History of the Flight
The pilot, accompanied by three passengers, took off at 07:15 from Saint-Paul L’Éperon heliport for a first local flight of about 55 minutes over La Réunion. After landing, he refueled the main fuel tank from a drum. At around 08:20, the pilot, his wife, and two new passengers boarded the helicopter. At 08:33, the pilot took off heading north for another sightseeing flight.
The pilot of another R44, registered F-GZBD, flying at 4,500 ft altitude heading towards Le Voile de la Mariée waterfalls, heard the pilot of F-HLOU announce that he had arrived at Piton d'Enchaing via Col des Bœufs and was also heading towards the waterfalls. He positioned himself about 500 m behind F-HLOU, which was approximately 600 ft below him, flying along the western slope of the mountain past the waterfalls towards Le Bois de Pomme.
At 08:47, as F-HLOU approached the pass to cross the ridge and enter the gorge towards Trou de Fer, the pilot announced "Turbulence, Turbulence," then a few seconds later, "PAN PAN." The pilot of F-GZBD saw F-HLOU veer left. The pilot of F-HLOU again announced "PAN PAN" during the turn. The pilot of F-GZBD heard the "LOW NR" warning in the background during both messages, saw a decrease in main rotor rotation speed, and then the sudden fall of F-HLOU, which collided with the mountainside and slid down the slope before stopping. The pilot of F-GZBD gained altitude and reported the accident.
Examination of the Wreckage
The accident site was at an altitude of 1,150 ft on the eastern slope of the mountain in the Mât river gorges at Le Bois de Pomme. The helicopter first struck vegetation and then ground 30 m above the main wreckage area. Debris from the main rotor blades, tail rotor, tail gearbox, tail boom, airframe components, and one skid were found along the slope. Observations indicated low rotor torque at collision. The tail gearbox had separated from the drive shaft with marks suggesting it was not rotating at rupture. The main wreckage included the badly damaged airframe, engine, fuel tanks, main gearbox, and rotor head with partial blades. The rotor mast turned freely; no blockages were found on the main gearbox. The freewheel was functional. The four drive belts were disengaged, one broken, likely due to impact. The clutch system was at least partially engaged. Ruptures on drive linkages were consistent with collision. Flight controls were continuous and functional before impact. The throttle lever was found in the full throttle position; the collective pitch control in high pitch; the friction control in maximum friction position (deformed). The governor switch was in the ON position.
Pilot Information
The 44-year-old pilot held a helicopter private pilot license obtained in 2005 and an R44 type rating obtained in 2022. He had logged 230 total flight hours. He stopped flying in 2006 with about 90 hours, then renewed his license and type rating in 2021 after 15 hours of training. He resumed flying with an association from November 2021, accumulating 128 hours in 143 flights. In August 2023, he dry-leased F-HLOU from HELILAGON after a satisfactory evaluation flight. Between 24 August and the accident, he flew F-HLOU for 9 hours and 30 minutes over 10 flights.
Additional Context
Flights were organized for relatives or friends; passengers only paid the helicopter lease cost. The pilot did not receive remuneration. Security camera recordings showed the refueling and pre-flight actions: the pilot did not drain the tanks after refueling. Approximately 10 minutes elapsed between refueling and engine start, 16 minutes until departure. No anomalies were visually detected.
Analysis of Video Recordings
Video from the first flight passengers showed the helicopter flying below ridge lines and close to vegetation, below the regulatory flight height of 500 ft. Spectral analysis of those recordings revealed no anomalies in engine or rotor speeds. The helicopter's acoustic signature indicated normal operation.