What was found
A/C ENTERED G/A MODE ON LEVEL OFF AT 3000' DURING APPROACH. F/D GAVE ERRENOUS DATA AND APPROACH SPEED WERE NOT CORRECT. GRD CHECK FCC NO 1 NO CURRENT FAULTS FCC NO 2 FAULTING FCC NO2 REPLACED NO 2 FCC IAW MM22-01-03-4 CHECKED CURRENT FAULTS NIL FAULTS RTS OF BOTH FCC CARRIED OUT BOTH FAILED TO/GO SWITCH. SWITCH CHECKED FOUND BOTH SETS OF CONTACTS CLOSED AWAITING NEW SWITCH. TO/GO SWITCH REPLACED IAW MM 22-31-02-4 AND FNC CHECKED SATIS IAW MM22-00-9-5 AFS RETURN TO SERVICE. TEST CARRIED OUT ON BOTH FCC 1 AND FCC 2 IAW MM 22-00-00-5 ALL TEST PASSED 30 DAY TIMER RESET.