What happened
During the initial climb phase of flight, while at an altitude of 350 feet and a speed of 55 mph, the engine of the helicopter failed. The pilot reported that power lines were positioned directly ahead of the aircraft's path, prompting a decision to execute a 90-degree left autorotation. During this maneuver, the aircraft experienced a fast descent and impacted the ground. The landing was described as hard, resulting in damage to the tail boom.
A passenger on board reported hearing a "pop pop" noise approximately 40 seconds after takeoff, followed by the rapid descent. The passenger sustained one injury, specifically a burst L1 vertebra.
The investigation
An FAA airworthiness inspector examined the aircraft to determine the cause of the engine failure. The inspection revealed that the engine could be turned by hand without any binding. The spark plugs were found to be in good condition, and the fuel filter was clean and unobstructed, with fuel present in the filter. Additionally, the flight controls were confirmed to be free and moving. No mechanical anomalies were reported regarding the aircraft or the engine following the inspection. A review of the aircraft logbooks indicated that the most recent annual inspection had been completed on June 01, 1997.