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Friday, September 14, 2007

AH 64 Apache











The AH-64 Apache is the United States Army's principal attack helicopter, and is the successor to the AH-1 Cobra. The AH-64 is powered by two General Electric T700 turboshaft engines. The crew sits in tandem, with the pilot sitting behind and above the copilot-gunner in an armored crew compartment. The AH-64 is armed with a 30mm M230 chain gun and carries a mixture of AGM-114 Hellfire and Hydra 70 rockets on four hard points mounted on its stub-wing pylons.
Designed by Hughes Helicopters in response to the Army's Advanced Attack Helicopter Program, it was built to endure front-line environments and to operate during the day or night and in adverse weather using avionics and electronics, such as the Target Acquisition and Designation System, Pilot Night Vision System (TADS/PNVS), passive infrared countermeasures, Global Positioning System (GPS), and the Integrated Helmet And Display Sight System (IHADSS). McDonnell Douglas purchased Hughes Helicopters and continued the development of the AH-64 resulting in the AH-64D Apache Longbow which is currently produced by Boeing Integrated Defense Systems.




Development
Following the cancellation of the AH-56 Cheyenne, the United States Army sought an aircraft to fill an anti-armor attack role. 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. To this end, the US Army issued a request for proposals (RFP) for an Advanced Attack Helicopter (AAH) in 1972.[2]
Proposals were submitted by 5 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.[2]
Each company built prototype helicopters and went through a flight test program. Hughes' Model 77/YAH-64 prototype first flew on September 30, 1975, while Bell's Model 409/YAH-63 prototype first flew the following day.[2] After evaluating test results, the Army selected Hughes' YAH-64 over Bell's YAH-63 in 1976.[3] The AH-64 then entered phase 2 of the AAH program. This called for building three preproduction AH-64s, and upgrading the two YAH-64 flight prototypes and the ground test unit up to the same standard.[4] Weapons and sensor systems were integrated and tested during this time,[2] including the new Hellfire missile.[4]
In 1981, three pre-production AH-64s were handed over to the U.S. 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).[2] In late 1981, the AH-64 was named the "Apache" keeping with the Army's traditional use of Native American tribal names for its helicopters. Hughes was approved for full scale production in 1982.[2] 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 $500 million. Hughes later became part of The Boeing Company with the merger of Boeing and McDonnell Douglas in August 1997. The total cost of the AH-64D program is US$ 10.5 billion through April 2007.[5]




Operators
The original unit cost for the AH-64A was about US$14.5 million. In September 2003, Greece ordered 12 AH-64D (in addition to the already existing fleet of 20 AH-64A+) for a total cost of $675 million (presumably including weapons and support), indicating a gross unit cost for the AH-64D of $56.25 million. Singapore purchased a total of 20 AH-64D Longbow Apache aircraft in two batches between 1999 and 2001. Pakistan is thought to have ordered 6 Apache Longbow for its various anti-terrorism missions;[citation needed] unofficial reports suggest that the Pakistan Army has a requirement of up to 30 AH-64D Apache Longbow by 2010.

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