As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BWI - FLT 2476 - ON CLIMB-OUT OF BWI, LOUD WHISTLING NOISE HEARD COMING FROM FORWARD ENTRY DOOR, FOLLOWED BY A LOUD BOOM. FLIGHT RETURNED TO BWI WHERE LANDING WAS WITHOUT FURTHER INCIDENT. MAINTENANCE REPLACED UPPER HINGE SEAL AND SEAL BRACKET. REFERENCE USAA950240.