What was found
AFTER FLT 306 BWI-CUN, IN CUN AT GATE, THE NR 1 FLIGHT MANAGEMENT GUIDANCE COMPUTER (FMGC) FAILED. DEFERRED PER MEL 22-83-01. IN BWI ON 3/25/03, RESET NR 1 FMGC IAW AMM AFS OPER TEST 22-96-00-710-001 AND SYSTEM OPS CHECKED OK. ON 3/25/03, NR 1 FMGC FAILED AGAIN. SWAPPED NR 1 & 2 FMGC'S AND OPS CHECKED BOTH FMGC NR 1 & 2 OK. C/W RVSM RETURN TO SERVICE REQUIREMENTS. ON 3/26/2003, FMGC NR 2 FAILED. REMOVED AND REPLACED NR 2 FMGC IAW 22-83-34-400-001 AND OPS CK'D OK. C/W RVSM RETURN TO SERVICE REQUIREMENTS.