in the AH-64D except for mast-mounted radar and newer −700C engine versions. However, the C designation was dropped after 1993. With AH-64As receiving the newer engine from 1990, the only difference between the AH-64C and the AH-64D was the radar, which could be moved from one aircraft to another; thus the decision was made to simply designate both versions as AH-64D. AH-64D The AH-64D Apache Longbow is equipped with a glass cockpit and advanced sensors, the most noticeable of which being the AN/APG-78 Longbow millimeter-wave fire-control radar (FCR) target acquisition system and the Radar Frequency Interferometer (RFI), housed in a dome located above the main rotor. The radome's raised position enables target detection while the helicopter is behind obstacles (e.g. terrain, trees or buildings). The AN/APG-78 is capable of simultaneously tracking up to 128 targets and engaging up to 16 at once; an attack can be initiated within 30 seconds. A radio modem integrated with the sensor suite allows data to be shared with ground units and other Apaches, allowing them to fire on targets detected by a single helicopter. The aircraft is powered by a pair of uprated T700-GE-701C engines. The forward fuselage was expanded to accommodate new systems to improve survivability, navigation, and 'tactical internet' communications capabilities. In February 2003, the first Block II Apache was delivered to the U.S. Army, featuring digital communications upgrades. The Japanese Apache AH-64DJP variant is based on the AH-64D; it can be equipped with the AIM-92 Stinger air-to-air missiles for self-defense. AH-64E Formerly known as AH-64D Block III, in 2012, it was redesignated as AH-64E Guardian. It has improved digital connectivity, the Joint Tactical Information Distribution System, more powerful T700-GE-701D engines with upgraded face gear transmission to handle more power, capability to control unmanned aerial vehicles (UAVs), full IFR capability, and improved landing gear. New composite rotor blades, which completed testing in 2004, increase cruise speed, climb rate, and payload capacity. Deliveries began in November 2011. Full-rate production was approved on 24 October 2012, 634 AH-64Ds will be upgraded into AH-64Es. Changes in production lots 4 through 6 include a cognitive decision aiding system and new self-diagnostic abilities. The updated Longbow radar has an oversea capacity, potentially enabling naval strikes; an AESA radar is under consideration. It will have a L-3 Communications MUMT-X datalink in place of two older counterparts, communicating on C, D, L, and Ku frequency bands to transmit and