As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ETREMELY LOUD NOISE COMMING FROM DOOR 1L INFLIGHT AIR RETURN DEBRIEFED CREW WAS LOUD AT ALL ALTITUDES AND AT ANY DIIFERENTIAL PRESS. NOISE LOUDEST AT LOWER AFT CORNER OF L-1 DOOR. RAGS AND BLANKETS NO HELP. DOOR SEAL HAS A HOLE IN THE LOWER AFT CORNER. REMOVED AND REPLACED L1 DOOR SEAL REF AMM 52-11-18. CONDUCTED LEAK CHECK REF AMM 05-53-00 OPS CHECK GOOD NO NOISE OR LEAKS PARTS USED: 18-5211-3-0157,QTY :1 ADD EMP:U400614