Engine Failure During Flight Leads to Crash on Rolling Terrain (N57751)

Incident Overview

According to the pilot, the engine was running smoothly during the flight but appeared to lack power. The pilot checked the instruments and observed that manifold pressure and engine RPM were within normal ranges. While at approximately 60 feet above ground level (AGL), all engine power was lost. The aircraft subsequently crashed on rolling terrain.

Investigation Findings

An investigation into the accident revealed that the aircraft was operating near its maximum weight limit, and the pilot had not jettisoned the load. A teardown inspection of the engine disclosed that the #1 exhaust valve rocker shaft cover was missing. This allowed the respective shaft to come out and the rocker arm to become loose. Additionally, the top rings on the #1 and #4 cylinders were found to be broken, with evidence indicating that these rings had been broken for an extended period of time. Oil was also found on the air side of the fuel control manifold. The engine had accumulated only 43 hours of flight time since its last major overhaul.