The Northland Rescue Helicopter pilot who helped save five lives after a fishing charter boat sunk off North Cape has called the incident "extreme."
Lance Donnelly, a pilot of 30 years, described the rescue mission for the vessel Enchanter as "the most extreme, most challenging rescue I've ever done."
Ten people were on board when the Enchanter sank in rough seas around 11pm near North Cape on Sunday.
Five people were saved by the Northland Rescue Helicopter team's efforts, and five people were found dead after large-scale air and water searches.
At 8.45pm the Northland Rescue Helicopter team received a call from the Rescue Coordination Centre in Wellington, Donnelly said.
"We got a call suggesting there was a beacon search to happen up in North Cape. At that point, we weren't too sure what it was."
The team of four took off from Whangārei at 10pm after further information that it was a boat charter and a beacon was going off.
"At that point, we didn't know whether the boat was in distress or if there were any people in distress," said Donnelly.
They landed in Kaitāia at 10.50pm to quickly refuel, after discovering their trip had become a rescue mission.
"We found out on the route to Kaitāia that there were 10 people supposedly in the water. That sort of changed things."
The team investigated options of sending other assets and boats to the scene, but a helicopter rescue proved to be the only option.
"We have very strict limitations on what weather we can fly in, and we determined before we even left Whangārei base that we could fly to Kaitāia hospital, and as we approached Kaitāia we determined the weather was okay to proceed further."
The helicopter departed Kaitāia to North Cape at 11.15pm, and the team began the search for the beacons.
"We located two lights in the water, at that stage we weren't too sure what they were, but on further investigation, we saw three persons on some structure of the boat."
The four members of the crew in the Northland Rescue Helicopter then began their mission battling bad weather and the dark of night, Donnelly and his co-pilot wore night vision goggles during the rescue.
"It was very challenging; night time, over the water, big swells and serious wind."
"We had four crew onboard to affect that rescue, I couldn't have done it without them," Donnelly said.
He said his main focus was keeping the helicopter in the right location and his crew safe; co-pilot Alex Hunt and St John critical care paramedics Paul Davis and Josh Raravula, who were in charge of the winch and bringing people to safety.
"The co-pilot, his job is just invaluable, he was calling all the capacities that are required, calling heights and calling the wind direction, he can see the weather coming in."
Meanwhile, another crew member operated the hoist and winch, lowering the rescue swimmer by a wire into the freezing water with lifesaving equipment.
"The structure the survivors were on was rocking quite a lot, so we couldn't risk putting the rescue swimmer onto that structure."
"The most dangerous situation to be in is in the hover, over the water, at night, over a small obstacle."
The rescue swimmer was instead dropped five metres away from the vessel to prevent the survivors from falling further overboard.
"(The rescue diver) had to get the survivors into the water for us to get them back, we couldn't winch them directly off the hull because the pilot couldn't see it."
Donnelly said the length of the wire varied from 25 feet to as long as 50 feet due to the magnitude of the swell.
The crew rescued the three survivors they could initially see and transported them to Te Hāpua, before returning to the scene.
"We went back out to the search area where we located another two persons on the upside-down hull."
At 1.30am, the crew finally landed at Kaitāia Hospital, and Auckland rescue teams took over the search.
"Our concern at the time was that there were still five more people out there and we felt a little bit helpless, to be honest," Donnelly said.
"Information was scarce at that point."
Donnelly described the team's effective communication and experience with working together as a "huge" part of the successes of the difficult rescue.
"You can't train for jobs like this. You've got to think on your feet quite a bit."
"You don't get jobs like this often; you feel really quite chuffed."