The son of one those killed in the Fox Glacier air crash in 2010 is calling on the Transport Accident Investigation Commission (TAIC) to apologise for a series of mistakes it made during its investigation.
The commission reinvestigated the crash, following revelations on the 3D current affairs programme.
Nine people died when the skydive plane ZK-EUF crashed near Fox Glacier shortly after take-off in 2010. TAIC concluded the most likely reason for the crash was the plane being excessively out of balance, and that it became airborne too early.
But a review of the tragedy now says they got that wrong.
"It's a complete turnaround, it's a complete reversal of what they originally said," says Jake Millar, whose father Rod Millar died in the crash. Rod was the company's co-owner and tandem master. "They haven't publicly apologised, but they have done a complete turnaround."
The review states that the commission is unable to determine that the aeroplane became airborne too early, that the aeroplane should have been controllable and that the plane being out of balance was not the most significant factor contributing to the crash.
"From day one, every single pilot and aviation I talked to said they had it wrong, they thought they had it right. It took a team of journalists from 3D for them to come and say 'No, you guys do have it wrong'," says Mr Millar.
3D enlisted the help of independent experts who said the plane being overweight and out of balance did not cause the crash.
It also revealed a large part of the plane was buried just a few days after the crash.
Prosolve air crash investigator Andrew McGregor says burying wreckage was a serious mistake.
"It demonstrates a serious process breach and could plague other future investigations," he says. "They have not demonstrated they are an open, transparent organisation."
Mr McGregor believes a control-systems defect remains the most likely cause of the crash. But the commission says while that possibility cannot be excluded, the true cause of the crash may never be known.