Definitions

rotor shaft

AH-64 Apache

The AH-64 Apache is an all-weather day-night military attack helicopter with a four-bladed main and tail rotor and a crew of two pilots who sit in tandem. The main fixed armament is a 30 mm M230 Chain Gun under the aircraft's nose. It can also carry a mixture of AGM-114 Hellfire and Hydra 70 rocket pods on four hard points mounted on its stub-wing pylons. The AH-64 is the principal attack helicopter of the United States Army, and a successor to the AH-1 Cobra.

The Apache was designed by Hughes Helicopters in response to the Army's Advanced Attack Helicopter program. 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. United States Army AH-64s have been in action in Panama, Gulf War, Afghanistan, and Iraq.

Development

Advanced Attack Helicopter

Following the cancellation of the AH-56 Cheyenne in favor of USAF and Marine projects like the A-10 and Harrier, the United States Army sought an aircraft to fill an anti-armor attack role that would still fall under Army command (the 1948 Key West Agreement having forbidden 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. To this end, the US Army issued a Request For Proposals (RFP) for an Advanced Attack Helicopter (AAH) in 1972.

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.

Each company built prototype helicopters and went through a flight test program. Hughes' Model 77/YAH-64A prototype first flew on September 30 1975, while Bell's Model 409/YAH-63A prototype first flew the following day. 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.

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. Weapons and sensor systems were integrated and tested during this time, including the new Hellfire 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 afterwards it was decided to upgrade to the T700-GE-701 version of engine, producing 1,690 shp (1,259 kW). 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. 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. In 1984, the incremental or flyaway cost for the AH-64A was US$7.8 million and the average unit cost was approximately US$14 million with development costs included.

In 2004, General Electric Aviation began producing more powerful T700-GE-701D engines, rated at for AH-64Ds. The total cost of the AH-64D program is US$10.5 billion through April 2007.

Design

The AH-64 is powered by two General Electric T700 turboshaft engines with high-mounted exhausts on either side of the rotor shaft. The Apache has a four-blade main rotor and four-blade tail rotor. The crew sits in tandem, with the pilot sitting behind and above the copilot-gunner in an armored crew compartment. The crew compartment and fuel tanks are armored against 23 mm gunfire. The helicopter is designed to remain flyable after sustaining hits by 23 mm rounds.

The helicopter is armed with a 30 mm M230 Chain Gun that can be slaved to the gunner's Helmet mounted display, fixed to a locked forward firing position, or controlled via the TADS (Target Acquisition and Designation System). The AH-64 carries a range of external stores on its stub-wing pylons, typically a mixture of AGM-114 Hellfire anti-tank missiles, Hydra 70 general-purpose unguided 70 mm (2.75 in) rockets, and AIM-92 Stinger anti-aircraft missiles for defense. In case of emergency the pylons also have mounting points for personnel transfer (mounting points are handles normally used by maintenance personnel).

The AH-64 is designed 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).

Operational history

United States

The Apache was first used in combat during the 1989 invasion of Panama, Operation Just Cause. The AH-64A Apache and the AH-64D Apache Longbow have played important roles in several Middle Eastern wars, including the Gulf War, Operation Enduring Freedom in Afghanistan, and Operation Iraqi Freedom in Iraq. The Apaches were proven to be excellent tank hunters and also destroyed hundreds of armored vehicles (mainly of the Iraqi army).

During Operation Desert Storm on January 17, 1991, eight AH-64As guided by four MH-53 Pave Low IIIs, were used to destroy a portion of the Iraqi radar network to allow bomber aircraft into Iraq without detection. This was the first attack of Desert Storm. The Apaches carried an asymmetrical load of Hydra 70 flechette rockets, Hellfires, and one auxiliary fuel tank each. During the 100-hour ground war, a total of 277 AH-64s took part. Apaches destroyed over 500 tanks, numerous armored personnel carriers and many other vehicles during Operation Desert Storm.

Deployment to the Balkans took place during the disputes in Bosnia and Kosovo in the later 1990s, but the Apache encountered problems which reduced their effectiveness considerably. Criticisms included lack of training for the crews, deficiencies in night vision equipment, in fuel tanks and in aircraft survivability. An Apache crashed during training in Albania on April 27, 1999. Eventually the entire fleet in the Balkans was grounded for two weeks in December 2000. Major General Dick Cody, commanding officer of the 101st Airborne at the time, wrote a strongly worded memo to the US Army Chief of Staff about the failures in training and equipment.

During Operation Iraqi Freedom, several Apaches were damaged in combat, including one captured by Iraqi troops near Karbala on March 24, 2003, and shown on Iraqi television. The captured helicopter was destroyed via air strike one day after it was downed. The March 24 attack, against an armored brigade of the Iraqi Republican Guard's Medina Division, was largely unsuccessful: US officials claimed that it was because the tank crews had set up a "flak trap" in broken terrain, employing their guns to good effect while Iraqi officials claimed that the Apache was shot down by a old farmer with a Brno rifle because "it was a terrible nuisance". The helicopter came down intact and neither the pilot nor co-pilot were injured in the incident. More recently two Apaches were lost along with their crews between January 28 and February 2, 2007 to Iraqi insurgent ground fire in Taji and Najaf.

American AH-64Ds are currently flying in Iraq and Afghanistan without the Longbow Fire Control Radar as there are simply no armored threats for coalition forces to deal with.

The vast majority of Apache helicopters that have taken heavy combat damage have been able to continue their assigned missions and return safely to their bases. For example, of the 33 Apaches employed in the March 24, 2003 attack, 30 were damaged by Iraqi ground fire with several being damaged beyond repair, but only one of these did not make it back to base.

Israel

The Israeli Air Force uses the Apache to strike various targets with guided missiles. The AH-64A attacked and destroyed some of Hezbollah outposts in Lebanon during the 1990s, attacking in many weather conditions — day and night. During the al-Aqsa Intifada, the IAF used the Apaches to kill senior Hamas figures, such as Ahmed Yasin and Adnan al-Ghoul, with guided missiles. In the Israel-Lebanon conflict of July – August 2006, two IAF AH-64A helicopters collided, killing 1 pilot and wounding 3, all critically. In another incident in the conflict, an IAF AH-64D Longbow crashed, killing the two pilots, due to a malfunction in the rotor hub.

United Kingdom

The UK operates an improved version of the Apache Longbow called the Westland WAH-64 Apache, and is designated Apache AH Mk1 by the British Army. Westland has built 67 WAH-64 Apaches under license from Boeing replacing the engines with more powerful Rolls-Royce units, able to generate an additional 25% thrust over US-made models. A folding blade assembly for naval operations is another important change, allowing British Apaches to operate alongside and in support of amphibious operations, flying from Royal Navy warships and auxiliaries. The Westland Apache replaced the Westland Lynx AH7 as the British Army's tactical attack helicopter. The WAH-64s are currently deployed in Afghanistan, where they are serving with distinction, in support of UK and Coalition forces in the south of the country. British WAH-64 Apaches are using the Longbow Fire Control Radar in Afghanistan, saying that it improves situational awareness and avoidance of other aircraft during tactical maneuvers.

The Netherlands

Royal Netherlands Air Force ordered 30 AH-64D Apaches in 1996, after leasing 12 AH-64As. The radar domes were not included, hence the Dutch AH-64Ds are not referred to as Longbows. Their first deployment was in Djibouti, Africa. They were also deployed alongside US AH-64s in support of NATO peacekeeping forces in Bosnia and Herzegovina. In 2004, Dutch AH-64s were deployed as part of the Netherlands contribution to Multinational force in Iraq. At the same time Dutch Apaches were also deployed to Kabul as part of the Netherlands contribution to ISAF. In February 2006, the Netherlands contribution to NATO forces in Afghanistan was increased from 600 to 1,400 troops and 6 AH-64s were sent in support.

Other users

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. The United Arab Emirates purchased a total of 30 AH-64A helicopters in 1991 and 1994, which they are now upgrading to AH-64D specification. Kuwait has purchased 16 Longbow helicopters. Other countries with the Apache include Egypt, Israel, Japan and Saudi Arabia.

Pakistan is thought to have ordered six Apache Longbow for its various anti-terrorism missions.

South Korea is currently reviewing plans to purchase 36 AH-64D while simultaneously co-developing a domestic attack helicopter, the Korean Attack Helicopter, (KAH) under the KAH program with partnership from Eurocopter, which will be based on the Eurocopter Tiger.

The Republic of China (Taiwan) plans to purchase 30 AH-64D from 2008 onwards for its Army.

India also issued a request for proposal for 22 attack helicopters for the Indian Air Force. The Apache Longbow is one of the three types competing in order to be supplied to the IAF in the future.

Variants

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 anti-aircraft 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. 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.

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

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'.

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.

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 U.S. Marine Corps and U.S. Navy from 1984 to 1987. Multiple concepts were studied with altered landing gear arrangements, improved avionics and weapons. Funding for the naval version was not provided and the Marine Corps continues to use the AH-1 SuperCobra as of 2008.

Operators

Specifications (AH-64A)

Popular culture

The Apache had a major role in the movie Fire Birds (or Wings of the Apache).

See also

Notes

  • Bishop, Chris. Apache AH-64 Boeing (McDonnell Douglas) 1976–2005. Osprey Publishing, 2005. ISBN 1-84176-816-2.
  • Donald, David. "AH-64A/D Apache and AH-64D Longbow Apache", Modern Battlefield Warplanes. AIRtime Publishing Inc, 2004. ISBN 1-880588-76-5.

External links

Search another word or see rotor shafton Dictionary | Thesaurus |Spanish
Copyright © 2014 Dictionary.com, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature