Robinson Helicopter's head of safety says Kiwi-run businesses are being decimated because of an unfair ruling by our transport safety watchdog.
Bob Muse says there's nothing wrong with the helicopter's design, but a pilot and mother of an 18-year-old who died in one of them told Newshub she's not convinced.
The Robinson helicopters are on a watchlist, meaning our transport safety worried is worried more will crash.
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"I think it was unfair to be put on a watchlist. I don't think that was justified," Mr Muse said.
"It's having a devastating effect on the operators here in New Zealand, and we think it's wrong and that's why I'm here. We are trying to set the record straight."
The debate is over something known as mast bumping - that's when the main rotor blade can end up striking the cockpit.
Te Anau aircraft engineer Russell Baker says he lost hundreds of thousands of dollars in business when the Department of Conservation stopped using Robinsons.
"As a maintenance provider, it's had a huge impact. We've dropped from 18 Robinsons we were maintaining in November down to four now," he told Newshub.
Mr Muse says the issue isn't because of a design flaw, but the way Kiwi pilots are flying them.
"In New Zealand, you have 300 of our helicopters, but you have nine times the rate of low-g mast bumping accidents," he said.
But our transport watchdog says there's more to it - it wants specialised testing to be done on the Robinson's main rotor.
Louisa Patterson lost her son James in a 2015 crash and agrees it needs to happen.
"I am very confident that should my one and only beautiful son been in any other aircraft type, that he would be alive today," she told Newshub.
She's developed a cockpit video recorder which she hopes will one day be in all helicopters.
"It'll happen again and unless we find out why... then we are not going to be able to fix it as pilots, operators and manufacturers."