Airbus’s A350XWB takes wing


The Airbus A350 twin-aisle twinjet development programme took wing for the first time last September, when flying began with a carbon fibre-reinforced plastic (CFRP) fuselage panel fitted to an A340 test aircraft.

The European manufacturer intends to use CFRP panels extensively in the A350’s fuselage structure, in place of conventional aluminium-alloy materials. The company’s factory in Nantes, France, produced the panel, which was flown for three weeks in tests to assess the material’s acoustic characteristics under pressurised conditions. Once full flight-testing of the A350 begins, five aircraft are scheduled to take part in the 2,600-hour programme.

Marketed as the A350 XWB (standing for “extra-wide body”), the jetliner is to be available in at least three variants, with 250 to 400-plus seats, that will be aimed at a predicted market for 6,240 twin-aisle aircraft over the next two decades. Airbus, which currently serves the widebody jetliner segment with its A330 twinjet and four-engined A340, values the market at US$1.34 trillion.

By the beginning of this year, Airbus had taken firm orders from 36 customers for some 583 A350s, including 63 during 2010. In the greater Asia region, these clients include AirAsia X (which has ordered ten aircraft), Air China (another ten), Asiana Airlines (30), Bangkok Airways (four), Cathay Pacific (30), China Airlines (14), Hawaiian Airlines (six), Hong Kong Airlines (15), Kingfisher Airlines (five), Singapore Airlines (20), and Vietnam Airlines (ten).

Three variants

The A350 family will comprise the -800, -900, and -1000 variants, offering ranges of up to 8,500 nautical miles. The A350-800 will be a ‘shrunk’ version of the larger -900, accommodating 270 passengers in a typical three-class layout, while the A350-900 and A350-1000 will seat 314 and 350 passengers, respectively. Each model can be configured in a high-density layout with as many as 440 seats.

Airbus says A350 passenger cabins offer more headroom, wider windows, and larger overhead storage space than current competitors. The 220-inch internal cross-section provides “the widest seats in its category”, the manufacturer claims. The cabin interior is only slightly smaller than the 222-inch external diameter of all previous Airbus widebodies, a size the manufacturer has always regarded as having been a “magic” dimension.

Design of the baseline A350-900 was frozen in December 2008 and Airbus is planning for entry-into-service with Qatar Airways in 2013. The smaller -800 is to enter service in 2014, a year ahead of the A350-1000 flagship. With the -900 taking most of the manufacturer’s attention, the planned mid-2010 timing for A350-1000 design freeze has slipped and detail design is now set for completion by the end of this year.

Although the Airbus website’s A350 airport-compatibility information still referred in February to the first example of the new aircraft being “produced in July 2011”, the company has conceded that final assembly will not begin now until the end of the year. Even so, Airbus officials continue to discuss a nine-month assembly and test period and a first flight in mid- 2012. Assembly of “main components” will start in the middle of 2011, Chief Operating Officer Fabrice Bregier says.

Meanwhile, the manufacturer expects this year to begin wing assembly in the UK, start flight trials with a Rolls-Royce Trent XWB engine mounted on an A380 test-bed, and commence A350 systems testing on the company’s ‘Iron Bird’ ground-test rig in Toulouse. Airbus intends that the A350 family will provide a 25 percent reduction in fuel-consumption compared with current long-range competition.

Structural composition

About 70 percent of the A350 airframe will constitute composite material structures, titanium, and advanced aluminium alloys. Composites alone will account for about 53 percent.

As well as improved efficiency, the CFRP-panelled fuselage is expected to offer easier maintenance. Many of the panels and other CFRP components being manufactured by Airbus’s first- and second-tier partners use Cetex CF laminates supplied by TenCate Advanced Composites Europe, part of the Royal TenCate aerospace composites business.

The latest A350 development update, released in January, says some 13,000 engineers are engaged in the programme, about half of them with suppliers and partners, and Airbus expects its in-house A350 workforce to peak at about 12,000. Selection of industrial suppliers is complete and major parts are now being manufactured and prepared for transport to Toulouse for final assembly.

Recent programme highlights include completion of the initial 64.6ft centre-fuselage “crown” panel at Spirit AeroSystems in the USA and curing of forward-section crown panels at Premium Aerotec in Germany. In January, the European Commission authorised a 129 million euro (US$174 million) reimbursable loan to Spain’s Aernnova to develop the A350’s tailplane.

Last November, Airbus began construction of the first 18ft CFRP rear-fuselage ‘Section 19’ barrel in Spain, where production of the first flyable lower wing skin (or “cover” in Airbus parlance) began almost simultaneously. Other recent work starts include that of the upper wing cover in Germany, assembly of the first centre wingbox, and production of the first keel beam in France. In the UK, the landing-gear systems test facility has opened and hydraulic pressurisation of the Iron Bird took place at the end of December.

To support its aim for a high level of maturity at service entry, Airbus is using component demonstrators as it moves from the “virtual” world of the A350 digital mock-up (DMU) to the reality of manufacture. For the first time, Airbus has built a full-scale cabin and fuselage mock-up, on which suppliers and partners can test and optimise systems installation.

A three-part, full-scale CFRP fuselage section that includes a composite door is being used to confirm manufacturing and assembly techniques for the material, as well as fatigue and damage tolerance properties. For systems ground-testing, Airbus has begun to install functional integration benches at a site near Toulouse. Electro-mechanical systems, hydraulic, and wiring tests under static and real flight conditions will be performed on the ‘Aircraft 0’ integration simulator.

The manufacturer has refined programme management to enhance decision-making and improve transparency as manufacturing and assembly begin. The move is seen as enabling Airbus and its suppliers to work more closely as the A350 moves out of the design phase, permitting faster decisions on engineering, manufacturing, and procurement matters.

In-service target

The virtual-to-real transition contributed to the A350 entry-into-service being postponed from mid-2013 to an unspecified date later in the year. Airbus has established a supplier-development process in its procurement department and reportedly has created a “head of A350 operation” position to manage those programme elements not being out-sourced. The function is to ensure parts and assemblies come together in final assembly punctually at the right cost and with the intended quality.

Related to the revised in-service target date is a decision to begin final assembly of the first A350 (MSN001) at the end of 2011, rather than in mid-year as previously planned – a move intended to ensure the new aircraft does not suffer any A380-like delays.

Initially, the programme schedule had included buffers that enabled Airbus to say, almost a year ago, that deliveries would remain unchanged even though the A350-900 schedule had slipped by three months. The machining of certain parts – and, by extension, the beginning of final assembly – was delayed after some detail design work had required more time to be devoted to validation of the finite element model.

Metal cutting began 12 months ago, with machining of the horizontal cruciform that had been scheduled for November 2009, and which held up centre wingbox assembly. A cautious Airbus had wanted to assign sufficient time to understand the implications of working with CFRP, particularly in airframe sizing, electric structural network, and damage tolerance and the wing-root joint.

At the beginning of this year, German supplier Premium Aerotec began machining of the first A350 aluminium-floor beam using high-speed tools introduced for the purpose. The company has invested in other equipment for the production and processing of the A350’s CFRP fuselage shells.

This followed the airframe manufacturer’s initiation of CFRP barrel manufacture in Spain in late 2010. This tapering, 18ft-long rear-fuselage section is distinct from other A350 body sections in being produced using a carbon fibre-placement process rather than being constructed with long, CFRP skin panels.

Also about three months ago, Airbus subsidiary and partner Aerolia began production of CFRP fuselage and shell panels for the A350 nose section at a new composite-materials unit in France. The site comprises five manufacturing areas: a ‘clean’ room for composite lay-up, an autoclave, panel trimming facility, and ultrasonic non-destructive testing section. Three paint booths feed panels to assembly lines, where robot stations attach clips and frames.

In late 2010, manufacture was under way on the centre wing box, upper and lower wing covers, and a landing-gear test facility had been opened.

Extended enterprise

Airbus claims that its “extended enterprise” approach to project partnerships enabled “key” suppliers to be committed to the A350 up to a year earlier than on previous programmes, with larger work packages having been contracted from fewer first-tier providers.

“The implementation of common processes, methods, and tools – including a single, integrated three-dimensional digital mock-up and a unified planning ‘tool’ – are resulting in more- efficient information-sharing,” the company says.

In February, Magellan Aerospace added a ten-year, US$20 million agreement to provide A350 crown fittings to an existing contract for centre wing box and pylon secondary-structure work. The new business covers machining, treatment, and delivery of 800 ship-sets of machined aluminium-lithium detail components, starting in April.

Involvement in the A350 has stimulated some suppliers and partners to invest in manufacturing capacity. For example, after acquiring Airbus’s former UK aerostructures business at Filton and following its selection to make A350 rear spars, GKN Aerospace has committed almost US$200 million to developing a “centre of excellence” (see box).

In attempts to ease Chinese market access, the manufacturer has placed 5 percent of its A350 airframe work in China. Airbus China president Laurence Barron points out that government and airline officials have been following the country’s 2011-2015 five-year plan, the period during which initial Chinese A350 deliveries fall – making orders more difficult to obtain. He says the backlog of almost 600 aircraft on order means prospective owners must wait a long time and “that makes it more difficult here in China”.

Six months ago, Airbus appointed China’s CAC Commercial Aircraft Company (CCAC) to manufacture A350 wing spoilers and leading-edge “droop” panels, largely of CFRP, an arrangement that completed the planned work allocation to the country. Related design work will be performed by the Airbus (Beijing) Engineering Centre joint venture, with Austrian composites specialist FCC charged with defining the industrial process. The spoiler’s centre hinge fitting will be manufactured using resin transfer moulding, a process Airbus describes as “innovative”.

Goodrich has been contracted to design, test, manufacture, and support the A350-1000’s main landing gear, while that for the smaller -800 and -900 variants is being developed by Messier-Bugatti. The higher-weight A350-1000 will sport six-wheel main bogies, while four-wheel units equip the other models. The US company says the business is worth more than US$2 billion over the life of the programme.

In addition, Goodrich is providing – for all three A350 variants – engine nacelles and thrust reversers, landing-gear wheels and brakes, air-data and ice-detection systems, external video equipment, and cabin-attendant seats. Last November, it announced shipment of the first thrust reverser for ground tests on a Trent XWB, initially at Rolls-Royce in the UK and later at the John C Stennis Space Centre in Mississippi.

The nacelle and thrust-reverser work, provided under a 2005 20-year contract, is valued at US$6 billion. “We went from engineering release to shipping hardware within 12 months,” says Tom Donnelly, Goodrich Aerostructures’ vice-president for Airbus business programmes.

Emirates requirement

A call by Arab carrier Emirates for improved A350-1000 payload-range performance is seen as a possible opportunity for General Electric to offer an engine to compete against the Rolls-Royce Trent XWB, a situation Airbus has said it would welcome.

Emirates, which included 20 A350-1000s in its order for 70 aircraft, would like to fly the 350-passenger model, with a near-100,000lb payload, year-round between Dubai and Los Angeles – a service currently operated using Boeing 777-200LRs.

The Gulf operator believes a 100,000-105,000lb-thrust GE90, possibly a derated variant of the Boeing 777’s GE90-115, would permit Airbus to meet the airline’s requirement, which otherwise could be satisfied by an upgraded 777 variant. It is thought that enhancing the 92,000lb-thrust Trent XWB could require a new engine core.

Ironically, GE was the original sole engine supplier for the original A330-derived A350 but did not compete against the UK powerplant manufacturer when Airbus re-launched the planned aircraft as a new, wider-cabined design. Now, the US engine company remains to be convinced of the business case for the A350-1000 – which accounts for only 75 of the 583 A350 orders to date – and is reluctant to make the large investment needed to create a new engine to power all three A350 variants.

GKN invests in A350 parts production

Involvement in the A350 has stimulated some suppliers and partners to invest in new manufacturing capacity. For example, after acquiring Airbus’s former UK aerostructures business at Filton and being selected to make A350 rear spars, GKN Aerospace has committed almost US$200 million to developing a manufacturing ‘Centre of Excellence’.

Participation in the Airbus A350 programme as the rear-spar supplier has enabled GKN Aerospace to establish itself as a manufacturer of large, fully integrated airframe sections. The contract requires GKN to design, integrate, and supply spars and related assemblies, which it began to do early last year after having produced prototype spars for the aircraft’s centre wing box demonstrator in 2009.

GKN will manufacture the near 100ft-long rear spars in three sections, to which it will attach the frames, rib posts, landing-gear fittings, and other accessories. Under the partnership, GKN is using Airbus procedures and design tools to carry out stress analysis of the rear spar and trailing-edge assembly.

GKN derives the main loads being transmitted from the wing panels, landing gear, and fuel tanks into the spar from a finite-element model of the A350 wing. Having inherited the former Airbus UK aerostructures business, it has now set up automated “moving-line” assembly of trailing-edge and landing-gear parts on to the spar.

Airbus has specified that it wants the supplier to use automated fibre placement (AFP) machines in manufacturing, so GKN’s first prototype parts came from such a machine before the equipment left its manufacturer in Spain. GKN will eventually have five AFP machines in the UK, enough capacity to provide Airbus with ten ship sets per month when A350 production is in full swing.

At the 2010 Farnborough Air Show, GKN announced two further A350 contracts to produce composite parts for inboard and outboard flaps at its German factory. The company says the first flap components will be delivered in the early part of this year.

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