Andrew Doyle/MUNICH
Airbus is to introduce an upgraded fly-by-wire (FBW)flight control system on the latest derivatives of its A340 long-range widebody.
The update forms part of a wider range of improvements which will eventually be extended to the consortium's other FBW production models. The changes will debut on the stretched A340-600 - the prototype of which is in final assembly and due to fly early next year - and the longer-range -500.
The new A340 variants will be the first Airbus aircraft to feature FBW rudder actuation, signalling the elimination of the current mechanical linkage between the vertical control surface and the cockpit rudder pedals.
Airbus Industrie explains that "the rudder will still have an independent back-up, separate from the primary and secondary flight control computers (FCC), with its own power supply."
The move will reduce the weight and complexity of the rudder control system, says the consortium. Horizontal stabiliser trim will, however, continue to be mechanically controlled. Among other changes, the autopilot "inner loop" functions - or "damping and stabilising" control inputs - which are currently provided by the flight management/guidance and envelope computers (FMGEC), will instead be embedded in the FCCs. The flight guidance functions of the autopilot will continue to be handled by the FMGECs.
The A340-500/600 will also be the first Airbus aircraft to feature an electrical load management system, designed to "optimise the power generated to the load required", says Airbus. Another change will be the introduction of flat-screen liquid crystal (LCD) primary flight displays in the cockpit, replacing cathode ray tubes.
Airbus says all of the improvements will be used on the recently-announced A340-300 "enhanced", which is expected to be certificated in the second quarter of 2003 (Flight International, 25 - 31 July, P8). The 295-seater will also feature upgraded CFM International CFM56-5C engines offering reduced maintenance costs, in an effort to boost the type's competitiveness with the Boeing 777-200.
The stretched 380-seat A340-600, which will be fitted with ground manoeuvring cameras to aid taxiing, and the ultra long-range 313-seat -500, will be powered by Rolls-Royce Trent 500 engines. Both use an enlarged version of the A340-300 wing and are due to enter service in 2002.
The cockpit LCDs will be progressively introduced throughout the Airbus FBW product range, including the A320 family starting with the A318, which is due to enter service in 2003.
Source: Flight International
