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Old 2nd January 2015 | 09:12
  #28 (permalink)  
vilas
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Joined: Jun 2007
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From: Wanderlust
Tubby and capt prop
The moment you say airbus FBW cannot be stalled some people counter it by saying under certain circumstances it can. Let us understand what it exactly does. You cannot bank Airbus more than 67 degrees means exactly that you cannot. But that doesn't mean in violent storm it cannot be turned upside down. Similarly stall is an angle of attack phenomenon which you cannot achieve with side stick in normal law. If it happens due to severe atmospheric conditions the computer will try and reduce the angle of attack to Alpha Max which is not the case in conventional aeroplane. When you enter an updraft the angle of attack will increase the auto pilot will try to maintain the altitude by pitching down which will increase speed etc. How ever unlike normal aircraft if the angle of attack exceeded alpha prot it will latch and aircraft will maintain that angle of attack even after autopilot trips. Whether aircraft can pitch up in alpha prot yes it can. This protection is designed to pitch down to maintain it when you are increasing the angle of attack but when angle of attack is changing due to updrafts it will maintain the latched condition by doing whatever it takes even by climbing unless pilot pushes the stick forward and unlatches it. It has happened and caused Air prox incidents.
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