Helicopter rollover during takeoff departure

Casualties unknown • Between Auckland and Frenchs Islands Latitude: 50° 32´ 28.08” South Longitude: 166° 17´ 14.40” East, NZ

A pilot lost control of a high-performance helicopter during takeoff, leading to a rollover and rotor strike that resulted in minor injuries.

What happened

During a flight involving VH-YHS, a high-performance helicopter, the pilot initiated a takeoff sequence that deviated from standard procedures. Rather than allowing the aircraft to settle lightly on the skids and transitioning into a balanced hover, the pilot applied control inputs more aggressively than usual. This rapid lift-off caused an imbalance between the main rotor torque and the anti-torque provided by the Fenestron tail rotor.

As the aircraft left the ground, it experienced a significant yaw to the left. This rotation was potentially exacerbated by a light wind blowing from the right. The pilot attempted to recover using primarily cyclic control instead of the necessary full right pedal input. Realising the yaw rate could not be arrested, the pilot opted to land the aircraft. During the descent, the left skid made contact with the ground, causing the helicopter to roll over and the main rotor blades to strike the earth. The impact destroyed the aircraft, though the pilot sustained minor injury.

The investigation

Investigators examined the maintenance history and the aircraft's condition following the accident. The maintenance organisation found no evidence of airworthiness issues that could explain the loss of control. Furthermore, the investigation found that the aircraft was operating well below its maximum capacity with only three occupants. The pilot's account and manufacturer feedback indicated that neither mechanical failure nor the prevailing wind conditions were contributing factors to the incident.

Probable cause

The accident was caused by the pilot's rapid application of control inputs during takeoff, which created an imbalance between main rotor torque and anti-torque, leading to an unrecoverable left yaw.

Frequently asked questions

What happened in the 2019-04-22 Kawasaki Heavy Industries BK117-C1 s/n: 1108 accident near Between Auckland and Frenchs Islands Latitude: 50° 32´ 28.08” South Longitude: 166° 17´ 14.40” East, NZ?

A pilot lost control of a high-performance helicopter during takeoff, leading to a rollover and rotor strike that resulted in minor injuries.

What aircraft was involved and where did it happen?

The accident on 2019-04-22 involved a Kawasaki Heavy Industries BK117-C1 s/n: 1108, registration 2x Turbomeca Arriel 1E2, serial numbers #18054 and #18055, operated by Southern Lakes Helicopters Limited, at Between Auckland and Frenchs Islands Latitude: 50° 32´ 28.08” South Longitude: 166° 17´ 14.40” East, NZ.

What was the probable cause of the accident?

The accident was caused by the pilot's rapid application of control inputs during takeoff, which created an imbalance between main rotor torque and anti-torque, leading to an unrecoverable left yaw.

Investigation report by the New Zealand Transport Accident Investigation Commission (TAIC). Original record: https://taic.org.nz/inquiry/ao-2019-005. This page is a structured re-presentation; facts and quotes are in the Transport Accident Investigation Commission (TAIC), New Zealand.

Loading the flight search…