Originally Posted by
DozyWannabe
Misd-again: Regardless of the cost angle, Airbus do have a point about fewer moving parts meaning lower failure rate though, and that's an engineering fact - the biggest example in aviation being the move from piston to jet engines.
How many rudder control failures have you heard about, from either system, that are related to the design of the rudder limiter? I can't recall any, which to me indicates that there's no empirical safety benefit from having fewer parts.
I don't know why Airbus changed the design. We have cost(proven), weight(proven), and better failure mode(hypothetical?). I'd vote for lower cost, weight, and ease of manufacture as the reasons behind the change.
It's obvious from the accident investigation that even the Airbus pilots had handling issues in the simulator if they pushed the rudder pedal .6 of an inch. Full scale deflection, and the potential for the unwary to start a PIO due to 'startle effect', occurred. To me that's a poor design.
The 737 rudder failures are related to hydraulic actuator issues that all a/c have.