Collision with terrain involving a Robinson R22 Beta, VH-JNL, 4 km south of South Alligator River Ranger's Station, Northern Territory, on 15 December 1994

The helicopter was being used for a controlled firebombing and burning off operation. The pilot had been flying very slowly just above the treetops, then after turning onto a southerly heading he believed the engine lost power and was unable to prevent it from striking the tops of the trees. It then descended steeply into the ground, the pilot receiving severe back injuries, and the passenger a broken arm.

An investigation of the helicopter and engine failed to find any fault, or malfunction, that may have caused the engine to lose power.

Weather conditions were very hot with a light northerly wind blowing.

The helicopters weight was calculated to be in excess of its maximum all up weight, with heavy items of equipment stored in the areas below the seats, contrary to the flight manual and placarded instructions.

Being overweight for the operation, and turning downwind, i.e. to the south, the helicopter probably suffered a loss of translational lift with subsequent overpitching of the rotor system by the pilot, giving the impression that the engine had lost power. With no available height margin the pilot was unable to avoid flying into the trees.