What was found
A CARGO FIRE WARNING LIGHT ILLUMINATED BRIEFLY AND THEN EXTINGUISHED AFTER SEVEN HOURS OF FLIGHT WHILE ON DESCENT INTO EWR AT 7,000 FEET. THE MASTER WARNING LIGHT ILLUMINATED, BUT COULD NOT TELL IF FORWARD OR AFT LIGHT CAME ON. ALL CARGO INDICATIONS WERE NORMAL. THE AIRCRAFT LANDED WITHOUT INCIDENT. INSPECTION OF THE CARGO COMPARTMENTS SHOWED NO EVIDENCE OF FIRE OR SMOKE. ALL DETECTORS AND WIRING WERE INSPECTED. THE NR 1 FORWARD SMOKE DETECTOR WAS REPLACED DUE TO GRIME. THE MASTER AUXILIARY WARNING CONTROLLER WAS REPLACED AS A PRECAUTIONARY MEASURE IAW MM 33-15-01.