ERA23LA173

About an hour into the flight, while cruising at 8,500 ft, light smoke entered the cabin momentarily, and the engine oil pressure dropped to zero. The pilot turned toward a nearby airport and shortly thereafter the engine lost power. Unable to glide to the airport, he saw a cleared field and set up for a forced landing. The airplane touched down on sandy soil, the nose gear dug in and separated, and the airframe was substantially damaged. The pilot was not injured. A postaccident examination of the engine revealed that the oil filter adapter separated at the engine case which likely resulted in a depletion of the engine’s oil supply and the subsequent total loss of engine power due to lack of lubrication. Residual oil covered the area around the adapter-to-engine case opening and below. The adapter threads appeared stripped. The adapter was safety wired in position and there was red torque putty applied as well. A review of the maintenance logbooks revealed that an annual inspection of the airframe and engine was completed about 29 hours before the accident. The logbook entries noted that an airworthiness directive that addressed security of the connection between the oil filter adapter and the engine case, including checking for proper torque, had been complied with during the inspection. The separation of the filter and stripping of the adapter threads were likely indicative of the oil filter adapter threads having failed due to improper torquing of the jam nut.

On March 5, 2023, about 1645 eastern daylight time, a Beech P35 airplane, N9777Y, was substantially damaged when it was involved in an accident near Perry, Florida. The private pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that he was on a cross-country flight from Peter O Knight Airport (TPF), Tampa, Florida, to Apalachicola Regional Airport (AAF), Apalachicola, Florida. About an hour into the flight, while cruising at 8,500 ft, light smoke entered the cabin momentarily and the engine oil pressure dropped to zero. The pilot turned toward Perry-Foley Airport (FPY), Perry, Florida, and shortly thereafter, the engine lost power. Unable to glide to the airport, he saw a cleared field and set up for a forced landing. He lowered flaps to full and lowered the landing gear. The airplane touched down on sandy soil. The nose landing gear dug in and separated. The airplane came to rest upright and the pilot egressed the cockpit and was met by first responders. An initial examination of the wreckage by a Federal Aviation Administration inspector revealed that the lower, forward fuselage had structural damage. The pilot initially reported that the air hose to the oil-air separator failed, and the separator’s canister was split open and empty of oil. The engine crankcase did not contain any oil and the engine was seized. Oil covered the lower fuselage surfaces. Further examination of the engine by an airframe and powerplant mechanic revealed that the oil filter adapter was separated at the engine case. There was residual oil covering the area around the adapter-to-engine case opening and below. The adapter threads appeared stripped. The adapter was safety wired in position, and there was red torque putty applied as well. A review of the maintenance logbooks revealed that an annual inspection of the airframe and engine was completed on December 9, 2022. At the time of the accident, about 29 hours had accrued on the engine since the last annual inspection. The logbook entries noted that Airworthiness Directive (AD) 96-12-22 had been complied with. The AD addressed security of the connection (jam nut) between the oil filter adapter and the engine case, including checking for proper torque. An article from AOPA [Aircraft Owners and Pilots Association] Pilot Magazine, dated May 5, 2005, addressed the oil filter adapter AD. The article stated that, “If the proper torque isn’t applied to the jam nut, the weight of the oil-filled filter combined with normal vibrations will soon cause thread damage to the adapter. In a few cases maintenance practices have been so mindless that the threads got in bad enough shape that the adapter was blown completely out of the engine.”