What was found
AIRCRAFT WAS GROUNDED: BURNT RUBBER ODOR THROUGHOUT A/C. DISSIPATED WITH RECIRCULATION FANS OFF IN 10 MIN. ACCOMPLISHED J/C 72L00021001. REPLACED ALL RECIRCULATION FAN FILTERS AS PRECAUTIONARY IAW AMM 21-25-02 AND AMM 21-25-08. CHECKED RECIRCULATION FAN LOWER, NO EVIDENCE OF ELECTRICAL FAULT, NO BINDING, NO RUBBING OF BLADES. UPPER FANS CHECKED, NO EVIDENCE OF FAULTS, NO BINDING, NO RUBBING. CHECKED LAVATORY FAN, NO EVIDENCE OF FAULTS. ENGINES RUN UP PER J/C 72L00021001 POINT D, NO SMOKE OR ODORS COMING FROM ENGINES OR APU. CONTACTED MOC FOR HISTORY REVIEW AND AUTHORIZATION TO CLOSE THE ITEM.