N154DC

On October 31, 2024, at 1620 mountain standard time, a Piper PA-32-300, N154DC, was substantially damaged when it was involved in an accident near Prescott Valley, Arizona. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 personal flight.

According to the pilot, on the flight before the accident flight he leaned the fuel mixture less and the engine ran richer than he was accustomed to during climb out. On the accident flight, he elected to conduct a local flight to see if he experienced the same fuel mixture discrepancy. He reported no anomaly during engine startup, taxi, or pre-takeoff runup. During the takeoff climb, he noted that again he leaned the fuel mixture less and the engine ran richer than expected. The pilot noted unusual EGT and fuel flow readings during the flight and decided to return to the airport to have maintenance personnel look at the airplane before he flew it again.

During the return to the airport the pilot heard two loud “booms” and then experienced a loss of total engine power. Shortly thereafter, smoke and flames appeared inside the cabin near the forward right-side floorboard area. The pilot successfully extinguished the fire with an onboard fire extinguisher and performed a forced landing to an open field. The forward right area of the fuselage sustained substantial damage.

Postaccident examination of the wreckage showed the No. 3 cylinder had separated from the engine case. Outward deformation of both the upper and lower right engine cowlings was evident, consistent with impact from the separated No. 3 cylinder. Thermal damage was visible to the lower right engine cowling and the forward fuselage.

Examination of the engine revealed the No. 3 connecting rod had fractured and mechanical damage was found to the engine case, camshaft, and crankshaft. Five of the eight base nuts for the No. 3 cylinder were not located. There was evidence of fretting at the engine case mating surfaces and on all six of the cylinders’ hold-down plates, consistent with reduced torque of the engine case nuts and bolts and the cylinder base nuts.

At the time of the accident, the engine had a total time of 1,168.83 hours since its last overhaul. Engine logbook records revealed that the last overhaul was completed on October 9, 1997, during which internal engine components were replaced with Parts Manufacturer Approval (PMA) parts. The latest annual inspection of the engine was performed on June 27, 2024, about 72 operating hours before the accident flight.

The pilot reported that he had identified an oil leak before the accident flight that concerned him, and he had intended to have maintenance personnel troubleshoot the leak.

Title 14 CFR Part 43, Appendix D, Scope and Detail of Items (as Applicable to the Particular Aircraft) To Be Included in Annual and 100-Hour Inspections—Item (d)(1) directs an inspection for visual evidence of excessive oil, fuel, or hydraulic leaks, and sources of such leaks. Item (d)(2) directs inspection of engine studs and nuts for improper torquing.

The pilot did not submit a Pilot Operator Aircraft Accident/Incident Report (NTSB Form 6120.1).