AH-64D Apache Longbow

Development History

The basic Apache design represents the second, or perhaps the third generation of American attack helicopter development. Though helicopters have been used for anti-submarine work ever since they first became practical, the first combat helicopter - a helicopter which was primarily a air-to-ground weapons platform rather than a utility type - was the HueyCobra. Though its development may have been influenced by early experience in Vietnam, it was a natural element of the US Army's Airmobile concept.

If you exploit the helicopter's mobility to move troops and supplies rapidly and flexibly, then you need an equally mobile and flexible source of fire support. Ever since 1916, infantry have increasingly operated with tanks and lighter armoured vehicles mounting heavy weapons. Lightly-armed troops who have just piled out of a helicopter are highly vulnerable. The helicopter gunship can provide instant, accurate heavy fire support under close control.

Though the HueyCobra gave good service and its descendants are still in widespread use, early versions were distinctly underpowered, making them slower than the troop-carrying 'slicks' they escorted, and limiting the size of the weapons load and the weight of armour the airframe could carry. The next step forward should be a more powerful, faster and altogether nastier helicopter.

The result was the development of the Lockheed AH-56 Cheyenne. This was an ambitious and unconventional design that straddled the boundary between helicopter gunship and ground attack aircraft. Its most novel design feature was the pusher propeller at the tip of the tail-boom, aft of the tail-rotor. The Cheyenne's outstanding performance feature was speed - a prototype reached 220 knots (407 km/hour), but it was over-complex and mechanically unreliable. The design emphasis on speed, together with its large size and weight, robbed it of the agility necessary to exploit ground cover in a period when SAMs of all sorts and radar-laid anti-aircraft cannon were coming into widespread service.

The Cheyenne project was cancelled, and a new Advanced Attack Helicopter requirement issued, specifying well-chosen and demanding criteria for performance, weapon load, endurance, toughness and crew protection. Electro-optical systems (infrared cameras, laser rangefinding and designation) were to be fitted to allow target detection and attack at longer ranges, and at night. Faced with the numerical superiority of the Warsaw Pact, NATO needed to multiply the effectiveness of its smaller forces. One direct and obvious way to do this was to develop night-fighting equipment and techniques. An additional advantage of this approach was that it posed a technical and industrial as well as a military challenge to the Soviet Union.

Five designs were submitted, by Bell, Boeing/Grumman, Hughes, Lockheed and Sikorsky. Bell and Hughes were selected to build their designs for a fly-off. Bell's YAH-63, a tubby, rounded, subtly dated-looking machine, was eventually rejected after these tests. With the benefit of hindsight, it seems clear that the Hughes YAH-64 was superior in the functionality and development potential of its design. It also undoubtedly looks the part, which is a real asset to any weapon.

After a troubled production run and service introduction, assailed by political agitation and some principled scepticism about the concept of the 'flying tank', the Apache decisively proved itself in Iraq in 1991 fighting very much the same equipment and systems it was designed against in the seventies.

Vindication in combat and export orders from discriminating customers in Europe gave impetus to the Longbow development program. The Longbow radar can see further, over a wider angle, in worse weather than the optical sensors, and the datalink allows crews to communicate and cooperate more effectively than ever before. The cockpit is updated with multi-functional displays displacing analogue instruments, the avionics and services are modernised and streamlined, and the engines are replaced with an uprated version. Despite all the new features, the parts count has been substantially reduced, which strongly suggests that maintainability has actually improved.

When the AH-64D was tested in realistic combat exercises against the AH-64A, the loss ratio in favour of the D-model was seven to one, and the A-models made many fratricidal kills. The margin was so decisive that the exercises were cut short. Among those who have flown and evaluated the AH-64D Apache Longbow, the common verdict seems to be that the new capabilities represent a revolutionary change, and the possibilities they open up will take years to explore. The Main Battle Tank may no longer be the master of the battlefield.

Specifications

Avionics

• Mast-mounted Longbow fire-control radar (FCR)
• Target acquisition and designation system (TADS)
• Integrated helmet and display sighting system (IHADSS)
• Pilot night vision system (PNVS)
• Doppler navigation system and global positioning system

Armament

• M230 30mm Chain Gun
• AIM-92 Stinger IR guided air-to-air missiles
• AGM-114L Longbow Hellfire radar guided anti-tank missiles
• AGM-114K Hellfire II laser guided anti-tank missiles
• Hydra 70 M255 unguided rockets (HE)
• Hydra 70 M261 unguided rockets (MPSM)

Combat Survivability

• Radar and laser warning receivers
• Chaff and flare dispensers
• Electronic counter measures (IR and radar jammers)
• Armour protected key components
• Airframe designed for crash-survival
• Energy absorbing seats
• Crash-resistant and self-sealing fuel cell