What was found
LRD - FLT 3564 - THE CREW REPORTED SMOKE IN THE CABIN AND PERFORMED AN AIR RETURN. THE AIRCRAFT LANDED WITHOUT INCIDENT. MAINTENANCE DETERMINDED THE SOURCE OF THE SMOKE TO BE COMING FROM THE NR 2 AIRCONDITIONING PACK AFTER PERFORMING OPERATIONAL CHECKS OF THE BLEED AIR SYSTEM. MAINTENANCE PLACED THE NR 2 AIRCONDITIONING PACK ON MEL REFERENCE 21-50-2, CATEGORY ''C'' CONTROL NR 003481. THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE. (M)