Accident Overview
On August 19, 2023, at approximately 1800 eastern daylight time, a Piper PA28-180, registration N7463W, sustained substantial damage during an accident near Preston, Connecticut. The pilot and one passenger were not injured. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal flight.
The pilot reported departing Martha’s Vineyard Airport (MVY), Vineyard Haven, Massachusetts, with a destination of Groton-New London Airport (GON), Groton, Connecticut. After reaching a cruise altitude of 4,500 feet mean sea level, the oil pressure gauge indication dropped to zero. Shortly thereafter, oil began pouring from the engine cowling and flowing up the windscreen. The engine subsequently lost total power. The pilot attempted to glide to GON but was unable to reach the runway, and instead set up for a landing in a field. The landing was successful, but during the rollout, the right wing struck a metal pipe concealed in brush. The airplane rotated 180 degrees and the right wing separated from the fuselage, resulting in substantial damage.
Engine Examination
Post-accident examination of the engine revealed that the left side of the engine case was ruptured, with fragments resting on top of the engine. The left crankcase half above the No. 2 cylinder was fractured and separated from the engine. The crankshaft end of the No. 2 connecting rod was separated from the crankshaft’s No. 2 rod journal. The rod was deformed, consistent with battering against the rod journal and the interior of the right crankcase half. One portion of the rod, including a rod bolt hole, was bent inward, and the rod bolt was missing from that hole. A bent portion of a rod bolt with a nut still installed was recovered from the crankcase interior, along with a portion of the rod cap with the head of the rod bolt still in place. The other portion of the connecting rod, the corresponding half of the rod cap, and the rod bolt were separated and not recovered. Thin ferrous material, consistent with remnants of the No. 2 bearing, was also found in the crankcase and oil sump. The No. 2 cylinder was removed, and the crankshaft was rotated via the propeller flange. Continuity of the crankshaft to the rear gears and to the valvetrain of cylinders Nos. 1, 3, and 4 was confirmed, and compression and suction were observed from those cylinders.
Maintenance History
A review of the airplane’s maintenance logs showed that the most recent engine overhaul was completed on October 1, 1998. A log entry dated June 20, 2007 documented that the engine was disassembled and inspected due to “metal contamination,” with installation of new main and rod bearings. An annual inspection entry dated June 1, 2022 noted that the oil and oil filter were replaced, but did not indicate whether the old filter was cut open and inspected for contamination. Cylinder compression readings recorded in that entry were: No. 1 – 80 psi, No. 2 – 42 psi, No. 3 – 75 psi, No. 4 – 42 psi, with no corrective actions noted. An entry dated May 12, 2023 indicated that the tachometer reading was 3,500.5 hours, engine time since major overhaul was 939.5 hours, and time since the 2007 disassembly was 631.5 hours. The oil was changed, the oil filter replaced, and the previous filter was cut open and examined with “no contaminants found.” Cylinder compressions were recorded as: No. 1 – 74 psi, No. 2 – 22 psi, No. 3 – 70 psi, No. 4 – 35 psi. The entry also stated, “Lap exhaust valves on cylinders #2 and #4. Recommend retest in 10 hours.” Lycoming Service Instructions No. 1191A and No. 1009BE provide guidance on cylinder compression limits and overhaul intervals, respectively, but no direct causal link is documented.