Advanced Attack Helicopter YAH-64 prototype with T-tail After the
AH-56 Cheyenne was cancelled in 1972 in favor of projects like the
U.S. Air Force A-10 Thunderbolt II and the
Marine Corps AV-8A Harrier, the United States Army sought an aircraft to fill an anti-armor attack role that would still be under Army command. The 1948
Key West Agreement forbade the Army from owning combat fixed-wing aircraft. The Army wanted an aircraft better than the
AH-1 Cobra in firepower, performance, and range. It would have the maneuverability for terrain following
nap-of-the-earth (NoE) flying. To this end, the U.S. Army issued a Request For Proposals (RFP) for the Advanced Attack Helicopter (AAH) program on 15 November 1972. As a sign of the importance of this project, in September 1973 the Army designated its five most important projects as the "Big Five", with the AAH included. Proposals were submitted by
Bell,
Boeing Vertol/
Grumman team,
Hughes,
Lockheed, and
Sikorsky. In July 1973, the U.S. Department of Defense selected finalists Bell and Hughes Aircraft's Toolco Aircraft Division (later
Hughes Helicopters). This began the phase 1 of the competition. Each company built prototype helicopters and went through a flight test program. Hughes'
Model 77/YAH-64A prototype first flew on 30 September 1975, while Bell's
Model 409/YAH-63A prototype first flew on 1 October 1975. After evaluating the test results, the Army selected Hughes' YAH-64A over Bell's YAH-63A in 1976. Reasons for selecting the YAH-64A included its more damage tolerant four-blade main rotor and the instability of the YAH-63's
tricycle landing gear arrangement. The AH-64A then entered phase 2 of the AAH program under which three pre-production AH-64s would be built, additionally, the two YAH-64A flight prototypes and the ground test unit were upgraded to the same standard. Development of the Hellfire missile had begun in 1974, originally known by the name of
Helicopter Launched, Fire and Forget Missile ('Hellfire' being a shortened acronym), for the purpose of arming helicopter platforms with an effective anti-tank missile.
Into production In 1981, three pre-production
AH-64As were handed over to the U.S. Army for Operational Test II. The Army testing was successful, but afterward it was decided to upgrade to the more powerful
T700-GE-701 version of engine, rated at . The AH-64 was named the
Apache in late 1981, after the
Apache tribe, following the tradition of naming Army helicopters after Native American tribes. It was approved for full-scale production in 1982. In 1983, the first production helicopter was rolled out at Hughes Helicopter's facility at
Mesa, Arizona. Hughes Helicopters was purchased by
McDonnell Douglas for $470 million in 1984 (). The helicopter unit later became part of The Boeing Company with the merger of
Boeing and McDonnell Douglas in August 1997. In 1986, the incremental or flyaway cost for the AH-64A was $7M and the average unit cost was approximately $13.9M based on total costs. As of 2024, the AH-64E is being produced at an economical rate of 82 aircraft a year. Boeing states that the minimum sustainment rate for the aircraft is 48 per year while current tooling and space allows for up to 98 aircraft to be manufactured per year. The U.S. Army states that with additional investment and labor, production could be raised to 144 aircraft per year. Technological advance led to the program's cancellation in favor of more ambitious changes. In August 1990, development of the AH-64D Apache Longbow was approved by the
Defense Acquisition Board. The first AH-64D prototype flew on 15 April 1992. Prototype testing ended in April 1995. During testing, six AH-64D helicopters were pitted against a bigger group of AH-64As. The results demonstrated the AH-64D to have a sevenfold increase in survivability and fourfold increase in lethality compared to the AH-64A. On 13 October 1995, full-scale production was approved; a $1.9-billion five-year contract was signed in August 1996 to upgrade 232 AH-64As into AH-64Ds. On 17 March 1997, the first production AH-64D flew. It was delivered on 31 March. Portions of the Apache are produced by other aerospace firms.
AgustaWestland has produced a number of components for the Apache both for the international market and for the
British Army's
AgustaWestland Apache. Since 2004,
Korea Aerospace Industries has been the sole manufacturer of the Apache's fuselage. Fuselage production had previously been performed by
Teledyne Ryan Aeronautical. The transfer of fuselage production led to a prolonged legal dispute between Teledyne Ryan and Boeing. The AH-64D program cost a total of $11 billion (~$ in ) through 2007. In April 2006, Boeing was awarded a $67.6 million (~$ in ) fixed-price contract for the remanufacture of several existing U.S. AH-64As to the AH-64D configuration. Between May 2009 and July 2011, a further five contracts were issued to remanufacture batches of AH-64As into AH-64Ds. Since 2008, nations operating the older Apaches have been urged to undertake modernization programs as support for the AH-64A is withdrawn. By May 2019, Boeing tested in a
wind tunnel a
compound Apache scale model with a
pusher propeller, a small wing to increase range and speed, and a counter-torque
tail rotor like the cancelled
Lockheed AH-56 Cheyenne of the 1960s.