Pilot error, faulty speed and other readings inside the cockpit of an Air France jet that crashed into the Atlantic in 2009 killing all 228 people on board, including a Canadian, were cited as causes of the accident.
French aviation investigators released their final report Thursday into the tragic crash, offering many safety recommendations including better pilot training.
Investigators said better instruction for pilots on flying manually at high altitudes and stricter plane certification rules are needed to avoid future accidents like Flight 447.
The aircraft had left Rio de Janeiro on June 1 and encountered a nighttime thunderstorm several hours into the flight before crashing into the sea.
According to the report, problems began when the speed sensors -- known as pitot tubes -- iced over, sending false data to the two co-pilots in the cockpit who were flying the plane through a storm during the captain’s break.
The erroneous speed readings triggered the autopilot, setting off alarms in the cockpit.
The pilots didn’t know whether the plane was stalling or speeding because one alarm indicated it was stalling, but another alarm, ringing for 34 seconds, "saturated the aural environment within the cockpit" and confused the pilots,” the report states.
At the same time, the aircraft’s flight director, which shows the pilot what movements to make to keep the plane on the right course and altitude system, was giving erroneous and conflicting information because it gets its data from the pitots and other sensors.
The pilots, thinking the plane was going too fast and the plane was in a dive, nosed the jet upward instead of down.
"I don't have control of the plane at all," the pilot said, a minute before it crashed.
The pilots called the captain to the cockpit, but by the time he arrived, it was too late.
The doomed aircraft plunged for four minutes in darkness in an aerodynamic stall while pilots failed to react to repeated stall alarms.
Chief investigator Alain Bouillard said the two pilots never understood that the plane was in a stall and “were in a situation of near total loss of control.”
He added that only a well-seasoned crew with a clear understanding of the situation could have stabilized the plane in those conditions.
BEA chief Jean-Paul Troadec told The Associated Press that when the pilots realized that ice was blocking the pitots, they should have turned off automatic signal systems and flown manually.
William Voss, president of the Flight Safety Foundation in Alexandria, Virginia, said, "Pilots a generation ago would have done that and (understood) what was going on, but (the AF447 pilots) were so conditioned to rely on the automation that they were unable to do this.”
Killed in the accident was Guelph, Ont., native Brad Clemes, who lived in Belgium for 14 years as an executive with Coca-Cola. His body was recovered from the ocean floor last year.
Clemes’ brother John said he was satisfied with the report.
“I think they did a very good job. They've gone into great detail. They made a very good analysis. They made a number of recommendations for security,” he said.
Family members of victims showed sympathy toward the pilots, saying they were dealing with bad equipment in an exceptionally challenging situation, with dozens of warning signals going off.
Robert Soulas, who lost his daughter and son-in-law in the crash, told the AP that manufacturers had known for years about problems with the pitot tubes - freezing over but didn't order the faulty models systematically replaced until after the crash.
Pilot Gerard Arnoux defended the pilots’ actions, saying they were doing what they had been taught to do.
“A normal pilot on a normal airliner follows” the signals on the flight director system, which tells them to go left, right, up or down, he told The Associated Press.
The final report included a study of the plane’s black box flight recorders, uncovered in a costly and complex search in the ocean depths.
In a separate French judicial investigation still underway, Air France and Airbus have been handed preliminary manslaughter charges.
Meanwhile, aviation experts say the travelling public shouldn't worry it could happen again.
Faulty sensors have been replaced and pilots around the world briefed on revised rules for stall recovery.
“If we get wrong information at night in turbulence we are going to be extremely cautious as pilots to ensure we follow the right procedures,” aviation analyst Marc-Antoine Plourde said.
With files from the Associated Press
