ANDREW DOYLE / TOULOUSE
Engineering work on the world's largest airliner is reaching a peak as production of long-lead items gets under way in preparation for its first flight in late 2004
Apart from its full-length upper deck and enormous wing span, the 555-seat Airbus A380 will, viewed from the outside at least, offer the travelling public little evidence to suggest civil-aircraft technology has moved on significantly since Boeing unveiled the classical lines of its 707 more than 40 years ago.
Mindful of arch-rival Boeing's attempts to seduce airlines with images of its futuristic, though purely conceptual, Sonic Cruiser, Airbus is quick to point out that the A380's conventional external configuration belies the many ground-breaking innovations which lie beneath its skin.
Airbus's marketing staff mock Boeing's assertion that airlines can reverse the decades-long trend of declining yields by offering passengers marginally shorter flight times, arguing instead that the battle to reduce seat-kilometre costs must continue unabated.
A significant proportion of the A380's claimed 15-20% lower seat-kilometre operating cost, compared with the contemporary long-haul workhorse, the 416-seat 747-400, stems from the fact that it is a much larger aircraft. Few airline bosses will be prepared to countenance diluting these savings by equipping their A380s with duty-free shops and gymnasiums, despite Airbus's advertising. Whatever the interior fittings, the A380 promises to provide passengers with a better travelling experience as it has 49% more net usable floor area than the 747-400, but just 35% more seats, says Airbus.
What is equally significant for airlines and their all-important bottom lines is the effort that has gone into eking out as many additional efficiency savings as possible, through the use of advanced design techniques, composite materials and computing technology. This, Airbus claims, will enable the A380 to break even with a 58% load factor, compared with 70% on the 747-400.
Two versions of the baseline A380-800 have been launched. The passenger version, seating 555 passengers in a three-class, long-haul configuration, is due to enter service with Singapore Airlines (SIA) in March 2006. FedEx has launched the freighter variant, which will follow in 2008 and use a stronger wing that can be applied to the planned -900 stretch passenger aircraft.
Twenty major airlines, half of them based in the Asia-Pacific region, have been helping Airbus shape the design of the A380 for six years. Of these, seven have already announced orders for the aircraft.
Record launch
Significantly, the 20 participants in the A380 advisory group operate about two-thirds of all the seats now installed in aircraft that can carry more than 400 passengers - a category dominated by the 747. In addition, they all operate 747-400s on a variety of missions over long, medium and short ranges, and in all-passenger, combi, or full-freight configurations.
With 97 firm commitments secured, the A380 represents a "record launch for a new programme", claims Airbus executive vice-president customer affairs and chief commercial officer John Leahy. He expects sales of the ultra-large airliner to slow to "one to two incremental orders per year" until entry into service, however, when Leahy predicts the A380 firm orderbook will stand at "between 160 and 175 aircraft".
The manufacturer has stated publicly that it expects the A380 programme to break even at 250 aircraft, although some observers believe this is optimistic given the level of discounting thought to have been negotiated by launch customers. The A380's design has evolved gradually in consultation with the airline group and the definition phase is nearly complete.
Meanwhile, Airbus is close to completing the selection of equipment vendors for the $10.7 billion A380 programme and claims to have found takers for the bulk of the risk-sharing work packages on offer. Although the company initially hoped to place 40% of the programme with outside partners, the final figure will be between 30% and 35%.
About $2.1 billion of the A380's development cost is being provided by risk-sharing partners on the airframe and $900 million by equipment vendors, according to Airbus executive vice-president A380 programme Charles Champion.
Suppliers have been signed for 80%, by value, of the A380 equipment items being outsourced, says Champion. The contracts cover major components for the aircraft's flight control, fuel, electrical, hydraulic and environmental systems, cockpit avionics, landing gear, engines, nacelles and evacuation slides.
Some major items are still out to tender. They include onboard maintenance and information; cargo loading; water/waste; oxygen; ground steering and brake control; inertial navigation; radio; fire detection; cabin lighting; anti-ice and miscellaneous cockpit systems, plus the flight recorders, tyres and cockpit seats and windows.
"We intend to be 99% complete by the end of the year," says Champion. "We know what we want to put outside and it is clearly defined."
The A380 development effort is due to peak this year, when more than 5,000 engineers will be working on the project. Metal for the first A380 part - a cruciform component for the wing/fuselage junction - was cut on 7 January this year in Nantes, France, and manufacturing is now under way at plants across Europe. The prototype A380 is due to have its first flight by the end of 2004.
"Most of the drawings will be finished by year-end," says Champion. "This year we are finishing the last critical design review of the structure and systems."
As with any major aircraft programme, airframe weight remains a primary concern, although Champion is adamant the aircraft will meet its performance guarantees from day one. "Weight is a battle that you never 'win', but you always fight," he says, "but we will deliver the required performance to the airlines."
Vendors are also under "extreme pressure" to meet Airbus's weight targets, says Champion. "What we wanted to do, because of the aircraft size, was to send strong messages on this issue," he says.
The structural weight of the aircraft had to be increased after launch customer SIA insisted the A380 be capable of meeting London Heathrow Airport's strict night time departure noise limits.
Project collaboration
To meet the noise requirement, the fan diameter of the engines had to be increased, pushing up the weight of the aircraft and increasing drag. Intense engineering work before the industrial launch of the A380 was required to reconcile the bigger engines with the aircraft's payload/range targets.
Champion points out that for the first time truly transnational engineering teams within Airbus are working together on an aircraft project, thanks to the integration of the Airbus assets of shareholders EADS and BAE Systems into a single company. Previously the work was divided strictly along geographical lines between BAE in the UK and the former Aerospatiale in France, DaimlerChrysler Aerospace in Germany and Spain's CASA. The team is now organised around the deliverables of the aircraft, says Champion.
Overall responsibility for each major subassembly has been awarded to the traditional Airbus "centres of competence", with St Nazaire in France taking the nose and parts of the centre fuselage, Hamburg in Germany handling the forward and rear fuselage sections, Broughton in the UK taking the wing and Getafe in Spain the horizontal stabiliser.
Airbus claims Fuji Heavy Industries and Jamco of Japan have agreed to take on risk-sharing work, while Mitsubishi (MHI) is taking an indirect stake through Eurocopter. However, the Japanese manufacturers are investing only in setting up their own production tooling and will not receive a share of A380 sales revenues, meaning they are still technically classified as subcontractors.
MHI said last year it would not take a stake in the A380 for fear of compromising its strong links with Boeing.
To date, 33 risk and revenue-sharing partners have been secured for 81% of the work packages being offered externally, by value, putting Airbus on course to offload "about 30%" of the A380's total development cost, according to Airbus chief executive Noël Forgeard. Among those selected are Alenia, Composites Technology Research Malaysia (CTRM), EADS Socata, EADS Sogerma, Eurocopter, Finavitec, Fokker, Gamesa, GKN, Labinal, Saab, Sabca, and Sonaca. Korea Aerospace Industries is expected to sign for a 1.5% stake to produce aluminium wing panels.
CTRM will supply wing leading-edge access panels, while Jamco will make the upper deck floor carbon crossbeams and Boeing-owned Hawker de Havilland (Australia) the wingtip fences. In all, Asian aerostructures suppliers have won A380 business estimated to be worth $1 billion.
Innovations
"We are quite comfortable with the commitments we have from risk-sharing partners and vendors," says Forgeard. Government-backed refundable loans account for a further 33% of the programme cost, with the rest being funded by Airbus partners EADS and BAE Systems.
Innovations being introduced on the A380 include the carbonfibre reinforced plastic (CFRP) centre wing box, rear pressure bulkhead and rear fuselage section 19 aft of the bulkhead. The aircraft's wing ribs will also be made from CFRP. Section 19 will be one of the largest and most complex CFRP parts yet produced by Airbus.
Also to be made from CFRP are the horizontal stabiliser and vertical fin, flight-control surfaces and cabin floor crossbeams. The upper fuselage will be partly constructed from glassfibre/aluminum composite material glare, bringing the percentage of the A380's total structural weight accounted for by composites and hybrid materials to an unprecedented 25%.
Other items that Airbus terms "major systems innovations" include bulbless external lighting, open avionics architecture and ethernet-based data communications, onboard electronic maintenance documentation and logbook, onboard cockpit and cabin services information system and onboard oxygen generating system.
The A380 will be the first airliner equipped with a hydraulic system pressurised to 35,000kPa (350 bar/5,000lb/in2) to reduce the weight of piping. The current standard pressure for airliners is 21,000kPa. US company Eaton will supply the engine-driven pumps, tubes, hoses and fittings.
The overall power distribution system comprises two hydraulic and two electrical systems, and the flight controls are equipped with electro-hydraulic actuators, meaning an electrical back-up is available in case of hydraulic systems failure.
The electrical system is variable frequency and power distribution is controlled by solid-state components, aimed at improving reliability and efficiency.
The aircraft's fly-by-wire system will be used to reduce the loading on the horizontal stabiliser, and therefore drag, by relaxing aerodynamic stability margins. In addition, the distribution of fuel in the wings will be controlled to provide optimum "bending relief".
Airbus also decided the passenger cabin doors will be opened and closed with the assistance of electro-mechanical actuators.
Manufacturing advances include laser-beam welding - recently introduced during production of the A318 - which will be used to attach stringers to the skin of the A380's lower fuselage.
Airbus executive vice-president manufacturing, Gerhard Eisen, says laser beam welding will make "a significant contribution to cost and weight savings".
Other innovations include automating assembly of the CFRP centre wing box and employing high-performance rotating cutting tools to produce other A380 parts. These tools can be used for all metal and composite materials and can shape complex parts with thin walls because cutting forces are lower compared with conventional cutting tools.
To minimise development and production costs, each part was reviewed on a "make or buy" basis, says Humbert, which led to Airbus's own factories being "challenged" to compete for work against outside suppliers.
A key requirement is "to try to reduce jigs and tools to a minimum" to cut production costs, says Humbert.
Using flexible, laser-guided tools means only software changes will be needed to start production of parts for other planned A380 variants such as the freighter and the stretched variant. "This is the real advantage," says Humbert.
Savings
The savings from introducing new manufacturing techniques to reduce tooling are not only attractive for the A380 programme, with its relatively low planned production rate of four aircraft a month.
"The driving factor is that we save on every programme," says Humbert. "We will use the new projects [such as the A380] to introduce new aircraft-manufacturing technology."
The decision to go ahead with longstanding plans to construct a substantial portion of the A380's upper fuselage from Fokker Aerostructures-developed Glare represents a marked achievement for Airbus's engineers. The green light follows an exhaustive test and evaluation programme to make sure the lightweight aluminium/glassfibre sandwich panels will be able to withstand the rigours of airline service. A full-size test fuselage panel was produced as part of the evaluation and another was flown on a German air force A310.
Key attractions of glare include its relatively high damage tolerance, improved corrosion resistance, light weight and improved fire resistance compared with traditional aluminium alloys. Airbus executive vice-president engineering, Alain Garcia, says that following the tests, "we thought that we were ready and we presented [Glare] to programme management".
The CFRP centre wing box is also an ambitious undertaking, given the fact that the assembly - measuring about 7 x 8 x 2.4m (23 x 26 x 8ft) - is equivalent in size to a small apartment.
"The basic technology is known," says Garcia, but the size of the box and its complexity meant "we had to develop a method to get the right product in time".
Unusually for a four-engined airliner, only the A380's inboard engines will be equipped with thrust reversers, to save weight and reduce maintenance costs. Airbus engineers say the manufacturer would have liked to eliminate thrust reversers altogether, but some airline customers felt more comfortable retaining a pair of the devices to give pilots the option of using them as a steering aid on contaminated runways.
The non-availability of reverse thrust would rarely, if ever, have resulted in operational restrictions for the A380, say the engineers. In certain cases, however, it could enable a higher payload to be carried, taking off from a relatively short, contaminated runway on a long-range flight.
Another notable change to the design introduced during pre-development was the reconfiguration of the main landing gear. This followed extensive pavement loading tests carried out with a specially constructed machine in Toulouse. The 20-wheeled device was loaded with concrete blocks to emulate precisely the aircraft's main landing gear footprint.
As a result of the tests, the two main body gears will now be equipped with six-wheel trucks, as opposed to four-wheel trucks, while the wing post trucks will have four rather than six wheels. The overall number of main landing gear wheels remains the same, at 20.
The width of the A380's fuselage has enabled Airbus's designers to extend the aft-cargo hold forwards between the main landing gear stowage bays, accommodating an extra row of LD3 containers.
One of the most challenging aspects of the A380 design has been the emergency evacuation system for upper-deck passengers. Concerns that some people may baulk at jumping on to a slide from such a height has led to Airbus opting for a curved "helter skelter"-style design, so a passenger is unable to see the bottom of the slide from the top. The manufacturer is also considering adding a hood at the top of each upper deck doorframe to avoid potential vertigo problems.
The A380 will be the first all-new Airbus aircraft to benefit from the reorganisation of the former consortium into an integrated company, says executive vice-president customer services Patrick Gavin. Previously, Airbus partners BAE Systems and the former Aerospatiale, DaimlerChrysler Aerospace and CASA were responsible for vendor selections relating to their respective subassemblies, whereas the sales and marketing headquarters in Toulouse would have separately overseen technical support provision for vendor-sourced parts.
Vendor support
"For the first time, support by vendors was taken into account," says Gavin, "made possible by the Airbus integration, which enables better vendor monitoring."
Previously, an operator needing a vendor item repaired or replaced would have to contact Airbus in Toulouse, which would then have to conduct a "sort of negotiation" with the relevant Airbus partner to get resolve the problem, says Gavin.
"It's essential to be efficient and reactive when you need to fix a problem on a vendor item," he says. "Support is one of the key criteria in the selection of vendors. It's a big improvement for us because the people facing the customers are those dealing with the vendors," he adds.
After studying a range of options for transporting major subassemblies to the final assembly line in Toulouse from factories elsewhere in France and in Germany, Spain and the UK, Airbus opted for a combination of land and sea transport.
Structural assembly and systems equippage will be performed in Toulouse. After roll-out, green aircraft will be flown to Hamburg for cabin furnishing and painting. Those A380s destined for European and Middle Eastern customers will be delivered from Hamburg, while aircraft for operators based further a field will be returned to Toulouse before handover.
A consortium of Louis Dreyfus Armateurs and Cetam has been contracted to provide the sea-transport services. Airbus expects to select suppliers of road and river transport and of the required transport jigs and tooling by year-end. Also due to start this year is work on road and harbour infrastructure modification. Airbus wants to carry out a pilot trial of the transport arrangements by October 2003.
Assembly of the first aircraft sections is due to begin within the next 12 months and construction of new A380 factories in Broughton (Airbus UK), Hamburg and Toulouse is under way.
Source: Flight International
