Close air support (CAS), by its academic definition, is air action by starfighters or atmospheric craft against hostile targets in close proximity to friendly forces. In practice, however, close air support can be defined simply as the support of ground forces by air and space assets against enemy forces that are tactically significant. Forward Air Controllers direct close air support to destroy enemy forces as needed by battlefield commanders.

Regardless of the specific mission, CAS is implemented in three distinct phases: planning, preparation, and execution.

Planning

Planning is regarded as the most important phase in CAS, as poor planning and bad intelligence can seriously endanger the lives of friendly forces, increasing the risk of fratricide. Planning starts as soon as the Forward Air Controller (FAC) receives a mission target, either from his commander, from another unit's staff, or through his own initiative. The process of planning will be discussed in "Mission Planning Basics".

Preparation

Preparation is the simplest phase in CAS, for the basic reason that in most instances, there is not much to prepare. Orders are forwarded to artillery positions, FACs move to their respective observation posts, and reconnaissance units in the area continue to observe targets and other areas of interest.

Execution

Execution is the final stage in CAS but by far the most complex. The FAC is required to track friendly units, scan for air threats and enemy movements, coordinate artillery fires, execute CAS requests to on-station air assets, and assess mission success. It is important to note that up until this phase, aircraft have not been provided orders on their exact mission.

During execution, the FAC must remain in contact with units nearby and be advised of changes in position to ensure all ground forces are a safe distance away from air-launched ordnance. They must also interface with artillery fire controllers to direct a safe flight path, ensuring any fires are either over or under the intended flight path. And finally, the FAC must direct aircraft to their targets (this will be covered in detail in "CAS Controlling"

Continue to "Conditions to Close Air Support"