Flight Details
The aircraft, named 'Clipper Racer', departed San Francisco on a cargo flight to Cam Ranh Bay, Vietnam, with en route stops at Elmendorf AFB, Tokyo, and Đà Nẵng. Due to below-minima weather at Anchorage International Airport, the aircraft landed at Elmendorf AFB instead. Several delays occurred before the flight taxied out at 06:02.
Sequence of Events
Flight 799 received a void time of 06:15 from Oceanic Control to avoid traffic conflicts; failure to meet this time would result in a 45-minute delay. During the pre-takeoff checks, when the 'wing flaps' checklist item was called, a 'follow me' truck arrived to guide the aircraft to runway 23. Consequently, the crew focused on steering the aircraft on slippery taxiways and communicating with Oceanic Control. The aircraft was cleared for takeoff at 06:14.
During the takeoff roll, the stick shaker activated shortly after reaching VR (154 knots). The aircraft rotated and climbed slowly. The right wing then contacted snow-covered ground 94 feet left of the extended runway centerline, at a distance of 2,760 feet from the runway. The aircraft rolled inverted and broke up.
Probable Cause
The official investigation determined the probable cause to be an attempted takeoff with the flaps in a retracted position. This resulted from a combination of factors: inadequate cockpit checklist and procedures; a warning system inadequacy associated with cold weather operations; ineffective control practices regarding manufacturer's Service Bulletins; and stresses imposed upon the crew by their attempts to meet an air traffic control deadline.