What happened
While performing a takeoff roll at Glendive-Dawson County Airport, the pilot experienced mechanical issues with the engine. In response to the developing trouble, the pilot initiated an aborted takeoff and attempted to use emergency braking to halt the aircraft. However, because the runway surface was covered in two inches of snow, the aircraft could not stop before the end of the pavement. The plane subsequently overran the runway and came to a stop at the base of a bank.
The incident resulted in one fatality and six injuries among the occupants on board.
Findings
Investigations into the accident identified several contributing factors related to both mechanical failure and environmental conditions. The primary cause was an engine failure triggered by the failure of the number 4 cylinder exhaust valve. This failure was linked to improper alignment and adjustment of the valve assemblies, as well as inadequate maintenance and inspection procedures.
Additionally, the investigation noted that the ignition system malfunctioned because it had not been properly secured. It was also determined that the pilot attempted to operate the aircraft despite knowing that the left magneto was inoperative. The presence of two inches of snow on the runway further prevented the aircraft from stopping safely during the aborted takeoff.