An interim report into the crash of an Air New Zealand Airbus A320 off the coast of France says a stall warning went off two minutes before the crash.
The aircraft was undergoing a test flight and the report says a testing manoeuvre was carried out at too low a speed.
The plane went down in the sea as it was coming in to land at Perpignan at 4.46pm on 27 November.
All seven people onboard were killed: two Germans and five New Zealanders.
Two minutes before the crash, the plane's speed decreased by 37 knots at a height of around 900 metres above sea level.
Stall warnings sounded and the pilots increased thrust and climbed.
Moments later. the plane's speed decreased again to less than 46 knots or 85km per hour and the stall warning sounded a second time
The plane then began to nosedive reaching a maximum angle of 51 degrees, as the captain tried to recover control.
The last recorded flight data showed the plane at a 14 degree angle and travelling at 263 knots or 487km per hour, before it hit the water half a second later.
The report says the crash was violent: spreading wreckage nearly 1km on the sea floor and the seven people on board could not have survived.
The report contains a recommendation to the European Aviation Safety Agency to reinforce regulatory requirements relating to how non-commercial flights are carried out.
The full report may take one to two years.
Aviation expert Peter Clark says the pilot also appeared to do all he could to save the plane.