Accident Sequence
During the takeoff roll, at approximately 800 feet down the left side of the runway, the left engine experienced a power loss. The aircraft subsequently swerved off the left side of the runway, colliding with a drainage ditch, and came to rest inverted.
Examination Findings
Examination of the fuel control unit revealed that the bellows within the assembly were found in an extended position, indicating a leak into the evacuated area. A failure was noted at the seam in the bellows.
Additionally, examination of the propeller revealed that the start locks were engaged and the blades were at the start lock position at impact. The start locks engage when the power lever is moved to reverse during shutdown with engine rpm below 50%. After engine start, the pilot must again retard the power levers to reverse to disengage the start locks; the locks will not disengage after the power lever is set to the flight range.
Official Findings
The following findings were documented by the investigation:
- Occurrence #1 (Loss of engine power - partial, mechanical failure/malfunction): Failure of the fuel system fuel control, specifically a leak at the bellows seam. Also, the propeller system start locks were engaged, indicating improper use by the pilot in command, and performance data was not identified by the pilot in command.
- Occurrence #2 (Loss of control on ground/water): Directional control was not maintained by the pilot in command, and an inadvertent ground loop/swerve occurred.
- Occurrence #3 (On ground/water encounter with terrain/water): An aborted takeoff was performed by the pilot in command, and the aircraft encountered a ditch.
- Occurrence #4 (Nose over): The aircraft nosed over during the takeoff phase.