What was found
REF LOG 6188005 CPCS REPORTS HI LEAK RATE. FOUND SUPPLY DUCT DISCONNECTED AT RECIRC FAN ON LEFT PACK LEFT RECIRC FAN REPLACED DUE TO FAILED CHECK VALVE, PER AMM DMC-B787-A-21-25-17-03B-720A-A, CONNECTING DUCT SEAL AND SLIP JOINT SEAL REPLACED BETWEEN FAN AND HEAT EXCHANGER. LEAK CHECK OF SYSTEM OK AND GROUND TEST PASSED. ROTABLE PARTS CHANGE WAS INDICATED - TT # 1999557 SN OFF 0406 FAN, ASSY, MIXE OFF 78-2125-9-9001 0406 ON 79-2125-9-9001 8077