YouTube - Aviation - Boeing 747 - Airplane Crash (Explosion)
Think the fuselage was presurised at the time....., not sure to what altitude. Nor am I sure what the size of the charge was, but I'm fairly certain it was about the same size at Lockerbie.
Yes, 'twas a United airlines 74 out of Hawaii that blew a forward cargo door. 9 pax didn't make it back.