The Boeing (formerly McDonnell Douglas, formerly Hughes) AH-64A Apache is the Army's primary attack helicopter. It is a quick-reacting, airborne weapon system that can fight close and deep to destroy, disrupt, or delay enemy forces. The Apache has been designed to fight and survive during the day, night, and in adverse weather throughout the world. The principal intended mission of the Apache is the destruction of high-value targets with the HELLFIRE missile, primarily hostile armor. It is also capable of employing a 30mm M230 chain gun and the Hydra 70 (2.75 inch) family of rockets that are lethal against a wide variety of targets. The Apache has a full range of aircraft survivability equipment and has the ability to withstand hits from rounds up to 23mm in critical areas. The AH-64 is air transportable in the C-5, C-141 and C-17.
The AH-64 Apache is a twin-engine, four bladed, multi-mission attack helicopter designed as a highly stable aerial weapons-delivery platform. It is designed to fight and survive during the day, night, and in adverse weather throughout the world. With a tandem-seated crew consisting of the pilot, located in the rear cockpit position and the co-pilot gunner (CPG), located in the front position, the Apache is self-deployable, highly survivable and delivers a lethal array of battlefield armaments. The Apache features a Target Acquisition Designation Sight (TADS) and a Pilot Night Vision Sensor (PNVS) which enables the crew to navigate and conduct precision attacks in day, night and adverse weather conditions.
The Apache program had the potential to evolve into four different models in service simultaneously. These models were, the AH-64A, an AH-64+ with product improvements applied, and an AH-64D Longbow Apache with glass cockpit display, advanced engines, wiring for Longbow systems, radar interferometer, and the Longbow missile system. This AH-64D standard was previously known as AH-64C. Approximately 1/3 of the Longbow fleet was planned to also be equipped with the Longbow millimeter wave fire control radar, the original AH-64D standard. Converting an A model to a D model costs about $10 million. The Longbow FCR adds another $3.6 million to the price tag.
As part of the reduction in the planned buy of the Comanche in late 2002, the Army was directed to formulate a service life extension program for the Apache. Although DoD did not provide the Army a specific end-date for the Apache, the AH-64 Longbow had the potential to remain in service until 2030.
The Apache can carry up to 16 HELLFIRE (Helicopter-Launched, Laser-guided, Fire and Forget) laser guided missiles. With a range of over 8000 meters, the HELLFIRE is used primarily for the destruction of tanks, armored vehicles and other hard materiel targets. The Apache can also deliver a maximum of 76, 70mm/2.75" wrap-around fin aerial rockets (WAFAR) for use against enemy personnel, light armor vehicles and other soft-skinned targets. Rounding out the Apache's deadly punch are 1,200 rounds of ammunition for its Area Weapons System (AWS), featuring the M230 30mm Automatic Gun.
An on-board video recorder has the capability of recording up to 72 minutes of either the pilot or CPG selected video. It is an invaluable tool for damage assessment and reconnaissance. The Apache's navigation equipment consists of a doppler navigation system, and most aircraft are equipped with a GPS receiver.
The Apache has state of the art optics that provide the capability to select from three different target acquisition sensors. These sensors are:
- Day TV - Views images during day and low light levels, black and white.
- TADS FLIR - Views thermal images, real world and magnified, during day, night and adverse weather.
- DVO - Views real world, full color, and magnified images during daylight and dusk conditions.
AH-64 aviators use the Integrated Helmet and Display Sighting System (IHADSS). The IHADSS helmet, at the time of its development, was lighter in weight and provided improved impact protection over the then-current SPH-4 series helmet. The IHADSS was the only helmet approved for the AH-64 and has been in use for over 20 years. A unique feature of the IHADSS helmet is that it serves as a platform for a Helmet Mounted Display (HMD). The HMD provides pilotage and fire control imagery and flight symbology. In order to view the HMD imagery, the helmet/HMD must be fitted such that the exit pupil of the HMD is properly aligned with the aviator's eye each time it is donned. This makes the fit and stability of the IHADSS helmet critical considerations. Achieving a proper fit of the IHADSS helmet is complicated by its intricate system of straps and pads. A proper, customized, repeatable fit is required in order to maintain the exit pupil position and optimize the resulting full Field of View (FOV). Fitting of the IHADSS helmet typically takes several hours to complete. This fitting process must be repeated every time aviators are transferred to a new duty station, as they cannot take the IHADSS helmet with them. It is part of the AH-64 aircraft system and is unit property.
The Apache has four articulating weapons pylons, two on either side of the aircraft, on which weapons or external fuel tanks can be mounted. The aircraft has a Laser Range Finder/Designator (LRF/D). This is used to designate for the HELLFIRE missile system as well as provide range to target information for the fire control computer's calculations of ballistic solutions.
Threat identification through the FLIR system is extremely difficult. Although the AH-64 crew can easily find the heat signature of a vehicle, it may not be able to determine friend or foe. Forward looking infrared detects the difference in the emission of heat in objects. On a hot day, the ground may reflect or emit more heat than the suspected target. In this case, the environment will be "hot" and the target will be "cool". As the air cools at night, the target may lose or emit heat at a lower rate than the surrounding environment. At some point the emission of heat from both the target and the surrounding environment may be equal. This is IR crossover and makes target acquisition/detection difficult to impossible. IR crossover occurs most often when the environment is wet. This is because the water in the air creates a buffer in the emissivity of objects. This limitation is present in all systems that use FLIR for target acquisition.
Low cloud ceilings may not allow the HELLFIRE seeker enough time to lock onto its target or may cause it to break lock after acquisition. At extended ranges, the pilot may have to consider the ceiling to allow time for the seeker to steer the weapon onto the target. Pilot night vision sensor cannot detect wires or other small obstacles.
Overwater operations severely degrade navigation systems not upgraded with embedded GPS. Although fully capable of operating in marginal weather, attack helicopter capabilities are seriously degraded in conditions below a 500-foot ceiling and visibility less than 3 km. Because of the HELLFIRE missile's trajectory, ceilings below 500 feet require the attack aircraft to get too close to the intended target to avoid missile loss. Below 3 km visibility, the attack aircraft is vulnerable to enemy ADA systems. Some obscurants can prevent the laser energy from reaching the target. They can also hide the target from the incoming munitions seeker. Dust, haze, rain, snow and other particulate matter may limit visibility and affect sensors. The HELLFIRE remote designating crew may offset a maximum of 60 degrees from the gun to target line and must not position their aircraft within a +30-degree safety fan from the firing aircraft.
Powered by two General Electric gas turbine engines rated at 1890 shaft horsepower each, the Apache's maximum gross weight is 17,650 pounds which allows for a cruise airspeed of 145 miles per hour and a flight endurance of over three hours. The AH-64 can be configured with an external 230-gallon fuel tank to extend its range on attack missions, or it can be configured with up to four 230-gallon fuel tanks for ferrying/self-deployment missions. The combat radius of the AH-64 is approximately 150 kilometers. With one external 230-gallon fuel tank the radius is approximately 300 kilometers. Both radii are dependent on temperature, pressure altitude, fuel burn rate, and airspeed. The addition of up to two wing tanks can further extend range. However, this configuration is currently authorized for ferry/self-deployment flights only. The Apache can attack targets up to 150 km across the FLOT. If greater depth is required, the addition of ERFS tanks can further extend the AH-64's range with a corresponding reduction in HELLFIRE missile carrying capacity (four fewer Hellfire missiles for each ERFS tank installed).
The Apache fully exploits the vertical dimension of the battlefield. Aggressive terrain flight techniques allow the commander to rapidly place the ATKHB at the decisive place at the optimum time. Typically, the area of operations for Apache is the entire corps or divisional sector. Attack helicopters move across the battlefield at speeds in excess of 3 kilometers per minute. Although dependent on mission, enemy, terrain, troops, time available, and civilian (METT-TC) considerations, typical planning airspeeds are 100-120 knots (185-222 km/hr) during daylight, and 80-100 knots (148-185 km/hr) at night. Speeds during marginal weather are reduced with respect to prevailing conditions.
The Russian-developed Mi-24 (NATO codenamed Hind) has been one of the Apache's closest counterpart. The Russians have deployed significant numbers of Hinds in Europe and have exported the Hind to many third world countries. The Russians have also developed the KA-50 (NATO codenamed Hokum) as their next generation attack helicopter. The Italian A-129 Mangusta is one of the the nearest NATO counterparts to the Apache. The Germans and French also co-developing the PAH-2 Tiger attack helicopter, which has many of the capabilities of the Apache.
Apache production began in FY82 and the first unit was deployed in FY86. As of November 1993, 807 Apaches were delivered to the Army. The US Army ordered 821 aircraft (excluding prototypes), with the last Army Apache delivery on December 1995. 33 attack battalions were deployed and ready for combat. The Army looked to procure a total of 824 Apaches to support a new force structure of 25 battalions with 24 Apaches for each unit (16 Active; 2 Reserve; 7 National Guard) under the Aviation Restructure Initiative. Army National Guard units in North and South Carolina, Florida, Texas, Arizona, Utah and Idaho have flown Apache helicopters. The Army fielded combat-ready AH-64A units in the United States, West Germany and in Korea, where they played a major role in achieving the US Army's security missions.
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