As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: LAVATORY 3L SMOKE DETECTOR ACTIVATED TWICE IN FLIGHT. NO ONE IN LAVATORY THE SECOND TIME. MAINTENANCE PERFORMED BITE TEST OF THE SMOKE DETECTION AMM 26-10-00-740-810-A. MAINTENANCE ALSO FOUND BAD FILTER CONDITION OF 3L SMOKE DETECTION SYSTEM AND RERPLACED BAD FILTER IAW AMM 26-17-15.