What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED DUE TO: RIGHT PACK TRIP OFF LIGHT CAME ON, STAYED ON EVEN WITH PACK RESET, HAD TO DESCENDED TO 10,000 WOULD NOT HOLD PRESSURE; AIRCRAFT AIR INTERRUPTED BACK TO AND LANDED SAFELY AT BOS. REMOVED AND REPLACED RIGHT HAND PACK ACM (AALA202501215685), PER AMM 21-51-04. REMOVE AND REPLACED PRIMARY (AALA202501229903) AND SECONDARY (AALA202501229679) HEAT EXCHANGER, PER J/C 08L13221001. REMOVE AND REPLACED DIFFUSER ASSEMBLY (AALA202501224784), PER AMM 21-51-03. REMOVE AND REPALCED FLOW CONTROL VALVE (AALA202501225598), PER AMM 21-51-01. RAN PACK NO LEAKS OPERTIONAL CHECK NORMAL.