A teenager who became trapped on a steep bluff in the Waitakere Ranges in darkness used the screen light from his cellphone to guide rescuers.
The German tourist, aged in his late teens, had to be winched by helicopter almost 35m from a bluff in Huia in West Auckland early yesterday.
The teen and a friend had ventured up a track on Thursday afternoon to swim in the Karamatura Stream in Huia Bay, Auckland Rescue Helicopter crewman Mark Cannell said.
Neither was equipped with the right gear to be in the area, he said.
On the way back down, the pair became separated and the teen wandered into a spot he couldn't get out of.
"There's some very big bluffs to the east of the Karamatura Stream just below those waterfalls and he got stuck between the two big bluffs," Mr Cannell said.
Luckily he had his mate's cellphone with him, which he used to raise the alarm with emergency services.
However, the steep terrain meant a ground rescue wasn't possible and the helicopter had to be called in just after 1am.
"He could still move around but unfortunately the only light that he had was the LCD [light] off the cellphone, and that's the only thing we used to find him."
The man, who was uninjured, was taken to safety by 2am and left with police.
"They went out for a bit of a walk, went for a couple of swims and that was meant to be the end of it. Next thing you know, he's bluffed, no light, shorts, wet clothing and a towel and inadequate footwear.
"He had the potential to get really badly caught out. He was a pretty worried man."
However, the man did the right thing in not moving around by cellphone light after dark, Mr Cannell said.
"With a different set of circumstances, it could have been a very bad outcome," he said. "If he had had a tumble he would have been crying out for his mother real quick."