What was found
DURING CLIMB, THE AIRCRAFT HAD A NR 2 A/C PACK FAIL, THE AIRCRAFT RETURNED TO DEPARTURE. AFTER AN UNEVENTFUL LANDING THE PILOT REPORTED THE NR 2 PACK REGUL FAULT, MAINTENANCE PERFORMED A FAULT ANALASYS IAW TSM 21-61-00-810-821-A, REPLACED THE NR 2 PACK FLOW CONTROL VALVE IAW AMM 21-51-51, PB401. PERFORMED THE CORRESPONDING TESTS WITH NORMAL RESULTS. REPLACED THE ACM IAW AMM 21-52-21, PB401. TESTED SATISFACTORY. THE AIRCRAFT WAS RETURNED TO SERVICE.