French investigators probing the 2009 crash of an Air France jet over the Atlantic have released a report linking pilot errors to the deadly accident and calling for better pilot training to cope with an emergency.

The report from the French air accident investigation agency says the pilots of Air France 447 did not realize the plane had stalled, were insufficiently trained in flying manually, and never told passengers anything was wrong before the aircraft hit the water. All 228 people on board were killed.

The agency, known as the BEA, also said in the findings made public Friday that the pilots failed to discuss the repeated “stall” alarms as the doomed Airbus A330 plunged toward the ocean at 200 kilometers per hour. The plane was traveling from Rio de Janeiro, Brazil to Paris, France, and crashed in stormy weather June 1, 2009.

The BEA says a stall warning sounded numerous times, and once for a full 54 seconds, but that the crew made no reference to it in cockpit exchanges before the jet crashed. At the time the warnings began sounding, the captain was on a rest break.

The agency says a co-pilot at the controls at that time pointed the nose of the plane upward, which is contrary to normal procedures to come out of an aerodynamic stall. Normally, the nose should be pointed slightly downward in order to regain lift. Two co-pilots were in the cockpit when the trouble started. By the time the captain returned, the situation had worsened considerably.

In one recommendation, investigators call for pilots to receive more training on how to fly aircraft manually at high altitudes.

Air France, for its part, issued a statement saying there was no reason to question the technical skills of the pilots flying the aircraft at the time of the crash.

The report says external speed sensors obstructed by ice crystals produced irregular speed readings on the plane. Since then, Air France has replaced the speed monitors on its A330 and A340 models.

Earlier this year, a French judge placed Airbus under investigation for possible involuntary manslaughter charges in the 2009 crash. The European aircraft maker said it disagreed with that decision. Preliminary manslaughter charges were also filed against Air France, which has strongly protested the move.