2018 Midtnorsk Helikopterservice R44 II accident in Skäckerfjällen (LN-OAL)

Overview and Investigation Authority On 24 July 2018, a Robinson Helicopter Company R44 II helicopter, registration LN-OAL, was damaged during an emergency landing in mountainous terrain in Skäckerfjällen, Jämtlands län, Sweden. The aircraft was operated by Midtnorsk Helikopterservice AS. Because the accident occurred in Sweden but involved a Norwegian-registered helicopter and operator, the Swedish investigation authority delegated the investigation to the Norwegian State Accident Investigation Board (Statens havarikommisjon) under a Nordic cooperation agreement. The investigation was conducted in accordance with ICAO Annex 13 and Regulation (EU) No 996/2010. ## Aircraft and Maintenance The helicopter was a 2006 Robinson R44 II, Clipper II version, with serial number 11239. It was powered by a Lycoming IO-540-AE1A5 engine. At the time of the accident, the helicopter had a total flight time of 4,140.7 hours. The engine had been replaced in March 2012 and had 2,866.7 total hours at the time of the accident. The last maintenance before the accident was a 50-hour inspection performed on 29 May 2018. The helicopter had a valid airworthiness certificate and airworthiness review certificate. ## Accident Sequence The helicopter was being used for commercial reindeer driving operations, starting from Ottsjö. The flight crew consisted of the pilot-in-command and a passenger/escort. During the accident flight, the pilot reported increasing wind and moderate to severe turbulence. While on the lee side of Sandfjället, a low rotor RPM warning activated. The pilot attempted to recover by lowering the collective, but the warning reactivated. The helicopter's performance degraded rapidly, and the pilot decided to make an immediate emergency landing in a nearby rocky area. The helicopter struck the ground with the landing gear first and came to rest upright. Both occupants were wearing seatbelts, and the pilot was wearing a helmet. No injuries were reported. The emergency locator transmitter was not activated due to insufficient impact energy. ## Damage and Aftermath The helicopter sustained extensive damage, including destroyed main and tail rotor blades, a bent tail boom, bent landing gear, a shattered left front windscreen, and dents and buckles in the fuselage structure. Due to poor mobile phone coverage at the accident site, the pilot climbed to a higher point to contact the operator. The two occupants were later recovered by another helicopter from Midtnorsk Helikopterservice.