Amateur-built Lancair IV-P N441L accident near Springfield, Kentucky

Probable cause

A total loss of engine power due to a loss of engine oil as a result of the installation of the wrong oil adapter O-ring seal.

NTSB analysis

Shortly after takeoff, the pilot radioed air traffic control to report that he was losing engine oil pressure and that his windscreen was covered with oil. He was advised that he was 4 miles from the nearest suitable airport. Air traffic control lost radar and communications with the pilot and the airplane crashed at the approach end of a runway at the airport. Visual examination of the engine revealed that the No. 2 connecting rod penetrated through the top of the aft section of the engine case. Examination of the accessory case revealed that a Supplemental Type Certificate (STC) SE5743NM Aviation Development Corporation oil filter adapter was attached to the accessory oil filter adapter fitting. A visual inspection of the oil filter adapter revealed that the O-ring between the mating surfaces was extruding 3/4 inch. Visual inspection of the O-ring revealed that it was leaking oil for an undetermined amount of time and was dry rotted and brittle. Review of the STC revealed that the O-ring was the incorrect part that was installed on the engine. A review of the engine and airframe logbooks did not reveal when the installation of the improper O-ring was performed. The engine had accumulated about 351 hours of operation since manufacture.

Text from the NTSB. Open the NTSB docket for MIA08FA122 for the full record.