What happened
On September 12, 2017, an Airbus Helicopters AS 350 B3, registration LN-OTR, operated by Helitrans AS, was conducting a wildlife monitoring mission in the Laksefjordvidda area of Finnmark, Norway. The flight was part of an operation for the Norwegian Nature Management Authority and the Reindeer Police to inspect hunting licenses and weapons.
After flying from Skiippagurra, the pilot identified a suitable landing area near a group of people and ATVs. The helicopter landed on slightly sloping terrain. After touchdown, the pilot intended to inspect the ground stability before shutting down the engine. While leaning to the right to check the terrain through the open cockpit door, the pilot's headset wire became entangled with the collective lever. This caused the lever to move upward, initiating an unintended movement of the aircraft. The pilot attempted to correct the motion, but the helicopter entered a state of dynamic rollover, quickly tipping onto its right side and striking the ground with the main rotor.
All four occupants—the pilot and three passengers—were able to evacuate the aircraft safely, though one passenger required assistance from the pilot to unbuckle their seatbelt.
The investigation
The Norwegian Safety Investigation Authority (NSIA) examined the aircraft, the pilot's actions, and the cockpit configuration. The investigation focused on why the aircraft became unstable after landing. The inquiry looked into the tension of the collective lever, the presence of loose objects in the cockpit, and the pilot's use of a non-spiral headset cord. The investigation also reviewed the operator's internal findings, which suggested that the pilot may have been influenced by habits from flying different aircraft types and that the collective lever had a tendency to creep upward due to low friction settings.
Findings
- The primary cause of the accident was a dynamic rollover triggered by the unintended movement of the collective lever.
- The movement was likely caused by the pilot's headset wire snagging on the collective lever as the pilot leaned toward the door.
- The collective lever was not sufficiently secured, and the friction setting was likely too low, allowing it to move easily when disturbed.
- The pilot's attempt to check the ground stability while leaning out of the cockpit contributed to the loss of control.
- The use of a straight headset cord, rather than a coiled version, increased the risk of entanglement with flight controls.
Safety action
- The NSIA noted that the use of helmets could reduce injury severity and assist in faster evacuations during emergencies.
- It is recommended that for operations where landing sites are not pre-defined, a task specialist should accompany the pilot to assist in assessing terrain suitability.
- Pilots should ensure that flight controls are secured and that loose items, such as headset wires, are managed to prevent interference with controls.