"He had fallen and apart from some lacerations to his arms he was in considerable pain with a back injury."
He said some of the other trampers - all foreigners - had cellphones but were unsure who they should contact in an emergency.
"I used my phone to dial the *555 police number and they had a rescue helicopter on the scene within an hour."
Drysdale said while he waited with the injured Dutchman, the other three in his group continued to climb Mt Ngauruhoe.
"It was a beautiful day and we wanted them to see the views," he said.
Both he and Ms Haigh had done the crossing before so he said it was not unfamiliar territory for them.
"The bloke wasn't too flash when we arrived on the scene but his spirits had lifted quite a bit by the time the chopper landed."
Staff from Taupo's Greenlea Rescue Helicopter said they were called to Mt Ngauruhoe to assist a 23-year-old man who fell while descending from the summit.
The man was slung from the mountain on a long line recovery system and taken to Rotorua hospital with back injuries and significant grazing.
The man was discharged yesterday.
After finishing the tramp Drysdale and his party headed back to Cambridge.
They were back on the water at Lake Karapiro yesterday morning for a training session before taking Ms Crow and Karonen through to Auckland to catch their flights back home.