WPR18LA051

The pilot reported that, while on final approach for landing, he felt a shudder followed by a loud bang. Immediately after, the windscreen was covered in oil and the engine lost all power. The airplane impacted trees about 2 miles short of the runway. Examination of the engine revealed a large hole in the crankcase above the No. 4 cylinder. Further examination revealed that one connecting rod bolt and the connecting rod cap were missing, and the connecting rod was not attached to the crankshaft. About 6 inches of the camshaft was also missing. The remaining components of the connecting rod, piston assembly, and pieces of connecting rod bearing were examined; all of the discernible fracture surfaces exhibited features consistent with overstress. Extensive postfracture damage to the recovered pieces precluded the determination of any preexisting damage. Based upon the lack of available evidence (the missing connecting rod cap and rod bolt), the cause of the connecting rod failure could not be determined.

On December 14, 2017 about 0854 eastern standard time, a Piper PA32-300, N4326X, was substantially damaged when it was involved in an accident near Hinesville, Georgia. The private pilot received minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. In a statement provided to the Federal Aviation Administration (FAA) Inspector, the pilot said he was on final approach to runway 24R at Wright Army Airfield (Fort Stewart)/Midcoast Regional Airport (LHW), when he felt a shutter, followed by a loud bang. Immediately after, the windshield was covered in oil and the engine experienced a complete loss of power. The pilot reported to the air traffic controller that he was unable to land on the runway, and that he is "going down". About 2 miles short of the runway, the airplane impacted trees. In the National Transportation Safety Board Pilot/Operator Aircraft Accident/Incident Report 6120.1 the pilot reported he was near LHW when "the plane's engine sustained a catastrophic failure; camshaft broke and blew through engine block". The FAA Inspector examined the engine and observed a large hole in the crankcase above cylinder No.4. The crankcase surrounding the hole appeared to be displaced from the inside of the engine, outward. Further examination revealed that one connecting rod bolt and the rod cap were missing, and the connecting rod was not attached to the crankshaft. Furthermore, about 6 in of the camshaft was separated and not located. The NTSB Office of Research and Engineering further examined the remnants of the connecting rod, piston assembly, and pieces of connecting rod bearing. Bearings Both bearing halves had been deformed and flattened; one of the halves was intact and the other had fractured. The fracture surfaces had been heavily damaged which was consistent with post-fracture damage. Portions of the undamaged fracture surface exhibited features consistent with tensile overstress. The fracture surface exhibited a general rough texture with a dull luster, while the areas adjacent to the fracture surface exhibited local plastic deformation in the form of thinning or necking. These features were consistent with overstress fracture. The mating fracture faces of the fractured bearing half also showed a circular impact imprint, consistent with impact from the head of a connecting rod bolt. Connecting Rod Bolt The remaining connecting rod bolt had fractured mid length. The fracture features were generally rough in texture and flat in luster, consistent with fracture from bending overstress. Piston The piston was intact, with the connecting rod still affixed to the piston with the piston pin. The connecting rod had fractured near the crankshaft side at the rod yoke. There were no cracks or indications of severe deformation on any portion of the piston. The underside of the piston exhibited multiple impact and gouge marks, consistent with repeated batter of adjacent or loose components. Thecrown of the piston, the side of the piston and the piston pin exhibited normal wear. Connecting Rod All of the discernible fracture surfaces on the connecting rod exhibited features consistent with overstress fracture. Due to the extensive post-fracture damage to the parts, no indication was found of pre-existing damage.