Originally Posted by
Scurvy.D.Dog
… design load … do you think the design load is right then?
Yes, obviously I do, on the basis that inflight structural failure as a result of pilot inputs is Extremely Improbable. The regulations for this aspect of the design are "as safe" as any other regulation. Absolute safety is NOT the goal.
The 1.2 inches is actually irrelevant, since no-one's flying by pedal deflection. Compare force levels if you like, but pedal travel is pretty much secondary. And, yes, the A300 pedal force to rudder deflection gradient is pretty low, but it's by no means the only type with that characteristic. I suspect that +/-45lbf inputs would cause problems on any type with sufficient reversals.
The regulations are all we have to work with; no-one's going to start designing to arbitrarily higher targets, and in any case the regs ARE good enough in this case.
The RTL would have worked against the design case conditions - and who knows how large an input might have been applied if no RTL had been here in this case? It did what it could, and what it was designed to do; but it couldn't do enough to save the structure.
I'm not being 'silly', I'm pointing out that the practicality of aircraft design is that we accept risk every single flight, due to myriad causes. We simply cannot make the sturcture proof against all possible loading; we can't provide redundancy against every failure scenario. All we can do is achieve acceptable risk - currently about one hull loss per ten million FH - and accept that, sadly, one is greater than zero.