Piper PA-28R-200 Arrow Force Lands In Pennsylvannia

The pilot said the airplane was in cruise flight at 7,500 feet when the engine began to "surge" and then, shortly thereafter, stopped producing power. He selected a forced landing area in a clearing, but the airplane entered trees before reaching the clearing and came to rest upright in flat, heavily wooded terrain. Examination of the engine at the scene revealed that it could not be rotated by hand, and metal particles were contained in the oil filter and the finger strainer. Disassembly of the engine at the manufacturer's facility revealed the oil sump contained debris associated with the No. 3 connecting rod, piston, and attachment hardware. The connecting rod had fractured at the crankshaft and punctured the crankcase. The fractured end of the rod was exposed in the hole and examination revealed evidence of oil starvation at the No. 3 connecting rod journals, which resulted in the rod's separation from the crankshaft. Metallurgical examination of No. 3 bearing fragments and intact bearings harvested from the engine revealed material and construction discrepancies between the aftermarket manufacturer's parts drawings and the bearings themselves. The connecting rods used in the accident engine were not approved for installation by the engine manufacturer; however, the bearings used with the connecting rods were properly matched to the rods installed. Because the connecting rods and, therefore, the connecting rod bearings, were not the correct parts for the engine, it is probable that the bearings failed from improper part selection and, therefore, possibly improper material selection. 

Probable Cause(s): The reinstallation of improper connecting rods at engine overhaul, which resulted in abnormal wear of the connecting rod bearings; while the bearings did not meet the manufacturer's specifications, the use of the unapproved connecting rods more likely caused the bearing wear.

Note: The report republished here is from the NTSB and is printed verbatim and in its complete form.