Dismiss Notice
Welcome to IDF- Indian Defence Forum , register for free to join this friendly community of defence enthusiastic from around the world. Make your opinion heard and appreciated.

How Panic Doomed Air France Flight 447

Discussion in 'Indian Defence Industry' started by lucifer, Dec 10, 2011.

Thread Status:
Not open for further replies.
  1. lucifer

    lucifer Lieutenant SENIOR MEMBER

    Joined:
    Aug 25, 2011
    Messages:
    785
    Likes Received:
    155

    On the evening of May 31, 2009, 216 passengers and 12 crew members boarded an Air France Airbus 330 at Antonio Carlos Jobim International Airport in Rio de Janeiro, Brazil. The flight, Air France 447, departed at 7.29 p.m. local time for a scheduled 11-hour trip to Paris. It never arrived. At 7 o'clock the next morning, when the aircraft failed to appear on the radar screens of air traffic controllers in Europe, Air France began to worry and contacted civil aviation authorities. By 11 a.m., they concluded that AF447 had gone missing somewhere over the vast emptiness of the South Atlantic.

    How, in the age of satellite navigation and instantaneous global communication, could a state-of-the art airliner simply vanish? It was a mystery that lasted for two years.

    Not until earlier this year, when autonomous submersibles located the airliner's black boxes under more than two miles of water, were the last pieces of the puzzle put together. What doomed the 228 men, women and children aboard Air France 447 was neither weather nor technological failure, but simple human error. Under pressure, human beings can lose their ability to think clearly and to properly execute their training.

    Over at Popular Mechanics I've got a long piece offering a detailed blow-by-blow account of how one of the co-pilots of the Air France jetliner managed, in the course of just five minutes, to take a perfectly operational airplane from an altitude of nearly seven miles down to impact with the ocean. Here, I'd like to offer a nutshell summary of what happened and what our understanding implies for the future of air safety.

    Air France 447 was operating with three pilots: a captain, who was the most senior crewmember, and two co-pilots. At any given time, two of them were required to be in the cockpit, seated at the pair of seats equipped with controls. Four hours into the flight, the captain went to take a nap, leaving the flying of the plane to the more junior of the co-pilots, Pierre-Cédric Bonin. Sitting beside him was the other co-pilot, David Robert.

    The crisis began mere minutes later, when the plane flew into clouds roiling up from a large tropical thunderstorm, and the moisture condensed and froze on the plane's external air-speed sensors. In response, the autopilot disengaged. For a few minutes, the pilots had no way of knowing how fast they were going, and had to fly the plane by hand -- something, crucially, that Bonin had no experience doing at that altitude.

    The proper thing for Bonin to have done would have been to keep the plane flying level and to have Robert refer to a relevant checklist to sort out their airspeed problems. Instead, neither man consulted a checklist and Bonin pulled back on the controls, causing the airplane to climb and lose airspeed. Soon, he had put the plane into an aerodynamic stall, which means that the wings had lost their ability to generate lift. Even with engines at full power, the Airbus began to plummet toward the ocean.

    As the severity of their predicament became more and more apparent, the pilots were unable to reason through the cause of their situation. Despite numerous boldfaced clues to the nature of their problem -- including a stall-warning alarm that blared 75 times -- they were simply baffled. As Robert put it, after the captain had hurried back to the cockpit, "We've totally lost control of the plane. We don't understand at all... We've tried everything."

    Psychologists who study performance under pressure are well aware of the phenomenon of "brain freeze," the inability of the human mind to engage in complex reasoning in the grip of intense fear. It appears that arousal of the amygdala causes a partial shutdown of the frontal cortex, so that it becomes possible to engage only in instinctive or well-learned behaviour.

    In the case of Air France 447, it appears that Bonin, in his panic, completely forgot one of the most basic tenets of flight training: when at risk of a stall, never pull back on the controls. Instead, he held back the controls in a kind of panicked death-grip all the way down to the ocean. Ironically, if he had simply taken his hands away, the plane would have regained speed and started flying again.

    Compounding the problem was a peculiar feature of the Airbus's cockpit layout. Unlike a Boeing jet, in which one pilot's movement of the control yoke moves the other pilot's yoke as well, an Airbus features "asynchronous" controls, meaning that moving one control doesn't cause the other to move as well. Bonin's colleagues probably never knew that he had the controls all the way back -- perhaps because they never imagined that any certified airline pilot could engage in such a misguided response.

    Perhaps the most tragic moment of the entire transcript occurs in the final moments, when Bonin at last tells the others that he has had the controls back the entire time. "No, no, no," says the captain. But by then it is already too late.

    What can we learn from AF447? Above all, the tragedy reinforces an unfortunate truth about air travel that many passengers do not appreciate: the most dangerous component of a modern commercial jetliner is the brain of its pilot. The majority of fatal airline accidents (vanishingly rare though they may be) are due to pilot error.

    One way that airline manufacturers have tried to work around this problem is to increase the amount of automation, so that planes can largely fly themselves, but this tendency has had the paradoxical of compounding the problem: The more pilots rely on automation, the less practiced they are at flying a plane by hand when an emergency requires it.

    As a pilot myself, I love taking the controls of an airplane and through it finding a perfect freedom of movement in the sky. I would never want a computer to take that away from me. The practical reality of moving passengers in perfect safety from point A to point B requires a different perspective. As technology improves, and flight control systems become more sophisticated, the relative inadequacy of we two-legged mammals will only become more apparent.

    Ultimately, the idea of a relying on a human being in the cockpit may come to seem both sentimental and unaffordably risky.
     
  2. vikas jat

    vikas jat Captain SENIOR MEMBER

    Joined:
    Aug 15, 2011
    Messages:
    1,199
    Likes Received:
    88
    sometimes we loose confidance n thinking under pressure or fear
     
  3. lucifer

    lucifer Lieutenant SENIOR MEMBER

    Joined:
    Aug 25, 2011
    Messages:
    785
    Likes Received:
    155
    yep.... thats what the article describes: "Brain Freeze"

    Maybe Vstol Jockey from his flying experience elaborate more on the environment in the cockpit under such circumstances.
     
  4. vstol jockey

    vstol jockey Colonel MILITARY STRATEGIST

    Joined:
    Mar 15, 2011
    Messages:
    13,790
    Likes Received:
    15,448
    Country Flag:
    India
    The airbus family is a fly by wire family. whenever there is a mismatch in indications beyond a threshold, the auto pilots trip and the flight augmentation computers take over to restore the ac to safety. the FBW system provides bank angle, AOA,low speed, high speed protection, pitch and load protections. This ac has three basic laws, Normal Law where all the protections are available, Alternate law whr only two protections are available and direct law whr none is available. In the direct law, the ac is like a normal ac wherein the pilot has to fly to maintain the ac within the flying parameters. A330 has only two laws, Normal and Alternate. However in thie case of AF447, once the airspeed indications became unreliable, the auto pilots tripped and the ac went into Alternate law. this caused the ac to lose the most of its protections. Most first officers are not very conversant with the automatics of these ac. They are very good at flying this ac with the help of flight directors but are well short of reqts while flying it in raw data mode. The jets are flown on Pitch & Power principle. every AOA has two speeds for a particular power setting at which the ac can be flown depending on whether you in region of normal command or region of reverse command. And evry power setting at a given altitude and weight will result in one set IAS for a particular power setting. whenever the speed indications become unreliable, the ac needs to be flown as a pure jet with pitch and power settings. The checklists contain this data for each altitude and weight of the ac.

    F/Os due to lack of thr exp and training get into panic and compound simple problems into complex ones. Take the case of an Air India express ac over Arabian sea a few years ago where the F/O plunged the ac 17000 feet as he panicked when the autopilot got disengaged while the captain was out of the cockpit. Thankfully the captain sensed the problem and returned to the seat to recover the ac otherwise India would have had a similar incident. I too faced a similar situation in Patna in 2002 when i did a high speed rejected take off on that famous patna runway. My F/O froze on controls and was so shocked as if he had a king cobra in front of him close to his nose. Stall recovery procedures are taught to everyone from the very basic flying days itself. However what probably made these F/Os take wrong recovery action was the inadequate knowledge of FBW system. It is impossible to stall FBW family of airbus ac. They probably did not realise that the ac had reverted to alternate law whr there was no protection left and that they needed to take standard recovery action. The fact that they kept on pulling the stick back and had it fully back even at the time of impact, clearly shows this. So many times in normal flying the autoplit disengages and you can see the panic which the F/Os get into. The problem lies in the fact that nearly all pilots who come from civil flying schools do thr training on C-152 and never get a chance to fly jets before getting into airbus family type of ac. had it not been an A330, the F/O would have taken the basic recovery action of lowering the nose to build up speed and then raise the nose to return to level speed keeping an approx attitude or pitch for the weight and altitude with sufficient power which would have given him a comfortable speed. But the inadequate knowledge of FBW system coupled with lack of exp compounded by panic caused them to lose situational awareness and they just failed to realise that the ac has reverted to alternate law and needs to be flown like a non FBW ac from then on.
     
    omya, lucifer and Guynextdoor like this.
  5. vstol jockey

    vstol jockey Colonel MILITARY STRATEGIST

    Joined:
    Mar 15, 2011
    Messages:
    13,790
    Likes Received:
    15,448
    Country Flag:
    India
    In Airbus FBW family each stick has an override button. Whenever any pilot presses it, the other pilot loses the control and his stick becomes non functional. If you keep this button pressed for 40 seconds, the other stick is rendered permanantly unusable. Also if both sticks are moved in opposite directions, the FBW system gives an output which is the algebric sum of the two inputs. In case of same side movements, it will add to control deflection and in case opposite movements, it will give a mean figure.

    BTW you need one pilot and a dog to fly Airbus FBW family. The pilot is thr to feed the dog and the dog is thr to bite the pilot in case he touches any of the controls. The automation in Airbus is atleast one generation ahead of B737NG. I have flown both the types and so can say it with authority.

    90% of the air accidents are caused by Pilot Error and 90% of humen are also born by Parental error.

    What is PILOT ERROR?
    A pregnant airhostess is called a PILOT ERROR.
     
    Last edited: Dec 10, 2011
    1 person likes this.
  6. Guynextdoor

    Guynextdoor Lt. Colonel SENIOR MEMBER

    Joined:
    Aug 24, 2010
    Messages:
    4,855
    Likes Received:
    1,740
    90% of the air accidents are caused by Pilot Error and 90% of humen are also born by Parental error.

    What is PILOT ERROR?
    A pregnant airhostess is called a PILOT ERROR.




    :lol:
     
Thread Status:
Not open for further replies.

Share This Page