What happened
On 21 November 2016, a Robinson R22 Beta II helicopter, registration ZS-RPT, was engaged in a private game darting operation at Sterkfontein Farm in the Free State Province. The mission involved a veterinarian using a darting gun to tranquilize blue wildebeest for relocation to another area of the farm. Prior to the flight, both doors had been removed from the aircraft.
During the operation, the pilot performed a right-hand turn to verify the success of a darting attempt. During this maneuver, the low main rotor RPM audible warning activated. The pilot attempted to initiate an autorotation to recover the aircraft; however, the low altitude prevented a successful recovery. The aircraft struck the ground heavily on its left skid, causing it to catch and subsequently undergo a dynamic rollover. The aircraft sustained extensive damage, though there were no injuries to the pilot or the passenger.
The investigation
An investigation by the SACAA AIID established that the aircraft was operating at a low altitude to facilitate the darting process. The inquiry examined the sequence of events following the activation of the low RPM warning and the subsequent impact with the terrain. The investigation confirmed that the pilot was properly licensed and rated for the type of operation being conducted.