Originally Posted by
joepilot
Va applies to all control surfaces in either direction.
Airbus did not believe that they were required to make the tail strong enough to withstand a rudder reversal, i.e. full throw one way followed by full throw the other way. This is what happened with AA587, and the tail broke off.
Boeing always believed that the reg required the plane to be strong enough to take this kind of abuse.
Joe
The FAA required that you can put the rudder hard-over without breaking off the tail. They did NOT require that the tail stay attached if you go hard-over and then at the moment of max yaw (before it stabilizes) go hard-over in the opposite direction...that is what happened to AA. The pilot probably did not intend to go full deflection, the airbus controls produced full deflection with only a tiny amount of pedal travel in that flight regime.
Airbus designed to the letter of the law..saves weight and money. Boeing overdesigns vertical stabs relative to the FARs.