What was found
THE AIRCRAFT WAS GROUNDED. AIR INTERRUPT, FLIGHT CREW EXPERIENCED FIRE DETECTION FAULT LIGHT ON DURING FLIGHT. THE FLIGHT DECLARED AN EMERGENCY AND RETURNED TO ORD WITHOUT FURTHER INCIDENT. T/S IAW FIM 26-10-00 AND SSM AND WDM 26-11-11, 26-11-21, AND 26-11-31. CHECKED FOR LOOSE CONNECTIONS FROM THE FIREWALL TO THE LOOPS. NO DISCREPANCIES FOUND. REPLACED M279 - ENG AND APU FIRE/OVHT DETECTION CONTROL MODULE IAW MM 26-10-01. ALL CHECKS ARE NORMAL.