What happened
On August 30, 2004, a Robinson R22 Beta, registration LN-OCI, was performing a series of private transport flights near Slogen in Norway. The pilot was transporting passengers and equipment for a private group to a landing site at Isvatn. During the final leg of the mission, the pilot flew at approximately 100 feet to allow a passenger to photograph the landing area.
As the pilot initiated a right-hand turn to transition to the downwind leg, the aircraft experienced a sudden drop in altitude. The low rotor RPM warning light activated, and the pilot realized that the aircraft could not maintain its height. Recognizing the imminent danger, the pilot executed an emergency ditching in the lake. The helicopter struck the water on its left skid and immediately sank to a depth of approximately 5 meters. Both the pilot and the passenger successfully exited the submerged aircraft and reached the surface. The passenger was later assisted to shore by a witness.
The investigation
The Norwegian Safety Investigation Authority (NSIA) examined the aircraft, the environmental conditions, and the flight maneuvers. The investigation focused on the mechanical state of the engine, the impact of weather on engine performance, and the pilot's decision-making during the approach. Investigators also reviewed the safety equipment on board and the flight planning regarding emergency landing options.
Findings
- The investigation found no technical malfunctions with the Robinson R22 Beta and determined the aircraft was airworthy prior to the accident.
- The pilot was operating the aircraft near its performance limits, likely entering a state where the power required exceeded the power available.
- Environmental conditions, specifically temperature and humidity, were conducive to carburetor icing, which may have further reduced available engine power.
- The pilot's maneuver—turning from a headwind to a tailwind—contributed to the loss of rotor RPM.
- The aircraft was not equipped with flotation devices, and neither the pilot nor the passenger was wearing a life vest.
- The flight path was planned such that the landing pattern occurred over water because no safe emergency landing sites were available on land.