Accident Overview
On 30 April 2001, at 0632Z, a Robinson R22 Beta helicopter, registration ZS-HWG, operated under private category, was involved in an accident on Farm Bondur in the Vivo/Messina district. The pilot, aged 34 and holding a valid private license, had accumulated approximately 3,000 total flying hours, including about 1,400 hours on type. The aircraft carried one pilot and one passenger (a veterinary surgeon). No injuries or fatalities were reported.
Flight Sequence
The flight originated from Farm Bondur for a game capturing operation. The veterinary surgeon on board darted a buffalo from the air. Following the darting, the pilot landed the helicopter on a farm road near the tranquilized animal so the veterinarian could disembark and attend to it. The pilot then took off again to hover near the area to direct ground crew to the animal's location.
Malfunction and Forced Landing
While in a hover, the pilot heard a loud noise and experienced an engine over-speed condition. He immediately initiated an autorotational landing. During the descent, the helicopter collided with a tree.
Probable Cause
The investigation determined that a foreign object entered between the forward V-belt and the pulley, causing the belt to be driven from its position and wedged between the rear pulley and belt. Both drive belts were subsequently driven from the pulley, resulting in a total drive failure.