Accident Overview
While returning to the home airport after an annual inspection, the pilot noticed the engine oil pressure decreasing to zero. Approximately three minutes later, the engine seized. The pilot subsequently executed an emergency landing with the landing gear retracted in a farm field.
Investigation Findings
Examination of the aircraft revealed that the oil pressure line had fractured at the flared end, where it connected to a 90-degree fitting on the crankcase. A metallurgical analysis of the broken component determined that the fracture resulted from overload. The investigation also uncovered additional maintenance discrepancies in the electrical system. Wires from the over-voltage relay's field terminal and the alternator field terminal were misrouted, causing the voltage regulator to operate without proper regulation. Furthermore, an alligator clip was found attached to the wiring.
Examination Details
The oil pressure line failure led to a total loss of oil pressure, resulting in engine seizure. The misrouted electrical wires and the presence of an alligator clip indicated improper maintenance practices. No further information was provided regarding the aircraft type, registration, operator, location, or any injuries.