Enhancements including increased power and directed energy weapons to be discussed

With the contract to develop the Block III upgrade for the AH-64D Apache Longbow signed, Boeing and the US Army have begun assessing technologies - including directed-energy weapons - that could be incorporated in future modernisation programmes.

Apaches are planned to remain in service until 2035, and increased power, enhanced survivability, advanced crew station, digital flight control system and directed-energy weapons are among technologies being assessed for incorporation in the 2015-20 timeframe, says Larry Plaser, director, future Apache modernisation.

Under the Block III programme, the army plans to modernise its 284 Block I AH-64Ds between 2011 and 2017. "The army position is it will upgrade the entire D fleet to Block III, but by 2017 we will be able to do better," says Plaser. As a result, Boeing expects the army to upgrade its Block II aircraft to an enhanced, but undefined standard it dubs "Block IV".

Boeing delivered the 501st AH-64D for the US Army on 8 August at Mesa, Arizona, completing its second multi-year contract. A further 96 remanufactured AH-64Ds and 27 new-build wartime replacement aircraft will give the army at least 340 Block IIs and will keep the line open until Block III deliveries begin in 2011.

"We've done an operational analysis for 2020 and identified advanced technologies such as directed-energy weapons," says Plaser. "Solid-state laser technology is developing quickly. There is a laser today weighing 800-900lb [360-400kg] that you could put in a Chinook and do some damage with. We need a 100-200lb weapon that uses half the power. There is a good chance we can get there by 2017," he says, adding: "It would do a lot of good not to run out of bullets."

Boeing is also looking at non-lethal effects such as disabling people using a microwave weapon or using a laser "dazzler" to temporarily blind anyone taking aim at the helicopter.

Block III lays the foundation for the next upgrade by introducing a new gearbox with growth capability. "Block II is transmission-limited: Block III is engine-limited," says Plaser. The face-gear transmission increases power capacity from 2,850shp (2,120kW) to 3,400shp, with growth capability to 3,850shp to allow use of a new 3,000shp common engine the army wants to develop, but has yet to fund.

Block III gets a new 150mm (6in) longer composite main rotor blade. A new rotor hub is earmarked for the next upgrade, and Boeing is designing a quiet tail rotor with advanced blade tip shape. The company is also looking at displaying the Apache's acoustic footprint to the crew so they can fly profiles that minimise detectability.

Boeing is completing a rapid mission prototype that will enable it to test advanced crew station technologies for the next upgrade. These include the enhanced visualisation system, which will provide a 360° view using static sensors and a helmet-mounted display.

Block III introduces an open systems architecture that will make future upgrades easier, says Col Derek Paquette, US Army Apache programme manager. It also introduces the system of systems common operating environment under development for the US Army's Future Combat Systems. This "middleware" provides machine-to-machine connectivity between air and ground systems, and future Apache upgrades will improve its link to joint forces, says Brig Gen Bill Phillips, deputy programme executive officer for aviation.

■ The investigation into the crash of an Israeli air force Boeing Apache AH-64D Longbow on July 24 near the Israeli-Lebanese border is now focused on a mechanical cause. The air force/Boeing investigation had earlier pointed to a possible strike from an Israeli multi-launch rocket system.

The accident occurred when two AH-64Ds were in the area on an enemy fire suppression mission. The Apache's main rotor suddenly separated, killing the pilots on impact. According to the air force, the pilots did not communicate any mechanical problem before the crash. By late last week the investigation had not been completed, but the ground fire option had "almost been ruled out", say industry sources.

Source: Flight International