What happened
On Thursday, June 11, 1998, at 10:50 AM, a Hughes-Schweizer 269 C helicopter, registration F-GGSH, was conducting a training flight at the Saint-Florentin aerodrome in France. The flight was part of a qualification program involving an instructor and a student pilot.
During the conclusion of a training session, the student pilot was performing a demonstration of an autorotation maneuver. As the aircraft approached the flare phase of the maneuver, the instructor noted that the rotor RPM was reaching its maximum allowable limit. The instructor advised the student to apply a correction using the collective pitch control to bring the rotor speed back within the normal operating range.
In response to this instruction, the student pilot executed a movement that was too abrupt and excessive. This action caused the rotor RPM to drop sharply below the normal operating limits. The instructor attempted to stabilize the aircraft, but the sudden loss of rotor energy prevented a successful recovery. The tail boom struck the unpaved ground with significant force, causing the right skid to break and the helicopter to overturn on its side. The aircraft was destroyed.
The investigation
The investigation focused on the sequence of events during the autorotation exercise and the control inputs made by the student pilot. Investigators examined the flight parameters, specifically the rotor RPM fluctuations, and the physical damage to the Hughes-Schweizer 269 C following the impact with the unpaved surface.