As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING DEPARTURE IN A 20KT LT TURN (LESS THAN 10 DEGREE AOB) THE AIR STAIR DOOR OPENED. PRIOR TO DEPARTURE THE CREW CHIEF SHUT AND LATCHED THE DOOR AND THE COCKPIT INDICATION CONFIRMED THE DOOR WAS CLOSED. IMMEDIATELY SLOWED ACFT DOWN TO 10KTS INDICATED TO ENABLE THE CREW CHIEF TO SAFELY CLOSE THE DOOR. ACFT RETURNED TO DEPARTURE FOR PRECAUTIONARY LANDING.