What was found
VENTILATION BLOWER FAN VERY LOUD. THEN AT 3.5 HRS INTO FLIGHT, SOUNDS CHANGED FOLLOWED BY METALLIC ODOR, SELECTED BOTH FANS TO OVERRIDE. NO FAULTS WERE INDICATED. REPLACED AVIONICS VENT BLOWER FAN IAW AMM 21-26-51. OPS CHECKED GOOD.
As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
VENTILATION BLOWER FAN VERY LOUD. THEN AT 3.5 HRS INTO FLIGHT, SOUNDS CHANGED FOLLOWED BY METALLIC ODOR, SELECTED BOTH FANS TO OVERRIDE. NO FAULTS WERE INDICATED. REPLACED AVIONICS VENT BLOWER FAN IAW AMM 21-26-51. OPS CHECKED GOOD.