The Royal New Zealand Air Force's (RNZAF) Red Checkers' aerobatics team has not performed the "Fishtail Pass" since it claimed the life of a squadron member.
Squadron Leader Nick Cree, 32, died on January 14 last year when his CT4 Trainer crashed near the Raumai weapons range, west of Bulls, on a training flight with four other Red Checkers aircraft. He left behind a wife and infant son.
An RNZAF inquiry, led by Wing Commander Shaun Clark, found he died when he overcorrected while performing a manoeuvre he had not been trained to do.
The Fishtail Pass involves the pilot waggling the back of the aircraft from left to right, like a fishtail, while holding it level.
Red Checkers pilots were not specifically trained in the manoeuvre, and it had not been known Mr Cree was performing it until his Fatigue Data Recorder (FDR) was found several months after the crash.
The FDR had been fitted only two months before the crash and was designed to monitor aircraft fatigue. However, it was also able to show Mr Cree had performed the fatal manoeuvre on 12 previous flights, unbeknown to the rest of his squadron as his physical position meant they could not see him constantly when in the air.
Many of those previous performances were "unstable and dangerous", the inquiry report released today said.
However, Mr Cree's persistence in performing it did not mean he was overconfident or a risk-taker, Chief of Air Force Air Vice-Marshal Peter Stockwell said.
"I don't think we would say he was known as a risk-taker," he said.
"Nick Cree was a very experienced and capable pilot. He was at the top level of our flying instructor flying categorisation.
"I guess the bit we don't know is why he persisted in carrying out this manoeuvre in the way that he did, and not recognising he was having lose of control points during that manoeuvre. We obviously can't be inside his head to determine that."
The Fishtail Pass was no longer performed by Red Checkers' pilots but that did not mean they would not return to it.
"It's not to say it's an unsafe manoeuvre, and we've certainly learned some lessons that we need to take account of, but right now the judgement is that it doesn't add much to the current display profile," AVM Stockwell said.
Squadron members considered the Fishtail Pass "boring" and "benign" and could not understand why it was so popular with the public, the report said.
On the day of the fatal flight, Mr Cree had had two "departures" - or losses of control - during the manoeuvre.
He had been able to recover from the first but overcorrected on the second and hit the ground three seconds later. He was flying at only about 178 feet and 65 knots when he lost control for the second and fatal time.
"Squadron Leader Cree was flying the Fishtail Pass in an unstable and inconsistent manner due to a lack of specific training in how to fly the manoeuvre," the report said.
"Guidance in Red Checkers' standard operating procedures was limited and ambiguous, and did not provide sufficient guidance to ensure the use of appropriate techniques to fly the Fishtail Pass.
"Squadron Leader Cree had not discussed the manoeuvre with any other pilot, nor had he advised of the fact that he was regularly departing from controlled flight during the Fishtail Pass."
Mr Cree was performing the manoeuvre at the height it would have been performed at an air show and it was "obviously a concern" that it could have happened during a display rather than a practice, AVM Stockwell said.
However, displays strict crowd lines were in place during shows to keep the aircraft well clear of the public.
The RNZAF had reviewed display flying practices since Mr Cree's death, and pilots were more closely monitored to ensure manoeuvres were performed how they were supposed to be.
"There are some organisational issues that we're addressing, and we have implemented many of them, but Nick did fly an unstable and inconsistent manoeuvre," AVM Stockwell said.
"We don't know why he persisted to the point where he lost control on a number of occasions."
Usually a pilot who had a departure would land and say "wow, that wasn't right" and review the incident. However, that did not happen in this instance.
The RNZAF had implemented a number of recommendations made by the court of inquiry, including introducing a new wing at Ohakea to command and supervise Ohakea-based flying operations.
The Court of Inquiry had been reopened in the interests of natural justice after Mr Cree's family expressed concerns over how it portrayed his "character and reputation".
Their issue was not with how the crash happened but with how his character was portrayed.
The family could not be contacted for comment.