Variants
Royal Netherlands Air Force AH-64D at the Farnborough Airshow, 2006.
AH-64A
The AH-64A is the original production attack helicopter. It is powered by two GE T700 turbo-shaft engines. The crew sit in tandem in an armored compartment.
The helicopter is armed with a 30 mm M230 Chain Gun that can be slaved to the gunner's helmet-mounted gunsight. The AH-64A carries a range of external stores on its stub-wing pylons, including a mixture of AGM-114 Hellfire anti-tank missiles, Hydra 70 general-purpose unguided 70 mm (2.75 in) rockets, and AIM-92 Stinger air-to-air missiles for defense.
AH-64B
In 1991 after Operation Desert Storm, the AH-64B was a proposed upgrade to 254 AH-64As. The upgrade included new rotor blades, a Global Positioning System (GPS), improved navigaton systems and new radios. Congress approved US$82 million to begin the Apache B upgrade. The B program was canceled in 1992.[2] The radio, navigation, and GPS modifications, would later be installed on most A-model Apaches as part of an upgrade program.
AH-64C
Additional funding from Congress in late 1991 resulted in a program to upgrade AH-64As to an AH-64B+ version. More funding changed the plan to upgrade to AH-64C. The C upgrade would include all changes to be included in the Longbow except for mast mounted radar and newer engines. However, after 1993, the C designation was dropped.[2]
The upgrades would go forward. However, since the only difference between the C model and the radar-equipped D model was the radar, which could be moved from one aircraft to another, a decision was made to not distinguish between the two versions, despite the presence or absence of the radar.
AH-64D
Israeli Air Force AH-64D "Saraf"
Republic of Singapore Air Force AH-64D on static display during open house
The advanced model, the AH-64D Apache Longbow, is equipped with an improved sensor suite and weapon systems. The key improvement over the A-variant is the AN/APG-78 Longbow dome installed over the main rotor which houses a millimeter-wave Fire Control Radar (FCR) target acquisition system as well as the Radar Frequency Interferometer (RFI). The elevated position of the radome allows detection and (arcing) missile engagement of targets even when the helicopter itself is concealed by an obstacle (e.g. terrain, trees or buildings). Further, a radio modem integrated with the sensor suite allows a D-variant Apache to share targeting data with other AH-64Ds that do not have a line-of-sight to the target. In this manner a group of Apaches can engage multiple targets but only reveal the radome of one D-variant Apache. Apaches that include all of the improvements of the Longbow Apache, with the exception of the Fire Control Radar are still designated as "AH-64D Apache Longbows", as the radome is removable and interchangeable between aircraft.
The aircraft was updated with more powerful T700-GE-701C engines, and a fully-integrated cockpit. The forward fuselage of the aircraft was expanded to accommodate new systems. In addition, the aircraft receives improved survivability, communications, and navigation capabilities. Most existing capabilities of the AH-64A Apache are retained.
The first of the upgraded Block II Apaches was delivered to the US Army in February 2003. Block II includes upgrades to the digital communications systems to improve communications within the 'tactical internet'.[35]
Block III improvements, slated for 2008 onwards, include increasing digitization, the joint tactical radio system, enhanced engines and drive systems, capability to control UAVs, new composite rotor blade and landing gear upgrades. The new blades, which successfully completed flight testing in May 2004, increase the Apache's cruise speed, climb rate and payload capability. The Block III System Development and Demonstration (SDD) contract was awarded to Boeing in July 2006.[35]
Export Apaches
A number of other models have been derived from both AH-64A and AH-64D for export. The British-built Westland WAH-64 Apache (assembled from kits purchased from Boeing) is based on the AH-64D with several different systems, including newer, more powerful engines.
Sea Apache
A naval version of the AH-64A was proposed for the United States Marine Corps and Navy from 1984 to 1987.[3] Multiple concepts were studied with altered landing gear arrangements, improved avionics and weapons.[36] Funding for the naval version was not provided and the Marine Corps continues to use the AH-1 SuperCobra as of 2008.[3]