[11th Earl of Mar]

However the official said it would be "extra-ordinarily difficult" for a light plane to crash into a large passenger plane due to collision avoidance systems in larger airliners.

How does a collision avoidance system help a plane that is parked at the airport?

[Moose4]

I was wondering the same thing. What good is TCAS going to do a fully-loaded British Airways 747 taxiing around at Riyadh, when some Islamonutburger in a suicide Cessna dives on it?

Now in the air, that's another matter. Between air traffic control and TCAS--assuming the controller is fast on the switch when he realizes he's got a plane with no transponder return running around in his airspace and puts 2 and 2 together--a passenger jet would have a chance to evade.

}:-)4