A. Active Electronically Scanned Array (AESA): The AESA upgrade must equip all F-15C/D's with a common state-of-the-art RADAR to detect, track, and target traditional and asymmetric threats for homeland defense and In-Theater air combat. The F-15C/D fleet is currently equipped with four separate RADARs. Maintaining, training on, and modifying four separate RADARs dilutes the weight of effort for a single RADAR. Additionally, adding new common capabilities to all four RADARs has become prohibitively expensive.