What was found
FLT CREW REPORTED SMOKE IN COCKPIT AND PERFORMED AN EMERGENCY EVACUATION VIA ESCAPE SLIDE. SLIDE DEPLOYED NORMALLY. CREW REPORTED LEFT PACK TRIP PRIOR TO SMOKE IN C/P. LEFT PACK TRIP LIGHT ILLUMINATED. FOUND LEFT PACK S/O AND FLOW CNTRL VLV BYPASSING WHEN SELECTED CLOSED. REMOVED AND REPLACED VALVE IAW DC8 MM 21-55-05-4. PERFORMED 4 ENG TO DUPLICATE FLT. CREW CONDITIONS. NO ABNORMAL CONDITIONS NOTED. LEFT AND RIGHT A/C PACKS OPERATING NORMALLY. NO SMOKE/SMELLS NOTED.