What happened
On 6 February 2015, a Hughes 269A helicopter, registered N 90584, was involved in an accident at Öresten Airfield in southern Sweden. The aircraft was being operated by a single pilot during a period of flight involving hovering maneuvers. While attempting to maintain a hover, the pilot experienced a loss of visual references caused by a whiteout condition. In an attempt to manage the situation, the pilot transitioned from the hover to a landing; however, during this maneuver, the rear portion of the helicopter's skids and the tail rotor assembly struck the ground. The impact caused the tail rotor and its associated gearbox to separate from the aircraft. There were no injuries reported following the incident.
The investigation
SHK examined the mechanical state of the aircraft and the environmental conditions present at the time of the accident. The investigation focused on the structural damage sustained by the tail boom, the tail rotor, and the gearbox. Investigators also reviewed the operational context, specifically the interaction between the helicopter's rotor wash and the ground surface, to determine how the loss of visual references occurred.
Findings
- The primary cause of the accident was that the risks of hovering over loose snow were not adequately accounted for during the flight.
- A contributing factor to the event was the pilot's lack of specific experience operating in such environmental conditions.