The crash happened about 4.30am yesterday at Swallows Crossing Vineyard. The pilot managed to get out of the wrecked Guimbal Cabri helicopter and walked away with moderate injuries, although he was later admitted to Dunstan Hospital in Clyde.
His injuries are believed to include cracked ribs and bruising. The helicopter hit a vineyard pole after the pilot opened a door to get his bearings when the cabin windows became fogged up, the Civil Aviation Authority (CAA) said.
CAA communications manager Mike Richards said the man was "very lucky to be alive".
The authority was satisfied the crash was caused by pilot error, he said. It did not name the man, but police, in a earlier statement said the pilot was in his 60s.
Central Otago Winegrowers Association president James Dicey manages the vineyard and said it was the fifth frost-fighting mission this spring.
To frost-fight, helicopters hover low over vineyards to push warmer air from the inversion layer down on to the freezing ground and circulate the air.
"Having spoken to the pilot, I think he was extraordinarily lucky to walk away from the crash.
"It was 4.30am, no moonlight so it was pitch dark, and if you lose your horizon, you can get disoriented.
"I’ve been talking to him and obviously it was a fairly traumatic thing to go through, but he’s doing OK, which is a relief because he’s a bloody nice guy."
Mr Dicey said the pilot was familiar with the area and had flown there before.
"I haven’t checked yet for damage to the crops but that and any mechanical damage are all irrelevant so long as the pilot’s OK."
He would notify WorkSafe New Zealand about the crash and follow the appropriate process. Mr Richards said the accident did not need an on-site investigation.
The CAA had spoken to the pilot and reviewed information and photographs taken by police at the crash scene.
"The pilot has confirmed to us there was no mechanical failure.
"He was flying over some large pine trees en route to the vineyard. He lost sight of the ground and there was moisture on the cabin window which restricted visibility, requiring him to open the door to try and locate the ground. While doing this he hit a vineyard pole."
The pilot was the sole occupant of the aircraft.