What was found
SUP - AT APPROX 10000FT THE DESCENT THE SMELL OF SMOKE WAS DETECTED IN THE FLIGHT DECK. SMOKE WAS OBSERVED COMING FROM THE CA SIDE AIR VENTS AS WELL AS OBERSVERD BY THE FA IN THE MAIN CABIN INSOLATED SOURCE OF SMOKE. THE L/H PACK WILL NOT COOL - BLOW WHITE SMOKE WHEN ON. DEFFERED IAW MEL 21-51-1B. PLCARD INSTALLED MOC NOTIFIED - 103619. MOD BB TRANSFERED TO MEL. REMOVED AND REPLACED LEFT ACM IAW CRJ 900 AMM 21-51-08. OPS CHECK GOOD. MM02 UPDATED, PLACARD REMOVED, MOC NOTIFIED#107743