Helicopter required to lift 18-20t and support planned Objective Force's new family of Future Combat System vehicles

The growing need to lift heavier loads over longer distances is causing the US Army to examine options to close the gap in capability between the remanufactured Boeing CH-47F Chinook, due to begin deployment in 2005, and the Air Manoeuvrability Transport (AMT) earmarked for around 2020.

The army needs a new transport capable of lifting 18-20t vertically and supporting the planned Objective Force's new family of Future Combat System vehicles due to start entering service in 2010. "AMT or some kind of joint tactical rotorcraft are growing in importance, particularly as we look at the further definition of the Objective Force and how much vertical manoeuvre of mounted forces that gives you," says Maj Gen John Curran, commander US Army aviation.

War in Iraq has highlighted the vulnerability of extended overland supply lines. The army's near-term plans focus on modernising 300 CH-47Ds to Fs, which are limited to a useful load of 12.5t. Another 36 Chinooks are being transferred to the US Special Operations Command to supplement its 24 MH-47Es, all of which are then being modernised into MH-47Gs, which feature avionics, mission systems, and extended-range fuel tanks different to the CH-47F.

Boeing has laid out options for further stretching the capability of the remaining 102 Chinooks, including the CH-47F+, with a maximum take-off weight increased from 22,700kg (50,000lb) to between 24,500kg and 27,240kg. The more ambitious CH-47X, with an all-up weight of 30,870kg, would offer about an additional 4t of payload, but requires new, more powerful engines and upgrading to four-blade tandem rotors.

"We see the Chinook requirement going up to an F+," says Curran. "It is then a question of whether the airframe is more like a G model with larger tanks or more like an F model with small tanks. The question then is: do you need an X after that, or is your F model going to meet your requirements when you then bring on the AMT?" The army does not plan to make a decision before 2008, though some officers are voicing the opinion it needs to be sooner.

Industry has presented a number of different concepts to meet AMT, including the Bell Quad Tiltrotor, the Boeing tiltwing Advanced Theatre Transport and the Sikorsky co-axial heavylift helicopter. In the longer term, Curran suggests, accelerating AMT is the only real solution to closing the gap, "because you're never going to get the capability to lift 18-20t with a CH-47".



Source: Flight International