What happened
While holding to the southwest of the airport at approximately 70 knots and 300 feet AGL, the turbine engine of the helicopter experienced a flameout while awaiting landing clearance.
Upon the engine failure, the instructor took control of the aircraft and initiated an autorotation toward an open athletic field. During the approach, the instructor performed an abrupt flare to avoid hitting a baseball backstop. This maneuver resulted in a hard landing, which caused the main rotor blades to droop and sever the tailboom.
The investigation
A post-accident examination of the fuel system identified an incorrectly installed float arm. Investigators found that approximately 250 ml of jet fuel had been drained from the main fuel cell. Additionally, an auxiliary fuel tank was discovered to be full of fuel, while the pilot's cockpit control lever for that tank was in the off position.