Pan Am Flight 923
Pan American World Airways Douglas DC-4 · CFIT for reasons unknown, possible Stall
From Seattle, Washington to Juneau, Alaska
Event
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- Event fatalities
- 18 · all aircraft and ground
- Ground fatalities
- Unknown
- Occupants
- 18
- Survivors
- 0
- InjuriesFatal: death within 30 days. Serious: over 48 hours in hospital within a week, most broken bones, severe bleeding, nerve or organ damage, or serious burns. Minor: anything less. Glossary
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- Airline
Douglas DC-4
- Aircraft type
- Douglas DC-4
- Category
- Airplane · from aircraft type
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- NC88920
- Operator
- Pan American World Airways
- Onboard fatalities
- 18
- Route
- From Seattle, WashingtonTo Juneau, Alaska
Cause areas
- Not determined › Not determined
From the investigation findings the Wikipedia article reports, sorted into the NTSB's cause areas with AI assistance.
Approximate · Coordinates from the Wikipedia article; not checked against an investigation report.
From the Wikipedia article
Pan Am Flight 923 was a Douglas DC-4 operating from Seattle, Washington to Juneau, Alaska, which crashed into Tamgas Mountain on Annette Island, Alaska, on October 26, 1947. All 18 passengers and crew on board were killed.
The crash was the worst in Alaskan commercial aviation at the time, as well as the first crash of a Pan Am four-engine aircraft. 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.
Flight history
Flight 923 was a regularly scheduled Pan American Airways flight between Seattle and Juneau, with a scheduled stopover at Annette Island Airport. The aircraft left Seattle at 10:30 A.M. on October 26, 1947. It was scheduled to arrive in Juneau around 3:00 P.M. that same day.
There were five Pan Am crew members aboard: three cockpit crew and two pursers. The pilot was Captain Alf N. Monsen, a veteran pilot with 13,565 hours of flying time. His copilot was First Officer Laurence A. Foster, another captain who was serving as copilot and first officer due to personnel reductions at Pan Am. The flight engineer was C. L. Dunwoody.
The aircraft for the flight was a Douglas DC-4, a four-engine propliner, registration NC88920, and had been in service since 1944, accumulating 4,146 hours of flying time. 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 aircraft departed Seattle on schedule at 10:30 A.M.. There were 13 passengers aboard, along with 822 lb of cargo and 2500 gal of fuel. The aircraft was well within weight and load limits, and was only carrying a quarter of its usual capacity of 44 passengers. Prior to departure, Captain Monsen received a weather report from Pan American's meteorologist, which indicated that a cold front would be passing through Annette Island prior to the flight's arrival.
The first leg of the journey was uneventful, up until the aircraft reached the radio range station near the Annette airport. The radio range station was located 1.5 mi northwest of the airport. Air Traffic Control cleared the flight to pass over the range station at 7,000 feet and then to proceed with a normal landing. Captain Monsen acknowledged the clearance at 1:38 PM and reported his position over the range station at 7,000 feet.
Five minutes later, at 1:43, the Captain radioed Annette control tower and aborted his approach. He reported extreme turbulence at lower elevations, and indicated that he would instead continue to Juneau without landing at Annette. This was the last radio contact made with the aircraft. After Captain Monsen had radioed his intent to Juneau, the control tower radioed an acknowledgement and asked for Flight 923's altitude. When the control tower was unable to reestablish radio communications, the station issued an alert that Flight 923 had gone missing. The alert was issued at 2:01 P.M..
Investigation and cause
Investigation
Pan Am Flight 923 was the first crash of a Pan American four-engined aircraft. At the time of the crash, it was also the deadliest crash in Alaskan commercial aviation. It was the 31st worst accident at the time, in terms of loss of life, and remains the 195th worst accident As of November 2013.
The Civil Aeronautics Board began its investigation at 2:30 P.M. on October 26, 1947, less than an hour after the last known communication with Flight 923. 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 wreckage of the plane was scattered over an area of 20000 sqft at a position 196 ft below the summit of the mountain. When investigators reached the scene, it was snowing heavily and it was determined that the investigation could not continue until the snow had melted in the summer thaw. The investigation therefore resumed in late August 1948, the time of maximum thaw on the mountain.
Investigators were able to gather little from the wreckage, most of which was severely damaged by the crash and the subsequent flash fire. The only instrument with readable settings which could be salvaged was the fluxgate compass, which was used to confirm the aircraft's heading. Propeller marks on the cliff face also confirmed the aircraft's heading and indicated that the aircraft was pitched nose upwards as it tried to climb. The propellers themselves were broken in such a fashion to indicate that they were functioning normally at impact. It was impossible to determine, however, the aircraft's speed at the time of the crash due to a lack of surviving instruments. Investigators were also able to determine that all of the damage to the plane was incurred during or after the crash; there was no indication of a midair mechanical failure.
Probable cause
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. While the investigation was able to determine a number of factors which may have contributed to the crash, there did not exist enough evidence to determine a definitive cause. To that end, the official statement of probable cause in the Accident Investigation Report reads:
Text from the Wikipedia article “Pan Am Flight 923” (revision 1339308191, retrieved 2026-09-18) by its authors, under CC BY-SA 4.0. Extracted as plain text: references, tables, images and some sections are left out. Read the article
Sources
Wikipedia article: Pan Am Flight 923
- Article
- Pan Am Flight 923
- Revision
- 1339308191 · 2026-02-19 · retrieved 2026-09-18
- Wikidata
- Q16983340
- Licence
- Text CC BY-SA 4.0, by the article's authors; Wikidata CC0; town positions GeoNames (CC BY 4.0)
Where each value comes from
- Record
- Wikipedia article "Pan Am Flight 923" (page 41113781, revision 1339308191)
- Date
- Wikipedia infobox: date
- Place and country
- Wikipedia infobox: site
- Map position
- Wikipedia article coordinates
- Aircraft, operator and route
- Wikipedia infobox: aircraft type, registration, operator, origin and destination; route airports from the linked airport articles' Wikidata codes (OurAirports)
- Operation
- flight number in the article title
- Fatalities
- Wikipedia infobox: aircraft fatalities
- Ground fatalities
- not stated in the Wikipedia infobox
- Summary
- Wikipedia infobox: summary
Source notes (1)
- Wikipedia · Facts from the Wikipedia article's infobox and coordinates, not checked against an investigation report. Independent review pending.