What happened
On June 10, 2020, a Piper PA32RT-300T, registration N543GS, was conducting a business flight from Walker County Airport – Bevill Field (JFX) in Jasper, Alabama, to Pensacola International Airport (PNS) in Florida. After climbing to a cruise altitude of 15,000 feet, the pilot reported an engine "fluctuation" approximately 40 minutes into the flight and requested a diversion to Craig Field Airport (SEM) in Selma, Alabama.
During the descent toward Selma, the pilot reported that the airplane had experienced a total loss of engine power and that an in-flight fire had started. While the pilot indicated the propeller was still turning, radar and voice communications were lost when the aircraft was approximately 3 miles from the airport at 3,100 feet MSL. The aircraft impacted a field, resulting in 2 fatal injuries.
The investigation
Investigators examined the wreckage and found the fuselage was largely fragmented, with the left and right wings separated at the wing roots. The engine had separated from the airframe upon impact.
An examination of the engine revealed a hole in the top of the crankcase near the No. 6 cylinder and a fracture in the camshaft caused by torsional overstress. The No. 6 connecting rod had detached from the crankshaft journal, which showed severe thermal discoloration. The oil pump body exhibited scoring, and the connecting rod journal bearings showed extensive damage, including heavy wear and overheating discoloration.
Analysis of the oil sump revealed the presence of oil, metallic particles, carbon chips, and organic debris. The oil filter also contained metallic debris and carbon chips. Crucially, the oil suction screen was found to be obstructed, with debris filling approximately 60% of the screen. The investigation noted that the last documented cleaning of the oil suction screen occurred on July 17, 2009, more than 10 years prior to the accident. Maintenance manuals for the engine and airframe required the oil suction screen to be cleaned at 50-hour or 100-hour intervals.
Findings
- The oil suction screen was significantly obstructed by debris, which likely caused oil starvation.
- The accumulation of nonmetallic debris over time contributed to the obstruction of the screen.
- A maintenance entry from the day before the accident noted low oil pressure, which was addressed by adjusting the regulator screw.
- The engine's failure led to a total loss of power and a crankcase penetration, which likely caused the in-flight fire.