As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
HEARD DULL THUMP FOLLOWED BY SQUEAL DURING AIRCRAFT ROTATION, POST FLIGHT INSPECTION REVEALED GROUND POWER UNIT DOOR NOT SECURED. INSPECTED FUSELAGE AROUND EXTERNAL ELECTRICAL RECEPTACLE AND FOUND NO DAMAGE. SECURED DOOR, RETURNED AIRCRAFT TO SERVICE.