What was found
AIRCRAFT 3055, LEAVING ATL CRUISING AT FL300, FLIGHT ATTENDANTS REPORTED VERY STRONG "BURNING RUBBER" SMELL FROM DOOR 3 AFT TO AFT GALLEY. AFTER APPROX. 10 MINS AT FL300, ODOR DISSIPATED. UPON DESCENT DURING ARRIVAL AT FL300, SAME ODOR RETURNED. DEFFERRED 3L & 3R FLOOR HEATING ELEMENTS INOP PER MEL 25-27-01. LATER, REPLACED CONTROL UNIT (14DS). (LP 8056616, 8056618)