Cessna 210 N5779J accident near Brent, Alabama

Probable cause

The inadequate maintenance of the oil filter adapter, which resulted in in an engine oil leak and subsequent loss engine oil pressure, and the subsequent off-airport landing.

NTSB analysis

During cruise flight, the pilot noticed a drop in engine oil pressure and turned toward the closest airport. The pilot subsequently elected to perform a precautionary off-airport landing during which the airplane sustained substantial damage.

A postaccident examination of the engine revealed that it was equipped with a screw-on oil filter adapter. Oil seepage was found on the area surrounding the oil filter adapter attachment point, in the engine compartment, and on the underside of the fuselage. Examination of the adapter found its tightening torque to be 38.5 ft-lbs, which was below the prescribed installation torque of 65 ft-lbs. Additionally, the adapter was found installed with the originally specified fiber gasket, which the manufacturer had subsequently advised to remove and replace with a copper gasket in a mandatory service bulletin. The fiber gasket was found torn and indented. It is likely that the loose adapter and the torn fiber gasket allowed the engine oil to be pumped overboard. This ultimately resulted in the loss of oil pressure and the pilot’s decision to perform the precautionary off-airport landing. It is likely that had the mandatory service bulletin been complied with, the loss of oil pressure would not have occurred.

Text from the NTSB. Open the NTSB docket for ERA22LA071 for the full record.