What happened
On 29 July 2010, a Robinson R22 Beta helicopter, registration ZS-RRM, was conducting a private flight within the Rand Aerodrome general flying area in Gauteng. While maintaining a stable hover approximately 10 feet above the ground, the pilot attempted to observe the effects of manual throttle adjustments on the aircraft's performance.
During this maneuver, the pilot briefly closed and then immediately opened the throttle. Because the aircraft's governor was not active, the engine and rotor RPM responded with unexpected intensity, quickly entering the yellow and red arcs on the tachometer. As the pilot focused on the instrument panel to manage the over-speed, the aircraft began to bank to the right and lose altitude. The right skid made contact with the ground, triggering a dynamic rollover that left the aircraft on its side with substantial damage. The pilot escaped the incident without injury.
The investigation
SACAA AIID investigators examined the aircraft and the pilot's actions following the accident. The investigation confirmed that the pilot held a valid private pilot license and a current medical certificate. While the aircraft was found to be in a serviceable condition with all documentation in order, the investigation focused on the operational state of the governor system.
Investigators determined that the governor system was not malfunctioning; rather, it had been manually switched off by the pilot. The investigation also reviewed the pilot's flight experience and the circumstances of the throttle inputs, noting that the pilot's focus on the tachometer readings led to a critical loss of situational awareness regarding the helicopter's attitude and altitude.