Incident
During a takeoff from a refueling pad, the helicopter's engine lost power. The pilot initiated an autorotation. However, because the aircraft did not yet have sufficient airspeed or altitude to complete a successful autorotation, it landed hard. The main rotor blades flexed downward and impacted the tail boom.
Investigation
It was later determined that water contamination had accidentally been transferred from a portable refueling barrel to the aircraft's fuel system during hot refueling, which was performed with the engine still running. Investigators could not determine how water was introduced into the portable refueling barrel.
Cause
The investigation established that water contamination, introduced from the portable refueling barrel into the helicopter's fuel system during hot refueling, led to the engine power loss.