The aircraft was engaged in pig shooting operations, and was making the second sortie for the day. While cruising at about 150 feet above ground level, the pilot heard a loud bang, and all engine power was lost. At the time the aircraft was over flat country with scattered trees. While manoeuvring the helicopter to a cleared area, the pilot carried out a descending turn, during which the tail rotor struck the branches of a tree. The tail rotor blades disintegrated and the helicopter struck the ground heavily. Initial inspection revealed the presence of several cracks in the engine crankcase. The connecting rod in one of the engine cylinders had broken just above the big end bearing. The fracture was typical of fatigue propagation, followed by overload, but the extent of the damage precluded the location of the origin of the fatigue. The cracks in the crankcase had been caused by the flaying of the connecting rod after the failure. The pilot had not seen the branches struck by the tail rotor, probably because they were protruding from the tree and had no foliage attached.
