Incident Description
Witnesses observed the aircraft become airborne near a slight rise in the runway, approximately 1,500 feet down the runway. The aircraft climbed to about 60 feet above ground level, then shuddered and the nose pitched up. Subsequently, the left wing and nose dropped, and the aircraft continued descending to the left across a small ravine that paralleled the runway, crashing into the easterly side of a ravine.
Investigation Findings
Investigation of the wreckage revealed that seat stops were not found in the pilot's seat rail. A stop screw was discovered on the cabin floor near the location of a hole provided for a seat stop in the inboard track of the seat. One half of a broken seat stop was found in the left channel of the right pilot's seat track, approximately one inch forward of the installation hole. The seat track surface was scored, and all holes in the track were elongated. Additionally, the seat rollers had been replaced in 1979 due to slippage. The aircraft contained a seat slippage warning placard stating, "INSURE AIRCRAFT SEATS ARE POSITIVELY LOCKED BEFORE TAKEOFF AND LANDING."