Background
Transocean Air Lines, an irregular carrier, was engaged in air transport operations in Alaska for the United States Navy. Flight 501 South was conducted under this contract.
Flight Details
The aircraft departed Point Barrow at 1655 on December 30, 1951, with six passengers, 9,243 pounds of cargo, 275 pounds of baggage, 900 gallons of gasoline, and two crew members—Captain R. R. Warren and First Officer R. V. Irwin. The gross takeoff weight was 47,646 pounds (allowable 48,000 pounds), and the load was properly distributed. An IFR flight plan was filed: Point Barrow to Umiat via Amber Airway 2 at 4,000 feet; Umiat to Bettles at 10,000 feet; Bettles to Nenabank intersection at 8,000 feet; and Nenabank to Fairbanks at 5,000 feet, with Big Delta as alternate. Weather forecasts indicated instrument and on-top conditions. The flight arrived at Umiat at 1754, remaining for one hour and 56 minutes. During the stop, the crew was advised of a recent repositioning of the north leg of the Bettles radio range. Winds aloft from 240 degrees at 40–60 knots were forecast for the cruise altitude to Nenabank. When the flight departed Umiat at 1950, the takeoff weight was 36,373 pounds. The only passengers were two employees of Wien Alaska Airlines, carried nonrevenue under a mutual assistance agreement; their names were listed as additional crew members.
Sequence of Events
The flight reported over Bettles at 2053. At 2144, it was 25 miles northwest of Nenabank and received clearance to cruise at 8,000 feet to Nenabank, then 5,000 feet to Fairbanks. At 2148, it reported over Nenabank at 8,000 feet descending. At 2155, it reported reaching 5,000 feet. At 2157, the flight was cleared for a standard range approach to Fairbanks, crossing at 4,000 feet. At 2205, the flight reported: "ADF OUT HAVE MISSED CONE PROCEEDING OUT WEST LEG WILL CALL WHEN OVER STATION." Fairbanks confirmed at 2206 and received confirmation at 2207. No further messages were received, and it is believed the aircraft crashed immediately thereafter.
Wreckage and Casualties
The wreckage was found on January 3, 1952, in hilly terrain. The aircraft was destroyed upon impact, and all four occupants—the two crew members and the two passengers—were killed.
Probable Cause
The official investigation determined that the probable cause was "the failure of the pilot to follow procedures and utilize properly the radio facilities for approach and letdown at Fairbanks, with the result that the flight became lost." Additional findings indicated that weather conditions were as forecast and would not have precluded a successful approach; the flight was off course when initially positioned by radar and was plotted on the west and east legs of the Fairbanks range for 12 minutes; all ground radio facilities functioned normally; and the flight made an authorized left turn while outbound on the east leg and subsequently struck a mountain northeast of the station while on a westerly heading.