Full Report: https://www.gao.gov/assets/720/711882.pdf
CAS is an air action by aircraft against hostile targets that are in close proximity to friendly forces and that requires detailed integration of each air mission with the fire and movement of those forces.14 All participants in CAS are responsible for identifying friendly and enemy forces and this relies on continuous communication between ground forces and aircrews. DOD relies on CAS to attack the enemy in a variety of military operations and to augment other fire support (e.g., surface-to-surface fires from artillery) in situations in which other fire support may not be able to effectively engage. Joint doctrine outlines a multiphase cycle for CAS, which includes planning, preparation, execution, and assessment.15