Wing commander

BAe’s Airbus wing factory in Chester is reaching for even greater heights with a two-phase investment plan. George Paloczi-Horvath reports

In January British Aerospace’s Airbus subsidiary decided to establish a centre of excellence for machining aircraft wings at the Broughton factory near Chester where it has long manufactured wings for airliners built by the pan-European Airbus consortium.

This two-phase project will begin with a £25m investment in a new milling machine for the Chester plant to manufacture wing spars, with a further £20m planned. The investment, topped up with £1m from the Welsh Office, will create 100 jobs and safeguard 60 more.

The project is an important part of BAe Airbus’s agenda to help the factory, which is by most measures already a centre of excellence, become an even stronger competitor in the world airliner technology market.

The rationale behind the investment is clear. BAe has a 20% stake in the Airbus consortium and supplies all the wings for Airbus airliners, which are mainly produced at Chester, with other work done at Filton near Bristol. BAe’s first Airbus wingset was delivered in November 1971 and the 1,500th – for an A319 for Lufthansa – was delivered last August. Last year Airbus delivered 126 airliners, but this year this is expected to rise by almost 45% to 183 aircraft, thanks to the major increase in orders achieved in 1996.

The Airbus programmes support 25,000 British jobs in more than 300 firms and contribute £1bn a year to the trade balance, or more than 1.5% of Britain’s total manufacturing exports. Protecting that investment has become vitally important for BAe and UK plc.

The wing box structures for all Airbus airliners are assembled at Chester from parts and subassemblies produced at this and many other factories. Chester is responsible for completing and testing the whole wing for the A319, A320 and A321 family of regional airliners, with the addition of all hydraulic, air and electrical systems, plus flying control surfaces. The complete A320 wing is then transported by the massive Airbus A300-600ST Beluga cargo transport to Toulouse in France for final assembly, while complete A319 and A321 wings are transported to Hamburg in Germany for final assembly.

Wings for the widebodied Airbus airliners – the A300/A310 and the new A330 and A340 – are taken from Chester to Dasa Airbus in Germany for the fitting of flying control surfaces, hydraulic and other systems and therefore do not leave Chester in as complete a form as those of the A319/320/321 family.

A typical delivery of an A340 wingset is loaded into the enormous Beluga cargo plane’s outsize fuselage and made safe for onward transport in about an hour.

Parts for the wings produced by BAe Airbus are supplied by 27 companies in North America, Europe, Asia and Australia. Among these are nine US suppliers, undermining the often heard US complaint that Airbus is no more than a featherbedded European-only enterprise; other US suppliers provide engines and avionics for Airbus.

At Chester the production of wings is accomplished by following a carefully planned 1.4 mile `wing flow route’ on a site in which the total roofed area covers 129,982m2. The clockwise production route begins in the major components centre, from which parts are supplied to the wing skin panel assembly hall next door. Top wing skins are creep-formed in a 12x3x2.1m oven at 200 degreesC.

From here completed wing skins are taken to the wing production jigs and also to the so-called `out of jigs’ areas where other manufacture takes place.

In the subassembly area, stringers – longitudinal stiffeners – are assembled. The choice of whether a bolt or a rivet is used will depend on the strength properties required for the given skin section. A typical skin panel will have a bolt and rivet mix within the space of about half a metre.

The panels next pass to two `Rosie the riveter’ wing fastening machines – five-axis CNC systems from Gencor. Accuracies within 10,000ths of a square inch are claimed for these machines. Wing panels for A330 and A340 aircraft can typically be made in as little as 12.5 hours.

The next stage in the production process is the Airbus wing final assembly plant, where wingboxes and other componentry for the widebody wings are assembled. Wings for the A319/320/321 family are assembled in the Wing Equipment Centre which is dedicated to the smaller Airbus airliners. For these virtually everything is done to produce a complete wing. Some wing parts are supplied from outside BAe – outboard flaps from Dornier and slats from Belairbus, for instance.

John Callaghan, the equipment centre’s production manager, says complete wings for these airliners can be supplied in as little as six days from the beginning of construction and assembly. Adjacent to the final assembly plant is the wing despatch centre, from where wingsets are carried on special vehicles which load them into the Beluga.

The A330 and A340 wings are produced to a common design except for their engine pylon arrangements – two for the A330, four for the A340. Significant amounts of aluminium lithium alloy are used on the A330/340 wing – a first in civil transport aviation. The shift to this alloy is part of a continuing development programme to cut the wing’s weight, though BAe admits the techniques involved are not yet mature.

Using the experience of earlier Airbus wing designs, important aspects of the A330/340 wing’s manufacture have been pushed to the limits of technology.

Thus the inner rear wing spar is machined from a single die-forged piece of metal no less than 6m long. BAe Airbus scientists who led the wing’s design, Sid Swadling, former director of engineering and his successor Jeff Jupp said in a submission to the Fellowship of Engineering: `Ensuring uniform material properties following heat treatment and machining in components of this size has proved a formidable task, utilising the combined efforts of the technical design team, the foundry/forging specialists and the BAe machining facilities.’

For the A319/320/321 wings, a major advance was the reduction of production cycle times through a complete reorganisation of the manufacturing strategy. Thus major subassemblies are subcontracted to companies world-wide with final assembly at Chester, instead of producing most of the wing in-house.

Investment in new buildings and reorganisation of the factory floor allowed the establishment of the wing flow route. New milling machines and five-axis automatic skin and stringer riveters have also played a major part in cutting production time – and cost.

An electro-mechanical riveting (EMR) process is used to install fuel-tight rivets in the wing covers. This allows rivet installation forces of 30,000lb to be supported on a lightweight structure of 2.5tonnes, compared with typical 70tonne weight for riveting machines used elsewhere. This improvement has made a major contribution to cutting cycle times and costs.

The management at Chester place great emphasis on their achievements in simplifying the production process over the past four years, but acknowledge that there is still a great deal to do. Chris Wilkinson, head of manufacturing engineering, defines it as a continuous process re-engineering activity. Initiatives include a policy which Wilkinson calls the `implant principle’, under which metal, fasteners and other components are not paid for until BAe Airbus takes delivery.

And while BAe Airbus has undergone a revolution in its approach and attitude towards producing airliner wings, it has also been learning from its Continental Airbus partners under the Airbus Concurrent Engineering programme.

BAe Airbus does not have production `cells’ as such but the product unit manager is completely responsible for production progress in a given area and the workforce under him can pass judgement on his effectiveness in an open reporting system. The intention is clear enough. The product unit managers recruited straight from the shopfloor can and do advance up the production heirarchy, which is flatter than before, with one tier of management removed since 1992.

There are strong reasons to suppose that Chester faces a busy and prosperous future, but there are unsettling reasons for worry too.

To accentuate the positive first, last month Airbus’s global market forecast forsaw a demand for almost 16,000 jet airliners over the next 20 years. The value to BAe of a 20% stake in this might be around $187.4bn (£115bn).

But BAe cannot rest easy in the assumption that it does not have to do much to keep itself at civil aviation’s top table. It is a leading light in Airbus’s drive to adopt a single management structure by 1999. The resulting single corporate entity will feel free to allocate work where it makes the most commercial sense and where a partner has put in the effort and investment to retain a given production responsibility.

This is the context for BAe’s January decision to fund its centre of excellence, which will reach its full production capacity by December 1998 – a welcome investment in Britain’s future strength in civil aerospace.