Incident Summary
While climbing through 6,000 feet, the aircraft experienced a loss of engine oil pressure. The pilot requested a return to the departure airport but was informed by ATC of a closer alternate airport. The pilot secured the engine, feathered the propeller, and executed a power-off descent toward that airport. Due to the aircraft's altitude, the pilot chose a downwind approach to runway 12L. The aircraft overflew the runway and touched down beyond its departure end. It then penetrated the airport perimeter fence and struck several trees, a sign post, a light pole, and an automobile before coming to rest in a residential area.
Investigation Findings
Examination of the wreckage revealed that the loss of oil pressure was caused by oil leaking from the engine. The oil filler cap was found to have been improperly adjusted following its original installation. The maintenance manual does not approve any field repairs on the engaging mechanisms of the oil filler cap. Additionally, the aircraft's flaps were found at a 7° intermediate setting.
Probable Cause
The official findings state that the probable cause was a loss of engine oil pressure due to improper maintenance performed on the engine oil filler cap by an unknown person. Furthermore, the pilot misjudged the landing approach during the forced landing, resulting in an overshoot and collision with objects. A tailwind was noted as a contributing factor to the overshoot.