DC8 FLT CREW HAS IMPROPER MEL PERFORMED ON AIR CONDITIONING PACK; WITH SMOKE AND FUMES OCCURRING DURING ENG START.

Narrative

PRIOR TO DEP FROM SJO; R AIR CONDITIONING PACK WAS DEFERRED. AT PRIOR STATION (MMMX) UPON FURTHER INSPECTION DISCOVERED ADDITIONAL CANNON PLUG WAS NOT DISCONNECTED PER MEL. CANNON PLUG DISCONNECTED AND VALUE WAS VERIFIED VISUALLY CLOSED. UPON ENG START; ACFT HAD DIFFICULTY OBTAINING ENOUGH AIR FROM GND CART FOR ADEQUATE ENG START. AIR FLOW WAS INCREASED FROM GND CART AND ACFT FILLED WITH SMOKE AND R DUCT OVERHEAT LIGHT ILLUMINATED. STOPPED START OBTAINED NEW AIR CART; CLRED BOTH SMOKE AND DUCT OVERHEAT LIGHT. SECOND ATTEMPT TO START ENG WAS SUCCESSFUL. PUSHED BACK TO TXWY TO START REMAINING ENGS. DURING ADDITIONAL ENG START COMMENT WAS MADE ABOUT EXCESSIVELY HIGH THROTTLE SETTING TO PRODUCE ENOUGH AIR TO START REMAINING ENGS. AFTER OTHER ENGS STARTED; PERFORMED PRESSURIZATION DECAY CHK ON R MANIFOLD WHICH FAILED MISERABLY. AFTER THIS CHK; R DUCT OVERHEAT LIGHT CAME BACK AND WOULD NOT EXTINGUISH. TAXIED BACK TO BLOCKS. FURTHER INVESTIGATION REVEALED THAT CONNECTING THE CANNON PLUG MISSED IN MMMX CORRECTED BOTH PRESSURE DECAY CHK AND DUCT OVERHEAT LIGHT. BY RECONNECTING THIS CANNON PLUG MEL/COM PROCS WERE NOT FOLLOWED. VALVE WAS INDEED CLOSED AND SYS WAS NOT OPERATED; NO DAMAGE TO ACFT WAS NOTED. IN THE FUTURE I WILL VISUALLY RECHK THE MANUAL POS INDICATOR ON THE PACK FLOW CTL VALVE. THE CANNON PLUG IN QUESTION IS SUPPOSED TO BE DISCONNECTED PER MEL/COM PROCS AND FLOW CTL VALVE VISUALLY CHKED CLOSED; SINCE REMOVAL OF PWR VALVE WILL DE-ENERGIZE OPEN.