A low-altitude stall which happened before an Air New Zealand Airbus crashed into the sea off the coast of France couldn't happen under normal flying operation, New Zealand air crash investigators say.
A preliminary report into the crash, which killed five New Zealanders and two Germans last November, said stall warnings sounded and the Air NZ A320 pitched and rolled before crashing into the sea off Perpignan.
Information for the report, perpared by the Bureau d'Enquetes et d'Analyses (BEA) , was gathered from witnesses, the flight voice recorder and flight data.
The Transport Accident Investigation Commission (TAIC) today clarified technicalities in the French report, but said it was premature to offer reasons about why the plane may have crashed.
However, TAIC deputy chief investigator and New Zealand's appointed investigation representative Ken Mathews said the stalling of the aircraft was unusual.
Factors like altitude, speed, angle and pitch were automatically governed by such aircraft under "normal law" or normal flying conditions.
"Under normal operations it is not possible to stall the aircraft," Mr Mathews told a press conference in Wellington.
Why that had happened and whether there were technical issues were being looked at in the continuing investigation.
He said the nose-down pitch angle of the aircraft shortly before the crash was "significant" but "one that could possibly be recovered from under other circumstances".
Chief investigator Tim Burfoot admitted TAIC had received a copy of the French report before family members or Air NZ, which had received it at the same time as the public - 5am today.
He said that was up to the French investigators and it was not up to TAIC to comment on whether it was appropriate.
Air NZ chief executive Rob Fyfe said it was not ideal for either the company or the families to have heard about it fr om media first.
Mr Burfoot said TAIC and Air NZ would have an opportunity to provide input into the final report and that further investigation updates may be released in the interim.
Flown by two German pilots, the plane was undergoing tests before being returned to Air NZ after having been leased to a German airline before crashing.
Air New Zealand staff killed were pilot Brian Horrell, 52, and engineers Murray White, 37, Michael Gyles, 49, and Noel Marsh, 35.
Civil Aviation Authority inspector Jeremy Cook, 58 , was the other New Zealand victim.
The names of the German victims have not been publicly released.
A final report into the crash may take up to two years but updates could potentially be released, Mr Burfoot said.
