What was found
DURING FLIGHT, PILOT REPORTED NR 1 AND 2 ENGINES, AND MAIN TRANSMISSION FIRE WARNING LIGHTS . AT THE SAME TIME, THE ENGINE MONITORING DISPLAY (IIDS) WENT BLANK. PILOT PROCEDED TO MAKE A PRECAUTIONARY LANDING. INSPECTION OF THE ACFT REVEALED NO EVIDENCE OF FIRE. MAINTENANCE TESTED THE WIRING FOR THE FIRE WARNING SYS. THE OVERHEAD ELECTRICAL PANEL WAS CHECKED FOR FAULTS. MFG RECOMMENDED REPLACEMENT OF THE IIDS. OPS CHECKED AFTER INSTALLATION WERE PERFORMED WITH NO FAULTS. GROUND RUNS AND A MAINTENANCE FLIGHT WAS PERFORMED WITH NO ADDITIONAL FAULTS.