It carries a 30 mm (1.18 in) 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.

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.

[11][12] 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.

[16] 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.

[35] 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.

[62] 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.

[63] 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.

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.

[68][69] 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.

[75] 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.

[79] 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.

[81] 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.

[105][106] 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.

[108] 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".

[111] 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.

[112] Apaches often flew in small teams with little autonomy to react to threats and opportunities, requiring lengthy dialogue with centrally micromanaged command structures.

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.

[132] 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.

[145] 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.

[153] 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.

[188][189] Important deviations made by AgustaWestland from the U.S. Apache variants include changing to more powerful Rolls-Royce engines,[190] and the addition of a folding blade assembly for use on naval ships.

[192] 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."

[193] 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.

[211] 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.

[250] 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.

[261][262] On 12 June 2018, the U.S. Department of State approved a possible Foreign Military Sales (FMS) to India for six more AH-64Es and associated equipment in an estimated $930 million deal.

[290][291] 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.

[354] 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.

[359] 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.

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.