Air battle manager has been a rated career field (Air Force Specialty Code 13BX) since October 1, 1999. This means that ABMs are career aviators who receive flight pay and must actively fly a certain number of months (called gate months) to maintain their rating. As a result, all active duty ABMs and those assigned to the Air Force Reserve unit at Tinker AFB, OK are assigned to flying duties after completion of undergraduate training. In the past a small number of graduates were initially assigned to ground assignments in the control and reporting centers (CRCs). This practice was temporarily ceased in 2004 but now occurs based on student merit and assignment availability. ABMs serving in the Air National Guard are typically assigned to a CRC unit, an air defense sector, or an air operatio