>I think "someone sitting in the pilot's seat will always be able to crash the plane" is a pretty reasonable assumption. The English language is a bit poor on

>I think "someone sitting in the pilot's seat will always be able to crash the plane" is a pretty reasonable assumption. The English language is a bit poor on existential and universal quantifiers, which renders the above sentence a bit ambiguous: it could be interpreted as 1) "For every flight and prevention method there will always exist some opportunities for a pilot to crash the plane" (with which I tend to agree) or 2) "For every flight and prevention method, the pilot will at all times be able to crash the plane" (with which I don't agree) >(How do you prevent an intentional cartwheel on takeoff or landing? There are regions of the flight envelope where 2-3 seconds of pessimal input are unrecoverable. ATC override won't help you there) I tend to agree. >So given that, we aren't trying to prevent the pilot/copilot from intentionally crashing the plane This doesn't follow. We can still limit the attack scenarios to say situations like landing and taking off. It doesn't need to be binary, a reduction in threats is still desriable. For example if Lubitz had been even more antisocial in his destruction by suicide, he could easily have crashed the plane into the surface storage for nuclear waste next to a nuclear power plant. The reactor itself does not house that much nuclear material, while the typical surface storage next to it tends to contain a lot of nuclear waste. He might still kill the passengers on landing and take off, but as crude as it sounds, it's still better than losing the very same passengers and having a nuclear contamination on our hands! The 2-in-cockpit rule sounds rather weak in my opinion, as it becomes a matter of who is stronger or who strikes first, the element of surprise etc...