thcrozier
"Also, are the engine pylons designed to shear off under the stress of a water landing?"
I think the answer is somewhere on PPrune. I know for a fact that in the early days Airbus adopted a different means from Boeing to meet the requirement that (from memory) in an accident large masses should not fly around and cause even more damage to the plane and pax cabin. Boeing always used the famous "fuse pins" designed to let the engines separate early under relatively low loads. Airbus chose to ensure, as far as possible, that the engines remain attached.
I'm not 100% sure that this philosophy was carried over to the A320 Family, but I think it was.