Helicopter tail rotor strike during takeoff at Länna

Casualties unknown • Accident with a helicopter in southern Stockholm, SE

A helicopter experienced an uncontrolled yaw during takeoff from a dolly, resulting in a collision with a parked wheel loader and subsequent ground impact.

What happened

During a takeoff maneuver from a helicopter dolly at an operational site south of Stockholm, a helicopter experienced a sudden and uncontrolled rotation. The flight was intended to be a distinct liftoff to ensure the aircraft cleared the dolly safely. However, as the pilot increased the collective, the aircraft immediately surged forward and began a rapid leftward turn. The helicopter rotated approximately one and a half turns around its yaw axis before the tail section struck a wheel loader that had been parked less than seven meters in front of the aircraft. Following the collision, the pilot lowered the collective, but the aircraft continued to rotate an additional 360 degrees before striking the ground near a hangar. The pilot sustained no injuries, but the helicopter suffered substantial damage to the tail section, all main rotor blades, and the right skid.

The investigation

SHK examined the circumstances surrounding the takeoff, specifically focusing on the pilot's inputs and the aircraft's configuration. The investigation established that the helicopter had been moved from a nearby hangar using a dolly. The presence of a wheel loader in close proximity to the takeoff path was noted as a factor in the severity of the impact. Investigators also reviewed the pilot's recent flight history and found that the pilot had limited experience with this specific aircraft model, having flown it for only two hours in the preceding 90 days. No technical or mechanical failures were identified as contributing to the incident.

Findings

  • The primary cause of the accident was the pilot's incorrect use of the anti-torque pedals, where applying pressure to the left pedal increased the leftward yaw instead of counteracting it.
  • The pilot's lack of familiarity with the specific torque characteristics of this aircraft type—specifically the need for right pedal compensation versus the left pedal compensation required in his previously flown models—contributed to the loss of control.
  • The limited obstacle clearance provided by the parked wheel loader contributed to the extent of the damage sustained during the rotation.

Probable cause

The accident was caused by the pilot applying incorrect pedal inputs during takeoff, which exacerbated the aircraft's leftward yaw, combined with a lack of recent experience with the specific torque requirements of the aircraft type.

Frequently asked questions

What happened in the 2018-07-11 aircraft accident near Accident with a helicopter in southern Stockholm, SE?

A helicopter experienced an uncontrolled yaw during takeoff from a dolly, resulting in a collision with a parked wheel loader and subsequent ground impact.

What aircraft was involved and where did it happen?

The accident on 2018-07-11 involved a aircraft, at Accident with a helicopter in southern Stockholm, SE.

What was the probable cause of the accident?

The accident was caused by the pilot applying incorrect pedal inputs during takeoff, which exacerbated the aircraft's leftward yaw, combined with a lack of recent experience with the specific torque requirements of the aircraft type.

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