NTSB Identification: NYC01LA013.
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Accident occurred Sunday, October 15, 2000 in SOUTHBOROUGH, MA
Probable Cause Approval Date: 11/06/2001
Aircraft: Piper PA-28-181, registration: N4381S
Injuries: 2 Uninjured.
NTSB investigators may have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
The airplane was in a climb, passing 3,500 feet, when the pilot heard a "bang". The engine lost power, and oil began leaking from the engine compartment. The pilot then made a forced landing on the Massachusetts Turnpike. During the landing flare, the airplane struck highway reflectors, a sign, and an automobile. Examination of the airplane's Lycoming O-360-A4M engine revealed a breach in the casing, in the vicinity of the number 1 piston. In addition, the number 1 piston connecting rod cap was missing, along with one complete rod bolt, and the manufactured head of the other rod bolt. The fracture surfaces were obliterated, and did not provide any clues of fracture event initiation. Type 74502 connecting rods were used in the overhaul of the engine. Since its certification in November 1974, the O-360-A4M engine had always been manufactured utilizing LW-11750 connecting rods. Predecessor O-360 series engines were manufactured using 74502 connecting rods; however, those rods and their immediate successors were superceded by LW-11750 connecting rods in May 1970. The LW-11750 connecting rod had a larger grip area than the 74502, and utilized a longer rod bolt to secure the connecting rod cap to the connecting rod yoke. There was, however, no evidence that the use of the 74502 connecting rod would have resulted in a rod or rod bolt failure. At the time of the accident, the engine's time since overhaul was 50 hours.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: A failed connecting rod assembly, with the initiating event undetermined. Full narrative available
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