The accident aircraft (Photo (c) Derek Quinn |
The accident aircraft (Photo (c) Derek Quinn |
BK117-C1, ZK-IMX Controlled Flight into Terrain (Water), Auckland Islands, 22 April 2019
Occurrence Date
Report Publication Date
What happened
On 22 April 2019, the operator was conducting a medical evacuation flight under visual flight rules (VFR) with a BK117-C1 helicopter, registration ZK-IMX. On board was the pilot, a paramedic in the front left-hand seat, and a winch operator in the rear cabin. The helicopter was to position south of New Zealand at Auckland Islands that day (the positioning flight). After camping overnight on Enderby Island, the helicopter crew would rendezvous with a fishing ship next day to heli winch and evacuate a sick crew member back to New Zealand.

The positioning flight was intended to arrive during daylight, but unexpected delays to the departure time resulted in them arriving after dark. The crew carried night vision goggles (NVGs) and donned them during the positioning flight to continue under VFR using NVGs.

The hills and coastline around Port Ross and part of Enderby Island were visible through NVGs, but the pilot believed that the landing area was covered in cloud. The pilot planned an alternative approach to descend in the clear area to below the cloud and then follow the coastline back to the landing area.

The pilot descended and was turning back towards the landing area when the crew member (paramedic in front left-hand seat) alerted them to cliffs rising immediately ahead. The pilot reacted, but the helicopter impacted the sea.

The crew were able to escape while the helicopter was partly submerged, but it sank soon after. They were all wearing immersion suits that kept them afloat and enabled them to make their way to shore. After sheltering under cover overnight, they were spotted the next day by one of the rescue helicopters and brought back to Invercargill to be checked in the hospital.

The winch operator in the rear cabin was knocked unconscious during the impact, but was able to be evacuated by another crew member. They regained consciousness during the swim to shore. Otherwise, the crew only suffered minor injuries.
The helicopter was recovered about three weeks later.

Why it happened
The helicopter was operating normally at the time of the accident.

The Commission found that the pilot had misinterpreted the image seen through the NVGs as cloud covering the landing area when it was very likely to have been fog near the sea surface and downwind of the shore. The planned descent and approach in the clear area was made using visual reference outside and to the global positioning system (GPS) map display. However, the helicopter’s descent rate became high as the pilot, relying primarily on visual depth perception, believed the helicopter was further from the surface of the sea than it was. When the crew did see an image through the NVGs it was the 20-metre high cliffs several hundred metres ahead and above them. During the manoeuvre to avoid the cliffs, the helicopter impacted the sea.

The Commission found that the operator’s exposition for single pilot VFR operations into the Southern Ocean was inadequate at the time to manage the risks associated with such operations. The operator has since made significant improvements, including engaging an external auditor and introducing a new standard operating procedure for Sub Antarctic Island flights. Therefore, the Commission considered that no safety recommendations to the operator were necessary.

The Commission also identified regulatory gaps in the New Zealand Civil Aviation Rules (CARs) regarding minimum safety requirements for helicopters operating under Part 119 and Part 135 air operator certificates (AOCs). The gaps related to:
• Helicopter air ambulance (HAA) operations.
• Night vision imaging systems (NVIS) and operations.
• Crew resource management (CRM) for operations conducted with multi-pilot or a single pilot with a non-pilot crew.
• Pilot logging of NVG flight time.

The Commission made two safety recommendations to the Civil Aviation Authority (CAA) in section 6 to address these safety issues.

What we can learn
The key lessons from this investigation are listed in section 7. In summary they are that:
• The minimum requirement for NVG currency does not equate to proficiency.
• Helicopter underwater escape training (HUET) and immersion suits can increase survivability.
• If the operation needs crew to wear immersion suits, they should also carry essential emergency items on their person.
• All crew with flight-related duties need to be aware of the importance of radio altimeters when conducting NVIS operations and how to interpret the instrument and its alerts.
• Pilots should ensure their NVG flight time is separately logged.
• Overloading helicopters is a safety hazard.
• To be effective, emergency equipment such as a life-raft must also be accessible in an emergency and deployable for the crew to use.

Who may benefit
Pilots and operators involved with HAA operations, those using NVIS, and the regulator may benefit from the findings and recommendations in this report.
vicinity of Auckland Island (-50.542127,166.287777) [may be approximate]