What was found
EMERGENCY DECLARED AT CRUISE 340, NR 2 A/C PACK FAILED, RAN ECAM NR 1 A/C PACK ALSO FAILED. INITIATED DESCENT TO 10,000 FT, DURING DESCENT BOTH PACKS INTERMITTENTLY WOULD OPERATE THEN FAIL. AT 10,000 FT, BOTH PACKS ARE OPERATING. REPLACED CONTROLLER 37HK IAW AMM 21-61-16/401, TESTED GOOD ALSO ACCOMPLISHED CABIN PRESSURE LEAK CHECK IAW AMM 05-53-00/001 CHECKED GOOD.