As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) JUST PRIOR TO DESCENT THE MAIN CARGO DOOR WARNING LIGHT ILUMINATED. THE CAPTAIN MADE AN EMERGENCY DESCENT AND THE AIRCRAFT LANDED WITHOUT FURTHER INCIDENT. THE MAIN CARGO DOOR WARNING SYSTEM WAS UNDER THE APPROVED MEL AT THE TIME. THE MEL HAD BEEN APPLIED ON A PREVIOUS LEG WHEN MAINTENANCE HAD DETERMINED THAT AS OUT OF RIG WARNING SWITCH HAD CAUSED FALSE WARNINGS. THE MEL HAD BEEN APPLIED IAW THE PUBLISHED INSTRUCTIONS AND THE SYSTEM WAS PLACARDED.