CAS (close air support)

CAS stands for close air support. It is a NATO air-operations term for an air action against hostile targets which are in close proximity to friendly forces, and which require detailed integration of each air mission with the fire and movement of those forces. NATO sets out this definition in its terminology and doctrine materials, including the NATO curriculum guide on lessons from the war in Ukraine.

The Government of Canada uses the same meaning. The Department of National Defence (DND) describes CAS as air attacks against targets so close to friendly ground forces that detailed integration with their fire and movement is required, in its evaluation method for the National Fighter Procurement project. For a supplier, the term signals a defence requirement in which aircraft, ground forces and communications systems must work together.

How NATO defines and publishes the CAS term

NATO identifies the CAS definition in several allied publications, including AAP-06, AAP-15 and AAP-39. The official source for NATO terms is NATOTerm, the alliance's terminology database, which is maintained by the NATO Terminology Office within the NATO Standardization Office. Bid teams that need the exact wording of a term can check NATOTerm directly.

How CAS differs from air interdiction

CAS is related to, but distinct from, air interdiction. Air interdiction generally attacks targets before they can directly engage friendly forces. CAS deals with targets that are already close to those forces. That closeness is why each mission needs detailed integration with ground fire and movement.

CAS normally requires coordination between the air and ground components. Personnel such as joint terminal attack controllers (JTACs) and forward air controllers take part in that coordination. The tools they use are a common source of procurement activity.

CAS in Canadian defence projects

Canadian public procurement uses CAS mainly in DND capability planning, equipment acquisition and joint-fires projects. Three examples show the range.

• Fighter aircraft: DND's National Fighter Procurement evaluation method lists Close Air Support as an aerospace capability and defines it using the NATO formulation.
• Digital CAS systems: The Canadian Army reports that it acquired a digitally aided close air support (DACAS) system in 2017 through a $4 million contract with Collins Aerospace. The system supports tactical networking, GPS, radios, laser range finding and the ATAK software environment, according to the Army's article A Digital Call for Fires.
• Joint Fires Modernization: DND describes this project as involving targeting and battle-management software, tactical equipment, and simulation and training systems for operators, commanders, planners and coordinators.

The DACAS acquisition also met Canada's requirement to be digitally interoperable for CAS with the United States and key allies. Interoperability is therefore a core theme in CAS-related buying.

What CAS means for a supplier

A supplier responding to a CAS-related requirement needs to meet the technical, interoperability, communications, targeting, training, safety, security and support requirements written into that solicitation. The Canadian examples above show where those requirements tend to sit: aircraft capability, digital networking with allies, targeting software, and operator training and simulation.

Each solicitation sets its own terms, so read the requirement language closely rather than assuming a standard CAS clause. When a bid refers to CAS, use the NATO wording consistently in your proposal. Show how your product or service supports the integration of air missions with ground forces, and address interoperability with allied systems directly.