope and visually. Northwestern Alaska could be eliminated because of its distance from the last known position. All of the territory of Alaska could be excluded because the sun would not yet have risen.

(2) The sun would not rise at this hour along the Canadian coastline unless the airplane had been east of 110 degree West longitude,

This leaves the Canadian Archipelago as the only possible area in which the airplane could have been. Moreover, it has been stated both in written reports and verbal accounts by the crew members that the land first encountered looked to be some sort of intermittent land and water area and within an hour and a half it was fairly definitely established that they seemed to be flying over island formations. Yet from a digest of the reports it can be assumed that the DR navigator, and perhaps other members of the crew, thought they were somewhere west of Ladd Field, Siberia as a possibility not excluded. Otherwise, why was the decision made to fly into the sun as a last resort? This direction would be roughly southeast. Certainly, a navigator would not fly in a southwesterly direction if destination were believed to be west or southwest of his position. At this point it is worthwhile to note that Lt. Lesman eliminated many of the possibilities of probable position as outlined above and expressed the opinion that the aircraft was somewhere in the Canadian Archipelago. He also expressed the desire to fly in a generally southwest direction in relation to the sun’s position. Evidently these theories were given no weight.

Once the crew had determined to some extent their general locality, it seems they could have done only two things which would have been of some practical value:

(1) The sun could be seen on the horizon and, consequently, a general southwest heading could be flown. Flying different headings for brief periods of time or a circling motion is not generally regarded as a sensible action to be initiated when lost.

(2) Remain on that heading until a sunline could be obtained for a line of position or until a definite checkpoint was picked up by visual means.

Since the return of the crew of airplane 768 to Ladd Field it has been quite definitely established that the airplane first made landfall at Ellesmere Island. They stated that they saw mountains with cliffs extending directly out of the sun. This fact was substantiated first by radar means and later visually when the airplane passed over this point. Ellesmere is the only island in the Archipelago which has mountains which extend into the sea, are 10,000 feet or more in height, and run in a series of ranges parallel to the coast. The general shape, features, and heading of the northern cost of this island have been identified by Lt. Adams, the radar operator, as being similar to what was seen on the radar scope.

After the airplane climbed to the altitude of 24,000 feet at 0420 AST to get on top of the overcast the C-1 autopilot was reset. The navigator continued to correct the airplane approximately 10 degrees to the left every 20 minutes on the basis of the previous 30 degree per hour precession. Evidently the precession of the autopilot gyro had changed at the time of resetting from a high rate of precession to the right to a lesser amount of precession to the left. On addition, the wind was out of the northwest quadrant and continued to give an increasing drift to the left which accounts for the airplane making a half circle to the left and ending up at Ellesmere Island.

WAYLAND W. WILLIAMS
1st Lt., Air Corps
Squadron Navigator

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