What happened
On the morning of 13 June 2002, a Robinson R-22, registration ZS-RGM, departed from Farm Maranda in the Letaba Area for a wildlife darting operation. The flight, which included a pilot and a veterinarian, was intended to capture a sable antelope. Weather conditions at the time of departure were favorable, characterized by clear skies and light winds from the north.
Roughly six minutes after takeoff, the crew identified the target antelope. As the helicopter positioned itself to the right of the animal to allow the veterinarian to dart from the left side, the aircraft was flying at an altitude of about 40 feet with an airspeed of 30 knots. During this maneuver, the engine emitted one or two backfire sounds before suffering a complete power loss.
With the engine failed, the pilot attempted an immediate forced landing directly ahead. The descent required navigating through thick vegetation and trees. Upon contact with the ground, the left skid of the helicopter struck a tree stump, causing the aircraft to roll onto its right side. There were no injuries to the occupants.
The investigation
The investigation focused on the sudden loss of engine power during the low-altitude flight. Investigators examined the mechanical state of the engine and the cockpit environment during the darting procedure. The inquiry looked specifically at the positioning of the crew and the physical actions taken during the animal identification phase.
Findings
- The engine failure was likely caused by the accidental movement of the fuel shut-off lever into the 'off' position.
- It is believed the veterinarian may have inadvertently disturbed the incorrectly installed fuel shut-off lever while attempting to dart the antelope.
- The forced landing was necessitated by the sudden loss of power at a very low altitude (40 feet).
- The impact with a tree stump during the landing sequence caused the subsequent rollover of the aircraft.