What happened
The aircraft was operating during cruise flight when it suffered a complete loss of engine power. Unable to maintain altitude or continue the planned route, the pilot executed a forced landing in an adjacent agricultural field. During the rollout phase after touchdown, the aircraft departed the field and impacted a highway embankment.
The investigation
Following the accident, the engine was removed and subjected to a detailed teardown inspection to determine the mechanical cause of the power loss. Examination of the internal components revealed significant damage consistent with catastrophic failure during operation.
- The number two bearing was found fragmented within the oil sump.
- The number two main bearing saddle exhibited deformation on both crankshaft halves.
- The crankshaft itself was fractured at the number three cheek, specifically at the aft radius of the number two main bearing.
Findings
The physical evidence points to a mechanical failure within the engine's rotating assembly. The fragmentation of the number two bearing likely initiated the sequence of events leading to the deformation of the bearing saddle and the subsequent fracture of the crankshaft. This internal structural failure resulted in the immediate loss of engine power while the aircraft was in flight.
Safety message
Regular inspection of engine components, particularly bearings and crankshafts, is critical for detecting early signs of fatigue or wear that could lead to in-flight power loss.