Accident Synopsis
On 7 July 2003, a Robinson R-22 Beta helicopter, registration ZS-RBK, was conducting a mountain flying training flight from Wonderboom Airport (FAWB) to the Magalies Mountain Ridge. The student pilot, accompanied by an instructor, had been airborne for approximately 40 minutes, flying along the ridge and assessing wind conditions.
Sequence of Events
After identifying a suitable landing area, the crew flew an approach in a westerly direction. They decided to overshoot and conducted a second approach, which revealed the area was unsuitable for landing due to very uneven and rocky terrain. At this point, the instructor took control of the aircraft and turned right towards the north. During the turn, the low rotor RPM warning sounded. Rather than attempting to fly the aircraft down the lee side of the ridge, the crew executed a forced landing.
Damage and Injuries
The right front skid gear assembly impacted the rocky terrain first at a very slow forward speed, causing the aircraft to roll over onto its left side. The helicopter was substantially damaged. Both occupants, properly secured by safety harnesses, escaped with minor bruises. Stranded on the mountain, they contacted the police air wing, which dispatched a helicopter to evacuate them to safety.
Probable Cause
The pilot exceeded the performance envelope of the aircraft by operating it beyond its design limits, resulting in a condition where the power required exceeded the power available, resulting in a decay in main rotor RPM in close proximity to the ground, rendering ground impact inevitable.