What was found
VERY SHORTLY AFTER LEVEL OFF, AT FL330, THE NR 1 ENGINE FIRE WARNING DISPLAYED. BEFORE INITIATING PROCEDURES, THE WARNING DISAPPEARED WITHIN A SHORT PERIOD, LESS THAN 10 SECONDS, THE WARNING DISPLAYED AGAIN AND REMAINED ILLUMINATED. COMPLIED WITH THE PROPER PROCEDURES AND DIVERTED TO LAND. FOUND THE NR 1 ENGINE LT UPPER HP RECOUP DUCT UPPER COUPLING LEAK DETECTING FOIL BLOWN OFF, ALSO FOUND PRESSURE REGULATOR VALVE LEAKING USING APU AIR. FOILED THE RECOUP TUBE COUPLING AND 7TH STAGE TURBINE COOLING TUBE FLEXABLE COUPLINGS. BLEEDS OPERATED NORMAL, NO FIRE DETECTION INDICATION, OPENED COWLINGS FOUND ALL TUBEING LEAK DETECT FOIL NOT BLOWN, NO LEAKS IAW MOCC. REMOVED AND REPLACED THE LEFT UPPER FIRE DETECTOR RAIL ASSY IAW MM 26-12-12-04-02, OPS TESTED GOOD IAW MM 26-12-00-05-02.