Accident Sequence
During the takeoff roll, at approximately 800 feet down the left side of the runway, the left engine experienced a loss of power. The aircraft subsequently swerved off the left side of the runway and collided with a drainage ditch. The aircraft came to rest in an inverted position.
Examination Findings
Examination of the fuel control unit from the left engine 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 of the bellows.
Additionally, examination of the propeller indicated that the start locks were engaged, and the blades were at the start lock position at the time of impact.
Start Lock Mechanism
To engage the start locks, the power lever must be moved to reverse during the shutdown sequence with the engine RPM below 50%. After engine start, the pilot must again retard the power levers to reverse in order to disengage the start locks. The locks will not disengage once the power lever is set to the flight range.