Boeing is modifying an AH-64D Apache attack helicopter with a full fly-by-wire (FBW) flight-control system for a flight-test programme that paves the way for the Apache Block 3 upgrade and provides a testbed for future applications ranging from unmanned combat air vehicles to a growth canard rotor-wing.

The hardware and initial software for the modified AH-64D is being developed under the vehicle management systems integration technology for affordable life cycle costs (VITAL) programme, a joint Boeing and US Defense Advanced Research Projects Agency effort involving 10 industry members including BAE Systems and Lockheed Martin. Through VITAL, Boeing plans to develop a set of common vehicle management system "building blocks" based on commercial parts that will be applicable to a wide range of Boeing fixed- and rotary-wing aircraft. Four main VITAL teams are involved, one developing the building blocks; another applying it to an F/A-18 testbed; a third working on potential tests on a 717-200 and a blended wing body ground test article; and the fourth planning the AH-64D test.

Collective and cyclic controls from the pilot and co-pilot cockpits will be replaced by sidestick controllers. The right hand will control pitch, yaw, roll and longitudinal acceleration; the left hand will control vertical movement. At high speeds the left hand will also control flightpath angle- rate change.

The use of FBW will "save 200lb [90kg] over a conventional system and provide a lot more space", says Phantom Works VITAL programme manager Jim Roos, who says the effort builds on three previous AH-64 FBW tests with partially modified flight control systems. The FBW system will make it "easier to fly" and "through carefree handling, pilots will be able to use all the capability of the aircraft," adds Roos.

Source: Flight International