Forced/precautionary landing involving a Agusta 47-J, VH-UTZ, Kings Canyon, Northern Territory, on 7 September 1994

The helicopter was conducting a scenic flight at Kings Canyon when the engine began to run rough and lose power. The pilot lowered the collective pitch lever, opened the throttle and turned towards lower terrain. The engine would not deliver sufficient power to sustain level flight, so the pilot commenced an approach to an adjacent helipad. During the landing the tail stinger and tail rotor struck the ground.

An examination of the engine revealed a spark plug malfunction and an intermittently sticking exhaust valve in the number 4 cylinder, and the pushrod ball end in the number 1 cylinder was also found to be loose, preventing the exhaust valve from fully opening.

The power loss from these engine faults, combined with the high-density altitude and weight of the helicopter at the time of the occurrence left the pilot with little option than to make a low powered, semi-autorotational landing as soon as possible.