Accident Overview
During a cross-country flight in dark night conditions, the aircraft suffered a total loss of engine power and a total loss of electrical power. Subsequently, the airplane impacted trees and terrain.
Investigation Findings
Post-accident examination confirmed engine continuity and revealed no conditions within the engine that would have caused a loss of power. The investigation focused on the electrical system. The primary electrical lead from the alternator to the main bus was found separated at the alternator terminal.
Metallurgical analysis conducted by the National Transportation Safety Board (NTSB) examined the broken ends of the alternator cable. Reconstruction of the cable ends showed that the cable was bent through an angle of 90 degrees adjacent to the separation point. This deformation is consistent with damage that can occur during the crimping process. Further examination of individual wires revealed that a few contained ductile dimple features on their fractured surfaces, along with necking deformation adjacent to the fracture. These features are indicative of overstress separation.
Fuel Details
The aircraft had a total usable fuel quantity of 72 gallons. The calculated fuel burn for the flight was 49 gallons, indicating that fuel exhaustion was not a factor in the power loss, as sufficient fuel remained onboard.