Why a helicopter should simply fall out of the sky is the question confronting accident investigators looking into the crash near Wanaka airport yesterday morning.
All three occupants of the Hughes 500 died in the crash, about 1500m from the airport.
Among the them was Nick Wallis, who was a director and general manager of Alpine Helicopters, and the youngest son of Sir Tim and Prue Lady Wallis.
• Chopper crash follows spate of tragedies
The crash comes less than three months after Wallis' brother and fellow pilot, Matthew Wallis, was killed in a helicopter crash.
The burnt-out wreckage is virtually unrecognisable as a helicopter.
It lies on flat ground, about 100m from the Clutha River and well clear of any apparent aerial hazards.
What appears to be the tail section is more than 100m away.
Yesterday afternoon, men in high-viz jackets could be seen searching even further afield for parts of the helicopter.
Prime Minister Jacinda Ardern confirmed yesterday two Department of Conservation staff were also on board, and director general Lou Sanson said he was "devastated" by the news, and knew all those involved.
"This is a tragedy for our staff, who are like family and are passionate about the work they do," Sanson said.
"We are still trying to come to terms with [the] tragedy.
"Our hearts go out to the families of the Doc workers involved."
He confirmed the helicopter was on the way to undertake tahr control in the Haast area.
"The tahr control operation has been put on hold while Doc focuses on the wider Doc family."
Ardern and Conservation Minister Eugenie Sage expressed their sympathies for the families, colleagues and friends of the three people killed.
"My heart goes out to the families and loved ones of all those who died in today's tragic crash," Ardern said.
"Doc staff go to work every day on our behalf to take care of New Zealand's precious environment.
"It's an absolute tragedy that these staff and the helicopter pilot, who were just going about their work, will never return home.
"We will make sure we get to the bottom of this crash as soon as we can."
Alan McKay, who was nearby when the crash happened, said he never heard a thing, but when he got to a point where he could see the crash scene, described it as looking like a camp fire.
"There was virtually nothing left."
He said the weather was perfect and there was no breeze.
"I'd say it's just a very very unfortunate accident.
"It's a sad day for Wanaka."
An official inquiry into the crash was opened yesterday, and four Transport Accident Investigation Commission staff, including chief investigator of accidents Captain Tim Burfoot, are understood to now be in Wanaka.
The helicopter is believed to have been under lease to Alpine Helicopters.
In a brief statement late yesterday, a company representative said the helicopter was heading to the Landsborough Valley and it "failed to reach its destination".
A former Doc worker who has flown with Mr Wallis on many occasions said it was a new Hughes 500 helicopter that was "super safe".
"It will be really interesting to find out what has happened here. I can't believe it would be pilot error, as Nick was super-experienced and a really talented pilot."
He said Wallis ran a well-organised operation and they were using a new machine that was specifically designed to be super-safe.
The ODT understands police officers met Sir Tim to inform him of the tragedy yesterday afternoon.
Sir Tim, who is in poor health, had been in hospital for the past month.
Warbirds Over Wanaka Community Trust chairman John Gilks paid tribute to Nick Wallis yesterday, saying the tragedy would have a huge impact on the Wanaka community.
"It's in the realm of being almost unbelievable.
"The community will be devastated."
Gilks, who knew Wallis well, said the pilot was a "lovely guy, a wonderful guy".
"He was a man's man and yet a real gentleman."
"The person I feel deeply sorry for is Nick's wife ... and their children."
Former New Zealand Deerstalkers Association president Bill O'Leary expressed deep regret at the "tragic loss of life".
"All our members, indeed hunters everywhere, will join in expressing their deepest sympathy to the families of those lost."