What happened
On November 13, 2002, a Robinson R22 Beta helicopter, registration ZS-RCI, departed Rand Airport for a private flight aimed at conducting recurrent training. The flight included a pilot and one passenger. Upon arriving at Panorama Flight Park, the crew engaged in various maneuvers, including hover exercises near the square.
After performing a series of maneuvers and an air taxi over the runway, the pilot initiated a circuit for Runway 01. During a period of hovering just past the runway threshold, the pilot focused on monitoring engine and rotor performance, noting that manifold pressure remained within the appropriate range. Following this, the crew decided to perform another circuit, returning toward the square.
While turning from the downwind leg onto the base leg at an altitude of roughly 600 feet AGL, the pilot observed the low rotor RPM warning light and heard the associated audio alert. The pilot immediately increased the throttle and monitored the gauges, which showed the rotor RPM had dropped to between 65% and 70%, significantly below the required green band. In an attempt to manage the situation, the pilot lowered the collective pitch while maintaining a speed of approximately 60 knots.
The investigation
The investigation focused on the pilot's response to the low rotor RPM warning and the subsequent flight path. It was established that the pilot waited for the RPM to recover, but the gauges showed no improvement. As the aircraft descended, the pilot attempted a skid landing. At approximately 30 feet above the ground, the pilot attempted to flare the aircraft. During this maneuver, the helicopter yawed to the left and struck uneven terrain, leading to a rollover.
Findings
- The primary cause of the incident was a maneuver induced by the pilot that resulted in a low rotor RPM condition.
- The pilot utilized an incorrect recovery technique following the RPM drop.
- This error led to a high rate of descent, which caused the heavy landing and subsequent rollover of the Robinson R22 Beta.
- There were no injuries to the pilot or the passenger.