Develops a new metric for measuring the effect of operations tempo on the readiness of the mobility air forces The authors provide a new metric–the mission-day–to assess the ability of the mobility air forces (MAF) to conduct missions, train its forces, and maintain readiness. The mission-day metric measures the availability of crewmem bers to fly missions while continuing training and other activities. It can detect problems arising from the operations tempo of MAF personnel as they take part in major theater operations and support U.S. forces engaged in peacetime operations around the world.