REQUIREMENT RATIONALE (3.1.5)
Fundamentally, system usage addresses the question, “are aircraft (and as applicable, UAV or UCAV control stations) available in sufficient numbers to accomplish assigned missions to the degree tasked?” Critical measures of system usage are mission dependent and may include the fraction of the aircraft (and control stations) available to perform a given mission, the number of sorties expected from each aircraft per day for a given duration, or other parameters, as
appropriate. Those missions vary depending on the readiness state of the force and the function the system is intended to perform for those missions. Thus, there are different measures for nominal peacetime conditions and wartime conditions. However, even in peacetime conditions, there are operational missions to be performed (as opposed to simply training). Thus, some parameters may need to be addressed in both states. For example, airlift aircraft perform operational roles in both peacetime and wartime. Some of the missions they perform are different and some the same. But the mission expectations can be different in peacetime vs. wartime for the same mission, in addition to differences in the tempo of operations and availability of maintenance personnel.
REQUIREMENT GUIDANCE (3.1.5)
While the requirements in the following subparagraphs are nominally grouped into peacetime and wartime conditions, the intent of the grouping is to communicate force readiness conditions. Select requirements appropriate to the missions the aircraft is intended to perform and adjust the conditions as necessary to reflect the expected state of force readiness. Based on the specific missions to be conducted, it may be prudent to adapt a mission from one state or another to reflect best the specific mission of the aircraft. Some missions under peacetime actually fall in the transition period from nominal peacetime conditions to wartime conditions.
Caution: It may be possible to select nearly all of the requirements for certain aircraft types and conditions. However, select only those requirements essential to satisfy life cycle requirements and tailor those requirements as needed to reflect operational requirements. Some requirements may be dispensed with, in the sense that users are willing to accept the risk consequences of not specifying a given requirement (that is, the warfighter/developer is willing to accept the fallout capability that the system provides). Keep in mind, however, that an aircraft usage profile is used to establish the durability characteristics of the design. For example, the peacetime mission capable rate may not be a driving factor in satisfying an operational requirement, but the resulting usage rate is important in constructing a life cycle profile of aircraft (and control station) use.