As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMBOUT THE CREW REPORTED A BANGING SOUND FROM THE RIGHT SIDE OF THE FORWARD FUSELAGE. THE FLIGHT RETURNED TO TLH AND LANDED WITHOUT INCIDENT. MAINTENANCE FOUND THE EXTERNAL SERVICE PANEL DOOR OPEN. THE DOOR WAS INSPECTED AND NO DAMAGE WAS FOUND. THE DOOR WAS PROPERLY SECURED AND THE AIRCRAFT WAS RELEASED FOR SERVICE.