Lancair LC41 N2514F accident near Cleburne, Texas

Probable cause

A total loss of engine power due to oil starvation as the result of the oil pressure switch failure due to a manufacturing defect.

NTSB analysis

The pilot departed on a maintenance test flight in the airplane to break in an engine cylinder, which had just been replaced. During the flight, the pilot noticed an oil pressure warning light illuminate, followed by a low oil temperature indication. The pilot attempted to divert to a nearby airport; however, the engine experienced a total loss of power, and he conducted a forced landing, during which the wings sustained substantial damage. Examination of the airplane revealed a hole in the engine case above the No. 4 cylinder. Further examination revealed that the engine oil pressure switch had separated into two pieces . A detailed examination of the switch found that it had failed at a manufacturing swaged joint between its threaded section and cap piece. Therefore, it is likely that the swaging process was insufficient during manufacture. The broken switch allowed engine oil to escape the system, resulting in oil starvation and failure of the No. 4 cylinder.

Text from the NTSB. Open the NTSB docket for CEN19LA159 for the full record.