Why did Air France Flight 447 slow to a stall after its speed sensors failed what would of been wrong if the?

We all want to know what happened, but speculating accomplishes less than nothing. People likely to answer this question here, aren't going to be familiar with the aircraft, Air France procedures, the weight of the aircraft, the flight conditions at the time and place where control was lost, why the junior pilot was flying, what the manoeuvre margins were at 38,000ft or why they were there. What technical problems were present, how was the crew alerted, if at all. What aircraft design, construction, maintenance, flight planning or procedural issues were there? What training, proficiency, medical, fatigue, crew complement, resource management, command issues might have affected the flight? How was the flight despatched? Was the load planned correctly? Were there flight following lapses, communication problems, ATC handling issues? This list is long but not endless. Give the investigators time, consider the feelings of the surviving families and friends, please don't speculate.

epic fail in instrument training and checkride procedures. i guess none of the guys was ever required to fly according the attitude indicator and generic engine RPM, or using groundspeed from GPS as a backup information, like >I< was trained. flying "backup" instruments with simulated complete loss of aerometric instruments is essential part of pilot curriculum here.

Pilots often fly using instrumentation, and if the instruments read incorrectly, they might make wrong decisions. Apparently, this is what happened to 447. Apparently the pilot didn't travel at the correct speed because the speed sensor failed and made him think that he was traveling at a different speed. Speed keeps planes in the air, because ( with the proper angle of attack) the speed of the air below the wing is greater than the speed of the air above it, thereby creating lift (lift is created by the Bernouli Effect). The Bernouli Effect is somewhat akin to the Torricelli Effect (see links on both the Bernouli Effect and Torricelli Effect). See links for the Jowkowski air foil and the Jowkowski theorem.

Auto pilot disengaged because there was a temporary disagreement between two independent airspeed sensors. Because of the light turbulence, the aircraft rolled slightly to the right when no longer controlled by the AP, and the Pilot Flying naturally made a sidestick input to bring the right wing back up and simultaneously pulled the stick back, pitching the nose up. The result of the PF's flight control input was a dramatic climb at 7,000ft/min and a similarly dramatic drop in the airspeed because of the climb. The aircraft reached 38,000ft, way beyond the height at which it could have sustained stable flight.

I like Skipper's answer the best. Buffet margins for your weight and altitude are really "need to know" stuff. I'll bet that the scenario for AF447 was pretty similar to that Northwest accident back in 1974 that was due to an iced up pitot tube. Airbus has since come out with a service bulletin or AD requiring certain makes of pitot tubes be replaced due to possible anti-ice failure.

The details are not yet known, but an inability to determine the airspeed of an aircraft always leads to problems, often fatal problems. The airspeed can decay dramatically without the crew being aware of it, leading to a stall. In the case of AF 447, the exact sequence of events that caused the accident is not yet clear, and faulty airspeed indications may not have been the proximate cause of the accident. Currently it looks like pilot error, but we shall see.

I keep reading these chilling answers about pilots not able to fly without autopilots, unable to recognize stalls, making wrong control input due to erroneous instrument readings. Keep thinking about an Air Florida capt. that pulled power off on TO roll because his EPR was to high. the FO was repeating "somethings not right, somethings not right". The guy ignored his N1. N2, EGT, and FF. Killed a whole bunch of people for nothing. EGO? Before I soloed a crusty old SOB that used to sit behind me with a yard stick in his hand so's he could thump me if I did anything he didn't like, once taped up all the instruments. Said I was relying on them too much!! Maybe us old farts actually learned to fly? Young pilots with college degrees seem unable to respond correctly to anything they haven't been specifically trained for.