Helicopter crashes in Porirua Harbour

An experienced helicopter pilot has told of his terror as his aircraft went down in Porirua Harbour, saying at one point he didn't expect to survive.

Rick Lucas was flying his BK117 twin-engine helicopter lifting power poles when he felt something was wrong on Tuesday morning.

Helicopter pilot Rick Lucas says he'd been bracing for a much worse outcome (Emma Jolliff / Newshub.)
Rick Lucas managed to get on top of the half-submerged helicopter (Georgina Russell / Facebook)

"I just experienced a medium-frequency vibration, but this just increased and continued to amplify and something went bang and the helicopter started to rotate so it was a total failure of some description," Mr Lucas, who has more than 35 years of flying experience, says.

Emergency services were called to the scene in Browns Bay just north of Wellington where they found the aircraft was in knee-deep water and lying on its side.

Mr Lucas says the entire incident happened quickly and he tried to manoeuvre the aircraft into a position where he'd most likely survive.

But the impact into the relatively shallow water was still significant and the worst crash he'd experienced.

"I've been in a helicopter accident before, but this one was frightening."

The helicopter cockpit ended up submerged in water, and Mr Lucas had trouble getting his seatbelt off.

"I couldn't tell up from down until I saw some light and then I was able to head toward the light and emerged in the cockpit so I was pretty happy."

He credits going back to his basic training with saving his life.

"I almost went into some sort of state that allows you to think logically and consciously. I looked for the seatbelt, found it and released it. I thought my leg was trapped which was my biggest concern.

"I wasn't feeling happy. I think for the first time ever in the helicopter I thought 'this is it' - probably because of the water thing."

An off-duty firefighter who witnessed the crash kayaked out to the site to make sure Mr Lucas was safe.

Witness Adam Power heard the helicopter crash into the bay and borrowed a kayak to get to the site.

He'd been mowing a lawn across the road from the bay with a friend at the time of the crash.

"We heard a commotion behind us and the helicopter had just splashed into the water," he said.

"We saw him climbing onto the roof and thought 'we'd best go out there' and I saw next door had a kayak so I pinched it and paddled out to him."

He had planned to take the man back to shore on the kayak, but a rescue boat was already on the way.

Mr Lucas thanked him and his colleague for their help.

"[They're] great guys, thanks very much," he said.

"Both had seen it happen and expected the worst, they were pretty happy to see me sitting on top of the helicopter."

He managed to walk away from the crash just "a little sore".

Mr Lucas has been hired many times by news organisations to cover stories of other aircraft crashes, and said he'd "rather not be the subject of one".

He hadn't lost faith in helicopters and the crash wouldn't stop him from flying.

He said the helicopter he was flying was the same as the ones used as Westpac Rescue Helicopters and were very reliable.

"I love flying helicopters and I have absolute faith in them. This is just something that in due course will be investigated and the cause will be discovered."

Newshub.