A US-based helicopter manufacturer has hit back at a report by New Zealand officials into a fatal crash involving one of its aircraft.
The Transport Accident Investigation Commission's report, out today, said mast-bumping, exacerbated by strong winds, was what caused a Robinson R44 helicopter to crash in a remote part of the Kahurangi National Park in 2014.
The pilot, Damian Webster, 37, died.
Mast-bumping is when the rotor blades strike the cabin, causing the helicopter to break up in mid-air.
The report said Mr Webster had 287 hours flying experience - and of that, 11 hours in total was spent flying the R44 model.
Transport Accident Investigation Commission (TAIC) manager of air investigations Peter Williams said, ultimately, mast-bumping was to blame but the pilot's limited experience might have been a factor.
"It is clear the pilot had slowed down under the conditions, which was a good thing to see.
"Whether he had handled the aircraft as optimally as one would hope under those conditions is completely unknown, because there were no recording devices on the [helicopter]."
He said the commission was recommending to the US Federal Aviation Administration that all Robinson helicopter models - R22, R44 and R66 - be subject to the same safety restrictions.
"We believe the flight characteristics of the three models are similar under those conditions. And also, that those limitations should be applicable to pilots, regardless of their operating experience on the helicopters.
"Because experience has shown, accidents have shown, that pilots of a wide range of experience have had these accidents."
Robinson Helicopter Company president Kurt Robinson said he rejected the bulk of the report and its recommendations, and pointed the finger at the Mr Webster's inexperience.
"I think that pilot was flying and doing something he shouldn't have been doing, unfortunately.
"The TAIC suggests somehow that there may have been conditions or something that no matter what pilot, no matter what the experience level, could've survived.
"And we don't agree with that at all."
Mr Robinson said R44 helicopters have been flying in trying conditions just fine for the past 20 years.
TAIC rejects Robinson's criticisms
However, Mr Williams said he rejected the criticisms from Robinson and said its arguments were not supported by evidence.
He said Robinson took part in the investigation, and gave submissions on the draft report.
In 2015, pilot Stephen Combe and trainee James Patterson-Gardner died when their Robinson R44 broke up in mid-air and crashed near Queenstown.
The crash led to a report late last year that prompted the TAIC to put Robinson helicopters on its official watchlist of "most pressing concerns".
In total, 18 people have been killed in 14 mast-bumping accidents involving Robinson R22, R44 and R66 helicopters in New Zealand since 1991.