What happened
On July 16, 2024, at 00:55 central daylight time, a McDonnell Douglas Helicopter 600N, registration N609RP, was destroyed following an accident near Eagle Lake, Texas. The aircraft was being operated by Last Shadow to provide flight services for law enforcement training.
The pilot was flying at approximately 60 feet above ground level and a speed of about 20 knots when he heard a bang. Following this sound, the helicopter experienced a partial loss of engine power and low rotor RPM. The pilot attempted an autorotation, but the aircraft struck the terrain, resulting in the destruction of the fuselage, main rotor, and tailboom. The accident resulted in one serious injury and four minor injuries, while the pilot was uninjured.
The investigation
Investigators examined the fuel system of the aircraft, which utilizes left and right fuel cells with baffles to separate forward and aft portions. While fuel is intended to be drawn from the aft portion of the left fuel cell, post-accident examination revealed the installation was drawing fuel from the forward portion instead. During recovery, only approximately 19.5 gallons of fuel were found in the aft portion of the left fuel cell.
Further inspection of the fuel system showed that the fuel start/boost pump was missing, and the electrical wires for the pump had been cut and secured with zip ties. An analysis of the Engine Control Unit (ECU) data showed the unit commanded the fuel metering valve to a full open position in response to declining rotor speed, and recorded reduced fuel flow to the engine until the impact.
Maintenance records indicated that the pilot, who held airframe and powerplant ratings, had performed maintenance on the fuel system on July 10, 2024, to install forward and aft fuel probes. This maintenance would have required the inspection of the components that were later found to be improperly installed.