Front-line helicopter gunships evolve for the modern battlefield

The delivery of the US Army's first Boeing AH-64D Apache Longbow attack helicopter on 3 October 2007 (built under the extended Block II contract) illustrates the continued importance of this particular genre of battlefield helicopter. The dedicated attack helicopter was born out of the armed close-air support applications for utility helicopters, notably the UH-1 'Huey' series, during the Vietnam conflict of the mid-to-late 1960s.

When it finally materialised, the attack helicopter - armed with anti-tank guided weapons (ATGWs) - was seen as the solution to mass Soviet armoured incursions into Europe. The end of the Cold War and the new counter-insurgency applications in Afghanistan, the Balkans and Iraq have seen the type expand - indeed effectively switch - its prime role from anti-armour back to close-air support.

Indeed, when one talks about 'battlefield helicopters' today, one thinks not only of the armed attack helicopters but also the traditional transport/cargo/utility types. For example, in Afghanistan, a UK helicopter will not operate without its Apache escort.

The 'granddaddy' of all attack helicopters was the Bell AH-1G HueyCobra, first flown in 1965. The AH-1 family has evolved over the years and is still in production, with more than 2,060 models of all versions having been built. The current list of operators covers: Bahrain (AH-1E/F); Iran (AH-1J); Israel (AH-1E/F); Japan (AH-1S); Jordan (AH-1F); Pakistan (AH-1F); South Korea (AH-1F/J); Taiwan (AH-1W); Thailand (AH-1F); Turkey (AH-1P/S/W); and the US Marine Corps (USMC) with the AH-1W SuperCobra. This latter is now about to begin transition to the AH-1Z ('Zulu') upgrade of the W-model.

Bell Helicopter Textron was awarded the H-1 upgrade contract in 1996, covering the upgrade of 180 in-service AH-1Ws to Zulu configuration and 100 UH-1Ns to UH-1Y standard, with both upgraded helicopters sharing 84 per cent common components, including a new tail boom. The twin General Electric T700-GE-401 turboshaft engines drive a composite, four-blade main rotor and four-blade 'scissors'-type tail rotor. An increase in fuel capacity of 100 US gal (379 litres) gives the Zulu a maximum range of 370 n miles (686 km) and a combat radius-of-action of 125 n miles (232 km). This is a vast improvement on the AH-1W's combat radius of 38 n miles (70.5 km).

A new stub wing with three hardpoints allows double the number of ATGWs to be carried, plus an air-to-air missile (AAM), such as AIM-9 Sidewinder or Air-To-Air Stinger (ATAS).

The AN/AAQ-30 Target Sighting System (TSS - also known as Hawkeye) was developed by Lockheed Martin, using an L-3 Wescam gimbal mounting the company's own Gen 3 FLIR (Forward-Looking InfraRed) sensor from its Sniper advanced targeting pod, plus a colour TV camera, laser rangefinder, laser spot tracker and laser designator. The aircrew are equipped with a Thales Aerospace TopOwl helmet-mounted sight/display (HMS/D) system.

The Zulu carries the latest self-defence suite, comprising a Northrop Grumman AN/APR-39A(V)2 radar warning receiver (RWR), Goodrich AN/AVR-2 laser warning receiver (LWR) and ATK AN/AAR-47 missile approach warner (MAW). These passive detectors interface with the BAE Systems Electronics and Integrated Solutions AN/ALQ-144 infrared (IR) jammer and AN/ALE-47 decoy dispensing system. A pre-planned upgrade will be the installation of a Directed InfraRed CounterMeasures (DIRCM) system.

Approval for low-rate initial production (LRIP) came in October 2003 and three re-manufactured AH-1Ws were authorised. In 2004, the USMC decided, partly because of operational reality, that the H-1 programme as a whole would be slightly re-configured, with some new-build AH-1Zs being procured as part of the 180 so that operational units would not be depleted during transition. At this stage, the exact breakdown between new-build and remanufacture is not known. The UH-1Y element was switched over to a complete new-build programme. The first phase of the Operation Evaluation (OPEVAL) of the AH-1Z and UH-1Y ran May to November 2006; OPEVAL Phase 2 is scheduled for January to April 2008.

Image: The USMC's AH-1Z is preparing to enter OPEVAL Phase 2 from NAS Patuxent River in January 2008. (Jane's/P Allen) 669 of 5,932 words