ies stranded after crashing at the edge of the crater lake on Mt Ruapehu. (See photo at right)

Mr Lilburn, who suffered a broken foot, was armed with just an ice axe yet still climbed 30m to get out of the crater and down the mountain.

"We could have died up there from exposure," Mr Taylor said. "He's a bloody hero in my book. He said he was thinking –- `I've got to walk, I've got to walk'.

"He went through the pain barrier."

Mr Lilburn and a co-pilot had been ferrying three Conservation Department staff – Mr Taylor, Ross Martin and Melissa Vedder – from the crater lake when the helicopter crashed about 5.30pm.

The helicopter failed to get enough altitude and they knew they were in trouble when they were about halfway across the 50

"There was a fair bit of panic. Everything was running through my mind – I basically had time to think: I'm bloody dead.

"We ended up in the lake.

"I crawled out from underneath – we were checking if everyone was clear."

Once everyone was accounted for it was Mr Lilburn who took charge of the situation, and made sure the the occupants were safe.

"The three of us (Doc workers) were pretty hyperthermic, we huddled together on the lake shore," Mr Taylor said.

The group's radios didn't work and it was then the pilot made the decision to climb the ice shelf to get out, Mr Taylor said.

Photo: GEORGE TAYLOR: Resting after surviving yesterday's helicopter crash on Mt Ruapehu. (Click on "Visit Author's Website")

Mr Taylor suffered a gash on the head and was a bit "banged up". His skin and eyes were irritated from the acidic crater water. His mates were in similar conditions, he said.

National Park police spokesman Tony Carne said the crash happened shortly after take off as the helicopter was returning after picking up Doc staff.

"It hit the side of the crater and ended up in the water. The occupants had to climb out on to a ledge between the lake and an ice wall," he said.

Lion Foundation Rescue helicopter pilot Dan Harcourt said the alarm was raised about 6.10pm by Mr Lilburn who had climbed "a near vertical 30m ice shelf". He found some hikers on the mountain and used their cellphone to call emergency services.

Emergency staff from National Park police, Ruapehu Alpine Rescue Organisation (Raro) and Doc responded to the emergency.

Mr Carne said four Raro members were airlifted in to assess the injured. They were lifted out of the crater and ferried down to the Whakapapa medical centre.

They had a variety of injuries including broken ribs, a dislocated shoulder, head wounds and hypothermia.

Mr Harcourt said Mr Lilburn had used all his skill to get the chopper to the edge of the ledge.

"He did a great job there, otherwise the chopper could have ended up in the middle of the lake and the occupants would probably have drowned.

"Speaking to him he said he got through the pain barrier because in his mind he had to be sure everyone would be all right, he had to raise the alarm or everyone would be stuck on the mountain overnight," he said.

Mr Harcourt said it was fortunate experienced mountain flyer Peter Masters was working nearby and was able to quickly assist with the rescue efforts.

"Mountains are a treacherous place for helicopters," he said.

"Pete was able to get in there and long-line the injured out. A 37-year-old Whakapapa man was flown to Waikato Hospital with chest, head and leg injuries alongside a Taupo man with a suspected spinal injury."

Mr Masters said it seemed Mr Lilburn made a mistake on take-off and had been forced to crash-land.

"He actually did a pretty amazing job because when he realised he couldn't fly out he then committed himself to crashing in the best place he could find," Mr Masters told National Radio.

Volcano seismologist Arthur Jolly told the Waikato Times the crater lake was very hot and very acidic. Anyone exposed to the acidity and 50c heat for any length of time would die.