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Bell AH-1 Cobra

The Bell AH-1 Cobra is a single-engined attack helicopter developed and manufactured by the American rotorcraft manufacturer Bell Helicopter. A member of the prolific Huey family, the AH-1 is also referred to as the HueyCobra or Snake.

The AH-1 was rapidly developed as an interim gunship in response to the United States Army's needs in the Vietnam War. It used the same engine, transmission and rotor system as the Bell UH-1 Iroquois, which had already proven itself to be a capable platform during the conflict, but paired it with a redesigned narrow fuselage among other features. The original AH-1, being a dedicated attack helicopter, came equipped with stub wings for various weapons, a chin-mounted gun turret, and an armored tandem cockpit, from which it was operated by a pilot and gunner. Its design was shaped to fulfill a need for a dedicated armed escort for transport helicopters, giving the latter greater survivability in contested environments. On 7 September 1965, the Model 209 prototype performed its maiden flight; after rapidly gaining the support of various senior officials, quantity production of the type proceeded rapidly with little revision.

During June 1967, the first examples of the AH-1 entered service with the US Army and were promptly deployed to the Vietnam theater. It commonly provided fire support to friendly ground forces, escorted transport helicopters, and flew in "hunter killer" teams by pairing with Hughes OH-6A Cayuse scout helicopters. In the Vietnam War alone, the Cobra fleet cumulatively chalked up in excess of one million operational hours; roughly 300 AH-1s were also lost in combat. In addition to the US Army, various other branches of the US military also opted to acquire the type, particularly the United States Marine Corps. Furthermore, numerous export sales were completed with several overseas countries, including Israel, Japan, and Turkey.

For several decades, the AH-1 formed the core of the US Army's attack helicopter fleet, seeing combat in Vietnam, Grenada, Panama, and the Gulf War. In US Army service, the Cobra was progressively replaced by the newer and more capable Boeing AH-64 Apache during the 1990s, with the final examples being withdrawn during 2001. The Israeli Air Force (IAF) operated the Cobra most prolifically along its land border with Lebanon, using its fleet intensively during the 1982 Lebanon War. Turkish AH-1s have seen regular combat with Kurdish insurgents near Turkey's southern borders. Upgraded versions of the Cobra have been developed, such as the twin engined AH-1 SeaCobra/SuperCobra and the experimental Bell 309 KingCobra. Furthermore, surplus AH-1 helicopters have been reused for other purposes, including civilian ones; numerous examples have been converted to perform aerial firefighting operations.

Background
Closely related to the development of the Bell AH-1 is the story of the Bell UH-1 Iroquois transport helicopter—an icon of the Vietnam War and one of the most numerous helicopter types built. The UH-1 made the theory of air cavalry practical, as the new tactics called for US forces to be highly mobile across a wide area. Unlike before, they would not stand and fight long battles, and they would not stay and hold positions. Instead, the plan was that the troops carried by fleets of UH-1 "Hueys" would range across the country, to fight the enemy at times and places of their own choice.

The massive expansion of American military presence in Vietnam opened a new era of war from the air. The linchpin of US Army tactics was the helicopters, and the protection of those helicopters became a vital role. It became clear that unarmed troop helicopters were vulnerable against ground fire from Viet Cong and North Vietnamese troops, particularly as they approached landing zones to disembark or embark troops. Without friendly support from artillery or ground forces, the only way to pacify a landing zone was from the air, preferably with an aircraft that could closely escort the transport helicopters, and loiter over the landing zone as the battle progressed. By 1962, a small number of armed UH-1As were used as escorts, armed with multiple machine guns and rocket mounts. However, these makeshift gunships came with considerable tradeoffs, particularly being barely able to keep up with the troop transports they were intended to protect.

While some officials within the Pentagon, particularly those within the US Army, had recognized the potential value of purpose-built armed rotary aircraft as early as 1962 and were keen to see such a vehicle developed promptly, the issue was complicated in part due to inter-service politics. The United States Air Force (USAF) largely held the opinion that most forms of US military aircraft should be operated only by their service, and that the US Army would be intruding into their domain by developing a complex armed aerial combatant, and ought to be largely restricted to transport aircraft. Meanwhile, some Army officials were concerned that the USAF did not take the close air support (CAS) mission as seriously as it ought to, and that response times of 30 minutes or more for fixed-wing aircraft would be unacceptable.

Iroquois Warrior, Sioux Scout and AAFSS

Bell had been investigating helicopter gunships since the late 1950s, paying particular attention to the Algerian War, in which French forces mounted weapons onto helicopters to fight the growing insurgency. The company created a mockup of its D-255 helicopter gunship concept, named "Iroquois Warrior". The Iroquois Warrior was planned to be a purpose-built attack aircraft based on UH-1B components with a new, slender airframe and a two-seat, tandem cockpit. It featured a grenade launcher in a ball turret on the nose, a 20 mm belly-mounted gun pod, and stub wings for mounting rockets or SS.10 anti-tank missiles.

In June 1962, Bell displayed the mockup to US Army officials, hoping to solicit funding for further development; rival manufacturers issued protests to this approach, alleging that it was an attempt by Bell to circumvent the competitive process. Nevertheless, the Army was interested and awarded Bell a proof-of-concept contract in December 1962. Bell modified a Model 47 into the Model 207 Sioux Scout which first flew in July 1963. The Sioux Scout had all the key features of a modern attack helicopter: a tandem cockpit, stub wings for weapons, and a chin-mounted gun turret. After evaluating the Sioux Scout in early 1964, the Army was impressed but also felt that it was undersized, underpowered, and that the Sioux Scout was generally not suited for practical operations.

The Army's solution to the shortcomings of the Sioux Scout was to launch the Advanced Aerial Fire Support System (AAFSS) competition. This called for a heavily armed helicopter capable of at least 200 mph. A total of seven companies, including Bell, opted to respond to the requirement. It was out of the AAFSS program that the Lockheed AH-56 Cheyenne emerged, a heavy attack helicopter with high speed capability. During testing, it proved to be too sophisticated and costly, and was ultimately canceled in 1972 after ten years of development. In its place, the Advanced Attack Helicopter program was launched. Under this initiative, the Army sought a conventional attack helicopter with a greater level of survivability.

Model 209
Despite the Army's preference for the AAFSS program —for which Bell Helicopter was not selected to compete— the company persisted with their own idea of a smaller and lighter gunship, noting that Lockheed had little experience in developing rotorcraft and correctly predicted that it would encounter considerable difficulties. Bell employee Mike Folse played a key role in developing this new gunship, which he intentionally based around the existing UH-1 on the rationale that, while the Army could not purchase a completely original helicopter without a formal design competition, the service was able to procure a modification of an aircraft that was already in its inventory without invoking such hurdles. This initiative quickly caught the approval of Bell's senior management team.

In January 1965, Bell elected to invest $1 million (~$ in ) to proceed with the concept's detailed design. Mating the proven transmission, the "540" rotor system of the UH-1C augmented by a Stability Control Augmentation System (SCAS), and the T53 turboshaft engine of the UH-1 with the design philosophy of the Sioux Scout, Bell produced the Model 209. It largely resembled the "Iroquois Warrior" mockup, particularly in its cockpit and tail boom; in broad visual terms, there was relatively little shared between the proposed design and the UH-1. Despite appearance, much of the Model 209's major elements, such as the tail rotor and much of the dynamic systems, were identical. Roughly 80 percent of its components already had existing Huey part numbers.

On 3 September 1965, Bell rolled out its Model 209 prototype, and four days later it made its maiden flight, only eight months after the project's go-ahead and slightly under budget. This first flight was witnessed by around 20 US Army officials, the service having had no awareness of the project's existence prior to this, and rapidly drew the government's attention. One early test flight was met with a reportedly enthusiastic visit by US secretary of defense Robert McNamara. Bell claimed at this phase of the project that production units could be ready for service within one year.

As the Vietnam War proceeded, pressure accumulated in favor of the Model 209. Attacks on US forces were increasing and, by the end of June 1965, there were already 50,000 US ground troops in Vietnam. 1965 was also the deadline for AAFSS selection, but the program would become stuck in technical difficulties and political bickering. The US Army needed an interim gunship for Vietnam and it approached five separate companies with its request to provide a quick solution. Submissions came in for armed variants of the Boeing-Vertol ACH-47A, Kaman HH-2C Tomahawk, Piasecki 16H Pathfinder, Sikorsky S-61, and the Bell 209.

During April 1966, Bell's submission emerged victorious in an evaluation against the other rival helicopters. The US Army promptly signed the first production contract, ordering an initial batch of 110 aircraft. By the end of the year, rapid follow-on orders had increased this to 500 Cobras. Bell added "Cobra" to the UH-1's Huey nickname to produce its HueyCobra name for the 209. The Army applied the Cobra name to its AH-1G designation for the helicopter. The Bell 209 demonstrator was used for the next six years to test weapons and fit of equipment. An additional use for the demonstrator was participating in marketing initiatives. It was also modified to match the AH-1 production standard by the early 1970s. The demonstrator was retired to the Patton Museum at Fort Knox, Kentucky and converted to approximately its original appearance.

Into production
The Bell 209 design was modified in several respects for production. The retractable skids were replaced by simpler fixed skids; this was not due to any recorded design flaw or serviceability, but it was feared that the landing gear bay could become inundated with mud. Furthermore, a new wide-chord rotor blade was adopted. It was also decided that a plexiglass canopy should replace the Model 209's armored glass canopy, which was heavy enough to negatively impact performance. The umbrella-shaped dive brake was deleted, having reportedly self-destructed during its first test flight.

Numerous changes of the design were incorporated after the Cobra had entered service. The principal amongst these changes was the repositioning of the tail rotor from the helicopter's left side to the right, which facilitated an increase in the effectiveness of the tail rotor. The AH-1 was the first U.S. Army helicopter not named for a Native American people since the practice began with the H-13 Sioux and continued with the UH-1 Iroquois, AH-56 Cheyenne, OH-58 Kiowa, and later helicopters.

Within its first decade of service, the US Army had put the original Cobra model through various exercises and operations, which highlighted both the attack helicopter's promise and areas in which it could be improved. By 1972, the US Army openly sought an improved anti-armor capability. Under the Improved Cobra Armament Program (ICAP), trials of eight AH-1s fitted with TOW missiles were conducted in October 1973. After passing qualification tests the following year, Bell was contracted with upgrading 101 AH-1Gs to the TOW-capable AH-1Q configuration. While early-production examples were not compatible with night vision goggles, the cockpit instrumentation of later Cobras was altered to facilitate their use.

Further variants of the Cobra were promptly developed, with both new-build models and early production examples being modified to incorporate the improvements. During March 1978, the US Army opted to procure a batch of 100 new-build Cobras that featured a new T-shaped instrument panel, improved composite rotor blades, revised transmission and gearboxes, the M128 helmet-mounted sight, and the M28A3 armament system. A major feature was the adoption of a more powerful version of the T53 engine. Designated AH-1S, the Cobra was upgraded in three stages, culminating with the AH-1F. The AH-1F integrated numerous countermeasures, including an infrared jammer, a radar jammer, and a hot plume exhaust suppressor.

The U.S. Marine Corps (USMC) quickly became interested in the Cobra, opting to order an improved twin-engine version in 1968 under the designation AH-1J. During the early 1970s, the USMC proceeded to order an upgraded model, the AH-1T, which featured dynamic elements derived from the abortive Bell 309 KingCobra; as such, it featured a longer fuselage and tailboom. These dynamic changes were combined with the adoption of heavier armaments, which provided the USMC with an effective anti-armor capacity, unlike the preceding model. The USMC's interest in the Cobra would lead to the production of more twin-engine variants of the helicopter.

Design
The Bell AH-1 Cobra is a dedicated attack helicopter, built to provide close air support and to escort friendly troop transports. The visual design of the Cobra was intentionally made to be sleek and be akin to that of a jet fighter. Aviation author Stanley McGowen observed that its appearance differed radically from any prior rotorcraft designed by Bell, possessing a relatively narrow fuselage and a then-unusual cockpit arrangement. This cockpit was covered by a large fighter-like canopy and its occupants protected by armor, such included tempered-steel seats and personal body armor. It was operated by both a pilot and gunner, who were seated in a stepped tandem arrangement in which the commander was placed in the rear seat while the gunner occupied the forward position. This forward position provided a higher level of visibility to that of the rear seat. Both positions were provided with flying controls while both crew would typically be certified pilots, enabling control of the Cobra to be exchanged quickly through the course of the mission.

Much of the Cobra's armaments could be installed upon the multiple hardpoints that were attached to the stub wings set on either side of the fuselage. In comparison to armed UH-1s, the Cobra would typically have carried twice as much ammunition and arrive on station in half the time, it also had three times the loiter time, which enabled the type to arrive in a designated landing zone ahead of transport helicopters to clear it, provide support fire while they are present, and to continue fighting as they withdraw. The slim profile of the helicopter allegedly provided defensive benefits by making it harder for opponents to accurately hit it with small arms fire, although man-portable air-defense system (MANPADS) did prove to be effective against the Cobra. Particularly vulnerable areas included the tail rotor drive shaft and the main transmission.

Typically, the Cobra would avoid hovering at any point in an active engagement; instead, emphasis was placed on maintaining speed and mobility. The gunner often fired the chin-mounted cannon with the intention of suppressing hostile targets in between barrages of 2.75-inch rockets, held in pods upon the stub wings, which were fired by the back-seater. It was unusual for Cobras to operate alone; instead, two or more would be dispatched and teamwork encouraged, leading to hunter-killer tactics being used to flush out and eliminate ground targets. Pairings with other helicopters, such as the Bell OH-58 Kiowa scout helicopter, were also common occurrences. Radio communications were handled by the gunner. Regardless of mission profile, low altitude flying was commonplace.

United States
By June 1967, the first AH-1G HueyCobras had been delivered. Originally designated as UH-1H, the "A" for attack designation was soon adopted and when the improved UH-1D became the UH-1H, the HueyCobra became the AH-1G. The AH-1 was initially considered a variant of the H-1 line, resulting in the G series letter.

The first six AH-1s arrived at Bien Hoa Air Base, South Vietnam on 30 August 1967 for combat testing by the U.S. Army Cobra New Equipment Training Team. On 4 September, the type scored its first combat kill by sinking a sampan boat, killing four Viet Cong. The first AH-1 unit, the 334th Assault Helicopter Company, was declared operational on 6 October 1967. The Army operated the Cobra continuously up to the U.S. withdrawal from South Vietnam in 1973. Typically, the AH-1 provided fire support for ground forces and escorted transport helicopters, in addition to other roles, including aerial rocket artillery (ARA) battalions in the two Airmobile divisions. They also formed "hunter killer" teams by pairing with OH-6A Cayuse scout helicopters; a team normally comprised a single OH-6 flying slow and low to find enemy forces. If the OH-6 drew fire, the Cobra could strike at the then revealed enemy.

On 12 September 1968, Capt. Ronald Fogleman was flying an F-100 Super Sabre when the aircraft was shot down and he ejected 200 mi north of Bien Hoa. Fogleman became the only pilot to be rescued by holding on to an Army AH-1G's deployed gun-panel door. Bell built 1,116 AH-1Gs for the U.S. Army between 1967 and 1973, and the Cobras chalked up over a million operational hours in Vietnam; the number of Cobras in service peaked at 1,081. Out of nearly 1,110 AH-1s that were delivered between 1967 and 1973, approximately 300 were lost to a combination of combat and accidents during the conflict. During Operation Lam Son 719 in Southeastern Laos, 26 U.S Army AH-1Gs were destroyed while a further 158 sustained some level of damage.

The U.S. Marine Corps also operated the AH-1G Cobra in Vietnam for a short time before acquiring the twin-engine AH-1J Cobras. The AH-1Gs had been adopted by the Marines as an interim measure, a total of 38 helicopters having been transferred from the U.S. Army to the Marines in 1969.

During Operation Urgent Fury, the invasion of Grenada in 1983, several AH-1T Cobras were deployed to fly close air support and helicopter escort missions. On the first day of the invasion, two of the four Cobras involved were lost to anti-aircraft fire in the attack on Fort Frederick.

During 1989, Army Cobras participated in Operation Just Cause, the U.S. invasion of Panama. It operated alongside its eventual successor in US Army service, the Boeing AH-64 Apache, for the first time during the combat in Panama.

During Operations Desert Shield and Desert Storm in the Gulf War (1990–91), both the Cobras and SuperCobras deployed in a support role. The USMC deployed 91 AH-1W SuperCobras while the US Army operated 140 AH-1 Cobras of various models in the theatre; these were typically operated from dispersed forward operating bases in close proximity to Saudi Arabia's border with Iraq. Three AH-1s were lost in accidents during fighting and afterward. Cobras successfully destroyed large numbers of Iraqi armored vehicles and various other targets during the intense fighting of the conflict.

US Cobras were deployed in further operations across the 1990s. Army Cobras provided support for the US humanitarian intervention during Operation Restore Hope in Somalia in 1993. They were also employed during the US invasion of Haiti in 1994.

During the 1990s, the US Army gradually phased out its Cobra fleet, completely retiring the type from active service in March 1999. The service, which had long sought a more capable successor to the Cobra, had procured a large fleet of AH-64 Apaches since receiving the first example of the type during early 1984. The withdrawn AH-1s were typically offered to other potential operators, usually NATO allies. The Army retired the AH-1 from its reserves in September 2001. The retired AH-1s were then disposed of, often through sales to overseas customers; the final portion of the fleet was liquidated in 2010. Some were also given to the USDA's Forest Service. The US Marine Corps retired the AH-1W SuperCobra in 2020, and continues to operate the AH-1Z Viper.

Israel

Israel was an early export customer for the Cobra, purchasing six AH-1Gs from the US Army. The government was keen to procure a capable attack helicopter as recent combat in the Yom-Kippur War had shown a need for a capable platform for countering enemy armour. The type was operated by the Israeli Air Force (IAF), with the First Attack Helicopter Squadron formally commencing on 1 December 1977. The service named the type as the "Tzefa" (צפע, for Viper).

On 9 May 1979, the IAF's Cobras performed their first attack, firing four Orev missiles at a house near Tyre, Lebanon, that was occupied by militants. Israel's fleet of Cobras was particularly active on the Lebanon front, having participated in the fighting there for in excess of 20 years. They were intensively used during the 1982 Lebanon War to destroy Syrian armor and fortifications alike, being reportedly responsible for the destruction of dozens of Syrian ground vehicles. In one operation alone, a pair of IAF Cobras destroyed three enemy tanks and one truck. Based upon its performance in the conflict, it was decided to remove the rocket pods and increase the amount of ammunition carried for the cannon instead. Other operational changes included a greater emphasis on cooperation with ground units to avoid friendly fire incidents.

Largely due to a US embargo that prevented the purchase of further Cobras, Israel procured alternative platforms instead, including around 20 McDonnell Douglas MD 500 Defenders in late 1979. Between 1983 and 1985, by which time the embargo had been lifted, 24 new Cobras were purchased; the expanded fleet enabled the creation of a second squadron, known as the Fighting Family Squadron, on 1 June 1985. During 1990, the IAF received its first Boeing AH-64 Apache attack helicopters, having acquired a fleet of 42 by 2000. At the time of the Apache's procurement, there was considerable political controversy over the IAF's decision to overlook upgrades to its existing Cobra fleet in favour of acquiring an entirely separate model of attack helicopter.

Throughout the 1980s and 1990s, the Cobras continued to play a role in major operations against groups such as Hezbollah, including Operations "Accountability" and "Grapes of Wrath", in southern Lebanon. During August 1996, the IAF's Cobra fleet was expanded yet again via 14 surplus US Army AH-1F Cobras being acquired, some of which were used by the front line squadrons while others were operated exclusively for flight training purposes. During the 2000s, the Cobra's precision strike capability was bolstered by the adoption of the Spike missile.

During late 2013, Israel opted to retire the last of its 33 AH-1 Cobras from front line service, largely due to budget cuts. Its role was taken up entirely by the IAI's squadrons of AH-64 attack helicopters, while an extensive fleet of unmanned aerial vehicles (UAVs) took over the role of patrolling combat zones. The Cobra fleet was considerably older than the Apaches, which contributed to several fatal crashes of the type. The Cobras were also more expensive to maintain than UAVs and their use exposed pilots to attacks from man-portable air-defense systems operated by guerrilla groups. Around the same time frame, the IAF also pursued upgrades to its AH-64 fleet. In late 2014, Israel transferred 16 of the recently-withdrawn Cobras to the Royal Jordanian Air Force to bolster the numbers of their existing fleet.

Japan
Japan manufactured 89 AH-1S Cobras under license by Fuji Heavy Industries from 1984 to 2000. The type is used by the Japan Ground Self-Defense Force, and are Step 3 models, which are roughly the equivalent to the U.S. Army's AH-1Fs. The engine is the T53-K-703 turboshaft, which Kawasaki Heavy Industries produced under license. During the 2010s, Japan was examining options for procuring a fleet of new rotorcraft to replace its aging Cobras; it has been specified that the replacement helicopter would need to be optimized for marine use and able to operate from expeditionary airstrips or sea bases, and that between 30 and 50 such craft would be purchased.

In December 2022, the Japanese government decided to replace 47 AH-1S, 12 AH-64D, 33 OH-1, and 26 U-125A with unmanned aerial vehicles. Japan plans to increase its defense budget from 1.24% of GDP in fiscal 2021 to around 2.0% within 10 years, and has decided to retire these helicopters and aircraft as part of an effort to spend its defense budget efficiently.

Jordan
Jordan obtained an initial batch of 24 AH-1Fs during the late 1980s. In 2001, nine additional ex-US Army Cobras were acquired to supplement the fleet. During 2010, Jordan transferred 16 AH-1F helicopters to Pakistan under a US-sponsored support program that provided Islamabad with 40 AH-1 refurbished helicopters.

In late 2014, Israel and Jordan came to an agreement under which the former transferred 16 ex-IAF Cobras to the Royal Jordanian Air Force. The deal was publicly stated to be for the purpose of increasing border security, which was viewed as a pressing concern of both nations due to the threats posed by Islamic State (IS) militants, as well as by other insurgent groups, at that time.

The Royal Jordanian Air Force has at least one squadron of Cobras in service, and is supposed to have used them in combat in Iraq and Syria.

Turkey
Turkey bought ten AH-1Ws in the early 1990s, and supplemented them with 32 ex-US Army Cobras. These additional units included several TAH-1P trainers while the majority were brought up to the AH-1F standard. During the 2010s, Turkish Cobras have repeatedly seen combat in operations against Kurdish insurgents around Turkey's borders with both Syria and Iraq. Two Cobras were reportedly lost to enemy fire during these operations. Amid the 2016 Turkish coup d'état attempt, Turkish Cobras were alleged to have fired upon several police vehicles.

Pakistan
Between 1984 and 1986, Pakistan was supplied with an initial batch of 20 AH-1S gunships by the US; these were later upgraded with the C-NITE thermal imaging package. Operated by Pakistan Army Aviation, the service first used Cobra overseas in Somalia during the United Nations Operation in Somalia II, where a single squadron was deployed in 1994. Pakistani Cobras subsequently saw action in Sierra Leone.

By 2013, Pakistan reportedly operated a fleet of 35 AH-1F helicopters. Maintaining these aircraft has been difficult, but possible through commercial channels. Additionally, the US government provided $750,000 (~$ in ) through 2013 to update the existing AH-1F/S Cobra fleet. However, controversy over how much of this funding has actually been spent on Pakistan's Cobras has also been present throughout the 2010s. Turkey has also become a key supplier of spare parts for the Cobra, often free of cost, to Pakistan. During the 2010s, Pakistan lost a total of three aircraft in separate incidents.

Pakistan repeatedly sought the Bell AH-1W SuperCobra from the US to supplement and replace its current AH-1 Cobras. Attempts to acquire the AH-1Z Viper or AH-64E Apache from the US were rejected, so Pakistan turned to buying other foreign attack helicopters. Possible candidates have included the Turkish T129, the Chinese CAIC Z-10, and the Russian Mi-35 Hind. In November 2014, Russia approved the sale of Mi-35M helicopters to Pakistan. In April 2015, China delivered three Z-10s to Pakistan. During the same month, the US Department of State approved the sale of 15 AH-1Zs and associated equipment to Pakistan. During October 2017, the T129 was also reported to be a contender for further orders.

Philippines

The Jordanian government offered to provide up to four surplus AH-1F Cobras to the Philippines for counter terrorism operations. The offer was later reduced to two units, which the Philippine government accepted. On 26 November 2019, an Antonov An-124 airlifter carried the two Bell AH-1F Cobras from Jordan to Clark International Airport/Clark Air Base. The helicopters are reportedly painted in a light grey livery similar to the paint scheme of the PAF's AgustaWestland AW109E armed helicopters.

PAF AH-1s conducted airstrikes on communist insurgent positions as part of OPLAN "Wrath of Polaris 2" conducted by Joint Task Force Tala in Gonzaga, Cagayan.

Civilian operators
In 2003, the US Forest Service acquired 25 retired AH-1Fs from the US Army. These have been designated Bell 209 and are being converted into Firewatch Cobras with infrared and low light sensors and systems for real time fire monitoring. The last two Firewatch Cobras were retired in October 2021.

The Florida Division of Forestry also acquired three AH-1Ps from the US Army. These are called Bell 209 "Firesnakes" and are equipped to carry a water/fire retardant system.

Single-engine

 * Bell 209: Original AH-1G prototype with retractable skid landing gear. This model number is also used by the FAA for the civilian registration of former U.S. Army AH-1s used in firefighting service.

 * AH-1G HueyCobra: Initial 1966 production model gunship for the US Army, with one 1400 shp Avco Lycoming T53-13 turboshaft.
 * JAH-1G HueyCobra: One helicopter for armament testing including Hellfire missiles and multi-barrel cannon.
 * TH-1G HueyCobra: Two-seat dual-control trainer.
 * Z.14 HueyCobra: The Spanish Navy purchased eight new-build AH-1Gs, designating the type the "Z-14". These were equipped with the M35 20 mm cannon system, and were used to support coastal patrol boats. Four of these were lost in accidents. The remaining helicopters were retired in 1985 with three sent back to the US, and one kept in storage in Spain.
 * YAH-1Q: Eight AH-1Gs with XM26 Telescopic Sight Unit (TSU) and two M56 TOW 4-pack launchers.
 * AH-1Q HueyCobra: Equipped with the M65 TOW/Cobra missile subsystem, M65 Telescopic Sight Unit (TSU), and M73 Reflex sight. All future versions will be equipped with the TSU and be equipped to fire the TOW missile subsystem.
 * YAH-1R: AH-1G powered by a T53-L-703 engine without TOW system.

 * YAH-1S: AH-1Q upgrade and TOW system.
 * AH-1S: The baseline AH-1S is an AH-1Q upgraded with a 1800 shp T53-L-703 turboshaft engine. The AH-1S is also referred to as the "Improved AH-1S", "AH-1S Modified", or "AH-1S(MOD)" prior to 1988. (Prior to 1988, all upgraded aircraft were referred to as variants of the AH-1S.)
 * QAH-1S: A target drone conversion of the AH-1S by Bell-Bristol Aerospace under a joint US and Canada development program started in 1994. Honeywell further modified the QAH-1S into the Hokum-X by installing systems and hardware to allow it to simulate the Russian Kamov Ka-50 attack helicopter.  Three Hokum-Xs were completed from 1998 to 2001.
 * AH-1P: 100 production aircraft with composite rotors, flat plate glass cockpit, and improved cockpit layout for nap-of-earth (NOE) flight. The AH-1P is also referred to as the "Production AH-1S", or "AH-1S(PROD)" prior to 1988. These improvements are considered Step 1 of the AH-1S upgrade program.
 * AH-1E: 98 production aircraft with the Enhanced Cobra Armament System (ECAS) featuring the M97A1 armament subsystem with a three-barreled M197 20 mm cannon. The AH-1E is also referred to as the "Upgunned AH-1S", or "AH-1S(ECAS)" prior to 1988. These improvements are considered Step 2 of the AH-1S upgrade program. AH-1E aircraft included the M147 Rocket Management Subsystem (RMS) to fire 2.75 in rockets.
 * AH-1F: 143 production aircraft and 387 converted AH-1G Cobras. The AH-1F incorporates all Step 1 and 2 upgrades to the AH-1S. It also featured Step 3 upgrades: a head-up display, a laser rangefinder, an infrared jammer mounted above the engine exhaust, and an infrared suppressing engine exhaust system, and the M143 Air Data Subsystem (ADS). The AH-1F is also referred to as the "Modernized AH-1S", "AH-1S Modernized Cobra", or "AH-1S(MC)" prior to 1988.
 * Model 249: Experimental demonstrator version fitted with the four-blade rotor system from Bell 412, an uprated engine, and experimental equipment, including Hellfire missiles.
 * Bell 309 KingCobra: Experimental all-weather version based on the AH-1G single-engine and AH-1J twin-engine designs. Two Bell 309s were produced; the first was powered by a PW&C T400-CP-400 Twin-Pac engine set and the second was powered by a Lycoming T55-L-7C engine.
 * AH-1FB
 * AH-1F modernized by Turkish Aerospace Industries for the Royal Bahraini Air Force.

Operators
A small number of former military helicopters are operated by civil organizations for display and demonstration, for example by Red Bull.

 * Royal Bahraini Air Force
 * Royal Bahraini Air Force

 * Japan Ground Self-Defense Force
 * Royal Jordanian Air Force
 * Kenya Air Force
 * Pakistan Army
 * $\phi$
 * Kenya Air Force
 * Pakistan Army
 * $\phi$
 * $\phi$
 * Philippine Air Force
 * Republic of Korea Army
 * Republic of Korea Army

Former operators

 * Israeli Air Force
 * Spanish Navy
 * Royal Thai Army
 * Turkish Army
 * United States Army
 * Washington Department of Natural Resources
 * U.S. Forest Service
 * Florida Department of Forestry
 * United States Army
 * Washington Department of Natural Resources
 * U.S. Forest Service
 * Florida Department of Forestry
 * Florida Department of Forestry

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Bell AH-1 Cobra


text:
Boeing AH-64 Apache

The Boeing AH-64 Apache is an American twin-turboshaft attack helicopter with a tailwheel-type landing gear and a tandem cockpit for a crew of two. Nose-mounted sensors help acquire targets and provide night vision. It carries a 30 mm M230 chain gun under its forward fuselage and four hardpoints on stub-wing pylons for armament and stores, typically AGM-114 Hellfire missiles and Hydra 70 rocket pods. Redundant systems help it survive combat damage.

The Apache began as the Model 77 developed by Hughes Helicopters for the United States Army's Advanced Attack Helicopter program to replace the AH-1 Cobra. The prototype YAH-64 first flew on 30 September 1975. The U.S. Army selected the YAH-64 over the Bell YAH-63 in 1976, and later approved full production in 1982. After acquiring Hughes Helicopters in 1984, McDonnell Douglas continued AH-64 production and development. The helicopter was introduced to U.S. Army service in April 1986. The advanced AH-64D Apache Longbow was delivered to the Army in March 1997. Production has been continued by Boeing Defense, Space & Security. As of March 2024, over 5,000 Apaches have been delivered to the U.S. Army and 18 international partners and allies.

Primarily operated by the U.S. Army, the AH-64 has also become the primary attack helicopter of multiple nations, including Greece, Japan, Israel, the Netherlands, Singapore, and the United Arab Emirates. It has been built under license in the United Kingdom as the AgustaWestland Apache. American AH-64s have served in conflicts in Panama, the Persian Gulf, Kosovo, Afghanistan, and Iraq. Israel used the Apache to fight in Lebanon and the Gaza Strip. British and Dutch Apaches were deployed to wars in Afghanistan and Iraq in 2001.

Advanced Attack Helicopter

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. Weapons and sensor systems were integrated and tested during this time, including the laser-guided AGM-114 Hellfire missile. 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 1690 shp. 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.

A 1985 Department of Defense engineering analysis by the inspector general's office reported that significant design deficiencies still needed to be addressed by the contractor. The Army project manager Col. William H. Forster published a list of 101 action items. In 1986, the four 22-foot-long main rotor blades, each made from steel and composite material glued together to maximize strength and minimize weight by the Composite Structures Division of Alcoa Composites, were added to the list. The steel-composite rotors could not meet the Army specification for a life of 1500 flight hours, and needed replacement after just 146 hours. After six changes to the design, the rotor blade life was extended to 1400 hours by early 1991.

Further development
During the 1980s, McDonnell Douglas studied an AH-64B, featuring 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 systems. 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. It competed for the U.S. Army's FLRAA unveiled in April, developed from the Future Vertical Lift Capability Set 3 (medium rotorcraft) without the attack requirement, while the U.S. Army's FARA should replace the retired Bell OH-58 Kiowa scout and up to half of the AH-64 fleet.

Overview

The AH-64 Apache has a four-blade main rotor and a four-blade tail rotor. The crew sits in tandem, with the pilot sitting behind and above the co-pilot/gunner. Both crew members are capable of flying the aircraft and performing methods of weapon engagements independently. The AH-64 is powered by two General Electric T700 turboshaft engines with high-mounted exhausts on either side of the fuselage. Various models of engines have been used on the Apache; those in British service use engines from Rolls-Royce. In 2004, General Electric Aviation began producing more powerful T700-GE-701D engines, rated at 2000 shp for AH-64Ds.

The crew compartment and rotor blades are designed to sustain a hit from 23 mm rounds. The airframe includes some 2500 lb of protection and has a self-sealing fuel system to protect against ballistic projectiles. This compartment also incorporates a transparent blast shield between the pilot and gunner seats so that at least one crew member can survive in the event of a direct hit, but the canopy and windows are otherwise unrated against ballistic threats.

The aircraft was designed to meet the crashworthiness requirements of MIL-STD-1290, which specifies minimum requirement for crash impact energy attenuation to minimize crew injuries and fatalities. This was achieved through incorporation of increased structural strength, crashworthy landing gear, seats and fuel system.

On a standard day, when temperatures are 59 °F (15 °C), the AH-64 has a vertical rate of climb of 1,775 feet per minute (541 m/min), and a service ceiling of 21,000 feet (6,400 m). However, on a hot day, when temperatures are 70 °F (21 °C), its vertical rate of climb is reduced to 1,595 fpm (486 m/min), and service ceiling is reduced to 19,400 feet (5,900 m) due to less dense air.

Avionics and targeting

One of the revolutionary features of the Apache was its helmet mounted display, the Integrated Helmet and Display Sighting System (IHADSS); among its capabilities, either the pilot or gunner can slave the helicopter's 30 mm automatic M230 Chain Gun to their helmet, making the gun track head movements to point where they look. The M230E1 can be alternatively fixed to a locked forward firing position, or controlled via the Target Acquisition and Designation System (TADS). On more modern AH-64s, the TADS/PNVS has been replaced by Lockheed Martin's Arrowhead (MTADS) targeting system.

U.S. Army engagement training is performed under the Aerial Weapons Scoring System Integration with Longbow Apache Tactical Engagement Simulation System (AWSS-LBA TESS), using live 30 mm and rocket ammunition as well as simulated Hellfire missiles. The Smart Onboard Data Interface Module (SMODIM) transmits Apache data to an AWSS ground station for gunnery evaluation. The AH-64's standard of performance for aerial gunnery is to achieve at least 1 hit for every 30 shots fired at a wheeled vehicle at a range of 800 –.

The AH-64 was designed to perform in front-line environments, and to operate at night or day and during adverse weather conditions. Various sensors and onboard avionics allows the Apache to perform in these conditions; such systems include the Target Acquisition and Designation System, Pilot Night Vision System (TADS/PNVS), passive infrared countermeasures, GPS, and the IHADSS. Longbow-equipped Apaches can locate up to 256 targets simultaneously within 50 km. In August 2012, 24 U.S. Army AH-64Ds were equipped with the Ground Fire Acquisition System (GFAS), which detects and targets ground-based weapons fire sources in all-light conditions and with a 120° visual field. The GFAS consists of two sensor pods working with the AH-64's other sensors, and a thermographic camera that precisely locates muzzle flashes.

In 2014, it was announced that new targeting and surveillance sensors were under development to provide high-resolution color imagery to crews, replacing older low definition black-and-white imaging systems. Lockheed received the first contract in January 2016, upgrading the Arrowhead turret to provide higher-resolution color imaging with longer ranges and a wider field of view. In 2014, the U.S. Army was adapting its Apaches for increased maritime performance as part of the Pentagon's rebalance to the Pacific. Additional avionics and sensor improvements includes an extended-range radar capable of detecting small ships in littoral environments, software adaptions to handle maritime targets, and adding Link 16 data-links for better communications with friendly assets.

Armament and configurations
The AH-64 is adaptable to numerous different roles within its context as Close Combat Attack (CCA). In addition to the 30 mm M230E1 Chain Gun, the Apache carries a range of external stores and weapons on its stub-wing pylons, typically a mixture of AGM-114 Hellfire anti-tank missiles, and Hydra 70 general-purpose unguided 70 mm rockets. The Hellfire is designed to defeat stationary or moving tanks as far away as 6,500 meters.

Since 2005, the Hellfire missile outfitted with a thermobaric warhead is designated AGM-114N; this missile version is intended for use against ground forces and urban warfare operations. In October 2015, the U.S. Army ordered its first batch of Advanced Precision Kill Weapon System (APKWS) guided 70 mm rockets for the Apache.

Starting in the 1980s, the Stinger and AIM-9 Sidewinder air-to-air missiles and the AGM-122 Sidearm anti-radiation missile were evaluated for use upon the AH-64. The Stinger was initially selected; the U.S. Army was also considering the Starstreak air-to-air missile. External fuel tanks can also be carried on the stub wings to increase range and mission time. The stub-wing pylons have mounting points for maintenance access; these mountings can also be used to secure personnel externally for emergency transport. Stinger missiles are often used on non-U.S. Apaches, as foreign forces do not have as many air superiority aircraft to control the skies. The AH-64E initially lacked the ability to use the Stinger to make room for self-defense equipment, but the capability was added back following a South Korean demand.

The AH-64E is able to control unmanned aerial vehicles (UAVs), used by the U.S. Army to perform aerial scouting missions previously performed by the OH-58 Kiowa. Apaches can request to take control of an RQ-7 Shadow or MQ-1C Grey Eagle from ground control stations to safely scout via datalink communications. There are four levels of UAV interoperability (LOI): LOI 1 indirectly receives payload data; LOI 2 receives payload data through direct communication; LOI 3 deploys the UAV's armaments; and LOI 4 takes over flight control. UAVs can search for enemies and, if equipped with a laser designator, target them for the Apache or other friendly aircraft.

Boeing has suggested that the AH-64 could be fitted with a directed energy weapon. The company has developed a small laser weapon, initially designed to engage small UAVs, that uses a high-resolution telescope to direct a 2–10 kW beam with the diameter of a penny out to a range of 5.4 nmi. On the Apache, the laser could be used to destroy enemy communications or radio equipment. On 26 June 2017, the Army and Raytheon announced they had successfully completed the first-ever helicopter-based flight demonstration of a high energy laser system from an AH-64.

On 14 July 2016, it was reported that the AH-64 had successfully completed testing of the MBDA Brimstone anti-armor missile. In January 2020, the U.S. Army announced it was fielding the Spike NLOS missile on AH-64E Apaches as an interim solution to acquire new munitions that provide greater stand-off capabilities.

Twentieth century
In January 1984, the U.S. Army formally accepted its first production AH-64A and training of the first pilots began later that year. The first operational Apache unit, 7th Battalion, 17th Cavalry Brigade, began training on the AH-64A in April 1986 at Fort Hood, Texas. Two operational units with 68 AH-64s first deployed to Europe in September 1987 and took part in large military exercises there.

Upon fielding the Apache, capabilities such as the FLIR's use in extensive night operations made it clear that it was capable of operating beyond the forward line of own troops (FLOT) to which previous attack helicopters were normally restricted. It was discovered that the Apache was coincidentally fitted with the Have Quick UHF radio system used by the U.S. Air Force, allowing inter-service coordination and joint operations such as the joint air attack teams (JAAT). The Apache has operated extensively with close air support (CAS) aircraft, such as the USAF's Fairchild Republic A-10 Thunderbolt II and the USMC's McDonnell Douglas AV-8B Harrier II, often acting as a target designator to conserve the Apache's own munitions. The Apache was first used in combat in 1989, during Operation Just Cause, the invasion of Panama. It participated in over 240 combat hours, attacking various targets, mostly at night. General Carl Stiner, the commander of the operation, stated: "You could fire that Hellfire missile through a window from four miles away at night."

Nearly half of all U.S. Apaches were deployed to Saudi Arabia following Iraq's invasion of Kuwait in 1990. During Operation Desert Storm on 17 January 1991, eight AH-64As guided by four MH-53 Pave Low IIIs destroyed part of Iraq's radar network in the operation's first attack, allowing the attack aircraft to evade detection. Each Apache carried an asymmetric load of Hydra 70 rockets, Hellfires, and one auxiliary fuel tank. During the 100-hour ground war, a total of 277 AH-64s took part, destroying 278 tanks, numerous armored personnel carriers and other Iraqi vehicles, for a total of over 500 kills. One AH-64 was lost in the war, crashing after a close range rocket-propelled grenade (RPG) hit; the crew survived. While effective in combat, the AH-64 presented serious logistical difficulties. Findings reported in 1990 stated "maintenance units could not keep up with the Apache's unexpectedly high work load..." To provide spare parts for combat operations, the U.S. Army unofficially grounded all other AH-64s worldwide; Apaches in the theater flew only one-fifth of planned flight-hours. Such problems were evident before the Gulf War.

The AH-64 played roles in the Balkans during separate conflicts in Bosnia and Kosovo in the 1990s. During Task Force Hawk, 24 Apaches were deployed to a land base in Albania in 1999 for combat in Kosovo. These required 26,000 tons of equipment to be transported over 550 C-17 flights, at a cost of US$480 million. During these deployments, the AH-64 encountered problems, such as deficiencies in training, night vision equipment, fuel tanks, and survivability.

In 2000, Major General Dick Cody, 101st Airborne's commanding officer, wrote a strongly worded memo to the Chief of Staff about training and equipment failures. Almost no pilots were qualified to fly with night vision goggles, preventing nighttime operations. The Washington Post printed a front-page article on the failures, commenting: "The vaunted helicopters came to symbolise everything wrong with the Army as it enters the 21st century: Its inability to move quickly, its resistance to change, its obsession with casualties, its post-Cold War identity crisis". Although no Apache combat missions took place, two were lost in training exercises. An effective network of Yugoslav air defenses stopped Apaches from being deployed on combat missions in Kosovo.

21st century
U.S. Apaches served in Operation Enduring Freedom in Afghanistan from 2001. It was the only Army platform capable of providing accurate CAS duties for Operation Anaconda, often taking fire and quickly repaired during the intense early fighting. Apaches often flew in small teams with little autonomy to react to threats and opportunities, requiring lengthy dialogue with centrally micromanaged command structures. U.S. AH-64Ds typically flew in Afghanistan and Iraq without the Longbow Radar in the absence of armored threats. On 21 December 2009, a pair of U.S. Apaches attacked a British-held base in a friendly fire incident, killing one British soldier.

In 2003, the AH-64 participated in the invasion of Iraq during Operation Iraqi Freedom. On 24 March 2003, 31 Apaches were damaged; one was shot down in an unsuccessful attack on an Iraqi Republican Guard armored brigade near Karbala. Iraqi tank crews had set up a "flak trap" among terrain and effectively employed their guns. Iraqi officials claimed a farmer with a Brno rifle shot down the Apache, but the farmer denied involvement. The AH-64 came down intact and the crew were captured; it was destroyed via air strike the following day. This incident had significant consequences for the AH-64 helicopter because it revealed an important vulnerability. Despite being considered by army aviators as flying tanks at the time, it became clear that the AH-64 was actually highly susceptible to rifle fire. As a result, the army quietly disclosed in early 2006 that AH-64s would no longer have a major role in carrying out attacks deep inside enemy lines.

By the end of U.S. military operations in Iraq in December 2011, several Apaches had been shot down by enemy fire and lost in accidents. In 2006, an Apache was downed by a Soviet-made Strela 2 (SA-7) in Iraq, despite it being typically able to avoid such missiles. In 2007, four Apaches were destroyed on the ground by insurgent mortar fire using web-published geotagged photographs taken by soldiers. Several AH-64s were lost to accidents in Afghanistan. Most Apaches that took heavy damage were able to continue their missions and return safely. By 2011, the U.S. Army Apache fleet had accumulated more than 3 million flight hours since the first prototype flew in 1975. A DOD audit released in May 2011 found that Boeing had frequently overcharged the U.S. Army for routine spare parts in helicopters like the Apache, ranging from 33.3 percent to 177,475 percent.

On 21 February 2013, the 1st Battalion (Attack), 229th Aviation Regiment at Joint Base Lewis–McChord became the first U.S. Army unit to field the AH-64E Apache Guardian; a total of 24 AH-64E were received by mid-2013. On 27 November 2013, the AH-64E achieved initial operating capability (IOC). In March 2014, the 1st–229th Attack Reconnaissance Battalion deployed 24 AH-64Es to Afghanistan in the type's first combat deployment. From April through September 2014, AH-64Es in combat maintained an 88 percent readiness rate. The unit's deployment ended in November 2014, with the AH-64E accumulating 11,000 flight hours, each helicopter averaging 66 hours per month. The AH-64E flies 20 mph faster than the AH-64D, cutting response time by 57 percent, and has better fuel efficiency, increasing time on station from 2.5–3 hours to 3–3.5 hours; Taliban forces were reportedly surprised by the AH-64E attacking sooner and for longer periods. AH-64Es also worked with medium and large unmanned aerial vehicles (UAVs) to find targets and maintain positive ID, conducting 60 percent of the unit's direct-fire engagements in conjunction with UAVs; Guardian pilots often controlled UAVs and accessed their video feeds to use their greater altitudes and endurance to see the battlespace from standoff ranges.

In 2014, the Army began implementing a plan to move all Apaches from the Army Reserve and National Guard to the active Army to serve as scout helicopters to replace the OH-58 Kiowa. Using the AH-64 to scout would be less expensive than Kiowa upgrades or purchasing a new scout helicopter. AH-64Es can control UAVs like the MQ-1C Grey Eagle to perform aerial scouting missions; a 2010 study found the teaming of Apaches and UAVs was the most cost-effective alternative to a new helicopter and would meet 80 percent of reconnaissance requirements, compared to 20 percent with existing OH-58s and 50 percent with upgraded OH-58s. National Guard units, who would lose their attack helicopters, criticized the proposal. In March 2015, the first heavy attack reconnaissance unit was formed with 24 Apaches and 12 Shadow UAVs.

In July 2014, the Pentagon announced that Apaches had been dispatched to Baghdad to protect embassy personnel from Islamic State militant attacks. On 4 October 2014, Apaches began performing missions in Operation Inherent Resolve against Islamic State ground forces. In October 2014, U.S. Army AH-64s and Air Force fighters participated in four air strikes on Islamic State units northeast of Fallujah. In June 2016, Apaches were used in support of the Iraqi Army's Mosul offensive and provided support during the Battle of Mosul, sometimes flying night missions supporting Iraqi operations. In December 2019, two Apaches provided overwatch for U.S. Marines to secure the U.S. embassy in Baghdad, Iraq after armed militants, supported by Iran, attempted to storm the facility.

In March 2024, two Apache crashes within two days increased scrutiny and made national news.

Israel

The Israeli Air Force (IAF) first received AH-64As in 1990, for a fleet of 42 by 2000. The IAF's choice to buy Apaches over upgrading its AH-1 Cobra attack helicopters was controversial. In 2000, Israel was interested in acquiring up to 48 AH-64Ds, but U.S. reluctance to share the source code complicated the prospect. In April 2005, Boeing delivered the IAF's first AH-64D. In 2001, the U.S. government was allegedly investigating misuse of the Apache and other U.S.-supplied military equipment against Palestinians. In 2009, the sale of six AH-64Ds was reportedly blocked by the Obama Administration, pending interagency review, over concerns they may pose a threat to civilian Palestinians in Gaza. In IAF service, the AH-64A was named Peten (פתן, for Cobra), while the AH-64D was named Saraph (שרף, for venomous/fiery winged serpent).

During the 1990s, Israeli AH-64As frequently attacked Hezbollah outposts in Lebanon. On 13 April 1996, during Operation Grapes of Wrath, an Apache fired two Hellfire missiles at an ambulance in Lebanon, killing six civilians. During the al-Aqsa Intifada in the 2000s, AH-64s were used to kill senior Hamas figures, such as Ahmed Yassin, Abdel Aziz al-Rantisi, and Adnan al-Ghoul. Human Rights Watch documented instances of IAF Apaches attacking civilian homes during the 2002 Jenin operation, killing one civilian. Consequently, HRW urged the US government to seek written assurances from Israel that Apaches would not be used to violate humanitarian law in the future.

In 2004, Israeli AH-64s carried out the assassination of Ahmed Yassin and also killed 7 bystanders. Ahmed Yassin was the spiritual leader of Hamas; given that he was also blind, paraplegic and in a wheelchair, Palestinians saw the killing as "a cowardly execution of a frail old man in a wheelchair who did not attempt to hide". The attack also killed 7 bystanders, and was internationally condemned.

IAF Apaches played a prominent role in the 2006 Lebanon War, launching strikes into Lebanon targeting Hezbollah forces. IAF Apaches also attacked civilian targets, killing many, including women and children. During this war, two AH-64As collided, killing one pilot and critically wounding three. In another incident in the conflict, an IAF AH-64D crashed due to a main rotor malfunction, killing the two crew. In late 2007, the IAF put further purchases and deliveries of AH-64Ds on hold while its performance envelope was investigated. Israeli officials praised the Apache for its role in Operation Cast Lead in 2008, against Hamas in Gaza. IAF Apaches have often patrolled the skies over Gaza; strikes against insurgents by these helicopters has become a frequent occurrence.

In the 2010s, the IAF pursued upgrades to its AH-64A fleet as new AH-64D orders had been blocked. In June 2010, Israel decided not to upgrade all AH-64As to AH-64Ds due to funding constraints and lack of U.S. cooperation. In December 2010, the IAF was examining the adoption of a new missile system as a cheaper and lightweight complement to the Hellfire missile, either the American Hydra 70 or the Canadian CRV7. By 2013, IAF AH-64As were receiving a comprehensive upgrade of their avionics and electrical systems. The AH-64As are being upgraded to the AH-64Ai configuration, which is near the AH-64D standard. IAF Apaches can carry Spike anti-tank missiles instead of the Hellfire. The latest AH-64D-I integrates Israeli systems such as Elta communications suite, Elbit mission management system, Rafael Combat Net system and Elisra self-protection suite.

IAF AH-64s occasionally saw use in the air-to-air role. The first operational air-to-air kill took place on 24 May 2001, when an IAF shot down a Lebanese civilian Cessna 152 aircraft. Israeli and Lebanese officials presented differing versions: Lebanon said Israel first intercepted the aircraft over Lebanese airspace and its pilot, flying without his instructor, mistakenly entered Israeli airspace, while Israel says the aircraft was already in Israeli airspace when it was intercepted and repeatedly refused to answer or comply with air traffic control (ATC) warnings. The second air-to-air kill occurred on 10 February 2018, after an Iranian UAV entered Israeli airspace from Syria, an AH-64 destroyed it with a missile.

United Kingdom
The UK currently operates a modified version of the AH-64D Block I Apache Longbow; initially called the Westland WAH-64 Apache, it is designated the Apache AH1 by the British Army. Westland built 67 WAH-64 Apaches under license from Boeing, following a competition between the Eurocopter Tiger and the Apache for the British Army's new Attack Helicopter in 1995. Important deviations made by AgustaWestland from the U.S. Apache variants include changing to more powerful Rolls-Royce engines, and the addition of a folding blade assembly for use on naval ships.

On 11 July 2016, the Ministry of Defence confirmed a U.S. Foreign Military Sale (FMS) worth $2.3 billion (~$ in ) for 50 AH-64Es to be built in Mesa, Arizona. Leonardo Helicopters in the UK will maintain the current fleet of Apaches until 2023–2024, with a long-term plan for Leonardo and other UK companies to "do most of the work" on the new fleet. The deal included an initial support contract for maintenance, spare parts, and training simulators; components from the older WAH-64s "will be reused and incorporated into the new helicopters where possible." The type entered service with the British Army in 2022. Approval for the re-manufacture of fifty of the UK's WAH-64 Mk 1 fleet to AH-64E Apache Guardian standard was given by the Defense Security Cooperation Agency in August 2015. They utilize the General Electric T700 engine rather than the Turbomeca RTM322 of the WAH-64; the first off-the-shelf purchase of a GE engine by the Ministry of Defence. The first two AH-64Es were delivered to the British Army on 26 November 2020. The older AH1 (WAH-64) were retired by 2024 in favour of the AH-64E models.

Netherlands

The Dutch government initially showed an interest in acquiring Apache helicopters in the late 1980s, when it stated that it may purchase as many as 52. A competition held in 1994 against the Eurocopter Tiger and the Bell AH-1 SuperCobra led to the Royal Netherlands Air Force ordering 30 AH-64D Apaches in 1995. Deliveries began in 1998 and ended in 2002. The RNLAF Apaches are equipped with the Apache Modular Aircraft Survivability Equipment (AMASE) self-protection system to counter infrared (IR) missile threats.

The RNLAF Apaches' first deployment was in 2001 to Djibouti, Africa. They were also deployed alongside U.S. AH-64s in support of NATO peacekeeping forces in Bosnia and Herzegovina. In 2004, six Dutch AH-64s were deployed as part of the Netherlands contribution to the Multinational force in Iraq to support the Dutch ground forces. The Apaches performed close combat support and display of force missions, along with providing reconnaissance information to ground forces. 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.

Shortly after Apaches were deployed to Hamid Karzai International Airport, as part of the Dutch contribution to ISAF, on 10 April 2004, a pair of Dutch Apaches came under light gunfire close to Kabul. On 17 December 2007, an RNLAF Apache flew into power lines during a night flying exercise in the Netherlands, forcing an emergency landing and causing a lengthy blackout in the region. On 17 March 2015, a RNLAF Apache crashed during a training mission in Mali. Both pilots died. The Ministry of Defence opened an investigation into the cause of the crash.

In February 2018, the Netherlands decided to upgrade all their AH-64Ds to the latest AH-64E standard via a FMS contract with the US, along with 17 APG-78 fire control radar units. In November 2021, the process to upgrade AH-64Ds began and RNLAF is to receive the upgraded AH-64Es between 2023 and 2025.

Saudi Arabia
Following the 1991 Gulf War, during which many U.S. Apaches operated from bases within Saudi territory, Saudi Arabia purchased twelve AH-64As for the Royal Saudi Land Force. It has been speculated that the Saudi purchase motivated Israel to also procure Apaches. In August 2006, Saudi Arabia began negotiations for Apache upgrades worth up to $400M (~$ in ), possibly remanufacturing their AH-64As to the AH-64D configuration. In September 2008, the U.S. Government approved a Saudi Arabian request to buy 12 AH-64Ds. In October 2010, Saudi Arabia requested a further 70 AH-64Ds as part of a possible massive arms deal.

In November 2009, the Royal Saudi Land Force, as part of a military effort against insurgent border intrusions, launched Operation Scorched Earth; this involved Apaches launching air strikes against Houthi rebels operating inside neighboring Yemen. In January 2010 the rebels claimed to have shot down an Apache; this was denied by the Saudi military. In late January 2010, the leader of the Shiite rebels announced their withdrawal from Saudi territory, this announcement followed a key battle on 12 January when Saudi forces reportedly took control of the border village of Al Jabiri.

As an escalation of the Yemeni Civil War, starting on 26 March 2015, Saudi Arabia, the United Arab Emirates, and several other regional allies started a military operation in Yemen. Both the Saudi Army Aviation and the United Arab Emirates Air Force used their AH-64s in combat against an alliance between elements of the Yemeni Army loyal to the former president Saleh and the Houthis. The Apaches were mostly involved in border patrol and strikes in Northwestern Yemen. Over the years, several Saudi and an Emirati Apaches were lost to incidents and enemy fire, although exact numbers have not been independently confirmed. On 17 March 2017, an Apache reportedly attacked a Somali refugee boat, killing 42 refugees. Saudi Arabia denied involvement, though it and the United Arab Emirates are the only militaries using Apaches during the conflict.

United Arab Emirates
The United Arab Emirates purchased 30 AH-64As between 1991 and 1994, and began upgrading to AH-64D specification in 2008. In December 2016, the U.S. State Department approved a proposed sale of another 37 AH-64Es and Congress was notified; this consisted of 28 re-manufactured and nine new-build helicopters.

A UAE AH-64 was reportedly lost on 17 October 2017; a replacement was approved by the US in 2019.

Egypt
In 1995, the Egyptian Air Force placed an order for 36 AH-64As. These Apaches were delivered with the same avionics as the U.S. fleet at that time, except for indigenous radio equipment. In 2000, Boeing announced an order to remanufacture Egypt's Apache fleet to the AH-64D configuration, except for Longbow radar, which had been excluded by the U.S. government. In 2009, Egypt requested a further 12 AH-64D Block IIs with Longbow radars through a FMS.

In August 2012, the Egyptian Armed Forces undertook a large-scale military operation to regain control of the Sinai Peninsula from armed militants. Air cover throughout the operation was provided by the Egyptian Air Force's Apaches, which reportedly destroyed three vehicles and killed at least 20 militants. Up to five Egyptian Apaches were temporarily stationed in the Sinai following an agreement between Egypt and Israel. In September 2015, an Egyptian Apache attacked a group of foreign tourists in the Western Desert, killing 12 people and injuring 10. The AH-64s fired at the civilians with rockets and 30mm machine guns for several hours, even though survivors said they waved the white flag. The Egyptian Interior Ministry stated that the group, whom were mistaken for militants, were in a restricted area. The tourists were reportedly accompanied by Egyptian police, and their vehicles were marked with logos of the tourist company.

In November 2018, the U.S. Department of State approved the sale of ten AH-64Es and associated equipment to Egypt, valued at US$1 billion, pending the sale clearing Congress.

The Apache entered service with Egyptian Armed Services, and in the 2020s was being further upgraded.

Indian Air Force

In 2008, the Indian Air Force (IAF) released a tender for 22 attack helicopters; there were six contending submissions: Sikorsky's UH-60 Black Hawk, the AH-64D, Bell's AH-1 Super Cobra, Eurocopter's Tiger, Mil's Mi-28 and AgustaWestland's A129 Mangusta. In October 2008, Boeing and Bell withdrew. In 2009, the competition was restarted. In December 2010, India requested the sale of 22 Apaches and associated equipment. On 5 October 2012, IAF Chief NAK Browne confirmed the Apache's selection. The IAF sought control of the 22 Apaches for air combat missions, while the Army Aviation Corps argued that they would be better used in army operations. In April 2013, the Indian Ministry of Defence (MoD) decided that the 22 AH-64s would go to the IAF. India ordered the 22 AH-64Es in 2015.

On 11 May 2019, the IAF received its first AH-64E in a ceremony at Boeing's Mesa, Arizona facility. On 3 September 2019, 8 AH-64Es were inducted into the IAF's 125 Helicopter Squadron at Pathankot Air Base, Punjab.

Indian Army
On 12 June 2018, the U.S. Department of State approved a possible FMS to India for six more AH-64Es and associated equipment in an estimated $930 million deal. The U.S. Defense Security Cooperation Agency notified Congress for approval. In February 2020, another six for the Indian Army were ordered, including weapons, equipment, and training; deliveries are planned to begin in 2023. These attack helicopters are often interlinked with squadrons of indigenous HAL Prachand attack helicopters. On 1 January 2024, senior Army officials told India Today that The Indian Army Aviation Corps is expected to induct the first batch of Apache helicopters in February-March of this year. This is to enable the army to protect its tanks on the battlefield when the Indian Air Force is unavailable. They will be deployed to Jodhpur, near the India–Pakistan border, enhancing the security of the area against Pakistani tanks. On 15 March 2024, Army Aviation Corps raised an attack squadron at Jodhpur which will operate Apache. The first batch of three Apache will be inducted in May 2024 and the rest will be inducted by July 2024.

Other users

Greece received 20 AH-64As by 1995; another 12 AH-64Ds were ordered in September 2003.

Singapore purchased 20 AH-64Ds in two batches between 1999 and 2001. In October 2010, training was suspended following the forced crash-landing of an Apache.

In 2005, Kuwait purchased 16 AH-64Ds.

On 26 August 2013, Indonesia and the U.S. finalized a contract for eight AH-64E Apaches worth $500 million (~$ in ). The first was displayed on 5 October 2017 as part of a military exercise in Indonesia, to mark the 72nd anniversary of its armed forces. The first batch of AH-64s for the Indonesian Army arrived in Indonesia on 18 December 2017.

Japan ordered 50 AH-64Ds, which were built under license by Fuji Heavy Industries, designated "AH-64DJP". The first helicopter was delivered to the JGSDF in early 2006. The order was halted after 13 aircraft were delivered due to cost. In 2017, it was announced that the targeting systems of the 13 aircraft would be upgraded. One was destroyed in a crash in February 2018 with the deaths of both crew.

In June 2011, Taiwan (Republic of China) agreed to the purchase of 30 AH-64Es with weapons and associated equipment. On 5 November 2013, Taiwan received the first six AH-64s. On 25 April 2014, a Taiwanese AH-64E crashed into a three-story building during a training flight in bad weather conditions, the first AH-64E airframe loss. An investigation ruled out mechanical failure and concluded that the pilots had rapidly descended through clouds at low altitude without checking flight instruments to maintain adequate height; the Army expanded simulator training in response. In October 2014, Taiwan's fifth and final batch of AH-64Es was delivered.

In 2009, South Korea showed interest in the Apache, potentially related to plans to withdraw many U.S. Apaches from the country. On 21 September 2012, the U.S. Congress was notified of the possible purchase of 36 AH-64E, along with associated equipment and armament. It competed against the Bell AH-1Z Viper and the TAI/AgustaWestland T-129; in April 2013, South Korea announced plans to buy 36 AH-64Es. The first four AH-64Es were delivered in May 2016, and all 36 were deployed by January 2017.

Future and possible users

Iraq requested the sale of 24 AH-64s in April 2013; In January 2014, a sale, including the helicopters, associated parts, maintenance, and training, was cleared by the U.S. Congress. However, the proposal was not accepted by the Iraqi government and expired in August 2014.

In July 2012, Qatar requested the sale of 24 AH-64Es with associated equipment and support. The sale was approved on 27 March 2014. In March 2019, Qatar received the first of 24 AH-64Es ordered.

In July 2016, the UK placed an order for 50 AH-64Es through the U.S. FMS program instead of upgrading their Westland-built WAH-64s.

In July 2019, Australia issued a request for information for Project Land 4503 to replace the Army's Eurocopter Tiger ARH helicopters. On 15 January 2021, the Australian Minister for Defence Linda Reynolds announced that the AH-64E had been selected to replace the Tiger ARH. A fleet of 29 AH-64Es will be acquired with a planned initial operational capability of 12 helicopters in 2026 and full operational capability in 2028.

In October 2019, the Bangladesh Air Force (BAF) was offered two types of attack helicopters and selected the AH-64, pending government approval. However, due to the Apache's high costs, the BAF choose the competing Russian Mi-28NE Night Hunter.

In November 2019, the U.S. State Department approved a FMS to Morocco of 24 AH-64Es (with an option for a further 12), this allows Morocco to negotiate an order.

On 30 April 2020, the U.S. Defense Security Cooperation Agency announced it had received U.S. State Department approval and notified Congress of a possible sale to the Philippines of either six AH-1Z attack helicopters and related equipment for an estimated cost of $450 million or six AH-64Es and related equipment for an estimated cost of $1.5 billion.

On 21 April 2022, Polish Ministry of National Defence shortlisted two models in competition for the "Kruk" (Raven) Program aimed at modernizing the Polish Land Forces' fleet of attack helicopters, with the competitors being the AH-64E and Bell's AH-1Z Viper. On 8 September 2022, Polish Minister of Defence Mariusz Błaszczak announced that the AH-64E has won and set out to procure 96 helicopters to form six squadrons.

AH-64A

The AH-64A is the original production attack helicopter. The crew sit in tandem in an armored compartment. It is powered by two GE T700 turboshaft engines. The A-model was equipped with the −701 engine version until 1990 when the engines were switched to the more powerful −701C version.

U.S. Army AH-64As are being converted to AH-64Ds. The service's last AH-64A was taken out of service in July 2012 before conversion at Boeing's facility in Mesa, Arizona. On 25 September 2012, Boeing received a $136.8M contract to remanufacture the last 16 AH-64As into the AH-64D Block II version and this was planned to be completed by December 2013.

AH-64B
In 1991, after Operation Desert Storm, the AH-64B was a proposed upgrade to 254 AH-64As. The upgrade would have included new rotor blades, a Global Positioning System (GPS), improved navigation systems and new radios. U.S. Congress approved $82M to begin the Apache B upgrade. The B program was canceled in 1992. The radio, navigation, and GPS modifications were later installed on most AH-64As via other upgrades.

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, which would include all of the changes to be included in the AH-64D except for mast-mounted radar and newer −700C engine versions. However, the C designation was dropped after 1993. With AH-64As receiving the newer engine from 1990, the only difference between the AH-64C and the AH-64D was the radar, which could be moved from one aircraft to another; thus, the decision was made to simply designate both versions as AH-64D.

AH-64D
The AH-64D Apache Longbow is equipped with a glass cockpit and advanced sensors, the most noticeable of which being the AN/APG-78 Longbow millimeter-wave fire-control radar (FCR) target acquisition system and the Radar Frequency Interferometer (RFI), housed in a dome located above the main rotor. The radome's raised position enables target detection while the helicopter is behind obstacles (e.g. terrain, trees or buildings). The AN/APG-78 is capable of simultaneously tracking up to 128 targets and engaging up to 16 at once; an attack can be initiated within 30 seconds. A radio modem integrated with the sensor suite allows data to be shared with ground units and other Apaches, allowing them to fire on targets detected by a single helicopter.

The aircraft is powered by a pair of uprated T700-GE-701C engines. The forward fuselage was expanded to accommodate new systems to improve survivability, navigation, and 'tactical internet' communications capabilities. In February 2003, the first Block II Apache was delivered to the U.S. Army, featuring digital communications upgrades. The Japanese Apache AH-64DJP variant is based on the AH-64D; it can be equipped with the AIM-92 Stinger air-to-air missiles for self-defense.

AH-64E

Formerly known as AH-64D Block III, in 2012, it was redesignated as AH-64E Guardian. It has improved digital connectivity, the Joint Tactical Information Distribution System, more powerful T700-GE-701D engines with upgraded face gear transmission to handle more power, capability to control unmanned aerial vehicles (UAVs), full IFR capability, and improved landing gear. New composite rotor blades, which completed testing in 2004, increase cruise speed, climb rate, and payload capacity. Deliveries began in November 2011. Full-rate production was approved on 24 October 2012, 634 AH-64Ds will be upgraded into AH-64Es.

Changes in production lots 4 through 6 include a cognitive decision aiding system and new self-diagnostic abilities. The updated Longbow radar has an oversea capacity, potentially enabling naval strikes; an AESA radar is under consideration. It will have a L-3 Communications MUMT-X datalink in place of two older counterparts, communicating on C, D, L, and Ku frequency bands to transmit and receive data and video with all Army UAVs. Lots 5 and 6 will have Link 16 data links. The AH-64E is to be fit for maritime use. The U.S. Army expressed interest in extended-range fuel tanks for greater endurance. , 500 AH-64Es have been delivered.

Work on a further upgraded AH-64E, version 6.5 was initiated by the U.S. Army in 2021, and first flew in 2023. The AH-64E is reported to have had problems with its electrical generation systems causing increased scrutiny.

AH-64F
In 2014, Boeing conceptualized an Apache upgrade prior to the introduction of the U.S. Army's anticipated attack version of the Future Vertical Lift (FVL) aircraft, forecast to replace the Apache by 2040. The conceptual AH-64F would have greater speed via a new 3,000 shp turboshaft engine from the Improved Turbine Engine Program, retractable landing gear, stub wings to offload lift from the main rotor during cruise, and a tail rotor that can articulate 90 degrees to provide forward thrust. In October 2016, the Army revealed they would not pursue another Apache upgrade to focus on funding FVL; the Army will continue buying the Apache through the 2020s until Boeing's production line ends in 2026, then FVL is slated to come online in 2030.

Piasecki Speed Apache
In the late 1990s, Piasecki conceived a proposal for an Apache with a tail–mounted ducted pusher rotor to enhance speed. However, the Speed Apache was not proceeded with.

Compound Apache
In October 2018, Boeing began testing the AH-64E Block 2 Compound, a compound helicopter design which added a larger fixed wing and a pusher propeller to the Apache airframe to provide additional lift and thrust, respectively. In addition, the engine exhaust was redirected downwards. Collectively, the modifications were anticipated to improve speed to 185 knot, range to 460 nmi, payload to 5900 lb, and fuel economy. A 30% scale model completed wind tunnel testing in January 2019. The Compound Apache has been pitched as an interim replacement for the Apache before its replacement under the Future Vertical Lift program.

Sea Apache

During the 1980s naval versions of the AH-64A for the United States Marine Corps and Navy were examined. Multiple concepts were studied with altered landing gear arrangements, improved avionics and weapons. The USMC conducted a two-week evaluation of the Apache in September 1981, including shipboard operation tests. Funding for a naval version was not provided; the USMC continued to use the AH-1.

The Canadian Forces Maritime Command also examined naval Apaches. In 2004, British Army AgustaWestland Apaches were deployed upon the Royal Navy's HMS Ocean (L12), a Landing Platform Helicopter, for suitability testing; there was U.S. interest in the trials. During the 2011 military intervention in Libya, the British Army extensively used Apaches from HMS Ocean. In 2013, US AH-64Ds were tested on several U.S. Navy ships.

Export Apaches
Several models have been derived from the AH-64A, AH-64D and AH-64E for export. The British-built AgustaWestland Apache (assembled from kits purchased from Boeing) is based on the AH-64D Block I with several different systems, including more powerful engines, folding rotor blades, and other modifications for operation from Royal Navy vessels.

Block modification
While a major change in design or role will cause the type designator suffix to change, for example from AH-64D to AH-64E, the helicopters are also subject to block modification. Block modification is the combining of equipment changes into blocks of modification work orders, the modifications in the block (sometimes called a block package) are all done to the helicopter at the same time.

Operators
The AH-64 has had some modest success on the export market. It has been popular in the middle east, where its role the Gulf War established a bit of reputation. Its main user continues to be the U.S. Army, and the largest user in Europe will be Poland.
 * Australian Army – 29 AH-64Es on order
 * Egyptian Air Force – 46 AH-64Ds
 * Hellenic Army – 28 AH-64A/Ds
 * Indian Air Force – 22 AH-64Es in inventory as of July 2020
 * Indian Army – 6 AH-64Es on order
 * Hellenic Army – 28 AH-64A/Ds
 * Indian Air Force – 22 AH-64Es in inventory as of July 2020
 * Indian Army – 6 AH-64Es on order
 * Indian Army – 6 AH-64Es on order
 * Indonesian Army 8 AH-64Es
 * Israeli Air Force – 48 AH-64A/Ds
 * Japan Ground Self-Defense Force – 12 AH-64D In December 2022, the Japanese government decided to replace 12 AH-64D, 47 AH-1S, 33 OH-1, and 26 U-125A with unmanned aerial vehicles. Japan plans to increase its defense budget from 1.24% of GDP in fiscal 2021 to around 2.0% within 10 years, and has decided to retire these helicopters and aircraft as part of an effort to spend its defense budget efficiently.
 * Kuwait Air Force – 24 AH-64Ds
 * Royal Moroccan Air Force – 36 AH-64Es on order
 * Royal Netherlands Air Force – 28 AH-64Es
 * Polish Land Forces – 96 on order, 8 leased
 * Qatar Emiri Air Force – 24 AH-64Es
 * Royal Saudi Land Forces – 47 AH-64A/D/Es
 * Saudi Arabia National Guard – 12 AH-64Es
 * Republic of Singapore Air Force – 19 AH-64Ds
 * Republic of Korea Army – 36 AH-64Es
 * Republic of China Army – 29 AH-64Es
 * United Arab Emirates Air Force – 28 AH-64D/Es
 * British Army – 38 AH-64Es, to be increased to 50 in 2024.
 * United States Army – 819 AH-64D/Es
 * Royal Saudi Land Forces – 47 AH-64A/D/Es
 * Saudi Arabia National Guard – 12 AH-64Es
 * Republic of Singapore Air Force – 19 AH-64Ds
 * Republic of Korea Army – 36 AH-64Es
 * Republic of China Army – 29 AH-64Es
 * United Arab Emirates Air Force – 28 AH-64D/Es
 * British Army – 38 AH-64Es, to be increased to 50 in 2024.
 * United States Army – 819 AH-64D/Es
 * Republic of China Army – 29 AH-64Es
 * United Arab Emirates Air Force – 28 AH-64D/Es
 * British Army – 38 AH-64Es, to be increased to 50 in 2024.
 * United States Army – 819 AH-64D/Es
 * British Army – 38 AH-64Es, to be increased to 50 in 2024.
 * United States Army – 819 AH-64D/Es
 * United States Army – 819 AH-64D/Es

title: Boeing AH-64 Apache


text:
Maurice Duverger

Maurice Duverger (5 June 1917 – 16 December 2014) was a French jurist, sociologist, political scientist and politician born in Angoulême, Charente. Starting his career as a jurist at the University of Bordeaux, Duverger became more and more involved in political science and in 1948 founded one of the first faculties for political science in Bordeaux, France. An emeritus professor of the Sorbonne and member of the FNSP, he has published many books and articles in newspapers, such as Corriere della Sera, la Repubblica, El País, and especially Le Monde.

Duverger studied the evolution of political systems and the institutions that operate in diverse countries, showing a preference for empirical methods of investigation rather than philosophical reasoning. He devised a theory which became known as Duverger's law, which identifies a correlation between a first-past-the-post election system and the formation of a two-party system. While analysing the political system of France, he coined the term semi-presidential system.

A staunch communist and Soviet Union admirer, he wrote following the February 1956 speech by Soviet leader Nikita Khrushchev that Stalin had been no better and no worse than the majority of tyrants who preceded him, adding that the Russian Communist Party was a living organism whose cells were continuously rejuvenated, and that the fear of purges had had the effect of keeping the militants on edge, constantly reviving their zeal. From 1989 until 1994, he was a member of the Italian Communist Party, later the Democratic Party of the Left, in the European Parliament. In 1981, he was elected a member of the Serbian Academy of Sciences and Arts. He died at the age of 97 on 16 December 2014.

Career
A member of Doriot's fascist Parti Populaire Français from age 20, Maurice Duverger completed his studies in from the Bordeaux Department of Law in 1942, before lecturing in law at Poitiers in 1942, and Bordeaux in 1943 (where he would, in 1948, found the Institut d'études politiques de Bordeaux as its first director). He also taught at Vichy France's Institut d'études corporatives et sociales. In his first publication, "The Constitutions of France" (1944), he explained that the French constitution of 1940 created a "de facto government". However, towards the end of the war, Duverger grew close to the Resistance, and in Libération analyzed the legitimacy of the new government of France and devoted himself to social-scientific theory.

After the War, he taught in the faculty of law and economic sciences in Paris, 1955 to 1985, and contributed to Libération and Le Monde. From 1989 to 1994, he sat in the European Parliament as an MEP for the Italian Communist Party. In 1946 he expanded his theses, with a special interest in the relation between electoral systems and party systems. This interest is at the heart of his most important publication: "The Political Parties" (1951). The work is one of the classics of party research, translated into several languages. That thesis led to Duverger's law, and later he coined the term "semi-presidentialism" and "semi-parliamentarism".

Political parties
Having as a point of reference their structure, Duverger in his book Les Partis Politiques (1951) distinguished parties between elite-based parties and mass-based parties. Elite-based parties rather prefer the quality of their members over their quantity, their affiliates being people of great influence on local or national scale. They have flexible and disorganized structures, in general are weakly disciplined and lack developed pragmatic content, allowing each of their members to benefit from an enormous freedom of action. Their funding is generally provided by a sponsor, and as their strength comes from their elected representatives, they are typical parties of parliamentarian creation, which depend on the reputation and support of their benefactors.

Mass-based parties possess a secure organization and a strong structure arranged as a pyramid, with superposed hierarchically arranged levels. Their members identify themselves more with the party's ideology than with its leader, so they have an abstract adhesion. Their decisions are based on the participation of each one of its members, and its founding is granted by their members' payments, a situation that leads them to gain as many adherents as possible. These parties tend to develop on a par with suffrage and democracy. For instance, elite-based parties execute an often sporadic political labor, focused on elections. However, the disadvantage this implies in relation to their contestant parties (which denote permanent labor and a disciplined and organic structure), impels them to modify their organization to become mass-based parties.

Duverger's Law
With discovery attributed to Duverger, he observed the effect and recorded it in several papers published in the 1950s and 1960s. In the course of further research, other political scientists began calling the effect a "law" or principle. Duverger's law suggests a nexus or synthesis between a party system and an electoral system: a proportional representation (PR) system creates the electoral conditions necessary to foster party development while a plurality system marginalizes many smaller political parties, resulting in what is known as a two-party system.

In political science, Duverger's law is a principle which asserts that plurality rule elections structured within single-member districts tends to favor a two-party system. This is one of two hypotheses proposed by Duverger, the second stating that "the double ballot majority system and proportional representation tend to multipartism."

Works

 * Les partis politiques (1951)
 * La participation des femmes à la vie politique (1955)
 * Les finances publiques (1956)
 * Méthodes de la science politique (1959)
 * De la dictature (1961)
 * Méthodes des Sciences sociales (1961)
 * Introduction à la politique (1964)
 * Sociologie politique (1966)
 * La démocratie sans les peuples (1967)
 * Institutions politiques et Droit constitutionnel (1970)
 * Janus: les deux faces de l'Occident (1972)
 * Sociologie de la politique (1973)
 * L'autre côté des choses (1977)
 * King's Mate (1978)
 * Les orangers du lac Balaton (1980)
 * Factors in a Two-Party and Multiparty System, in Party Politics and Pressure Groups (New York: Thomas Y. Crowell, 1972), pp. 23–32.
 * Political Parties: Their Organization and Activity in the Modern State
 * The Study of Politics ISBN 0-690-79021-X
 * La République des Citoyens (1982) ISBN 2-85956-311-3
 * Lettre Ouverte aux Socialistes (Collection Lettre ouverte) ISBN 2-226-00326-6
 * Modern Democracies: Economic Power Versus Political Power ISBN 0-03-077280-X
 * La Cohabitation des Français ISBN 2-13-041498-2
 * Europe des Hommes: Une Métamorphose Inachevée (1994) ISBN 2-7381-0262-X
 * The Idea of Politics: the Uses of Power in Society(1966)
 * The French Political System
 * L'Europe dans tous ses États (1995)

title: Maurice Duverger