What was found
ON LANDING AT YMX COCKPIT AND COURRIER AREA FILLED WITH SMOKE AND MAIN DECK CARGO SMOKE DET SYSTEM ACTIVATED IN ALL ZONES. SMOKED CLEARED AFTER 5 MIN. SUSPECT EXHAUST FUMES ENTERED AIR CONDITIONING SYS, RELEASED FOR SERVICE PER MEL/CDL: 21-11-08-B MEL 21-11-08-B: PACK (IDENTIFY 1 OR 2). FOUND LEFT PACK OVERHEATING IN AUTO MODE, OPS NORMAL IN MANUAL MODE. FURTHER T/S FOUND BY-PASS VALVE ACTUATOR MODULATING WITH NO PACK AIR APPLIED, SWAPPED PACK TEMP CONTROLLERS, NR 1 PACK ACTUATOR STILL MODULATING, REMOVED CANNON PLUG FROM BY-PASS VALVE, ACTUATOR CONTINUED MODULATING, ONLY STOPPING BLEED PROBLEM ON NR 1 ENGINE, WHEN REPAIRED CLEARED LT PACK PROBLEM. NR 1 PACK OPS.