The Transport Accident Investigation Commission (Taic) yesterday released its findings and recommendations after an Alpine Adventures' AS350 Squirrel helicopter crash on Fox Glacier in November 2015, which killed the 28-year-old Queenstown pilot and his six passengers.
At a press conference in Wellington yesterday, Taic chief commissioner Jane Meares acknowledged the investigation had taken "longer than usual to complete" - more than three and a-half years compared with an average of about 18 months.
Part of the delay was due to the lack of "primary evidence" - there were no witnesses, no survivors, no on-board data or video recorders and because the helicopter crashed in a remote part of the West Coast, not all of the wreckage could be recovered.
Investigators also needed to work with parties in France, the United States, the United Kingdom and Australia.
Ultimately, the commission still could not be "definitive" about the cause of the crash.
"Whilst we know that the weather was unsuitable for a flight of this nature ... what happened in the moments before the [helicopter] crashed, we can't say," Ms Meares said.
Mr Gameren's brother, Brett Gameren, said the family first read the report six months ago, but was still dissatisfied.
"Honestly, considering it's taken them that long to put together and that's all they could come up with? I'm pretty disappointed.
"Everything they've said I kind of knew anyway.
"To be honest, I'm a little bit angry about, probably, the way it's being perceived because the report still hasn't told us how the accident happened, or what happened."
Taic ultimately found it likely Mr Gameren became spatially disorientated in the weather, which was not suitable for a scenic flight, lost awareness of the machine's height over the glacier and crashed at "high forward speed and a high rate of descent, with the engine delivering power".
There was no sign the helicopter struck terrain or any object between Chancellor Shelf, where it had landed, and the crash site.
The report was also critical of the Civil Aviation Authority's lack of oversight of Alpine Adventures and the training, or lack thereof, the operator had given Mr Gameren.
Under its pilot categorisation system a newly-hired pilot would normally begin with a C-category rating, flying under direct supervision of a higher-category pilot - for, it appeared, two seasons - before promotion to B-category, where they could operate under the indirect supervision of a more senior pilot.
A-category pilots operated unsupervised and acted as lead pilots.
Chief executive James Scott told Taic a pilot could reach the A-category after four or five years and with 3000 to 4000 hours' experience.
Mr Gameren was hired by Alpine Adventures in September 2014, with 1209 hours' total flight time prior, and worked there until April 2015.
He returned in October that year and by the time of his death had been promoted to A-category in the Squirrel.
His logbook showed 1792 hours' total flight time, which included 415 hours on the AS350, of which 406 were flown with Alpine Adventures.
Brett Gameren says the family is trying to move on, but that is not easy.
"For me, personally, [I have] no closure because I don't know what happened and I think, probably, it would be fair to say we're all in the same boat with that."
Key findings:
•The AS350 Squirrel helicopter exceeded maximum permitted weight.
•Weather conditions on November 21, 2015, not suitable for scenic flight.
•‘‘Very likely’’ pilot Mitch Gameren hit the glacier after he lost awareness of the machine’s height — either by cloud, rain, flat light conditions or windscreen condensation — until it was too late to avoid a collision.
•Mr Gameren received insufficient training from his employer Alpine Adventures Ltd
