This is what about 200
grams of Semtex (Combloc C4) will do to a pressurized 747
(9 PSI to simulate 30,000 foot elevation). That's about 6.5 ounces
(enough to fill the spaces around a pair of feet in shoes). While we
regard the "Shoe Bomber" as a joke, if he'd been successful, no one
would be laughing today.