2013 Robinson R44 accident at Font-Romeu (F-GXRF)

Flight and accident sequence On 16 September 2013 at about 10:40 local time, a Robinson R44 helicopter registered F-GXRF was operating a general-aviation navigation flight from the Château de Pennautier heliport to the Font-Romeu heliport, at an altitude of 1,573 metres. The pilot was accompanied by one passenger, and three other helicopters were making the same flight. During the approach, the helicopter was following a north-east axis at low speed. While the pilot was looking for a landing area near other helicopters already parked, at about two metres above the ground, the “LOW RPM” alarm sounded. The helicopter then struck the ground hard and rolled onto its right side. ## Conditions and aircraft data Estimated weather at the accident site was wind from 195° at 2 kt, CAVOK, and a temperature of 14 °C. The pilot held a private pilot licence for helicopters (PPL(H)) and had 230 hours on type, including 15 hours in the preceding three months. Fuel remaining was 110 litres. The estimated mass of 968 kg and the helicopter’s centre of gravity were within the manufacturer’s limits. According to the flight manual, the maximum mass for the day’s conditions was 1,089 kg for a no-wind hover out of ground effect (DES) and about 970 kg for a no-wind hover in ground effect (HES). The investigation did not determine whether the pilot had calculated mass and performance limits before the flight. ## Technical and investigative findings The helicopter’s collective pitch control is conventional and includes a rotating power-control handle. The engine governor automatically maintains rotor speed within the normal operating range; its switch is at the end of the collective control and is normally set to “ON.” When disabled, the pilot must manually coordinate pitch and power. The audible and visual “LOW RPM” alarm activates when the minimum main-rotor speed threshold of 97% is reached. The BEA concluded that the pilot had made the approach with a tailwind component while the helicopter was close to its performance limits; these factors may have contributed to the reduction in main-rotor speed. It was also possible that the pilot had inadvertently disabled the governor, preventing automatic pitch/power coordination. Without pilot action on the power-control handle, main-rotor speed decreased, triggering the low-rotor-speed alarm and leading to the hard landing. The BEA had previously investigated a similar accident involving inadvertent governor deactivation.