What was found
ON TAKEOFF OUT, CREW DOOR CAME OPEN AND PILOT RETURNED TO BASE SECURED DOOR THEN TOOK OFF TO CONTINUE FLIGHT.
As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
ON TAKEOFF OUT, CREW DOOR CAME OPEN AND PILOT RETURNED TO BASE SECURED DOOR THEN TOOK OFF TO CONTINUE FLIGHT.