Mistaking water for clear air led to a helicopter plunging into freezing water off Auckland Island, narrowly missing steep cliffs, an inquiry into the accident has found.
Recommendations around the accident, which occurred just under four years ago, say rules and standards have to be tightened around the operation of night vision goggles.
On April 22, 2019, Southern Lakes Helicopters (SLH) pilot Andrew Hefford and paramedic John Lambeth suddenly found themselves immersed in seawater in a rapidly sinking aircraft, while volunteer crewman Lester Stevens had been knocked unconscious by the impact.
All three were wearing immersion suits that kept them afloat - Mr Stevens was pulled from the cabin by Mr Lambeth, and regained consciousness during the short swim to Auckland Island.
The crew members made it to shore with non-life-threatening injuries and sheltered under cover for 15 hours until they were spotted the next day by a rescue helicopter.
The Transport Accident Investigation Commission (TAIC) investigated the incident, releasing their final report today.
TAIC chief investigator of accidents Naveen Kozhuppakalam said the chain of events leading to the accident began when the pilot, using night vision goggles, very likely misinterpreted fog near the surface as cloud some height above.
"The area believed to be clear air near cloud was in fact calm water near fog," he said.
"The pilot flew towards it while relying primarily on visual references, looking outside through the night vision goggles (NVGs), without enough scanning of the instrument panel. At the time, a radio altimeter warning light was illuminated and would have alerted the pilot to being below their selected altitude."
The BK117 helicopter was nearing the end of its 478km flight from Invercargill to evacuate a sick crew member from a fishing ship.
The pilot and another crew member were using NVGs as the flight was due to end after dark.
Mr Hefford saw what he believed to be cloud covering the landing area, so re-routed and descended towards an area believed to be clear of cloud.
The other non-pilot night vision imaging systems (NVIS) crew member saw cliffs immediately ahead and alerted the pilot, who took avoidance action but was too late to avoid the helicopter hitting the sea.
The second is crew resource management (CRM), the report stating New Zealand lacks requirements and guidelines for comprehensive training and qualifications in CRM for helicopter operations where the NVIS crew member is a non-pilot crew member.
The TAIC also found that the helicopter operator’s procedures for single-pilot VFR (visual flight rules) operations into the Southern Ocean were incomplete and inadequate for safe flights.
In a statement, SLH said it agreed with the findings and recommendations in the report.
SLH chief executive Michael Hayes said the company had implemented a number of operational and safety improvements recommended by the CAA and independent evaluators since the accident.
"We are extremely grateful to have our team here with us today. To have an accident of this nature, with no loss of life, has provided us with many lessons learned that we will share with the aviation industry, improving safety for us all."
SLH will continue working with CAA and the industry to improve the safety of operations in the Southern Ocean, he said.
"It is vitally important this rescue service continues, and we remain committed to providing assistance to those in need."
The previous chief executive of SLH, Sir Richard Hayes, also the rescue pilot that found the survivors, said finding the missing crew on the beach safe and well was the best result he could have wished for.
"The day turned from the worst day of my life to the best. Words cannot describe the total joy and elation we felt when we found all three standing on the shore.
"I believe ourselves and others in aviation industry will benefit from TAIC’s recommendations in this report."
All three crew members still work with SLH. The helicopter was recovered from the sea within a few weeks.
