As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ACRID SMOKE SMELL LIKE BURNING RUBBER EMINATING FROM ROW 3 TO ROW 5 AREA IN CABIN. PASSENGERS COMPLAINED ABOUT SMELL. FLIGHT ATTENDANTS ALSO COMPLAINED OF SMELL WHICH EVENTUALLY WAS DETECTABLE FROM COCKPIT. FOUND OILY SMELL IN COCKPIT FROM APU AIR PERFORMED DUCT BURNOUT