What was found
PILOTS REPORT: JUST PRIOR TO LANDING, A WARNING SYSTEM AUDIO “GONG” WENT OFF IN THE PILOTS HEADSET WITH NO ASSOCIATED LIGHT ON CAUTION & WARNING PANEL. WITHIN 4 SECONDS, 2 MORE WARNING AUDIO ALARMS WITH NO ASSOCIATED LIGHT FOLLOWED BY A 5TH AUDIO ALARM WITH AN ENGINE FIRE LIGHT (LIGHT EXTINGUISHED). FINALLY, A 6TH AUDIO ALARM AND SUBSEQUENT ENGINE FIRE LIGHT ILLUMINATED AND REMAINED ON UNTIL THE AIRCRAFT WAS SAFELY ON THE GROUND AND SHUTDOWN.
MECHANICS REPORT: INSPECTED THE 3 ENGINE FIRE DETECTORS AND ASSOCIATED WIRE HARNESSES (NO DAMAGE NOTED). REMOVED THE ASU CARDS INSPECTED, CLEANED AND REINSTALLED. OPERATIONAL CHECK GOOD. AIRCRAFT RETURNED TO SERVICE.