Development

[edit] Advanced Attack Helicopter

Following the cancellation of the AH-56 Cheyenne in favor of United States Air Force and Marine Corps projects like the A-10 Thunderbolt II and Harrier Jump Jet, 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 commanding fixed-wing aircraft. The Army wanted an aircraft better than the AH-1 Cobra in firepower, performance and range. It would have the maneuverability to fly nap-of-the-earth (NoE) missions.[3] To this end, the US Army issued a Request For Proposals (RFP) for an Advanced Attack Helicopter (AAH) on 15 November 1972.[4]

Proposals were submitted by five manufacturers: Bell, Boeing Vertol (teamed with Grumman), Hughes, Lockheed, and Sikorsky. In 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.[5]

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.[5] After evaluating 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.[6]

The AH-64A then entered phase 2 of the AAH program. This called for building three preproduction AH-64s, and upgrading the two YAH-64A flight prototypes and the ground test unit up to the same standard.[7] Weapons and sensor systems were integrated and tested during this time,[5] including the new Hellfire missile.[7]
[edit] Moving into production
A YAH-64 in 1984

In 1981, three pre-production AH-64As were handed over to the US Army for Operational Test II. The Army testing was successful, but afterwards it was decided to upgrade to the T700-GE-701 version of engine, producing 1,690 shp (1,259 kW).[5] In late 1981, the AH-64 was named the "Apache" keeping with the Army's traditional use of American Indian tribal names for its helicopters. Hughes was approved for full scale production in 1982.[5] In 1983, the first production helicopter was rolled out at Hughes Helicopter's facility at Mesa, Arizona. In 1984, Hughes Helicopters was purchased by McDonnell Douglas for $470 million.[8] 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 US$7.03 million and the average unit cost was approximately US$13.9 million based on total costs.[8]

In the mid-1980s, McDonnell Douglas studied an improved "AH-64B" design with an updated cockpit, new fire control system and other upgrades. In 1988 funding was approved for a multi-stage upgrade program to improve sensor and weapon avionic systems and incorporate some digital systems. However, improved technology was becoming available. It was decided to cancel the upgrade program for more ambitious changes. This would lead to the more advanced AH-64D Apache Longbow. Development of the AH-64D was approved by the Defense Acquisition Board in August 1990. The first AH-64D Apache Longbow prototype was flown on 15 April 1992.[9] On 13 October 1995 full-scale production of the Apache Longbow was approved. The first production AH-64D flew on 17 March 1997 and was delivered to the Army on 31 March 1997.[10]

In 2004, General Electric Aviation began producing more powerful T700-GE-701D engines, rated at 2,000 shp (1,500 kW) for AH-64Ds.[11] The total cost of the AH-64D program is US$10.5 billion through April 2007.[12]