The helicopter was being used to transport empty fuel drums from a dump at an elevation of about 6500 feet on the summit of the mountain to the valley floor. One load of 5 drums had been successfully lifted about 10 minutes previously, and the pilot returned to sling load a further 4 drums. He subsequently reported that as he began to lift the drums he detected a change in the engine note. The load was immediately jettisoned, but the engine continued to wind down and the pilot was committed to a landing in a confined clearing. Full collective was applied to arrest the forward speed and the aircraft landed heavily. After the helicopter had come to rest the pilot extinguished a small fire which had broken out at the rear of the engine compartment. At the time of the accident, the helicopter was being operated well within its performance capabilities. When the heavy touchdown occurred, the exhaust pipe was severely distorted, restricting the flow of exhaust gasses. As a result, the turbine assembly experienced an extreme over-temperature condition and the blades and guide vanes were melted before the engine was shut down. This damage precluded the investigation of any possible malfunction of the assembly during the hover immediately before the engine apparently lost power. No other defect or malfunction was discovered and the reason for the reported loss of power remains undetermined.
