An Air France crash in 2009 that killed all 228 on board was caused by pilot error, technical problems, inadequate training and poor oversight, investigators say.
France’s BEA air investigation agency final report into the mid-Atlantic plane crash has called for improved pilot training and stricter plane certification rules, among 25 recommendations to prevent a repeat of the Flight 447 disaster.
The plane flying from Rio de Janeiro to Paris crashed into the sea during a night-time thunderstorm in Air France's deadliest ever accident.
BEA confirmed earlier findings that the crew had mishandled its response to the loss of speed readings from faulty sensors that became iced up in turbulent conditions.
In one fatal decision, the report says, one of the co-pilots in the cockpit at the time nosed the Airbus A330 upward during a stall - instead of downward, as he should have - because of false data from sensors about the plane's position.
Chief investigator Alain Bouillard said the two pilots at the controls never understood that the plane was in a stall. He said only a well-experienced crew with a clear understanding of the situation could have stabilised the plane in those conditions.
"In this case, the crew was in a state of near-total loss of control," he said.
The report also found that the A330's speed sensors, known as pitot tubes and designed by France’s Thales, were only upgraded after the disaster, even though there had been previous incidents with the equipment.
The report urged Airbus to review the aircraft's stall warning system following criticism of the alarm's erratic behaviour when the plane was deep into its 38,000-foot plunge. And it urged an overhaul of the way France’s aviation and airline industries are supervised.
The BEA's findings in a preliminary report last year raised worrying questions about the reactions of the two co-pilots as the A330 went into an aerodynamic stall, and their ability to fly manually as the autopilot disengaged. Broader concerns were raised about training for pilots worldwide flying high-tech planes when confronted with a high-altitude crisis.
The final report included a study of the plane's black box flight recorders, uncovered in a costly and extraordinarily complex search in the ocean depths.
In a separate French judicial investigation still under way, Air France and Airbus have been handed preliminary manslaughter charges.