As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(AIRCRAFT NOT GROUNDED) HIGH PITCH NONSTOP HISSING SOUND IN MID-CABIN BETWEEN ROWS 14 AND 18 AIRCRAFT LEFT. LOUDER IN CRUISE FLIGHT AND THEN SLOWLY GETTING QUIETER DURING DESCEND. DP AND CABIN VIS WERE NORMAL. / FOUND SEAL OF AFT LH OVERWING HATCH TORN. REMOVED AND REPLACED SEAL OF AFT LEFT OVERWING HATCH REF AMM 25-21-18-960-003-A. "