A combination of faulty sensors and mistakes by inadequately trained pilots caused an Air France jet to plunge into the Atlantic Ocean in 2009, killing all 228 people aboard in the airline's deadliest ever crash, French investigators said Thursday. Investigators are urging better instruction for pilots on flying manually at high altitudes and stricter plane certification rules as a result of a three-year investigation into what happened to Flight 447. Airbus, manufacturer of the A330 plane, said in a statement that it is working to improve speed sensors known as pilot tubes and making other efforts to avoid future such accidents. Air France stressed the equipment troubles and insisted the pilots "acted in line with the information provided by the cockpit instruments and systems. .... The reading of the various data did not enable them to apply the appropriate action. But the Bureau for Investigations and Analysis' findings raised broader concerns about training for pilots worldwide flying high-tech planes when confronted with a high-altitude crisis. The report also could have legal implications: A separate French judicial investigation is still under way, and Air France and Airbus have been handed preliminary manslaughter charges. FILE - In this Sunday, June 14, 2009 file photo shows workers unloading debris, belonging to crashed Air France flight AF447, from the Brazilian Navy's Constitution Frigate in the port of Recife, northeast of Brazil. The French air accident investigation agency BEA is releasing its final report Thursday, July, 5, 2012 into the crash of the Airbus A330 jet en route from Rio de Janeiro to Paris that killed 228 victims. (AP Photo/Eraldo Peres, File) Close The BEA analysis lists a combination of "human and technical factors" behind the crash. The plane flying from Rio de Janeiro to Paris slammed into the sea during a nighttime thunderstorm on June 1, 2009. Some families of victims felt investigators didn't focus hard enough on the equipment problems, saying the two pilots at the controls were doing what they could while faced with a barrage of inaccurate information. Ice crystals that blocked the pilot tubes were the "unleashing event" that set off the plane's troubles, chief investigator Alain Bouillard said. The plane's autopilot shut off and the co-pilots had to fly manually, while a succession of alarms were going off. The captain was on a rest break. In one fatal decision, the report says, one of the co-pilots 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. Bouillard said that was an "important element" of the cause of the crash. He 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 stabilized the plane in those conditions. "In this case, the crew was in a state of near-total loss of control," Bouillard said. Robert Soulas, who lost his daughter and son-in-law in the crash, says investigators said the flight director system indicated the "erroneous information" that the plane was diving downward, "and therefore to compensate, the pilot had a tendency to pull on the throttle to make it rise up." However, the plane was in a stall instead. A basic maneuver for stall recovery, which pilots are taught at the outset of their flight training, is to push the yoke forward and apply full throttle to lower the nose of the plane and build up speed. But because the pilot thought the plane was diving, he nosed up. Some families of people who died in the crash showed sympathy toward the pilots, saying they were dealing with bad equipment in an exceptionally challenging situation.