What happened
During the takeoff roll, the Aerostar 601P utilized roughly 4,000 feet of the runway before rotating. Shortly after liftoff, the aircraft reached an altitude of approximately 400 to 500 feet before entering a left-hand spin. The aircraft subsequently struck trees, collided with the ground, and ignited.
Prior to the accident, the pilot had reported to a maintenance facility witness that one of the engines had sputtered and stopped during the initial engine start sequence. The pilot had expressed an intention to fly the aircraft to the facility for inspection.
Findings
Post-accident investigations focused on the two engines. While the right engine showed external fire damage, no mechanical malfunctions were identified. However, a detailed examination of the left engine revealed significant internal damage. Specifically, the rear side of the No. 5 piston was found to be eroded, with characteristics indicating engine detonation occurred.
Further inspection of the spark plugs showed that the No. 5 bottom plug contained fragments of a piston ring, and the No. 5 top plug exhibited heavy soot. Additionally, the nose core of the No. 2 bottom plug was fragmented. While the left fuel servo appeared normal, the fuel flow manifold diaphragm showed signs of heat damage. No obstructions were found within the fuel injector lines or nozzles.