What was found
AT FL310 THE RED CABIN PRESS WARNING LIGHT ILLUMINATED. BOTH ENGINE & AIRFOIL ICE PROTECTION SYS OPERATING. ATTEMPT TO REGAIN CONTROL OF CABIN PRESSURE COMPLIED WITH, CABIN CONTINUED CLIMB. DECLARED EMERG & INITIATED EMERG DESCENT. CABIN PRESS FOLLOWED CONTROLLER COMMANDS AT ABOUT 3.5 PSI DURING DESCENT. LANDED SAFELY. BITE CHKED BOTH CONTROLLERS & NO FAULTS. TAIL BAY INSPECTED FOR LOOSE OR BLOWN DUCTS WITH BOTH APU & EACH PACK INDIVIDUALLY. NO LEAKS FOUND & VESSEL PRESSURIZED NORMAL. FOUND ACFT WOULD NOT PASS CABIN PRESSURE DECAY CHK. FOUND LEAKS IN CABIN & LT PACK THE CAUSE. LEAKS REPAIRED & PRESSURE SYS OPS NORMAL. (A)