What happened
On 1 February 2002, a Robinson R-22 Beta, registration ZS-REH, was conducting a recurrent training flight at Rand Airport (FAGM). The flight, which involved an instructor pilot and a private pilot, was intended to practice emergency procedures, specifically a power recovery auto-rotation from 500 feet altitude.
During the maneuver, the aircraft entered a turn from the downwind position. While the initial phase of the auto-rotation appeared stable due to a slow turn rate, the rate of descent increased significantly as the pilot applied more bank. Recognizing the danger, the instructor attempted to abort the maneuver by initiating an early flare. Despite applying full throttle and collective, the aircraft continued to descend rapidly. The helicopter struck the ground at an airspeed of approximately 30-35 knots, causing the main rotor blades to sever the tail boom and the skid gear to collapse. Both occupants disembarked from the upright aircraft without injury.
The investigation
The investigation focused on the flight dynamics during the auto-rotation and the environmental conditions present at the time of the accident. Investigators examined the aircraft's performance during the turn and the pilot's recovery attempts. Meteorological data revealed an approaching thunderstorm from the south, which was generating wind conditions of 350 degrees at 12 knots.
Findings
- The primary cause of the high rate of descent was the pilot's failure to compensate for changing wind directions during the maneuver.
- Severe wind gust conditions were present due to an approaching thunderstorm.
- The instructor continued the auto-rotation toward the west, which, combined with the southern wind, led to an unrecoverable descent rate.
- The aircraft sustained structural damage to the tail boom and landing gear upon impact.