Accident Overview
On August 22, 2014, at 1554 central daylight time, a Piper PA-28-161, registration N8440N, ditched into Lake Pontchartrain near Lakefront Airport (NEW), New Orleans, Louisiana. The pilot, the sole occupant, was not injured. The aircraft sustained substantial damage. The flight was operated under 14 CFR Part 91 as a personal flight, with visual meteorological conditions prevailing. It departed Jack Brooks Regional Airport (BPT), Beaumont/Port Arthur, Texas, at 1353 bound for NEW.
Pilot Report
The pilot stated he departed BPT with about 17 gallons of fuel in the left tank and 24 gallons in the right tank. He took off with the right tank selected and switched tanks every 30 minutes. The flight was uneventful until descending from 1,500 feet above ground level (agl), when the engine experienced a total loss of power. Multiple restart attempts failed. He was cleared to land on runway 09 but could not glide to the runway. The pilot ditched the airplane a quarter mile west of runway 09's threshold, egressed, and swam to shore. The aircraft sank.
Postaccident Examination
An FAA inspector noted fuel leaking from the right wing after the aircraft was recovered inverted on a barge. Examination revealed that the engine's crankshaft gear retaining bolt was separated at the head; the lockplate did not appear bent or out of place. The bolt, gear, and lockplate were sent to the NTSB Materials Laboratory for analysis.
Laboratory Findings
Scanning electron microscopy revealed very fine fatigue striations in the fracture surfaces of the bolt, which fractured at the fillet radius between the shank and head. The crankshaft gear's counterbore inner surfaces showed fretting and polishing wear scars, including a defined wear scar partially around the bolt through-hole. The lockplate exhibited similar wear and its retention tab was in the open position, without typical deformation from bending to 90°.
Service Bulletin and Airworthiness Directive
Lycoming Service Bulletin 375 Revision C (January 30, 2003) stated that damage to the crankshaft gear and counterbored recess results from improper assembly or reuse of worn parts, and that failure of these parts would cause complete engine stoppage. Compliance was mandatory during engine overhaul, gear removal, or after a propeller strike. FAA Airworthiness Directive 2004-10-14 made the SB mandatory and required compliance before further flight after a propeller strike.
Additional Information
The pilot initially reported no knowledge of prior propeller strikes. However, on December 11, 2014, he told an FAA inspector that a propeller strike occurred days before the accident flight. The pilot stated he was unaware of the AD, so it was never completed.