Split second to act as helicopter plummets

Arrowtown helicopter pilot and businessman Mark Cotton had only a split second to think when his $750,000 Hughes 500 helicopter suddenly lost height and hit the water in a remote area near the mouth of Milford Sound this week.

He had managed to slow the helicopter's descent by auto-rotation, an emergency manoeuvre which keeps the blade spinning despite loss of engine power.

And, at the last moment, he had also "flared" the machine, lifting the nose to soften the impact.

As he plummeted about 300m, he had also turned the machine towards the side of the sound.

"You've got no time ... It all happens in seconds."

Asked how he had survived, he said: "It's all in the training."

After extracting himself unhurt from the helicopter, which subsequently sank, about 4.45pm on Wednesday, he then swam about 20m to safety at the edge of the coast.

"Luckily, it didn't happen earlier."

If his machine had gone down in the middle of the sound, he might not have lived, he said.

The emergency occurred when he was returning to his Haast base after a 90-minute, relatively low-altitude survey of wild deer, carried out on behalf of his company, Snowline Safaris.

For some reason, the machine's emergency radio beacon did not activate on impact.

After his unexpected swim, he waited on a rock poking about 7m out of the water.

About two and a-half hours later, just before nightfall, he saw the "fantastic" shape of a Milford Sound-based crayfish boat heading back into the sound.

Attracted by his waving, its crew picked him up, much to his delight, and "gave me a stubby [beer], straight in the hand".