What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
On October 31, 2024, at 1620 mountain standard time, a Piper PA-32-300, privacy data omitted, 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 part 91 personal flight. According to the pilot he was about 2,000 ft above the ground when he heard two loud “booms” followed by a loss of engine power. Shortly after, smoke and flames appeared inside the cabin near the forward right-side floorboard area. The pilot successfully extinguished the fire with a fire extinguisher and performed a forced landing to an open field. The forward right side area of the fuselage was substantially damaged. Preliminary examination of the engine revealed that the no. 3 cylinder was separated from the crankcase. Detailed examination revealed signs of engine case fretting. Further signs of fretting were noted on each cylinder hold-down plate. Damage to the engine was consistent with the no. 3 cylinder base nuts losing torque. Subsequently, the nuts came of the studs and enabled the cylinder barrel to come off the cylinder piston, which resulted in mechanical damage to the studs and engine case, followed by a secondary failure to the no. 3 connecting rod, consistent with the mechanical damage to the engine case, camshaft, and crankshaft. It was also noted that the no. 4 cylinder upper rocker box cover bolt (12 o'clock) was finger-tight. The no. 6 cylinder upper right, lower right, and no. 5 cylinder upper left base nuts were loosened with minimal resistance when using a cylinder wrench. The mating surfaces of the left and right engine case and each cylinder hold down plate (top and bottom) showed signs of fretting indicating improper torque on attaching hardware. The fuel system, ignition system, and intake/exhaust valve trains all displayed signs of normal operation prior to engine stoppage. The propellor, governor, and governor arm were all intact showing no signs of damage. The oil system showed signs of normal operation, except that metal particulates were found in the oil sump and filter. The particulates were consistent with metal from the damaged engine case and cylinder head. The accessory case was unremarkable, and each accessory remained attached to its respective mounting location. At the time of the accident, the engine had a total time of 1168.83 hours since last overhaul. Engine logbook records revealed that is last overhaul was completed in October 9,1997, in which internal engine components were replaced with parts manufacturer approval (PMA) parts. An annual inspection referencing 14 CFR part 43, appendix d, was performed on 06/27/2024 with aircraft total time of 4552.53 and a tach time of 2552.53. The annual inspection was performed by a part 145 repair station. Additional maintenance was performed on the engine on 10/03/2024 by a part 65 certificated mechanic with inspection authorization.
As the FAA filed it
ON OCTOBER 31, 2024, AT 1620 MOUNTAIN STANDARD TIME, A PIPER PA-32-300, ^PRIVACY DATA OMITTED^, 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 PART 91 PERSONAL FLIGHT. ACCORDING TO THE PILOT HE WAS ABOUT 2,000 FT ABOVE THE GROUND WHEN HE HEARD TWO LOUD “BOOMS” FOLLOWED BY A LOSS OF ENGINE POWER. SHORTLY AFTER, SMOKE AND FLAMES APPEARED INSIDE THE CABIN NEAR THE FORWARD RIGHT-SIDE FLOORBOARD AREA. THE PILOT SUCCESSFULLY EXTINGUISHED THE FIRE WITH A FIRE EXTINGUISHER AND PERFORMED A FORCED LANDING TO AN OPEN FIELD. THE FORWARD RIGHT SIDE AREA OF THE FUSELAGE WAS SUBSTANTIALLY DAMAGED. PRELIMINARY EXAMINATION OF THE ENGINE REVEALED THAT THE NO. 3 CYLINDER WAS SEPARATED FROM THE CRANKCASE. DETAILED EXAMINATION REVEALED SIGNS OF ENGINE CASE FRETTING. FURTHER SIGNS OF FRETTING WERE NOTED ON EACH CYLINDER HOLD-DOWN PLATE. DAMAGE TO THE ENGINE WAS CONSISTENT WITH THE NO. 3 CYLINDER BASE NUTS LOSING TORQUE. SUBSEQUENTLY, THE NUTS CAME OF THE STUDS AND ENABLED THE CYLINDER BARREL TO COME OFF THE CYLINDER PISTON, WHICH RESULTED IN MECHANICAL DAMAGE TO THE STUDS AND ENGINE CASE, FOLLOWED BY A SECONDARY FAILURE TO THE NO. 3 CONNECTING ROD, CONSISTENT WITH THE MECHANICAL DAMAGE TO THE ENGINE CASE, CAMSHAFT, AND CRANKSHAFT. IT WAS ALSO NOTED THAT THE NO. 4 CYLINDER UPPER ROCKER BOX COVER BOLT (12 O'CLOCK) WAS FINGER-TIGHT. THE NO. 6 CYLINDER UPPER RIGHT, LOWER RIGHT, AND NO. 5 CYLINDER UPPER LEFT BASE NUTS WERE LOOSENED WITH MINIMAL RESISTANCE WHEN USING A CYLINDER WRENCH. THE MATING SURFACES OF THE LEFT AND RIGHT ENGINE CASE AND EACH CYLINDER HOLD DOWN PLATE (TOP AND BOTTOM) SHOWED SIGNS OF FRETTING INDICATING IMPROPER TORQUE ON ATTACHING HARDWARE. THE FUEL SYSTEM, IGNITION SYSTEM, AND INTAKE/EXHAUST VALVE TRAINS ALL DISPLAYED SIGNS OF NORMAL OPERATION PRIOR TO ENGINE STOPPAGE. THE PROPELLOR, GOVERNOR, AND GOVERNOR ARM WERE ALL INTACT SHOWING NO SIGNS OF DAMAGE. THE OIL SYSTEM SHOWED SIGNS OF NORMAL OPERATION, EXCEPT THAT METAL PARTICULATES WERE FOUND IN THE OIL SUMP AND FILTER. THE PARTICULATES WERE CONSISTENT WITH METAL FROM THE DAMAGED ENGINE CASE AND CYLINDER HEAD. THE ACCESSORY CASE WAS UNREMARKABLE, AND EACH ACCESSORY REMAINED ATTACHED TO ITS RESPECTIVE MOUNTING LOCATION. AT THE TIME OF THE ACCIDENT, THE ENGINE HAD A TOTAL TIME OF 1168.83 HOURS SINCE LAST OVERHAUL. ENGINE LOGBOOK RECORDS REVEALED THAT IS LAST OVERHAUL WAS COMPLETED IN OCTOBER 9,1997, IN WHICH INTERNAL ENGINE COMPONENTS WERE REPLACED WITH PARTS MANUFACTURER APPROVAL (PMA) PARTS. AN ANNUAL INSPECTION REFERENCING 14 CFR PART 43, APPENDIX D, WAS PERFORMED ON 06/27/2024 WITH AIRCRAFT TOTAL TIME OF 4552.53 AND A TACH TIME OF 2552.53. THE ANNUAL INSPECTION WAS PERFORMED BY A PART 145 REPAIR STATION. ADDITIONAL MAINTENANCE WAS PERFORMED ON THE ENGINE ON 10/03/2024 BY A PART 65 CERTIFICATED MECHANIC WITH INSPECTION AUTHORIZATION.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.