Advanced Attack Helicopter

{{Short description|Family of United States attack helicopters}} {{Use American English|date = February 2019}} {{Use dmy dates|date=March 2020}} {{Infobox aircraft |name = Advanced Attack Helicopter (AAH) |image = File:YAH-64 1982 01761 cr.jpg |caption = A YAH-64A during a demonstration flight in 1982 |aim = [[Attack helicopter]] |requirement = |issuer = [[United States Army]] |service = |value = |initiated = |proposals = |prototypes = [[Bell YAH-63]] <br> [[Boeing AH-64 Apache|Hughes YAH-64]] |concluded = |outcome = YAH-64 selected for production as AH-64 Apache |predecessors = [[Advanced Aerial Fire Support System]] |successors = [[Light Helicopter Experimental]] |related = }}

The '''Advanced Attack Helicopter''' ('''AAH''') was a [[United States Army]] program to develop an advanced ground [[attack helicopter]] beginning in 1972. The Advanced Attack Helicopter program followed cancellation of the [[Lockheed AH-56 Cheyenne]]. After evaluating industry proposals, the AAH competition was reduced to offerings from [[Bell Helicopter|Bell]] and [[Hughes Helicopters|Hughes]]. Following a flight test evaluation of prototypes, Hughes' [[Boeing AH-64 Apache|YAH-64]] was selected in December 1976.<ref name="Bishop_AH-64" />

==Background== [[File:Probable Axes of Attack.jpg|thumb|Probable axes of attack of the [[Warsaw Pact]] through the [[Fulda Gap]] and the [[North German Plain#Military importance|North German Plain]]s (according to the U.S. Army)]]

During the mid-1960s, the [[United States Army]] initiated the Advanced Aerial Fire Support System (AAFSS) program, which led to the development of the [[Lockheed AH-56 Cheyenne]] for use in the anti-tank gunship role. The US Army pursued the [[Bell AH-1 Cobra|AH-1G HueyCobra]] as an "interim type" for the "jungle fighting" role. However, the Army's broader concern was the task of protecting Western Europe from the legions of [[Warsaw Pact]] armor to the east.<ref name="Vectorsite_Cobras">{{usurped|1=[https://web.archive.org/web/20060521033221/http://www.vectorsite.net/avcobra_1.html First Generation Cobras]}}, Vectorsite.net, 1 December 2008. </ref><ref>[https://apps.dtic.mil/sti/pdfs/ADA450121.pdf Critical Technology Events in the Development of the Apache Helicopter]</ref> The main scenario used by [[NATO]] throughout the [[Cold War]] was that, if the [[Soviet Union]] and Warsaw Pact forces were to conduct a massive tank offensive attack on Western Europe, they would probably cross either the [[Fulda Gap]] (capturing [[Frankfurt-am-Main|Frankfurt]] first and then aiming for the westward bend of the [[Rhine]] south of [[Wiesbaden]]: a total distance of just 85 miles), or cross the [[North German Plain]] (see map). The Advanced Attack Helicopter was conceived from the need to defend against such an attack.

In 1971, political friction increased between the Army and the Air Force over the close air support (CAS) mission.<ref name="Campbell84">Campbell, Douglas. ''The Warthog and the Close Air Support Debate'', p. 84. Annapolis, MD: Naval Institute Press, 2003. {{ISBN|978-1-55750-232-2}}.</ref> The Air Force asserted that the Cheyenne would infringe on the Air Force's CAS mission in support of the Army, which had been mandated with the [[Key West Agreement]] of 1948.<ref name="Dahl_p2">Dahl, Arden B. ''[https://web.archive.org/web/20110522033448/http://handle.dtic.mil/100.2/ADA442118 The Warthog. The Best Deal the Air Force Never Wanted]'', p. 2. National War College. 2003.</ref> The Department of Defense (DOD) conducted a study which concluded that the Air Force's A-X program, the Navy's proposed [[Hawker Siddeley Harrier|Harrier]], and the Cheyenne were significantly different and that they did not constitute a duplication of capabilities.<ref name="Army_p9">OAVCSA 1973, p. 9.</ref>

The Army convened a special task force under General Marks in January 1972, to reevaluate the requirements for an attack helicopter.<ref name="Army_p9"/> The task force conducted flight evaluations of the AH-56, along with two industry alternatives for comparison; the [[Bell 309 KingCobra]] and [[Sikorsky S-67 Blackhawk]].<ref name="Army_p9"/> In 1972, the Army conducted a competitive fly-off of the helicopters from the spring 1972 until July 1972.<ref name="Vectorsite_Cobras"/> The Army determined that the three helicopters could not fulfill its requirements.<ref name="Army_p9"/><ref name="DAHSUM-1972">Center of Military History. [http://www.history.army.mil/books/DAHSUM/1972/ch05.htm#b6 "Chapter V: Force Development"] {{Webarchive|url=https://web.archive.org/web/20170101044225/http://www.history.army.mil/books/DAHSUM/1972/ch05.htm#b6 |date=1 January 2017 }}. ''Dept. of the Army Historical Summary, 1972''. Washington, D.C.: Headquarters, Department of the Army, 1972. Accessed on 31 October 2008.</ref><ref>Verier, Mike. ''Bell AH-1 Cobra'', p. 138. Osprey Publishing, 1990. {{ISBN|978-0-85045-934-0}}.</ref>

In April 1972, the Senate published its report on CAS. The report recommended funding of the Air Force's A-X program, which would become the [[Fairchild Republic A-10 Thunderbolt II|A-10 Thunderbolt II]], and limited procurement of the Harrier for the Navy. The report never referred to the Cheyenne by name and only offered a lukewarm recommendation for the Army to continue to seek to procure attack helicopters, so long as their survivability could be improved.<ref name="Bonin_p33">Bonin, John A., MAJ, USA. [https://web.archive.org/web/20110215113508/http://cgsc.cdmhost.com/cdm4/item_viewer.php?CISOROOT=/p4013coll11&CISOPTR=356&CISOBOX=1&REC=9 ''Towards the Third Dimension in Combined Arms: The Evolution of Armed Helicopters into Air Maneuver Units in Vietnam''], p. 33. Fort Leavenworth, Kansas: US Army Command and General Staff College, 22 April 1986.</ref> The Cheyenne program was canceled by the Army on 9 August 1972.<ref name="Army_p9"/><ref name="Landis_p79-82">Landis and Jenkins 2000, pp. 79–82.</ref> The helicopter's large size and inadequate night/all-weather capability were reasons stated by the Army for the cancellation.<ref name="Landis_p79-82"/>

Following the cancellation of the AH-56 Cheyenne the US 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.<ref name="Bishop_AH-64">Bishop, Chris. ''Apache AH-64 Boeing (McDonnell Douglas) 1976–2005''. Osprey Publishing, 2005. {{ISBN|978-1-84176-816-8}}.</ref> On 17 August 1972, the Army initiated the Advanced Attack Helicopter (AAH) program.<ref name="Army_p10">OAVCSA 1973, p. 10.</ref> AAH sought an attack helicopter based on combat experience in Vietnam, with a lower top speed of 145 knots (269 km/h) and twin engines for improved survivability.<ref name="Landis_p81-82">Landis and Jenkins 2000, pp. 81–82.</ref> To this end, the US Army issued a Request For Proposals (RFP) for an Advanced Attack Helicopter (AAH) on 15 November 1972.<ref name="Army_p10"/> The AAH requirements for reliability, survivability and life cycle costs were very similar to the [[Sikorsky UH-60 Black Hawk#Initial requirement|UTTAS requirements]].<ref>[http://www.globalsecurity.org/military/systems/aircraft/aah.htm Advanced Attack Helicopter (AAH) (1970–1981)] – Global Security</ref>

The Army specified that the AAH was to be powered by twin [[General Electric T700]] turboshaft engines that produce 1,500 shp (1,120 kW) each. The T700 was the same powerplant fit specified for a new Army utility helicopter competition that would be won by the [[Sikorsky UH-60 Black Hawk|UH-60 Black Hawk]]. The AAH would be armed with a 30 millimeter cannon and 16 TOW anti-tank missiles. The missile armament specification was later modified to include an alternate load of 16 laser-guided [[AGM-114 Hellfire]] anti-tank missiles. The Hellfire was then in development and promised greater range and lethality than TOW.<ref name="Vector Bell">{{usurped|1=[https://web.archive.org/web/20060521033221/http://www.vectorsite.net/avcobra_1.html#m4 Model 309 KingCobra / Model 409 AAH (YAH-63)]}}, Vectorsite.net, 1 December 2008. </ref>

Proposals were submitted by five manufacturers: [[Bell Helicopter|Bell]], [[Boeing-Vertol]] (teamed with [[Grumman]]), [[Hughes Aircraft]], [[Lockheed Corporation|Lockheed]], and [[Sikorsky Aircraft|Sikorsky]]. In June 1973, Bell and Hughes Aircraft's [[Toolco Aircraft Division]] (later [[Hughes Helicopters]]) were selected as finalists, and were each awarded contracts for the construction of two prototype aircraft.<ref name="Vector Bell"/> This began the phase 1 of the competition.<ref name="Bishop_AH-64" />

Each company built two prototype helicopters for a flight test program.<ref name="Bishop_AH-64" /> Bell's [[Bell YAH-63|Model 409/YAH-63A]] prototype featured a three-wheel landing gear in a tricycle arrangement, and placed the pilot in the cockpit front instead of the usual rear seat, to help with nap of earth flying.<ref name="Bishop_Cobra">Bishop, Chris. ''Huey Cobra Gunships''. Osprey Publishing, 2006. {{ISBN|978-1-84176-984-4}}.</ref> Hughes' [[Boeing AH-64 Apache|Model 77/YAH-64A]] prototype featured a three-wheel landing gear with the third gear at its tail. Its cockpit placed the pilot in the rear seat.<ref name="Bishop_AH-64" />

Faced with a flight deadline of the end of September,<ref name="under attack">[https://www.flightglobal.com/pdfarchive/view/1975/1975%20-%202194.html "AAH under attack"]. ''Flight International'', 16 October 1975.</ref> Hughes' YAH-64 first flew on 30 September 1975, while Bell's YAH-63 first flew on 1 October.<ref name="Bishop_AH-64" /><ref name="under attack"/> The second YAH-64's first flight was on 22 November, and second YAH-63 flew on 21 December 1975.<ref name="Vector Apache"/> The first YAH-63 crashed in June 1976, but a static test prototype was brought up to flight standard and, along with the second prototype, entered the flyoff against Hughes' YAH-64s.<ref name="Vector Bell"/>

The Army put all four helicopters through a demanding program of flight testing during 1976.<ref name="Bishop_AH-64" /> The Army flyoff began in June of that year.<ref>[https://www.flightglobal.com/pdfarchive/view/1976/1976%20-%200870.html "Attack helicopter contenders"]. ''Flight International'', 22 May 1976.</ref><ref>[https://www.flightglobal.com/pdfarchive/view/1976/1976%20-%201000.html "The soldier's helicopter"]. ''Flight International'', 12 June 1976.</ref>

A separate competition was conducted for the sensor and targeting suite for the AAH, with Martin Marietta and Northrop submitting proposals in November 1976.<ref name="Vector Apache"/>

During the prototype evaluation, the Army changed the AAH primary antitank weapon from the proven TOW wire-guided missile to the new Hellfire laser-guided missile, with over twice the effective range.<ref name="Bishop_AH-64" /> This was risky because Hellfire had not even been flown at the time, with the initial development contract with Rockwell International signed in October 1976.<ref name="Vector Apache">{{usurped|1=[https://web.archive.org/web/20030811141209/http://www.vectorsite.net/avah64.html Boeing AH-64 Apache]}}, Vectorsite.net, 1 July 2007. {{Cite web |url=http://www.airvectors.net/avah64.html |title=Archived copy |access-date=15 November 2018 |archive-date=13 April 2013 |archive-url=https://archive.today/20130413154937/http://www.airvectors.net/avah64.html |url-status=bot: unknown }}</ref>

==Selection and afterward== [[File:Ah-64 ground with weapons.jpg|thumb|right|A YAH-64A]]

After evaluating test results, the Army selected Hughes' YAH-64A over Bell's YAH-63A on 10 December 1976. Both designs were regarded as good, but the Hughes design seemed to have an edge in survivability.<ref name="Vector Apache"/> Reasons for selecting the YAH-64A included its more damage-tolerant four-blade main rotor and reduced stability of the YAH-63's tricycle landing gear arrangement.<ref name="warplanes">Donald, David. ''Modern Battlefield Warplanes''. AIRtime Publishing Inc, 2004. {{ISBN|978-1-880588-76-5}}.</ref>

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.<ref name="Vector Apache" /> Weapons and sensor systems were integrated and tested during this time,<ref name="Bishop_AH-64" /> including the new [[AGM-114 Hellfire|Hellfire]] missile.<ref name="Vector Apache" />

The Phase 2 program suffered through a number of delays for various reasons and stretched out to over five years. The first Phase 2 flight, of an upgraded initial prototype, was on 28 November 1977, with the first flight of a newbuild preproduction prototype on 31 October 1979. Initial Hellfire launches had already taken place by then, with first firings in April 1979. A competitive evaluation of preproduction helicopters, one fitted with the Martin Marietta sensor / targeting suite and the other fitted with the Northrop suite, was performed, with Martin Marietta winning the competition in April 1980. An initial production order for 11 "[[AH-64 Apache|AH-64A Apache]]" attack helicopters was issued on 26 March 1982.<ref name="Vector Apache"/>

==See also== {{Portal|Aviation}} * [[List of attack aircraft]] * [[List of military aircraft of the United States]] * [[List of rotorcraft]]

==References== ===Notes=== {{reflist}}

===Bibliography=== * Donald, David. "AH-64A/D Apache and AH-64D Longbow Apache", ''Modern Battlefield Warplanes''. AIRtime Publishing Inc, 2004. {{ISBN|978-1-880588-76-5}}. * Government Accounting Office. [http://archive.gao.gov/f0202/092647.pdf ''Staff Study: Advanced Attack Helicopter'']. Washington, D.C.: US Government Accounting Office, 1974. * Landis, Tony and Jenkins, Dennis R. ''Lockheed AH-56A Cheyenne – WarbirdTech Volume 27''. Specialty Press, 2000. {{ISBN|978-1-58007-027-0}}. * Office of the Assistant Vice Chief of Staff of the Army (OAVCSA). [https://web.archive.org/web/20060712135303/http://cgsc.cdmhost.com/cdm4/item_viewer.php?CISOROOT=/p4013coll11&CISOPTR=175&REC=1 ''An Abridged History of the Army Attack Helicopter Program'']. Washington, DC: Department of the Army. 1973.

==External links== {{commons|AH-64 Apache}} * [http://www.globalsecurity.org/military/systems/aircraft/ah-63.htm YAH-63 page on GlobalSecurity.org] * [http://www.janes.com/defence/air_forces/news/jawa/jawa001013_1_n.shtml Jane's AH-64 page] * [http://www.globalsecurity.org/military/systems/aircraft/ah-64.htm AH-64 page on GlobalSecurity.com]

[[Category:Military aircraft procurement programs of the United States]] [[Category:United States military helicopters]] [[Category:Attack helicopters]] [[Category:Helicopter procurement programs]]