2009 Air France crash blamed on pilot error, bad data

By Luis Cabrera

An Air France plane crash that killed all 228 people onboard three years ago was blamed on pilot error and faulty sensors. An investigation into the aviation disaster revealed that the crew failed to properly maintain control of the Airbus 330 in the midst of a violent storm over the South Atlantic. Flight AF447 from Rio de Janeiro to Paris had been en route for only two hours when it disappeared off ground control radars on June 1 2009.

According to the report, released July 5th by the French Agency BEA, while flying into severe turbulence and with several warning systems activated, the copilot turned the nose of the plane up instead of down; a fatal error that resulted in the plane stalling and plunging into the ocean. “I don’t have any control of the plane at all,” the pilot said one minute before the crash, according to the 224-page document released by French investigators.

A series of events lead to the grim and final outcome, beginning with faulty speed sensors that were followed by human error. Ice build-up was the original culprit because it caused the plane underbelly’s wind speed readers to send erroneous information to the “flight director” computer. The computer system tells a pilot which moves he needs to execute to maintain proper altitude and speed of the aircraft. The bad data caused the autopilot to disengage, and alarms started sounding in the cabin. Ensuing error in judgment by a crew making the wrong moves resulted in the tragic crash.

Aviation experts concluded that there was confusion in the cockpit about the plane’s actual speed. To make matters worse, the main pilot had taken a rest break, and by the time he came back to the controls, it was too late. Instead of maneuvering for stall recovery, the co-pilot at the controls believed the Airbus 330 was gaining speed and going on a dive, so he pitched the nose of the plane sharply upward, causing the stall. The plane lost altitude quickly and moments later crashed into the sea below.

The crash that killed 216 passengers of different nationalities and 12 crew members is the worst disaster in Air France history. After the disaster, submarine robots were used to retrieve the “black box” data recorders of the aircraft, an operation that took nearly two years. The wreckage of the Airbus was found after a long and extensive search of the ocean floor that extended to 10,000 square kilometers (3286 sq mi) and took 23 months.

Alain Bouillard, the chief investigator of the collision, said the crew was “in a near-total loss of control” of the commercial aircraft, and that ice build-up had been the “unleashing element” of the disaster. Bouillard added that only a more experienced crew with a better understanding of the conditions could have taken corrective measures to stabilize the Airbus. Investigators agreed that the “flight director” system should have been turned off early on by those behind the controls and manual operation of the aircraft adopted at that point.

Legal action is likely to be taken by families of the deceased. There are allegations of negligence made against Air France and Airbus, the builder of the plane. Investigators have found fault with the two companies, and French magistrates are investigating them both for possible manslaughter charges. A separate judicial report will be released next week.

The final minutes of Flight AF447

1. 0135 GMT: The crew informs the controller of the flight’s location.

2. 0159-0206 GMT: The co-pilot warns of turbulence ahead before the captain leaves the cockpit for a rest break.

3. 0208 GMT: The plane turns left, diverting from the planned route. Turbulence increases.

4. 0210 GMT: The auto-pilot and auto-thrust mechanisms disengage. The plane rolls to the right. The co-pilot attempts to raise the nose. The stall warning sounds twice and the plane’s speed drops. The co-pilot calls the captain.

5. 0210 GMT: The stall warning sounds again. The plane climbs to 38,000 ft.

6. 0211-0213 GMT: The captain re-enters the cockpit. The plane is flying at 35,000 ft but is descending 10,000 ft per minute. The co-pilot says “I don’t have any more indications”, pulls the nose down and the stall warning sounds again.

After location 6. 02:14 GMT: Recordings stop.

Source: BEA. Note: Last known position = last known position before the plane’s “black boxes” were retrieved.

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