The Civil Aviation Authority may have been able to pursue legal action against the pilot involved in the Fox Glacier tragedy had he survived, but it was unable to lay charges against the company responsible for the ill-fated operation.
A coroner's investigation into the 2010 tragedy has found it was unlikely the cause of the crash would ever be fully understood but pointed at the plane being over the allowable weight limit and unbalanced as possible causes.
The families of the four tourists who died in the crash said the fact no one had been held accountable showed a lack of intent to improve safety in the adventure tourism industry.
The CAA said the aircraft operator, Skydive NZ, was not covered by the new Adventure Aviation rule, so could not be subject to prosecution.
However, acting Director of Civil Aviation John Kay said: "The CAA did have jurisdiction over the pilot and, had he survived the accident, action could have been taken only if it could be proven that there had been a breach of the civil aviation rules."
Following the release of the coroner's report, the CAA was now drafting a New Zealand-specific "airworthiness directive" to enforce the use of restraints during the take-off and climbing phases for larger aircraft used in parachuting and skydiving.
"These measures will enhance the regulation already in place around the weight and balance of aircraft during take-off, as well as those regulations specifically targeted at adventure aviation operators," Mr Kay said.
He added that since the tragedy, changes already been implemented which meant adventure aviation operators were subject to the same surveillance and audit regime as commercial aviation operators.
"New Zealand is now the only country in the world with such comprehensive regulation of the sector."
Chris Coker, whose 24-year-old son Brad was on a gap-year trip around the world when he died in the Fox Glacier crash, said holding a person or company accountable for the tragedy "isn't about money".
"This isn't about money, this is about doing the right thing," Mr Coker said.
"If you don't hold anyone to account how on earth are you going to bring about a better level of safety? The answer is you won't."
The CAA is considering two recommendations made by Coroner Richard McElrea as a result of his investigation into the Fox Glacier crash, which killed four international tourists, four skydiving masters and the pilot.
Mr McElrea's report, released today, recommends imposing a six-person limit on Fletcher aircraft used in parachuting operations and mandatory passenger restraints on planes used for tandem parachuting.
The inquest found the plane that crashed at Fox Glacier was over the allowable weight limit and unbalanced when it plummeted to the ground shortly after takeoff.
One witness said none of the passengers were restrained, which may have thrown the plane off its centre of gravity as they slid to the rear of the aircraft during the ascent. The inquest was told that eight of the bodies were found in the tail section of the plane.
Mr McElrea said other unknown factors - including possible engine malfunction, control column failure or pilot error - probably accounted for the aircraft's loss of control.
He said said although it was unlikely the cause of the crash would ever be fully understood, it was important to take a conservative approach to safety "to better prevent the possibility of the events of 4 September 2010 recurring"
Mr Coker and the families of the other tourists killed on the flight have written an open letter to Prime Minister John Key pleading for urgent action to improve the safety of the adventure tourism industry.
"We did expect more from [the inquest], to be quite honest. But an inquest will not bring back our children, the people who have died," Mr Coker said.
"We're still concerned that New Zealand's not quite as safe as it ought to be."
A spokeswoman for Mr Key said he continued his "personal commitment" to ensure tourists to New Zealand did not face unnecessary risks.
She said the Government would consider the recommendations made by Mr McElrea.
Mark Horning, the director of Skydive Fox Glacier which took over operations in the region after the 2010 crash, said the proposed passenger limit would have no impact on safety because weight and balance limits were already imposed on aircraft.
"From an engineering standpoint it [the suggestion by the coroner] just doesn't make any sense," he said.
"Obviously he's given the best opinion that he can, and it is a suggestion, all of these are suggestions. It will be up to Civil Aviation whether they take it up or not."
Mr Horning said he supported passenger restraints and had implemented that safety measure in his operations for several years.
- Patrick Michael Byrne, 26, of Ireland
- Glenn James Bourke, 18, of Australia
- Annika Charlotte Kirsten, 23, of Germany
- Bradley Victor Coker, 24, of England
- Adam Bennett, 47, of Moteuka, skydive master
- Michael John Suter, 32, of New Plymouth, skydive master
- Christopher McDonald, 62, of Tasman, skydive master
- Rod Clifford Miller, 55, Greymouth, skydive master
- Chaminda Nalin Senadhira, 33, of Queenstown, pilot