2019 Robinson R44 Raven II accident at Chessenaz (F-HNAF)

Flight details and accident sequence On 26 May 2019, at about 10:55 local time, a Robinson R44 Raven II helicopter, registration F-HNAF, operated by Société Alpes Hélicoptères, was destroyed during an instruction flight. The aircraft was carrying an instructor and a student. The flight began at Annecy Meythet aerodrome for local training. After about 35 minutes, the instructor landed in a field to allow the student to rest. During the subsequent takeoff for a hover exercise, the helicopter began rotating around its yaw axis, apparently to the right. The instructor took control but was unable to stop the rotation despite rudder input. The collective was lowered, and the helicopter struck the ground hard, rolling onto its left side. Both occupants evacuated as a post-crash fire started. ## Site, weather, and aircraft condition The accident occurred in a field with grass about 40 cm high and a slight slope. Estimated weather at the site included a 5 kt variable north wind, visibility over 10 km, cloud bases between 3,000 and 4,000 ft, and a temperature of 18 °C. The aircraft examination was partial due to fire, but the tail and anti-torque rotor were preserved. Observations indicated the engine was producing and transmitting power. Fuel likely flowed onto hot engine parts after the impact and rollover, initiating the fire. ## Personnel and training context The instructor held a CPL(H) obtained in October 2018 and an FI(H) qualification obtained in December 2018, with about 320 flight hours, including 44 as an instructor. The student had about 7 flight hours in six flights, all in dual command; the accident flight was the seventh. The instructor noted the student had difficulty controlling height and yaw precisely. The chosen field was not on the ATO’s approved list for such exercises, though nearby aerodromes were. The student’s progress record showed three different instructors over seven flights, with a note on excessive control amplitude during flight 3 that appeared corrected. The student had requested less instructor presence on the controls.