The AH-64D "Longbow Apache" is a remanufactured and upgraded version of the AH -64A "Apache" attack helicopter. The primary modifications to the " Apache " are the addition of a " Longbow " millimeter-wave Fire Control Radar (FCR) target acquisition system, the fire-and-forget "Longbow Hellfire" air-to-ground missile, updated T700-GE -701C engines, and a fully-integrated cockpit. In addition, the aircraft receives improved survivability, communications, and navigation capabilities. Most existing capabilities of the AH -64A Apache are retained. Boeing delivered the first remanufactured Longbow Apache in March 1997. A total of 501 AH -64A Apaches are to be upgraded to the AH-64D configuration, 227 of which will be equipped with the FCR.