What happened
The incident occurred during the initial phase of flight, specifically while the aircraft was attempting to depart. Shortly after beginning the takeoff roll, the pilot experienced a partial loss of engine power. Recognizing the inability to continue the climb safely, the pilot made the decision to jettison the chemical load carried in the aircraft to reduce weight.
Despite this action, the aircraft lacked sufficient performance to clear the terrain beyond the end of the runway. The aircraft struck an embankment located just past the runway threshold. Upon impact with the embankment, the nose of the aircraft collapsed downward, causing it to nosed over. Following the collision, the aircraft began to burn.
The investigation
A thorough examination of the wreckage and engine components was conducted to determine the root cause of the power loss. Investigators focused on the engine's supercharger system, which is critical for maintaining manifold pressure and engine performance at various altitudes and throttle settings.
The inspection revealed significant internal damage within the supercharger assembly. Specifically, the investigation found that a bearing within the supercharger had failed. This mechanical failure prevented the supercharger from functioning correctly, leading directly to the partial loss of power observed by the pilot during the critical takeoff phase.
Findings
The primary factor contributing to the accident was the mechanical failure of the engine's supercharger. The specific component that failed was a bearing within the supercharger unit. This failure resulted in a partial loss of engine power, which compromised the aircraft's ability to climb and clear obstacles after takeoff.
The pilot's decision to jettison the chemical load was an appropriate emergency response to improve performance, but it was insufficient to overcome the power deficit caused by the mechanical failure. The subsequent impact with the embankment and the resulting nosed-over position were direct consequences of the inability to gain altitude.