On June 14, 1993, an Enstrom F-28C (registration N51717) was involved in an aviation accident near Buckner, MO. Investigators recorded the probable cause as: THE NUT BACKING OFF THE CONNECTING ROD BOLT RESULTING IN ROD FAILURE. A FACTOR INVOLVED IN THIS ACCIDENT WAS THE LACK OF SUITABLE TERRAIN FOR THE PILOT IN COMMAND TO MAKE A RUN ON LANDING. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
During a power line inspection flight, a helicopter experienced a mechanical jolt and made an emergency landing. A fire started in the engine area, destroying the aircraft and a nearby shed. The occupants evacuated safely.
Incident Overview
During an aerial observation flight to inspect the Sibly-Blue Springs power line, the pilot and passenger reported hearing a 'clunk'/'pop' and felt a jolt. The pilot initiated an immediate autorotation. With no suitable area for a safe run-on landing, the pilot executed a hard emergency landing. The helicopter slid to a stop next to a corrugated metal and pole shed.
Fire and Evacuation
Upon landing, the pilot noticed a fire had started in the engine area. The pilot and passenger evacuated the aircraft before it and the nearby pole shed were completely engulfed in flames.
Engine Examination
A subsequent teardown of the engine revealed that the No. 2 cylinder connecting rod was embedded in the skirt of the cylinder. A connecting rod nut found in the crankcase was ovalized; however, the internal threads appeared free of substantial damage and were not stripped.