What happened
On 12 January 2025, an Airbus AS350 B3, registration ZK-ITY, was performing a passenger pickup at Turners Bivouac, located on a plateau on Mt Madeline. The mission, operated by Te Anau Helicopter Services Limited, involved collecting two climbers from the remote site. To ensure a safe loading process, the pilot and a ground crew member had planned to land the aircraft while maintaining enough power to remain light on the skids.
As the helicopter settled onto the uneven, rocky terrain, a rock positioned under the rear of the right skid fractured. This sudden shift caused the tail rotor to drop and strike a boulder located beneath the aircraft. Fearing structural damage, the pilot attempted to maneuver the helicopter forward to a more stable landing area. During this repositioning attempt, the main rotor blades struck a large boulder outcrop to the right of the aircraft, causing the helicopter to shake violently. The pilot successfully shut down the engine, and while the aircraft sustained significant damage, there were no injuries to the pilot, ground crew, or the climbers.
The investigation
Investigators examined the landing site, which had been manually leveled with rocks over several years to create a usable pad. They identified a broken rock measuring approximately 0.5m by 0.4m directly under the area where the rear skid had rested. The investigation also reviewed the aircraft's maintenance records, which showed the AS350 B3 was fully compliant with all safety inspections and had no relevant defects.
Technical analysis of the wreckage confirmed that the tail rotor drive shaft had sustained torsional damage consistent with striking an object while rotating at high speed. The investigation also looked into the operator's safety protocols, noting that the company's flight-following and emergency response systems functioned effectively, allowing for the rapid recovery of all four people involved within 90 minutes of the accident.
Findings
- The pilot was properly trained and qualified for the operation.
- The landing site was a confined and challenging area that required extreme precision.
- A rock under the rear of the right skid broke during touchdown, leading to the initial tail rotor strike.
- The pilot's decision to avoid attempting an immediate flight away from the site likely prevented a more serious in-flight breakup of the tail boom.
- The subsequent main rotor strike occurred while the pilot was attempting to reposition the aircraft to a safer spot for shutdown.