What was found
DURING CLIMB-OUT OF PIE NR 1 ENGINE FIRE WARNING SYSTEM ACTIVATED. EMERGENCY PROCEDURE FOLLOWED. RETURNED TO PIE AIRCRAFT LANDED WITHOUT INCIDENT. OVERWEIGHT LANDING SINK RATE LOW. FOUND NR 1 ENGINE FIRE DETECTION LOOP SHORTED. REPLACED FIRE DETECTION LOOP, INSPECTED ENGINE, REPLACED FIRE EXTINGUISHER CONTAINERS AND COMPLIED WITH OVERWEIGHT LANDING INSPECTION IAW BOEING MM 5-51-291. LOW TO MODERATE SINK RATE, PHASE 1 STEP 2A. (M)