Accident Overview
On April 11, 2024, at approximately 0825 central daylight time, a Piper PA-32 (registration N651ED) was substantially damaged during a forced landing near Sullivan, Missouri. The passenger sustained minor injuries, while the pilot was not injured. The flight was conducted as a personal flight under Title 14 Code of Federal Regulations Part 91.
Flight History
The flight departed Rochester International Airport, Rochester, Minnesota, around 0600 after a preflight check and normal engine run-up. The intended destination was Kirk Field Airport (PGR) in Paragould, Arkansas. About two hours after takeoff, the pilot noticed a slight drop in engine rpm. He attempted to troubleshoot by turning on the auxiliary fuel pump, switching fuel tanks, and adjusting the fuel mixture, but was unable to restore power. Approximately two minutes after the initial rpm drop, the engine surged and then lost all power.
The pilot notified air traffic control of the engine power loss and prepared for a forced landing in a field. During the landing roll, the airplane struck trees at the edge of a down-sloping, wet field. The aircraft came to rest upright, with substantial damage to the stabilator, fuselage, and both wings.
Engine Examination
Postaccident review of the engine monitor data showed an increase in oil temperature and a decrease in oil pressure before the total loss of engine rpm. An initial examination at the accident site revealed a bent No. 3 cylinder intake valve pushrod tube and a crack in the engine case.
Further examination of the engine and its accessories revealed little to no impact damage except for a crack in the right engine case above the No. 3 cylinder and bent pushrods on cylinder No. 3. The engine mount exhibited minor impact damage consistent with damage from the nose gear during the accident sequence. The three-bladed propeller remained attached to the engine crankshaft, with one blade having a small bend near the tip; the other two blades were undamaged.
The engine crankshaft was fractured in two areas. Examination by the NTSB Materials Laboratory indicated that the crankshaft fractured through the webs between the second main (M2) and third crankpin (C3) journals, and between the fourth crankpin (C4) and third main (M3) journal positions. The fractures were caused by fatigue cracking that initiated at multiple sites along the radius between the bearing journals and the webs. The fatigue crack initiation sites were located near rotational wear bands. The bearings exhibited wear patterns consistent with rotational contact between the faying surfaces on both sides. The inner diameter surfaces and edge faces of two sets of main bearing journals had severe gouging, cracking, and material spalling, consistent with rotational abrasive wear. Additionally, the cylinder No. 4 connecting rod exhibited a reverse-bending fatigue fracture that initiated at each flange face, and the associated bearing had severe spalling and wear on the interior surface.
Maintenance History
According to maintenance records, the engine was rebuilt in 1986 and later overhauled in 1997 due to a crack in the case. The bearing part numbers and build dates on the accident engine were consistent with having been replaced during that overhaul. Lycoming Service Instruction 1512, issued in 2004, listed those bearing part numbers as obsolete and superseded by improved bearings. The instruction required the use of upgraded bearings whenever new bearings were installed; however, it was issued about seven years after their installation. Lycoming Engine Service Instruction 1009BE stated that the time between overhaul (TBO) for the accident engine was 2,000 hours of operation or 12 years, whichever occurred first. Federal aviation regulations do not require Part 91 operations to follow manufacturer service instructions.
The airplane's most recent annual inspection was completed on August 24, 2023, about seven months before the accident. At that time, the engine had accrued about 2,353.7 hours since the 1997 overhaul. An oil sample analysis performed as part of the inspection returned normal results.