They're the cavalry for growers, a dawn cacophony rescuing crops from the devastation of freezing temperatures.
The popularity of helicopters for frost control has waned, as growers increasingly rely on fixed frost fans to pull in warmer air from above. But the choppers still have their place, Helicopters Hawke's Bay frost co-ordinator Mike Knobloch says.
"In the old days you'd have 30 to 35," he said.
"These days there's probably not much more than 10, I would think. A lot of people have put in water, windmills - that sort of thing."
He said there was a perception helicopters were relatively expensive "but if you look at the last few years and you put in a windmill at $35,000 to $40,000 and it covers about 5 hectares, helicopters are actually quite a cheap investment".
"Sometimes on an odd-shaped blocks it's not economic to put in a windmill or water or things like that.
"Sometimes with lease blocks the operators don't want to fork out the capital for a windmill for something that may not continue over time, so that's where there's still a demand for helicopters."
While apples and grapevines are most vulnerable when flowering, grapes have the potential to be damaged throughout the growing cycle. And frosts as late as December are possible.
Frost control is not the most exciting flying job, as most of it happens at night.
"It's a job," Knobloch said.
"I think some of the younger guys starting out and they've got their night ratings, they do it to build up their hours.
"As long as you've got a good block it is relatively easy flying, but if it's a big frost it can be a bit monotonous.
"People use frost lights - they glow a certain colour depending on the temperature and the pilot can see if there are different coloured lights through the block.
"If it hits zero they'll go red and if it's half-a-degree they might go yellow so they'll know to give a bit more attention and air over that particular area of the block."
Growers must book their chopper by 3pm, to give pilots time to fly in for a safety check, ahead of a later flight with Jack Frost.
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