Each stage of the Civil Reserve Air Fleet activation is only used to the extent necessary to provide the amount of civil augmentation airlift needed by Department of Defense. When notified of call-up, the carrier response time to have its aircraft ready for a Civil Reserve Air Fleet mission is 24, 48, and 72 hours after the mission is assigned by AMC. The air carriers continue to operate and maintain the aircraft with their resources; however, AMC assigns the aircraft missions.