What happened
On March 16, 2021, a helicopter was performing a flight from Skavsta to Grene, north of Gothenburg. The flight path included a stop at Skeberg in Dalarna County to pick up two passengers for a brief fifteen-minute local flight. During the approach for landing, the pilot reduced the aircraft's airspeed. During this phase, the helicopter experienced an unexpected yaw that transitioned into a rotation around the yaw axis.
In an attempt to avoid obstacles, the pilot sought an emergency landing spot within a forest clearing. However, the vegetation was too dense, causing the helicopter to strike treetops. The impact severed the tail rotor and its attachment, and the main rotor blades struck several trees before the aircraft fell from a height of approximately 10 to 15 meters. The helicopter struck the ground with the front left side of the cabin. While the emergency transmitter was activated and rescue services were alerted by a witness, responders arrived at the site 19 minutes later. The accident resulted in one fatality and two extensive injuries.
The investigation
The Swedish Accident Investigation Authority examined the wreckage and the circumstances leading to the loss of control. The investigation focused on the aerodynamic behavior of the aircraft during the transition to a hover and the pilot's response to the sudden movement. Investigators found no evidence of technical defects in the aircraft that contributed to the accident.
Findings
As the pilot reduced speed to transition into a hover, the tail rotor was likely disturbed by the airflow from the main rotor. This aerodynamic interference caused an unexpected rightward yaw. The pilot's attempts to counteract this rotation were insufficient, leading to an increasing yaw rate. A significant contributing factor was that the pilot had low total flying hours and limited recent flight experience, which hindered the ability to anticipate the aerodynamic consequences of the speed reduction and execute effective corrective maneuvers.