History of the Flight
The student-pilot completed two runway circuits in dual flight with an instructor for runway 32, then took off for a solo local flight at 11:25. After 32 minutes, returning to the aerodrome traffic, the controller requested joining the right-hand downwind leg for runway 14, which had just come into use. The student was cleared to land with a 200° wind of 5 to 10 kt. After a near hover at a height of 3 to 4 meters, the student began hover taxiing over the runway at a height between 2 and 5 meters. While preparing to turn left to clear the runway at taxiway A, control was lost and the helicopter made two or three complete rotations to the left about its yaw axis. The student then lowered the collective pitch control. The helicopter contacted the ground, bounced, then fell hard and flat onto the runway. On impact, the skids sagged on either side of the fuselage, and the helicopter came to a stop on its belly at taxiway A.
Examination of the Wreckage
The wreckage came to rest at the junction of the runway and taxiway A. The landing gear rear arch separated from the skids, and the helicopter lay on the lower fuselage, damaged from compression of the landing gear. The tail skid and lower part of the Fenestron were folded 90° to the left. Several Fenestron blades were damaged, and friction marks from tail rotor blades were visible inside the Fenestron skin structure at the bottom. All damage resulted from the accident. Flight control linkages were continuous; transmission linkages between the main gearbox and engine, and between the main gearbox and tail gearbox, showed no anomalies. Throttle/mixture control travel was nominal. Test bench examination of the engine governor revealed no operating anomalies. The fuel and lubrication systems showed no anomalies. Two of the four upper spark plugs had cracked ceramic sections, but engine ground tests with those plugs showed normal operation.
Meteorological Conditions
No METAR or TAF are available for Aix-les-Milles. The nearest reports, from Marseille-Marignane (14 km away), indicated CAVOK conditions with a 200° wind of 9 kt, varying between 160° and 230°. The ATIS for Aix-les-Milles at 11:50 reported runway 14 in service, wind 210° at 5 to 10 kt, visibility 10 km, temperature +24°C. Météo-France estimated at the time of the accident (12:00) a 210° wind of 5 kt with gusts up to 13 kt at a height of 10 m, with possible low turbulence at ground level. Analysis showed the student performed the final approach and hover with a 70° crosswind from the right.
Helicopter Information
The Guimbal Cabri G2 is a light two-seat helicopter with a piston engine (160 hp), a clockwise-rotating main rotor, and a shrouded tail rotor (Fenestron). According to Service Letter SL 12-001 A, “Yaw Control in Approach,” Guimbal demonstrated Fenestron manoeuvrability with wind over 40 kt in all directions. The helicopter was equipped with a Multi-Purpose Display (MPD) that records flight parameters on an SD card; no data from the accident day was recorded due to a software problem.
Training and Procedures
The Operational Suitability Data (OSD) for the Cabri G2 type rating specifies special attention to yaw control in approach and transition from forward flight to hover, particularly for pilots used to conventional tail rotors. The Declared Training Organisation (DTO) included theoretical training on “loss of tail rotor effectiveness,” with a module on Guimbal Service Letters and tail fin stall depending on wind. The student recalled attending a one-hour module on Fenestron characteristics. The instructor stated that specific briefings on the Service Letter were not formally presented but addressed verbally throughout training. Practical dual instruction did not include loss of tail rotor effectiveness in hover; after the first solo, it included sideways and backwards hover manoeuvres in crosswind and spot turns. The training manager demonstrated in-flight tail fin stall and recovery. Guimbal’s Instructor Factory Training (IFT) includes a module on Fenestron and yaw control, recommending that pilots press the right rudder pedal fully without hesitation and remain vigilant with wind from the right during approach.