 The further improved APG-63(V)3 AESA radar is expected to be fitted to 179 F-15C aircraft; the first upgraded aircraft was delivered in October 2010.The ZAP (Zone Acquisition Program) missile launch envelope has been integrated into the operational flight program system of all U.S. F-15 aircraft, providing dynamic launch zone and launch acceptability region information for missiles to the pilot by display cues in real-time.The largest operator of the F-15 is the United States Air Force.