As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT, THE CREW FELT A VIBRATION AND RETURNED TO YUL. MAINTENANCE INSPECTED AND FOUND THE FORWARD NOSE LANDING GEAR DOOR LATCHED OPEN. MAINTENANCE THEN REPLACED THE PSEU IN ACCORDANCE WITH DORNIER MAINTENANCE MANUAL 32-00-00. OPERATIONAL CHECKS WERE PERFORMED AND THE AIRCRAFT WAS RELEASED FOR SERVICE.