What was found
IN FLIGHT PHASE 06, ECAM MESSAGE BSCU 1, FOLLOWED BY BCSU 2 MESSAGES AT 2216 UTC, BOTH MESSAGES IDENTIFIED BRAKE NORMAL SERVO VALVE 1 (15GG). WITH LOSS OF NORMAL BRAKING AND ANTI SKID. CREW DECLARED EMERGENCY LANDING. ALTERNATE BRAKING OPERATED NORMAL DURING LANDING WITH NO ADDITIONAL ISSUES. DURING TROUBLESHOOTING IAW TSM 32-42-00-810-805A, TREST REPORTED BAD SERVO VALVE 15GG. R&R THE NORMAL BRAKE PRESSURE TRANSDUCER IAW AMM 32-42-21-04. PN OFF CZ 9284E SN HEK41206. PN ON CZ9DM6A, SN ON HAK 38168. LEAK CHECK GOOD. PERFORMED BSCU 1 AND 2 BITE TEST IAW AMM 32-46-00-05. OPS CHECK VERIFIED GOOD WITH NO FAULTS NOTED. THE ACFT WAS RETURNED TO SERVICE 05/21/2012.