As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) ON DEPARTURE, ON TAKEOFF ROLL JUST AT THE POINT OF ROTATION THE MAIN ENTRANCE DOOR OPENED. THE CREW IMMEDIATELY RETURNED TO THE AIRPORT AND EXECUTED AN UNEVENTFUL LANDING. THE MAINTENANCE CREW INSPECTED THE DOOR AND SURROUNDING STRUCTURE, AND CHECKED THE RIGGING OF THE DOOR LOCKING SYSTEM. NO DEFECTS WERE FOUND AND THE AIRCRAFT WAS RETURNED TO SERVICE.