What was found
YYZ/IAD - FLT 4897 - AT 23,000 FEET CRUISE ALTITUDE, THE CABIN ALTITUDE WARNING SYSTEM SOUNDED. THE CREW PERFORMED AN EMERGENCY DESCENT LANDING IN IAD WITHOUT INCIDENT. MAINTENANCE WAS DISPATCHED TO THE AIRCRAFT AND FOUND THE CARGO DOOR SEAL HAD COME LOOSE AND WAS TORN. IAD MAINTENANCE SECURED THE SEAL AND DEFERRED THE PRESSURIZATION PER THE MEL AND RETURNED THE AIRCRAFT TO SERVICE. (X)