ITCZ,
Not meaning to be anal, but I think a small correction to your post is needed for the benefit of other readers (since the limitation is a major structural one for the aircraft):
With a max pressure diff of 7.5psi
Max diff in the Metro is 7.25Psi (at which point the safety dump valve will open). Max normal operating diff is 7.0 Psi.
Regards,
TJ
