Piper PA-28-R200 N1939T accident near York, South Carolina

Probable cause

Loss of engine power due to improper welding of the crankcase, which resulted in fatigue failure of the through-studs and a subsequent separation of the number two cylinder. Contributing to the accident was the unsuitable terrain for a forced landing.

NTSB analysis

Shortly after departure, while climbing through 4,000 feet, the airplane experienced a "sudden and violent shuddering," followed by smoke penetration into the cockpit. The pilot performed a forced landing to a field, during which the airplane was substantially damaged. Examination of the engine revealed the number two cylinder had separated from the engine crankcase and the through-bolts that attached the cylinder to the crankcase were fractured due to fatigue. Evidence of welding in the cylinder deck area of the crankcase was observed, which produced a soft condition in the cylinder mounting flanges and subsequent non-standard loading and fatigue fracture of the studs. The engine manufacturer does not allow welding in the critical cylinder deck area of the crankcase. According to the engine maintenance records, the engine was overhauled 2 years prior to the accident and had accumulated 679 hours since then.

Text from the NTSB. Open the NTSB docket for NYC08LA086 for the full record.