An investigation by the Civil Aeronautics Board (CAB, the precursor to the NTSB) was unable to determine probable cause and it remains unknown to this day.

[3] Maintenance records obtained by the CAB after the crash indicated that the airplane was in good working condition, with no reported mechanical failures or issues.

The alert was issued at 2:01 P.M..[2]: 1 Initial search and rescue operations were hampered by severe weather and the arrival of the cold front forecasted by the Pan Am meteorologist.

Initial search operations were undertaken by the United States Coast Guard as well as the Army Air Force's Alaska command.

[1] However snow, fog, heavy winds of 45 to 50 miles per hour (72 to 80 km/h), and severe icing conditions around the airport limited the abilities of searchers and completely hid the crash scene from view.

[4][5] The wreckage lay on the north face of Tamgas mountain, a 3,591-foot (1,095 m)[6] peak approximately 6 miles (9.7 km) east of the Annette Island air field.

[4] The CAB team sent on site to investigate, determined that the wreckage was buried under significant snowfall on a part of the mountain that was difficult to access by foot.

Instead, the Coast Guard members and CAB employees retrieved the bodies of the victims from the scene, a process which took several days due to ongoing foul weather.

[2]: 6  Once the wreckage was located, investigators flew a seaplane to a lake near the foot of Tamgas mountain and accompanied Coast Guard members up to the crash site.

The Pan American Airways meteorologist had forecast that the cold front would reach Annette Island prior to the flight's arrival, and that conditions would be light rain, gusty, and overcast.

The updated forecast called for the cold front to reach Annette Island at 4:00 PM PST, but still made no mention of turbulence.

[2]: 4 The CAB, upon reviewing available weather data, determined that the Pan Am meteorologist should have been able to predict, with some amount of certainty, that there would be severe turbulence at lower altitude and high winds.

Such a forecast would have warned the crew of the weather conditions they encountered when they decided to abort their landing at Annette Island airport.

[2]: 4 Investigators were able to conclude that there was significant foul weather and severe turbulence in the area at the time Flight 923 was attempting to land at Annette Island.

Furthermore, the incorrect weather report by the Pan Am meteorologist left the pilot unaware of the turbulence and high winds he would encounter on approach.

[2]: 5 Given the lack of communication, witnesses, and evidence, the Civil Aeronautics Board was unable to determine a probable cause for the crash of Flight 923.