History of Flight
On Wednesday, 19 April 2023, at 1145Z, a flight instructor and a student pilot departed Mossel Bay Aerodrome (FAMO) in a Guimbal Cabri G2 helicopter, registration ZS-HKC, for autorotation training (Exercise 14). The flight was conducted under visual meteorological conditions (VMC) by day in accordance with Part 141 of the Civil Aviation Regulations.
During the third autorotation, initiated at 800 feet above ground level (AGL) with the student pilot as the pilot flying, the instructor called out "opening throttle" at 300ft AGL and opened the throttle, but the engine did not respond. The low oil pressure warning light (red) had illuminated. The instructor took control and observed a slight decay in main rotor RPM. He lowered the collective pitch lever fully and initiated a flare at approximately 40ft AGL.
The helicopter touched down hard at about 15 knots on its skid gear on even ground approximately 1.6 nautical miles west of FAMO. It bounced, rotated about 90° to the right, and came to rest upright.
Injuries and Damage
The flight instructor sustained a mild head injury with a superficial abrasion (10 cm) to his right temple. The student pilot was not injured. The helicopter sustained substantial damage. The tail boom was severed by the main rotor blades during the bounce and rotation.
Meteorological Conditions
Surface wind was 260° at 3 knots, temperature 21°C, dew point 16°C, with CAVOK conditions.
Probable Cause
The flight instructor initiated the flare at 40ft AGL and the helicopter touched down hard on its skid gear as there was not enough inertia in the main rotor blades to cushion the landing. The helicopter bounced back into the air and rotated approximately 90° to the right after the tail boom was severed by the main rotor blades.