Boeing AH-64 Apache
The Boeing AH-64 Apache (//) is an American twin-turboshaft attack helicopter with a tailwheel-type landing gear arrangement and a tandem cockpit for a crew of two. It features a nose-mounted sensor suite for target acquisition and night vision systems. It is armed with a 30 mm (1.18 in) M230 chain gun carried between the main landing gear, under the aircraft's forward fuselage, and four hardpoints mounted on stub-wing pylons for carrying armament and stores, typically a mixture of AGM-114 Hellfire missiles and Hydra 70 rocket pods. The AH-64 has significant systems redundancy to improve combat survivability.
|An AH-64 Apache from the U.S. Army's 101st Aviation Regiment in Iraq|
|National origin||United States|
|First flight||30 September 1975|
|Primary users||United States Army|
|Number built||2,400 as of April 2020|
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 was first flown 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 purchasing 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, with over 2,400 AH-64s being produced by 2020.
The U.S. Army is the primary operator of the AH-64. It 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 in its military conflicts in Lebanon and the Gaza Strip. British and Dutch Apaches have seen deployments in wars in Afghanistan and Iraq.
Advanced Attack Helicopter
Following the cancellation of the AH-56 Cheyenne 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 an Advanced Attack Helicopter (AAH) 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.
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 1,690 shp (1,260 kW). The AH-64 was named the Apache in late 1981, following the tradition of naming Army helicopters after American Indian 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.
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 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 $11bn through 2007. In April 2006, Boeing was awarded a $67.6M 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 to the upgraded D variant. Since 2008, nations operating the older AH-64A have been urged to undertake modernization programs to become AH-64Ds, as Boeing and the U.S. Army plan to terminate support for the A-model.
By May 2019, Boeing tested in a wind tunnel a compound Apache scale model with a pusher propeller and small wing to increase range and speed, retaining the counter-torque tail rotor like the cancelled Lockheed AH-56 Cheyenne of the 1960s. It would compete 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.
|Engine version||Engine power|
|AH-64A+/D||General Electric T700-701||1,696 shp (1,265 kW)|
|AH-64A+/D||General Electric T700-701C||1,890 shp (1,410 kW)|
|AH-64E||General Electric T700-701D||1,994 shp (1,487 kW)|
|WAH-64D||Rolls-Royce Turbomeca RTM322||2,100 shp (1,600 kW)|
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 2,000 shp (1,500 kW) for AH-64Ds.
The crew compartment has shielding between the cockpits, such that at least one crew member can survive hits. The compartment and the rotor blades are designed to sustain a hit from 23 mm (0.91 in) rounds. The airframe includes some 2,500 lb (1,100 kg) of protection and has a self-sealing fuel system to protect against ballistic projectiles. 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 800–1,200 m (870–1,310 yd).
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 (31 mi). 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 (2.756 in) rockets. An 18-aircraft Apache battalion can carry 288 Hellfire missiles, each capable of destroying a tank. Since 2005, the Hellfire missile is sometimes outfitted with a thermobaric warhead; designated AGM-114N, it is intended for use against ground forces and urban warfare operations. The use of thermobaric "enhanced blast" weapons, such as the AGM-114N, has been a point of controversy. 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 re-added 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 (10.0 km; 6.2 mi). 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.
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 have 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. 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 some 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". No Apache combat missions took place in Kosovo due to fears of casualties.
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.
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 (32 km/h) 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.
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 (Hebrew: פתן, for Cobra), while the AH-64D was named Saraph (Hebrew: 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. IAF Apaches played a prominent role in the 2006 Lebanon War, launching strikes into Lebanon targeting Hezbollah forces. During the Lebanon War in 2006, 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.
As orders of new AH-64Ds have been blocked, the IAF pursued upgrades to its AH-64A fleet. In June 2010, Israel decided not to upgrade all AH-64As to the D model 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, after a civilian Cessna 152 aircraft entered Israeli airspace from Lebanon and repeatedly refused to answer or comply with air traffic control (ATC) warnings; an IAF AH-64A fired on the Cessna, resulting in its disintegration. 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.
The UK currently operates a modified version of the 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 worth $2.3 billion for 50 AH-64Es to be built in Mesa, Arizona. Leonardo Helicopters in the UK is to 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 includes an initial support contract for maintenance of the new helicopters, along with spare parts and training simulators for UK pilots. The first UK helicopters are due off the U.S. production line in early 2020 and will begin entering service with the British Army in 2022. Components from the current Apache helicopters "will be reused and incorporated into the new helicopters where possible." Approval for the re-manufacture of fifty of the UK's WAH-64 Mk 1 fleet to AH-64E Apache Guardian standard had been given by the Defense Security Cooperation Agency in August 2015. The aircraft will utilise the General Electric T700 engine rather than the Turbomeca RTM322 from the current fleet; 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 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 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 Netherlands contribution to ISAF, on 10 April 2004, a pair of Dutch Apaches came under light gunfire close to the 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 configuration through a Foreign Military Sales contract with the US, along with 17 APG-78 fire control radar units.
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, 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-64 Apache helicopters 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 North Western Yemen. Over the years, several Saudi and an Emirati AH-64 Apache helicopters were lost to incidents and enemy fire, although exact numbers have not been independently confirmed.
On 17 March 2017, an Apache was reportedly involved in an attack on 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 Yemeni Civil War.
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.
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 refused by the U.S. government. Egypt requested a further 12 AH-64D Block IIs with Longbow radars through a Foreign Military Sale in 2009.
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 Egyptian Interior Ministry stated that the group, whom were mistaken for militants, were in a restricted area.
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, India 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. On 12 June 2018, the U.S. Department of State approved a possible Foreign Military Sale 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 helicopters for Indian Army were ordered, including weapons, equipment, and training. The deliveries for the Indian Army Apaches are planned to begin in 2023.
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. 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) reached an agreement to purchase 30 AH-64Es with weapons and associated equipment. On 5 November 2013, Taiwan received the first 6 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, the fifth and final batch of AH-64Es was delivered to Taiwan.
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 its first AH-64E, the first of 24 such helicopters ordered.
In July 2019, Australia issued a request for information for Project Land 4503 to replace the Army's troubled Eurocopter Tiger ARH helicopters. In August 2019, Boeing offered the AH-64E. 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 up to 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, Bangladesh proposed to purchase military equipment from the U.S. The Bangladesh Air Force (BAF) was offered two types of attack helicopters and BAF selected the AH-64, pending government approval. In January 2020, Boeing confirmed that its AH-64E has been down-selected for a potential program in Bangladesh.
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-64E Apache attack helicopters and related equipment for an estimated cost of $1.5 billion.
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.
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 A-model Apaches through other upgrades.
Additional funding from Congress in late 1991 resulted in a program to upgrade AH-64As to an AH-64B+ version. More funding changed the plan to upgrade to AH-64C. The C upgrade would include all changes to be included in the Longbow except for mast-mounted radar and newer −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 C model and the radar-equipped D model was the radar, which could be moved from one aircraft to another; thus the decision was made to simply designate both versions "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.
Formerly known as AH-64D Block III, in 2012, it was redesignated as AH-64E Guardian to represent its increased capabilities. The AH-64E features improved digital connectivity, the Joint Tactical Information Distribution System, more powerful T700-GE-701D engines with upgraded face gear transmission to accommodate more power, capability to control unmanned aerial vehicles (UAVs), full IFR capability, and improved landing gear. New composite rotor blades, which successfully 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, with 634 AH-64Ds to be upgraded to AH-64E standard and production of 56 new-build AH-64Es to start in 2019/20. Changes in production lots 4 through 6 shall 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. The E model is to be fit for maritime operations.
The Army has expressed a desire to add extended-range fuel tanks to the AH-64E to further increase range and endurance. AH-64Es are to have the L-3 Communications MUM-TX datalink installed in place of two previous 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 be equipped with Link 16 data-links. As of April 2020, 500 AH-64E have been delivered.
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.
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 kn (343 km/h; 213 mph), range to 460 nmi (850 km; 530 mi), payload to 5,900 lb (2,700 kg), 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.
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 was very interested and conducted a two-week evaluation of the Apache in September 1981, including shipboard operation tests.
Funding for a naval version was not provided; the Marine Corps continued to use the AH-1. The Canadian Forces Maritime Command also examined a naval Apache. In 2004, British Army AgustaWestland Apaches were deployed upon the Royal Navy's HMS Ocean, 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, U.S. 36th Combat Aviation Brigade AH-64Ds were tested on a variety of U.S. Navy ships.
Several models have been derived from both AH-64A and 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.
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.
- Egyptian Air Force (AH-64D)
- Indian Air Force - 22 AH-64Es in inventory as of July 2020
- Indian Army - 6 AH-64Es on order
- See also AgustaWestland Apache (Apache AH2 is the likely UK designation for the AH-64Ev6 configuration)
- United States Army (AH-64D/E)
- Crew: 2 (pilot, and co-pilot/gunner)
- Length: 58 ft 2 in (17.73 m)
- Fuselage length: 49 ft 5 in (15.06 m)
- Height: 12 ft 8 in (3.87 m)
- Empty weight: 11,387 lb (5,165 kg)
- Gross weight: 17,650 lb (8,006 kg)
- Max takeoff weight: 23,000 lb (10,433 kg)
- Powerplant: 2 × General Electric T700-GE-701 turboshaft engines, 1,690 shp (1,260 kW) each (upgraded to 1,890 shp (1,409 kW) T700-GE-701C for AH-64A/D from 1990)
- Main rotor diameter: 48 ft 0 in (14.63 m)
- Main rotor area: 1,908.5 sq ft (177.31 m2) 4-bladed main-rotor and 4-bladed tail-rotor in non-orthogonal alignment
- Blade section: root: HH-02; tip: NACA 64A006
- Maximum speed: 158 kn (182 mph, 293 km/h)
- Cruise speed: 143 kn (165 mph, 265 km/h)
- Never exceed speed: 197 kn (227 mph, 365 km/h)
- Range: 257 nmi (296 mi, 476 km) with Longbow radar mast
- Combat range: 260 nmi (300 mi, 480 km)
- Ferry range: 1,024 nmi (1,178 mi, 1,896 km)
- Service ceiling: 20,000 ft (6,100 m)
- Disk loading: 9.8 lb/sq ft (48 kg/m2)
- Power/mass: 0.18 hp/lb (0.30 kW/kg)
- Guns: 1× 30 mm (1.18 in) M230 Chain Gun with 1,200 rounds as part of the Area Weapon Subsystem
- Hardpoints: Four pylon stations on the stub wings. Longbows also have a station on each wingtip for an AIM-92 Stinger twin missile pack.
- Rockets: Hydra 70 70 mm, CRV7 70 mm, and APKWS 70 mm air-to-ground rockets
- Missiles: Typically AGM-114 Hellfire variants; AIM-92 Stinger and Spike missiles may also be carried.
- Aviation and Missile Research, Development, and Engineering Center
- United States Army Aviation and Missile Command
Aircraft of comparable role, configuration, and era
- Agusta A129 Mangusta
- Bell AH-1Z Viper
- Bell YAH-63
- CAIC Z-10
- Denel Rooivalk
- Eurocopter Tiger
- HAL Light Combat Helicopter
- Kamov Ka-50
- Mil Mi-24/25/35
- Mil Mi-28
- TAI/AgustaWestland T129
- List of active United States military aircraft
- List of aviation shootdowns and accidents during the Iraq War
- List of rotorcraft
- "Boeing Marks 25th Anniversary of Apache First Flight Sept. 30". Boeing. 2 October 2000.
- Haynes, Mary L. and Cheryl Morai Young, ed. "Department of the Army Historical Summary, FY 1987, Chapter 5: Modernizing and Equipping the Army". Center of Military History, United States Army, 1995.
- Verdict Media (17 April 2020). "US Army takes delivery of 500th Boeing AH-64E Apache Helicopter". www.airforce-technology.com. Archived from the original on 18 April 2020. Retrieved 18 April 2020.
- "Army Cancels Helicopter Contract". Victoria Advocate. 10 August 1972.
- "Army Decides To Scrap Cheyenne Helicopter Gunship". Boca Raton News. 3 September 1972.
- Bishop 2005, pp. 5–6.
- OAVCSA 1973, p. 10.
- "Army Seeking Bids on New Helicopter". The New York Times. 16 November 1972.
- "New Army Tactic". Reading Eagle. 11 September 1973.
- Bishop 2005, p. 7.
- Richardson and Peacock 1992, p. 8.
- Donald 2004, p. 114.
- Bishop 2005, p. 8.
- "AGM-114 Hellfire missile". Boeing. Archived from the original on 14 September 2011. Retrieved 30 July 2011.
- "AGM-114 Hellfire Variants". Retrieved 27 September 2011.
- "AGM-114 Hellfire Chronology". Retrieved 27 September 2011.
- Bishop 2005, pp. 8–9.
- Donald 2004, p. 119.
- Wilson, Cynthia; Dale Singer (13 January 2004). "McDonnell-Boeing Merger". St. Louis Post-Dispatch.
- "Helicopter Contract Awarded". Prescott Courier. 17 August 1988.
- Donald 2004, pp. 150–153.
- "Great Planes: Apache Helicopter" Archived 17 January 2013 at the Wayback Machine. Military Channel
- Foote, Sheila (4 April 1995). "DOD Halts Apache Longbow Tests Early". Defense Daily. Archived from the original on 20 July 2012.
- Donald 2004, pp. 156–158.
- Foote, Sheila (16 October 1995). "DoD Approves Production of Longbow Apache Attack Helicopter". Defense Daily. Archived from the original on 18 July 2012.
- Caires, Greg (19 August 1996). "Army Inks $1.9 Billion AH-64D Apache Deal". Defense Daily. Archived from the original on 23 July 2012.
- Eden, Paul, ed. "Boeing AH-64 Apache". Encyclopedia of Modern Military Aircraft. Amber Books, 2004. ISBN 1-904687-84-9.
- "Ensure Israel arms curbs, say MPs". BBC News. 30 March 2010.
- "KAI Signs Cooperation Agreement With Boeing, To Produce Apache Fuselages". Defense Daily. 20 February 2003. Archived from the original on 4 September 2015.
- "F-15/Apache Fuselage Monopolization Program". Korea Aerospace Industries. Archived from the original on 9 August 2017. Retrieved 21 January 2012.
- Lisa, Dunbar (2009). "Boeing celebrates milestone: 100th AH-64D Apache fuselage delivery". Boeing. Archived from the original on 20 February 2012.
- "Arbitrator will rule on AH-64 fuselage production dispute". FlightGlobal. 8 April 1998.
- "AH-64D Apache Longbow". Deagel.com. Retrieved 28 October 2010.
- "Boeing Remanufactures AH-64A Apaches to AH-64D Block II". defenseindustrydaily.com. 21 July 2011.
- Hoyle, Craig (15 October 2008). "Greece urged to commit to Apache upgrade, as air force eyes new utility model". FlightGlobal.
- Garrett Reim (17 May 2019). "Boeing suggests propulsor, winged AH-64 Apache variant for US Army". FlightGlobal.
- US Army TM 1-1520-251-10 OPERATOR'S MANUAL for HELICOPTER, ATTACK, AH-64D LONGBOW APACHE, dated 29 MARCH 2002 pp. 2-31 to 2-36.
- "Model T700-701C" Archived 17 December 2013 at the Wayback Machine. GE Aviation
- "Model T700-701D" Archived 17 December 2013 at the Wayback Machine. GE Aviation
- "RTM 322". Turbomeca
- Hudson, Joel B. (2 April 1997). "Attack Helicopter Operations" (PDF). Department of the Army. p. 166.
- Donald 2004, pp. 110–11.
- "How Apache Helicopters Work". HowStuffWorks. Retrieved 10 October 2013.
- Donald 2004, pp. 111–112.
- "GE Says T700 Operating Well in Gulf". Defense Daily. 20 December 1990. Archived from the original on 19 July 2012.
- "T700-GE-701D Engine Awarded U.S. Army Qualification". GE Aviation. 4 November 2004. Archived from the original on 21 November 2008.
- Richardson and Peacock 1992, pp. 16–17.
- "The History of Helicopter Safety" (PDF). Archived from the original (PDF) on 18 April 2013.
- "AH-64 Apache – Military Aircraft". fas.org. Retrieved 22 June 2016.
- "Boeing AH-64D Longbow Apache Attack Helicopter". military-today.com. Retrieved 22 June 2016.
- Rash, Clarence E.; Martin, John S. (August 1988). The Impact of the U.S. Army's AH-64 Helmet Mounted Display on Future Aviation Helmet Design (Report). Army Aeromedical Research Lab Fort Rucker. Archived from the original on 27 February 2012. Retrieved 31 January 2010.
- Casey, Curtis J. (5 August 2002). "Emergence of Solid State Helmet-Mounted Displays in Military Applications". Helmet- and Head-Mounted Displays Vii. SPIE. 4711: 28. Bibcode:2002SPIE.4711...28C. doi:10.1117/12.478896. S2CID 110336810.
- "Boeing AH-64 Apache". Jane's Information Group. 13 October 2000. Archived from the original on 25 February 2008. Retrieved 1 April 2010.
- "Boeing To Develop Electric Gun Turret for the AH-64D". Boeing. 5 May 1999. Archived from the original on 1 July 2013.
- "$262.4M in Arrowheads For Apaches". Defense Daily. 2 May 2005.
- "PEO STRI AWSS LBA TESS". PEO STRI. Archived from the original on 20 March 2014. Retrieved 20 March 2014.
- "ASP Motion Base for Stabilized Mounts" Archived 8 July 2013 at the Wayback Machine. Department of Defense Small Business Innovation Research. Retrieved June 2012.
- FM 1–140, Appendix B "Helicopter gunnery tables". U.S. Army via GlobalSecurity.org. Retrieved June 2012.
- Harris, Tom. "How Apache Helicopters Work: Apache Sensors". howstuffworks.com. Retrieved 2 February 2010.
- Richardson and Peacock 1992, pp. 26–31.
- Apache Guardian set to deploy on May Archived 4 March 2016 at the Wayback Machine – Koreatimes.co.kr, 26 January 2016
- Ground Fire Acquisition System Archived 28 October 2012 at the Wayback Machine – Armedforces-int.com, 26 October 2012.
- "Lockheed tech lets U.S. Apache helicopter pilots aim in color". 19 February 2014. Retrieved 9 February 2019 – via www.reuters.com.
- Drew, James (7 January 2016). "Lockheed secures first order for Apache day sensor kits". FlightGlobal. Retrieved 9 February 2019.
- Oct 2014, 13 (13 October 2014). "Army Configures Apaches for Sea Duty". Military.com. Retrieved 9 February 2019.CS1 maint: numeric names: authors list (link)
- Donald 2004, pp. 124–127.
- "US approves full new warhead production". New Zealand Herald. 25 August 2005.
- Smith, Michael (22 June 2008). "Army 'vacuum' missile hits Taliban". The Times. London.
- "BAE secures US Army Apache as APKWS laser-guided rocket customer" FlightGlobal, 14 October 2015
- Donald 2004, pp. 134–135.
- Richardson and Peacock 1992, pp. 40–41, 60.
- "Boeing AH-64 Apache". Jane's All the World's Aircraft. Jane's Information Group, 2010. subscription article, 1 February 2010.
- "Helicopter rescue bid for Marine". BBC News. 17 January 2007.
- Raytheon Sells Stingers for Apaches Abroad Archived 1 March 2014 at the Wayback Machine – DoDBuzz.com, 23 October 2013
- Weapon, sensor upgrades coming for Apache fleet. FlightGlobal, 31 March 2015.
- "Apache-UAV teaming combines 'best capabilities of man, machine'". Army.mil, 8 May 2014
- "Boeing Apache demonstrates UAV Control". gizmag.com, 12 April 2006.
- Boeing, Lockheed unveil competing UAV-killing concepts FlightGlobal, 14 October 2015
- "Raytheon, US Army complete first ever helicopter-based firing of High Energy Laser" – Airrecognition.com, 26 June 2017
- "MBDA fires Brimstone missile from Apache helicopter". UPI.com. 14 July 2016. Retrieved 14 March 2017.
- "US Army to field Israeli-made long-range missile on helicopters". Defense News. 9 January 2020.
- Richardson and Peacock 1992, pp. 14–15.
- Apache news 2004, pp. 33–34. Boeing, 2004. Archived 30 June 2013 at the Wayback Machine
- Richardson and Peacock 1992, pp. 47–48.
- Bernsteein 2005, p. 6.
- Donald 2004, p. 121.
- Williams 2005, pp. 212–213.
- Williams 2005, pp. 215–218.
- Richardson and Peacock 1992, pp. 51–52.
- Bishop 2005, pp. 16–17.
- Bernstein 2005, p. 7.
- Bishop 2005, pp. 17–18.
- Donald 2004, pp. 144–145.
- Taylor, Thomas. Lightning in the Storm. Hippocrene Books, 2003. ISBN 0-7818-1017-5.
- Ference, Edward W. (December 2002). "Case Study of the Development of the Apache Attack Helicopter (AH-64)" (PDF). Naval Postgraduate School.
- Donald 2004, p. 147.
- "OPERATION DESERT STORM: Apache Helicopter Was Considered Effective in Combat, but Reliability Problems Persist" Archived 13 December 2013 at the Wayback Machine. GAO
- "High Tech Weapons in Desert Storm: Hype or Reality?". Project on Government Oversight. 1 July 1992. Archived from the original on 17 February 2016.
- "APACHE HELICOPTER: Serious Logistical Support Problems Must Be Solved to Realize Combat Potential" Archived 23 January 2016 at the Wayback Machine. GAO
- Bishop 2005, pp. 21–24, 33.
- "U.S. Mulls More Copters in Bosnia – The Aircraft Were Requested For U.N. Troop Reinforcement". Sarasota Herald-Tribune. 18 July 1995.
- Adams 2006, p. 60.
- Bowman, Tom (16 July 1999). "Army Hunts For Answers As Apaches Fail in Kosovo; Readiness, Training Faulted As 21st-century Helicopter Stumbles". The Baltimore Sun.
- Thompson, Mark (20 June 1990). "Army Defends Troubled Copter". Spokesman-Review.
- Anderson, Jon R. (19 December 2000). "Apaches Are Ailing Warriors". European Stars and Stripes.
- Luttwak 2001, pp. 78–80.
- Adams 2006, p. 61.
- Bishop 2005, pp. 33–35.
- Bernstein 2005, pp. 16–17.
- Adams 2006, pp. 223–224.
- "Afghan Field Report: British WAH-64Ds". Defense Industry Daily. 26 November 2007.
- "Christopher Roney inquest: 'Failures led to friendly fire death'". BBC News. 7 September 2012.
- Bishop 2005, pp. 35–37.
- Schechter, Erik (13 June 2003). "Choppers on the Chopping Block?". Jerusalem Post.
- "U.S. Apache Pilots Taken Prisoner". CNN. 24 March 2003.
- Fred Kaplan (23 April 2003). "Chop The Chopper: The Army's Apache Attack-Helicopter Had A Bad War". Slate.
- "A City And Regime Steel For Reckoning To Come". Sydney Morning Herald. 26 March 2003.
- "The 'Apache' Farmer's Tale". BBC News. 23 April 2003.
- "Downed Apache Blown Up To Keep Secrets From Iraq". Evening Times. 25 March 2003.
- "Downed US Apache Blown Up With Missile". New Straits Times. 26 March 2003.
- "Surface-to-Air Missile Downed U.S. Chopper in Iraq". ABC News. 17 January 2006.
- Cheryl Rodewig (7 March 2012). "Geotagging poses security risks". army.mil.
- "Helicopter crashes in eastern Afghanistan". ISAF – International Security Assistance Force. 6 January 2012. Archived from the original on 24 March 2012.
- "Marlborough Soldier Dies in Helicopter Crash in Afghanistan". Wmur.com. 28 May 2011. Archived from the original on 13 March 2012.
- "Army Chief Warrant Officer 3 William T. Flanigan". militarytimes.com. Retrieved 1 April 2015.
- "Amputee Combat Vet Daniel McConnell's Inspiring Story". celebdirtylaundry.com. Retrieved 1 April 2015.
- "AH-64D Apache – Overview" (PDF). Boeing. Archived from the original (PDF) on 29 June 2011. Retrieved 30 July 2011.
- "Leaked Audit: Boeing Overcharged Army Up to 177,000 Percent on Helicopter Spare Parts". Project on Government Oversight (POGO). 28 June 2011.
- Paulsboe, Jesse (12 March 2013). "'Guardian' rises at Joint Base Lewis-McChord". US Army. Retrieved 15 March 2013.
- "US Army's AH-64Es reach initial operating capability" FlightGlobal, 27 November 2013
- Army's First AH-64E Unit Deploys to Afghanistan Archived 6 May 2014 at the Wayback Machine – DoDBuzz.com, 5 May 2014
- "US Army details combat experience with AH-64E". FlightGlobal, 14 October 2014
- Commander: Army's New AH-64E Apache Surprised Enemy in Afghanistan – Military.com, 28 January 2015
- New Apache confounded the enemy in combat, commander says – Armytimes.com, 1 February 2015
- Taliban Troubled By Timing – Strategypage.com, 19 February 2015
- Budgets & 'Betrayal': National Guard Fights To Keep Apache Gunships – Breakingdefense.com, 23 January 2014
- Head, Elan. "Arizona Guard leader blasts Army plan to 'seize' Apaches" Vertical Magazine, 28 April 2014.
- First of 10 Apache units converts, adds 12 Shadow UASs – Armytimes.com, 16 March 2015
- "Army Apache helos used in strikes against Islamic State". Military Times, 5 October 2014
- In Iraq, Apache Gunships Deploy to Mosul, But Not Fallujah: Pentagon – Military.com, 15 June 2016
- Apache Helicopters Go into Action in Mosul Offensive Archived 20 October 2016 at the Wayback Machine – DoDBuzz.com, 19 October 2016
- "100 U.S. Marines, two Apache helicopters reinforcing embassy in Baghdad after attack". MarineCorpsTimes.com. Retrieved 31 December 2019.
- "Iran launches missiles at US military facilities in Iraq". ABC News. Retrieved 7 January 2020.
- Donald 2004, p. 157.
- Orme, William A. (3 February 2000). "Israeli Says U.S. Fears Endanger Major Purchase of Apache Copters". The New York Times.
- Pinkas, Alon (23 March 1994). "IA Experts Criticize Air Force For Preferring Apache Over Upgraded Cobra". Jerusalem Post.
- "Israel Accepts First AH-64D Apache Longbows". Boeing. 11 April 2005.
- Powers 2002, pp. 11, 49.
- Bryen, Shoshana (23 January 2010). "QME, Part II: U.S. Arms Sales to the Arabs, And Will There Be Help For Israel". Right Side News. Archived from the original on 26 January 2010.
Indeed, Israel's request for six AH-64D Apache Longbow attack helicopters was blocked by the Obama Administration in June-the same time the Egyptian sale was approved. U.S. sources reported that the request was undergoing an "interagency review to determine whether additional Longbow helicopters would threaten Palestinian civilians in the Gaza Strip".
- "Administration Blocks Helicopters for Israel due to Civilian Casualties in Gaza". World Tribune. 27 May 2009. Archived from the original on 4 May 2011.
- Donald 2004, p. 191.
- Alon, Ben-David (18 October 2007). "Performance Dispute Puts Israeli Apache Buy on Hold". Jane's Information Group.
- Smolowe, Jill (2 March 1992). "Vengeance Is Mine". Time.
- Kampeas, Ron (25 July 1993). "Thousands Flee Fleet, Fickle Missiles". Lakeland Ledger.
- "Three Killed in Hizbollah, Israeli Retaliatory Attacks". New Straits Times. 24 December 1994.
- Fisk 2005, pp.773–788.
- Urquhart, Conal; Gaby Hinsliff (18 April 2004). "Israeli Missile Attack Kills New Hamas Chief". The Guardian. London, UK.
- Philps, Alan (24 August 2001). "Second Israeli Rocket Attack Misses Target". The Telegraph. London, UK.
- Blanford, Nicholas (8 August 2006). "Hezbollah's Hidden Stronghold Sends Death Across The Border". The Times. UK.
- Ilsemann, Siegesmund von (31 July 2006). "Israeli's Puzzling Military Strategy". Der Spiegel.
- "Hezbollah Defies Israeli Pressure". BBC News. 21 July 2006.
- Egozi, Arie (1 August 2006). "Israeli Air Power Falls Short As Offensive in Southern Lebanon Fails To Halt Hezbollah Rocket Attacks". FlightGlobal.
- Egozi, Arie (27 February 2009). "Israel seeks more Apache attack helicopters". FlightGlobal.
- "Israeli choppers blast Gaza City". oil.co.za. 3 December 2001.
- "Israeli airstrike in Gaza kills one, wounds 2". english.eastday.com. 6 November 2011. Archived from the original on 2 March 2014.
- "Israel expands Gaza offensive". euronews.com. 6 January 2009.
- "Israel's AH-64A Attack Helos Get Custom Upgrades – Despite the USA". Defense Industry Daily. 17 March 2014. Archived from the original on 21 March 2014.
"Israel's AH-64A Attack Helos Get Custom Upgrades – Despite the USA [updated]". Defense Industry Daily. 26 October 2017. Archived from the original on 4 November 2017.
- "Israel Upgrades Apache Helicopters After US Blocked Their Modernization". World Tribune. 14 March 2014. Archived from the original on 24 June 2015.
- Egozi, Arie (30 June 2010). "Israel ditches Apache upgrade plan, commits to CH-53K". FlightGlobal.
- Katz, Yaajov (31 December 2010). "Rapid-fire rocket system aims to reduce civilian casualties". Jerusalem Post.
- Egozi, Arie "Israeli Apache upgrade adds avionics pod." FlightGlobal, 8 October 2013.
- Bryen, Shoshana; Bryen, Stephen (17 November 2016). "Israel Puts the Spike Missile on its Apache Helicopters". Jewish Policy Center.
- "Israel shows off Spike on Apache – Air Forces Monthly". www.airforcesmonthly.com. Archived from the original on 1 December 2017. Retrieved 23 November 2017.
- "מטוס ססנה לבנוני הופל מעל מכמורת" [Lebanese Cessna shot down over Mikhmoret] (in Hebrew). Ynet. Retrieved 6 February 2015.
- "Israel shoots down light aircraft". CNN. 24 May 2001.
- "Iranian UAV Intercepted by an Israeli Helicopter". Israel Defense Forces. 10 February 2018.
- "British Army receives 67th Apache in ceremony held at the Farnborough Airshow 2004". AgustaWestland. 21 July 2004. Archived from the original on 7 July 2011.
- Cook, Nick (1 May 1995). "High Noon For Tiger And Apache". Interavia Business & Technology. Archived from the original on 19 July 2012.
- Flannery, William (14 July 1995). "Mac Lands $3.5 Billion Copter Order – British Buying 67 Antitank Craft". St. Louis Post-Dispatch.
- "RTM 322". Turbomeca. Archived from the original on 3 August 2009. Retrieved 29 January 2010.
- "Apache Moves Closer To Front Line". Navy News. 11 May 2004. Archived from the original on 11 June 2011.
- "UK Announces P-8, Apache Buys". Defense News. 11 July 2016.
- "MOD orders new fleet of cutting-edge Apache helicopters for Army". UK Ministry of Defence. 11 July 2016.
- "United Kingdom – AH-64E APACHE GUARDIAN Attack Helicopters". DSCA. 27 August 2015.
- "Despite Brexit, UK Not Holding Back on New Aircraft". Aviation Week. 15 July 2016.
- "Apache AH-64E heralds new era in modern British military aviation". British Army. Retrieved 17 February 2021.
- "McDonnell in Talks With Dutch on Apache Role". St. Louis Post-Dispatch. 13 April 1989.
- "Dutch May Buy McDonnell Copter". St. Louis Post-Dispatch. 14 December 1994.
- Fitchett, Joseph (13 April 1995). "Ignoring EU Solidarity, The Dutch Opt For U.S. Helicopters". The New York Times.
- Flannery, William (8 April 1995). "McDonnell Wins Big Helicopter Contract But Layoffs Are Looming at Commercial Air Arm". St. Louis Post-Dispatch.
- "First AH-64D Apache Pilots From The Netherlands Complete Training at Boeing". Boeing. 29 March 1999.
- "Boeing Delivers 30th AH-64D Apache to Royal Netherlands Air Force". Boeing. 10 June 2002.
- "News: Last dutch Apache delivered". helis.com. Retrieved 1 April 2015.
- "Aircraft Survivability Equipment" (PDF). TERMA. July 2004. Archived from the original (PDF) on 27 September 2011.
- "AMASE/DIRCM Pod During Flight Certification Testing in the Netherlands" (PDF). TERMA. July 2006. Archived from the original (PDF) on 27 September 2011.
- Strass, Marc (6 March 2002). "Army Conducts First Deployment of AH-64D Apache Longbows To Kuwait". Defense Daily. Archived from the original on 4 September 2015.
- Atkinson, Rick (4 December 1995). "U.S. Bound for Bosnia By Train, Truck, Air". The Washington Post.
- "Six Apaches to Iraq to Boost Security". Government.nl. 24 May 2004.
- "More Dutch troops for Afghanistan". BBC News. 3 February 2006.
- "Two Peacekeeping Helicopters Fired on in Kabul". CTV News. 10 April 2004. Archived from the original on 3 March 2021.
- Gravemaker, Anno (18 December 2007). "Dutch Apache Accident Leaves 50,000 Homes Without Power". FlightGlobal.
- "2 Apache-vliegers omgekomen in Mali". Retrieved 12 July 2020.
- "US clears RNLAF for $1.19b Apache deal". FlightGlobal. 21 February 2018.
- "Apache Copters All Set if Iraqis Make a Move". Eugene Register-Guard. 25 August 1990.
- Jehl, Douglas (22 January 1991). "Desert Air, Sands Alive With Modern Warriors". Los Angeles Times.
- Koenig, Robert L. (3 June 1992). "Bush Endorses Sale of Arms to Saudis...McDonnell Douglas Could Benefit from Pact". St Louis Post-Dispatch.
- "U.S. Plans $1.8 Billion Saudi Military Sale". The Washington Post. 3 June 1992.
- Friedman, Thomas L. (15 September 1992). "U.S. and Israel Working Out Deal To Offset Warplane Sale to Saudis". The New York Times.
- "The 2006 Saudi Shopping Spree: $400M to Upgrade AH-64A Apache Helicopters". Defense Industry Daily. 1 August 2006.
- Shalal-Esa, Andrea (12 September 2008). "US OKs sale of Boeing helicopters to Saudi Arabia". Reuters.
- Lakshman, Narayan (21 October 2010). "Huge U.S.-Saudi arms deal". The Hindu. Chennai, India.
- "Saudi Arabia – AH-64D APACHE, UH-60M BLACKHAWK, AH-6i Light Attack, and MD-530F Light Turbine Helicopters" (PDF) (Press release). US Defense Security Cooperation Agency. 20 October 2010. Archived from the original (PDF) on 16 May 2013.
- "Saudi troops combing Yemen border; security stepped up". BBC News. 20 November 2009. Archived from the original on 25 October 2012.
- "Saudi Apache gunships prevent incursion by "infiltrators"". Saudi Gazette. 6 December 2009. Archived from the original on 9 June 2011.
- "Saudi Military Operations along the Yemen Border Repel Houthist Incursion". The Jamestown Foundation. 28 January 2010.
- "Yemen rebels announce pullout from Saudi land". The Jordan Times. 26 January 2010. Archived from the original on 13 September 2015.
- Cenciotti, David (2 December 2019). "Houthi Rebels Claim To Have Shot Down Saudi Apache Gunship And Wing Loong UAV in Yemen".
- "Apache Helicopter Guns Down Boat Full of Somali Refugees Fleeing Yemen". Foreign Policy. Retrieved 11 August 2018.
- "Yemen migrant boat attack kills at least 42". BBC News. 17 March 2017.
- "The Escalating Northern Front in Yemen". Washington Institute for Near East Policy.
- "US Copters Set For Middle East". Toledo Blade. 4 June 1991.
- "UAE's 30-Helicopter Apache Upgrade Program Underway". Defense Industry Daily. 10 May 2009.
- "United Arab Emirates – Apache AH-64E Helicopters and Services". Defense Security Cooperation Agency. 8 December 2016.
- "Two Emirati pilots die in Yemen crash". The National.
- "UAE to replace lost Apache | Jane's 360". www.janes.com.
- Bishop 2005, pp. 40–44.
- Bishop 2005, p. 42.
- "Egypt to Upgrade 35 Apaches to AH-64D Configuration." Boeing, 25 September 2000. Archived 10 September 2013 at the Wayback Machine
- Feldman 2004, p. 106.
- "AH-64D Apache Longbow helicopters for Egypt". Defence Talk. 29 May 2009.
- "Egypt Aims to Add AH-64D Block II Attack Helicopters". Defense Industry Daily. 28 May 2009.
- "Egypt launches airstrikes in Sinai after troop massacre." CNN, 8 August 2012.
- Friedman, Ron. "Israel allows Egypt to keep attack helicopters in Sinai". Times of Israel, 9 August 2012.
- "Mexican tourists killed by Egyptian security forces". BBC News, 14 September 2015.
- "Egypt – AH-64E Apache Attack Helicopters and Related Equipment and Support" (Press release). US Defense Security Cooperation Agency. 27 November 2018. Archived from the original on 27 November 2018. Retrieved 27 November 2018.
- "IAF conducting trials for attack helicopters". Hindustan Times. 22 July 2010. Archived from the original on 18 June 2013.
- Govindasamy, Siva (10 October 2008). "Bell, Boeing Quit Indian Attack Helicopter Contest". FlightGlobal.
- "Boeing Submits Proposals To India For Apache And Chinook Helicopters". Boeing. 23 October 2009.
- "US government details AH-64D bid for Indian air force contract". FlightGlobal. 4 January 2011.
- "India – Support for Direct Commercial Sale of AH-64D Block III APACHE Helicopters" (PDF) (Press release). US Defense Security Cooperation Agency. 27 December 2010. Archived from the original (PDF) on 15 June 2013.
- "IAF getting 22 Apache helicopters: NAK Browne". Indian Express, 5 October 2012.
- "Going To War Over Gunships". Strategypage.com, 3 January 2013.
- "IAF, not Army, will get Apache attack helicopters". The Times of India. 2 April 2013. Archived from the original on 4 April 2013.
- "PICTURES: Indian air force Apache, Chinook make flight debuts". FlightGlobal. 30 July 2018.
- "In big boost, IAF gets first Apache Guardian attack helicopter". Times of India, 11 May 2019.
- Sura, Ajay (3 September 2019). "IAF inducts 8 Apache AH-64E attack helicopters". The Times of India. Archived from the original on 3 September 2019.
- Gurung, Shaurya Karanbir (3 September 2019). "Eight US made Apache attack helicopters inducted into IAF". The Economic Times.
- "India – Support for Direct Commercial Sale of AH-64E Apache Helicopters". U.S. Defense Security Cooperation Agency. 12 June 2018.
- "India, US sign contract for additional Apache attack choppers". The Economic Times. 25 February 2020. Retrieved 29 May 2020.
- Fiszer, Michal (1 October 2003). "Greece Buying New Helicopters (12 AH-64D Longbow helicopters)". Journal of Electronic Defense. Archived from the original on 21 July 2012.
- "Singapore to Purchase 12 Additional Boeing AH-64D Apache Longbows". Boeing. 23 August 2001. Archived from the original on 3 June 2013.
- "Apache training suspended". The Straits Times. 1 October 2010.
- "Kuwait Runs Apache Longbow Contract To $262.2 M". Defense Industry Daily. 26 August 2005.
- "USA and Indonesia formalise AH-64E Apache deal". FlightGlobal, 26 August 2013.
- "Indonesian military displays Kaplan MT prototype, Apache helicopter". Jane's 360 (janes.com). Archived from the original on 8 October 2017. Retrieved 9 October 2017.
- Yeo, Mike (18 December 2017). "First AH-64E Apache Guardian for Indonesia arrives from US". defensenews.com.
- "Indonesia receives first AH-64E Apache Guardian attack helicopter". quwa.org. Retrieved 13 May 2018.
- "Fuji Heavy Industries Delivers First Apache Longbow Helicopter to Japanese Government Under Boeing Licensing Agreement". Boeing. 15 March 2006. Archived from the original on 26 November 2011.
- Hirokawa, Seiji (10 September 2007). "Japan to halt AH-64D Apache orders after 13th airframe". FlightGlobal.
- Gady, Franz-Stefan (4 May 2017). "US to Upgrade Japan's Attack Helicopter Fleet". thediplomat.com.
- "SDF helicopter crashes, goes up in flames in Saga residential area". Asahi Shimbun. 5 February 2018.
- "Japanese Apache helicopter crashes in residential area of Saga Prefecture". Japan Times. 5 February 2018.
- "GSDF helicopter had main rotor replaced before crash". Japan Times. 5 February 2018.
- Trimble, Stepehen (10 June 2011). "Taiwan buys 30 AH-64 Apaches". FlightGlobal.
- "Taipei Economic and Cultural Representative Office in the United States – AH-64D Apache Helicopters and Related Weapons" (PDF). Defense Security Cooperation Agency (DSCA). 3 October 2007. Archived from the original (PDF) on 27 February 2009.
- "Taiwan receives first batch of AH-64E Apaches". FlightGlobal, 5 November 2013
- "Taiwan's AH-64Es Grounded After Apache Crash" Archived 27 April 2014 at the Wayback Machine. Armedforces-Int.com, 25 April 2014
- "Crash destroys Taiwanese AH-64E Apache". FlightGlobal, 26 April 2014
- "Pilots Blamed for Taiwan Apache Crash". Defensenews.com, 15 July 2014
- "Taiwan received fifth and last batch of AH-64E Apache attack helicopters". Airrecognition.com, 20 October 2014
- Jung, Sung-ki (14 January 2009). "Seoul Seeks To Deploy Apaches In 2012". Korea Times.
- "South Korea Dithers Over Apaches". United Press International. 7 August 2009.
- Sung-ki, Jung (8 February 2009). "US May Withdraw More Apache Helos From Korea by 2012". Korea Times.
- "Republic of Korea (ROK) – AH-64D APACHE Attack Helicopters". DSCA.mil, 25 September 2012.
- "Korea helicopter bids". FlightGlobal, 26 September 2012.
- Song, Sang-ho (17 April 2013). "Seoul to Purchase 36 Apache Helicopters". Korea Herald.
- South Korea's first four AH-64E combat helicopters delivered to combat units – Airrecognition.com, 27 May 2016
- South Korea completes deployment of its 36 AH-64E Apache Guardian helicopters – Airrecognition.com, 30 January 2017
- "Quarterly Report to the United States Congress" (PDF). sigir.mil. 30 April 2013. Archived from the original (PDF) on 22 June 2013.
- "Congress Clears Apache Sale to Iraq". Foreign Policy, 27 January 2014.
- "Agreement reached to sell billions in Apache helicopters to Iraq". Militarytimes.com, 28 January 2014
- "Iraq passes on Apache buy". Jane's, 25 September 2014.
- "Qatar – AH-64D APACHE Block III LONGBOW Attack Helicopters" (Press release). US Defense Security Cooperation Agency. 12 July 2012. Archived from the original on 18 November 2013. Retrieved 29 March 2014.
- $23.9B in Deals Announced on Last Day of DIMDEX – Defensenews.com, 27 March 2014
- "MOD orders new fleet of cutting-edge Apache helicopters for Army". UK Ministry of Defence. 11 July 2016.
- McLaughlin, Andrew (10 July 2019). "Tiger ARH replacement RFI released". Australian Defence Business Review. Retrieved 22 March 2021.
- Frawley, Gerard (26 February 2016). ""Troubled" Tiger set for early retirement, new light helicopter for Special Forces on the way". Australian Aviation. Retrieved 23 March 2021.
- "Boeing offers AH-64E Apache for Australia's reconnaissance helicopter program". Boeing (Press release). 30 August 2019. Retrieved 22 March 2021.
- Minister for Defence Senator Linda Reynolds (15 January 2021). "Future ready - strengthening Army's armed reconnaissance capability". Department of Defence Ministers (Press release). Retrieved 12 March 2021.
- Pittaway, Nigel (19 January 2021). "Australia selects Boeing Apache as next armed reconnaissance helicopter". Defense News. Retrieved 20 January 2021.
- "Apaches for Army". Army: The Soldiers' Newspaper (1481 ed.). Canberra: Department of Defence. 4 February 2021. p. 2. ISSN 0729-5685. Retrieved 23 March 2021.
- "Bangladesh wants to buy combat fighters, Apache helicopters, missile systems from US". Dhaka Tribune. 17 October 2019.
- "Apache down-selected for Bangladesh attack helicopter requirement". Jane's. Retrieved 26 January 2020.
- "Morocco – AH-64E Helicopters". United States Defense Security Cooperation Agency. Retrieved 21 November 2019.
- "Philippines – AH-1Z Attack Helicopters and Related Equipment and Support | The Official Home of the Defense Security Cooperation Agency". www.dsca.mil.
- "Philippines – Apache AH-64E Attack Helicopters and Related Equipment and Support | The Official Home of the Defense Security Cooperation Agency". www.dsca.mil.
- Mehta, Aaron (30 April 2020). "US approves Apache, Viper attack helicopter options for Philippines". Defense News.
- Bishop 2005, p. 12.
- Bledsoe, Sofia. "Army 'retires' last A model Apache helicopter". Defense Video & Imagery Distribution System. Retrieved 18 July 2012.
- Boeing Remanufactures AH-64A Apaches to AH-64D Block II. Defense industry daily.
- Bishop 2005, p. 10.
- Donald 2004, p. 153.
- "McDonnell-Bell plan Longbow-radar for LHX". Defense Daily. 22 February 1990. Archived from the original on 21 July 2012.
- "AN/APR-48A Radar Frequency Interferometer" (PDF). Lockheed Martin. Archived from the original (PDF) on 29 September 2011. Retrieved 20 July 2011.
- "Defense & Security Intelligence & Analysis: IHS Jane's – IHS". janes.com. Retrieved 1 April 2015.
- "Defense & Security Intelligence & Analysis: IHS Jane's – IHS". janes.com. Retrieved 1 April 2015.
- "Helicopter profile: Boeing AH-64 Apache". FlightGlobal. Retrieved 2 February 2010.
- "Apache Stinger Testing in Holding Pattern until Starstreak Integration Finished". Defense Daily. 15 June 2000. Archived from the original on 18 July 2012.
- Taylor, Ed (21 December 2005). "Japan to get first Boeing copter". East Valley Tribune.
- Bledsoe, Sophia. "Team Apache announces nickname for the Apache Echo Model." U.S. Army, 14 January 2013.
- "Army Renames Apache Block III Helicopters." Archived 9 November 2013 at the Wayback Machine National Defense Magazine.
- "Interlocking gears used in clocks give Army helicopters more power Archived 20 February 2014 at the Wayback Machine", HeliHub, 28 October 2013. Archived on 20 February 2014.
- "Boeing, US Army Mark Delivery of 1st AH-64D Apache Block III Combat Helicopter". MediaRoom. Retrieved 9 February 2019.
- "Technology gives Apache block III more lift, capability, landing ability". www.army.mil. Retrieved 9 February 2019.
- "Boeing-Developed Composite Rotor Blade Spins Forward". Boeing, 10 May 2004. Archived 29 June 2011 at the Wayback Machine
- Trimble, Stephen (3 November 2011). "From Albania to Afghanistan, US Army integrates lessons into latest Apache". FlightGlobal.
- John Pike. "Upgraded Apache helicopter OK'd for production". globalsecurity.org. Retrieved 1 April 2015.
- Jennings, Gareth (30 October 2013). "ADEX 2013: US sequestration buys time for UK Apache decision makers". IHS Jane's Defence Weekly.
- Majumdar, Dave (9 January 2013). "US Army fields first AH-64E unit, but more improvements to come". FlightGlobal.
- Drwiega, Andrew (10 November 2014). "U.S. Army's Apache Maritime Role". Aviation Today.
- Trimble, Stephen (14 October 2015). "US Army replaces Lockheed data link on AH-64 Apache". FlightGlobal.
- "ViaSat to produce Link 16 terminals for AH-64E Apache Guardian helicopter Lots 5 and 6". airrecognition.com. Retrieved 9 February 2019.
- Trimble, Stephen (26 June 2014). "Boeing proposes high-speed Apache, heavier Chinook". FlightGlobal. Retrieved 9 February 2019.
- Giangreco, Leigh (4 October 2016). "Army will not pursue AH-64F model Apache". FlightGlobal. Retrieved 9 February 2019.
- Host, Pat (26 October 2018). "Boeing testing high-speed Apache concept". Jane's International Defence Review.
- Wolfe, Frank (26 April 2019). "Boeing Finished Six Wind Tunnel Tests on Compound Apache in January, Company Says". Rotor & Wing International.
- Richardson and Peacock 1992, pp. 60–61.
- Donald 2004, p. 150.
- Donald 2004, p. 170.
- Curran, Peggy (6 August 1986). "Local firms hope for spin-offs from big naval aircraft project". Montreal Gazette.
- "HMS Ocean". Royal Navy/MOD. Archived from the original on 18 June 2012.
- Myers, Meghann (5 September 2013). "Army helicopters fly from Navy ships, test joint ops". Army Times.
- "Army Regulation 750-10 Army Modification Program" (PDF). Archived from the original (PDF) on 20 February 2013.
- "World Air Forces 2019". FlightGlobal. 2019.
- "US aerospace major Boeing completes delivery of 37 military helicopters to India". hindustantimes.com. Retrieved 11 July 2020.
- "India, US sign contract for additional Apache attack choppers". India Times. 25 February 2020.
- "Morocco Orders 24 Boeing AH-64E Apache Helicopters". MediaRoom. Retrieved 27 June 2020.
- Jennings, Gareth (20 March 2019). "Qatar receives first Apache attack helicopter". Jane's 360. Archived from the original on 20 March 2019. Retrieved 20 March 2019.
- Judson, Jen (23 February 2017). "Saudi Arabian National Guard helicopter force takes shape". Defense News. Retrieved 27 February 2018.
- Bishop 2005.
- Lednicer, David. "The Incomplete Guide to Airfoil Usage". m-selig.ae.illinois.edu. Retrieved 16 April 2019.
- "AN/APG – Equipment Listing". designation-systems.net
- Bernstein, Jonathan. AH-64 Apache units of operations: Enduring Freedom and Iraqi Freedom. Oxford: Osprey Publishing, 2005. ISBN 1-84176-848-0.
- Bishop, Chris. Apache AH-64 Boeing (McDonnell Douglas) 1976–2005. Osprey Publishing, 2005. ISBN 1-84176-816-2.
- Donald, David. "AH-64A/D Apache and AH-64D Longbow Apache". Modern Battlefield Warplanes. AIRtime Publishing Inc, 2004. ISBN 1-880588-76-5.
- Feldman, Shai. The Middle East Strategic Balance, 2003–2004. Sussex Academic Press, 2004. ISBN 1-8451-9003-3.
- Fisk, Robert. The Great War for Civilisation: The Conquest of the Middle East. Fourth Estate, 2005. ISBN 978-1-4000-7517-1
- Government Accounting Office. Staff Study: Advanced Attack Helicopter. Washington, D.C.: U.S. Government Accounting Office, 1974.
- Luttwak, Edward. Strategy: the Logic of War and Peace. Harvard University Press, 2001. ISBN 0-674-00703-4.
- Office of the Assistant Vice Chief of Staff of the Army (OAVCSA). An Abridged History of the Army Attack Helicopter Program. Washington, D.C.: Department of the Army. 1973.
- Powers, Adam. United States Israeli Relations. Nova Publishers, 2002. ISBN 1-59033-133-8.
- Richardson, Doug and Lindsay Peacock. Combat Aircraft: AH-64 Apache. London: Salamander Books, 1992. ISBN 0-86101-675-0.
- Thomas, Adams K. The Army After Next: The First Postindustrial Army. Greenwood Publishing Group, 2006. ISBN 0-275-98107-X.
- TM 1-1520-251-10 Technical Manual for Helicopter, Attack, AH-64D Longbow Apache, U.S. Army.
- Williams, James W. A History of Army Aviation: From Its Beginnings to the War on Terror. iUniverse, 2005. ISBN 0-595-36608-2.
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