Balloonists have rejected as "unnecessary" calls for an urgent maintenance review of all hot-air balloons after an investigation into the Carterton disaster.
The investigation found the balloon should not have been in the air on January 7, when it crashed killing all 11 people in it.
The burners and LPG fuel system had not been correctly inspected, the balloon material had not been properly strength-tested, and a safety logbook was left incomplete, preliminary findings from the Transport Accident Investigation Commission show.
Though it is not yet known if these oversights caused the crash, they meant the balloon may have been in breach of Civil Aviation Authority standards, and therefore not "airworthy".
The commission has recommended that the CAA make urgent checks on the maintenance of all 74 balloons in the country – a move that balloon operators have labelled as unnecessary and "knee-jerk".
Carterton balloon pilot Rick Walczak said he was "dumbfounded" by how the lapses could have happened.
"The balloons get strictly tested every year by inspectors; there's only a handful around the country, and they're the same guys that test commercial aircraft and helicopters."
The balloons and burners were checked by CAA-approved inspectors, with the gas cylinders tested by a certified gas company, he said.
Balloon Aviation Association president Martyn Stacey described the recommendation as a "knee-jerk reaction".
"I'm getting calls from balloonists all over the country worrying if their balloons are safe. They're saying it might have an effect on customers, and that is a worry."
Allan Still, whose daughter Alexis died on the flight, said he had mixed feelings about the findings, but was pleased the commission had found something "that may be of benefit to others".
"But it's only a little bit of the puzzle, and if you look at any disasters worldwide there's often a whole lot of little things that go wrong. This may prove to be one of those things."
The balloon was being flown by pilot Lance Hopping, who also died. It was maintained by Hawke's Bay Aviation, a company that services most Wairarapa and Hawke's Bay balloons. A spokesman confirmed the balloon was inspected there, but would not comment further.
Early Morning Balloon owners Andrew and Sally Livingstone, for whom Mr Hopping was flying at the time, also refused to comment.
TAIC chief commissioner John Marshall, QC, said yesterday that he was very concerned about the investigation's finding. If he had been a passenger and had known about the breaches, he would not have been willing to continue the flight.
An interim report to be issued within a few months would describe what happened and why, ahead of a final inquiry report expected early next year.
Meanwhile, Mr Stacey – who is also flight director at Balloons Over Wairarapa – said next month's festival would go ahead as planned.
"If there is any doubt about the integrity of a balloon's maintenance inspection ... the balloon will not fly at the festival."