A3XX: technical and design progress

Citation

(1999), "A3XX: technical and design progress", Aircraft Engineering and Aerospace Technology, Vol. 71 No. 1. https://doi.org/10.1108/aeat.1999.12771aaf.003

A3XX: technical and design progress

A3XX: technical and design progress

Keywords Airbus Industrie, Aircraft

When it is launched in 1999, the A3XX will, it is believed, be the biggest aircraft in commercial aviation service and the effort to define and launch it will be one of the largest peacetime engineering efforts in history.

A team of some 1,000 engineers, pilots, airline working group members, suppliers and commercial personnel have made concrete progress towards defining the specifications and performance of the flagship aircraft family of the twenty-first century. With operating costs 15 to 20 percent lower than the next largest competitor in the category, the A3XX will be able to carry up to 555 passengers in three classes. The first full-length, double-deck aircraft in history, the basic version will have a range of up to 14,100km/7,650nm and the extended range version will travel 16,200km/8,750nm, enough range to serve city pairs such as London to Singapore and San Francisco to Hong Kong.

The technical achievement of designing the A3XX is significant. As aircraft increase in size, so do the design challenges. Nevertheless, Airbus Industrie has already made significant progress in overcoming the major technical obstacles identified in the earliest stages of the programme and is strongly committed to this project. Applications for aircraft type certification were made to the JAA in January and to the FAA last month.

Interiors

The greatest challenge in defining the interior design of the A3XX has been ensuring that it is innovative, with maximum flexibility built into the cabin in the most efficient manner. With a cabin area on the main and upper deck more than 40 percent greater than a 747-400, the available real estate provides tremendous possibilities for passenger facilities. Nonetheless, Airbus Industrie is approaching the project with the philosophy that every square metre of space has value and will provide interiors that optimise that space.

Lower operating costs for the aircraft will allow airlines greater flexibility in how they approach the interior layout, but the key for Airbus Industrie designers is to help airlines give passengers more choice in how they would like to spend their time.

Today's aircraft designs limit passengers' ability to choose their on-board activities. Whether passengers care to use their time for work, rest or leisure, this ability will be reflected in the design of the aircraft. Consequently, facilities that enhance this flexibility are the focus of Airbus Industrie's design team. Business centres, lounge facilities and sleeping facilities are examples of the type of amenities that permit passengers to have this flexibility.

With a fuselage 25.4 cm(10in.) wider than a 747, a ten-abreast economy class seating configuration means each seat can be wider, without affecting the width of aisles. The lower deck area, which may also be utilised for cargo, is another area where Airbus Industrie is pioneering air travel amenities with the A3XX. The concept of lower deck sleeping areas and crew rest areas, currently available on the A340 series, will be expanded in the A3XX possibly to include galley space and lavatories, among other functions. Offering modular units that can be installed and removed with relative ease, perhaps on a seasonal basis, is one area of great interest to the design team.

With aircraft entry into service still six years away, one of the most difficult passenger amenities to envisage is in-flight entertainment. While personal televisions in every seat are becoming standard with the world's leading airlines, the challenge for designers is one of technology and reliability. They must create a flexible enough approach to allow definition of the systems closer to the aircraft's entry into service because the power and capability that passengers have in their office and home systems is what drives their expectations.

Privacy issues also feature heavily in the deliberations of the Airbus Industrie A3XX design team. While communication and entertainment systems currently available on commercial aircraft offer functionality, they do not offer high degrees of privacy. Methods to protect passengers' privacy are now under study.

The consultation process for the interior design of the A3XX has been one of the most comprehensive in commercial aviation history. Many of the world's leading airlines are currently offering their input on the process. And never before has so much consultation taken place so early in the design process. With entry into service scheduled for 2004, the design timeline is still in very early stages.

Aerodynamics

The A3XX, in aerodynamic terms, is the sixth generation of European swept-wing transport aircraft. The continuous evolution of the Airbus Industrie wing means that aerodynamic technology has kept Airbus Industrie products significantly ahead of the competition in terms of performance since the A300B first flew in 1972.

Span and other constraints have imposed unique aerodynamic challenges in the development of the A3XX, however, research and technology acquisition programmes within the Airbus Partnership and with the involvement of European research institutes and universities has meant that Airbus Industrie has risen to those challenges. Theoretical design activity, including use of state-of-the art CFD methods, has been complemented by substantial wind-tunnel developments, making use of world-class facilities across Europe. These facilities include the European Transonic Wind Tunnel where testing can be done to full-scale conditions. Testing to date has covered powered and unpowered testing at high speed, and unpowered testing at low speed, including all aspects of aerodynamic development. Further testing is imminent and will include powered testing at low speed in the high lift configuration.

Results from the tests done so far show that low speed/high lift performance targets have already been met or exceeded and that cruise drag is very close to the extremely challenging targets set. At this stage in the development programme, this is a very satisfactory position to be in and, with the additional development work already committed, Airbus Industrie is confident that the A3XX will exceed the excellence in aerodynamic efficiency demonstrated by its current products.

Powerplants

From the start it was obvious that new engines were required for the A3XX. Current A330 powerplants were not suitable, while 777 powerplants are too big and expensive. To this end, Airbus Industrie has signed agreements with all major engine manufacturers to develop new engines for the A3XX.

Rolls-Royce has committed to develop the Trent 900 engine, a derivative of its successful Trent family that can already be found on Airbus A330 aircraft in the Trent 700 version and the Trent 500, which is available on the A340-500/600.

The Engine Alliance, a joint venture between General Electric and Pratt & Whitney, is also making progress to define a new powerplant. The engines will each be in the 298-333kN/67-75,000lb thrust class, allowing manufacturers to concentrate on efficiency, rather than achieving higher thrust levels.

Airport and ground operations

All design aspects of the A3XX have taken the so-called 80 × 80 metre (263 × 263ft) box into consideration, ensuring that the aircraft will be able to operate within the design confines of all the world's major airports. In addition, Airbus Industrie has been very actively discussing ground handling requirements for the A3XX. Earlier this year, Airbus Industrie presented the aircraft to the IATA Ramp Handling Group. We are also evaluating the input from questionnaires sent to 116 ground handling equipment manufacturers, soliciting their input on ground handling issues. In addition, input from 60 of the world's largest airports is also providing useful feedback on A3XX design considerations.

Although the aircraft will not enter service until 2004, numerous airports are already actively planning for the aircraft's introduction to the world fleet. Last June, Airbus Industrie held the second A3XX Ground Handling workshop in Amsterdam where five major airports (Amsterdam, London Heathrow, Paris CDG, Washington Dulles, and Hong Kong's Chek Lap Kok) presented their plans for accommodating the A3XX. Other airports have similar strategies. Airbus Industrie is actively addressing how the size of this aircraft will affect airport ground operations. Landing gear and runway loads have been successfully reconciled and overall improvements in maximum takeoff weights will further aid airport operational considerations. Ground maneuvering will be comparable to current aircraft.

The aircraft's spacious double-deck design allows efficient circulation of passengers and will make boarding and deplaning quicker and more efficient than competing aircraft in its category. The grand staircase that has become emblematic of the A3XX is an integral functional element of this efficiency. While modified airbridges will not be essential for airports served by the A3XX, major airports have already indicated their intentions to make dedicated facilities, such as direct upper deck boarding, available to the A3XX for efficient aircraft ground handling.

Structures

Significant progress has been made towards selecting new materials and structural materials that will give the A3XX required weight and strength advantages over competing large aircraft. Workshops have been conducted with airlines to have a common understanding of the applications of new materials being considered, including aluminum lithium alloys, glass-fibre metal laminates, and carbon-fibre reinforced plastics.

It is estimated that of the expected 540 tonne (1.2 million lb) takeoff weight of the A3XX, about 140 tonnes will consist of aluminum alloy structure, 35 tonnes will be carbon fibre re-inforced plastics, 15 tonnes will be titanium and 13 tonnes will be high strength steel.

Airbus Industrie and its partners and suppliers are also looking at new manufacturing techniques, such as casting, extrusion and welding. Casting, which requires less assembly work, is being examined for the A340-600 and A3XX passenger doors. Extruded panels with integral stiffeners are being investigated as well as skins with welded stringers or welded frames. The welding process is accomplished with laser beams to achieve very accurate welds. This technology has weight and manufacturing advantages as well as providing better in-service behaviour than riveted structures.

Environmental achievements

Through the application of new technology, in many ways the A3XX will be more environmentally friendly than many of the aircraft in operation today. Ambitious targets have been set for noise and pollutant emissions, as well as improved fuel efficiency.

In spite of its higher weight and thrust requirements, the A3XX will make less noise than a 747-400 while carrying 30 to 50 percent more people. Current noise certification rules (ICAO "Chapter 3") will be met by significant margins. The A3XX will help to cope with growing passenger numbers without negatively affecting the airport environment because of these significantly reduced noise levels.

To meet these targets, engine manufacturers engaged in the project have applied the most modern technology to reduce fan, jet and turbo-machinery noise. Airbus Industrie is working on a comprehensive research and technology programme including wind-tunnel tests with original landing gear and a full-sized wing with deployed slats and flaps.

Noise during ground operations can also affect airport neighbourhoods and airport staff, therefore, the A3XX will taxi with only two engines, will use only two thrust reversers and employ a low-noise auxiliary power unit to help eliminate any noise concems.

Although it will carry many more passengers, emission quantities from A3XX engines will be as low as current large aircraft and future ICAO-CAEP 4 rules, with reduced limits for nitrous oxides, will be met by a significant margin. The economic fuel consumption of the A3XX will also help reduce the impact of exhaust gases on the high atmosphere.

The flagship of the twenty-first century

The A3XX is progressing rapidly and promisingly through its design programme. At this pace, this aircraft is on schedule to become the flagship of commercial aviation fleets around the world when it enters service shortly after the turn of the century. No other aircraft has the range, capacity and technological innovation of the A3XX and, therefore, the A3XX has no feasible competitors in the ultra-large aircraft category.

Further details are available from Airbus Industrie. Tel: +33 (0) 5 61 93 33 87; +33 (0) 5 61 93 34 31; Fax: +33 (0) 5 61 93 49 55; +33 (0) 5 61 93 48 34.