On a radiant day in Bristol, the sun pours like honey through the stained-glass windows of Pegasus House, bathing the zodiac symbols on the floor of the listed art deco building in light. The windows celebrate the once-resident pioneers in aerodynamics – an endeavour that continues on the Filton site – with illuminated brown-and-gold biplanes and aviators arising next to a spiral staircase, and dating back to the dawn of the aerospace industry in the city.

The building, which now houses many of Airbus’s back-office functions in Britain, and sits adjacent to a sleek modern building in which the company’s teams of engineers are based, was not always in such good nick. Left empty for years, it was a site prone to vandalism, raves and squatting. Indeed, the grade II-listed structure, otherwise known as New Filton House, which opened in 1936, had been left derelict for 20 years before reopening in September last year. 

The celebratory mosaic in the main entrance vestibule, featuring a sun, winds and the 12 signs of the zodiac, and picked out in German silver and inlaid in marble, was designed by sculptor Denis Dunlop and seems ironic in intention: the French Zodiac plane was a design that Sir George White of the Bristol Aeroplane Company first intended for production, having acquired the UK manufacturing rights, but the plan flopped. 

Across the way from the refurbished building is the new Barnwell House, where more than 2,000 Airbus engineers and designers are situated. It is a large, modern, open-plan office space created for Airbus’s operations in Britain, and purpose-built to house the engineering teams – previously situated in various locations throughout the existing Filton site – under one roof. At the time of delivery, the project was the third largest Airbus construction scheme in the world, according to contractor Miller Construction. 

Rob Kay, the engineer now responsible for landing gear for single-aisle aircraft, has also been involved in developing ‘sharklets’ – new winglets intended to boost the performance of the revamped fleet workhorse, the A320, which came into service in 1988 and has an economic and environmentally friendly ‘new engine option’ (NEO). Airbus is offering customers for future A320s a choice of new engines, including one from the CFM International joint venture between General Electric and Snecma, called Leap-1A, and another from Pratt & Whitney – the PW1100G-JM. With the sharklets, the new engines will burn around 16% less fuel, it is claimed. Airbus is targeting 2015 as the first delivery for a re-engined A320. The aircraft family competes, or has competed with, the Boeing 737, 717, 757, and the McDonnell Douglas MD-80/MD-90. The design is popular with low-cost airlines such as EasyJet, and with full-service carriers such as British Airways.

Kay, who has been with Airbus since 2000, welcomes the new working arrangements at Filton’s Barnwell House, which features engineering teams for wing and landing gear design and integration, fuel systems, and structures physics and testing. “We have all the engineering teams here now, from leading gear to fuel. Formerly, we were everywhere: if you wanted to see an expert, first you’d have to get an appointment – and then get on the bus. Now you can just wander downstairs and bump into people.”

Single-aisle Airbus aircraft rely on Messier Dowty to supply the main landing gear, which in turn has a supply chain of its own feeding the firm’s Gloucester operation. “The focus for Airbus is on integrating components and systems from other suppliers. That is where we add value. We will verify the landing gear systems and landing gear itself, and make sure that it functions,” says Kay. “Airbus is at the top of a pyramid of companies. Major structural components or systems can be made in the supply chain. Essentially, our specialism is in overall engineering integration.”

Where landing gear is concerned, progress is incremental rather than revolutionary. For example, A350 landing gear features a double-sided stay – lateral struts extending fore and aft of the main leg – which reinforces the gear to absorb the high loads otherwise transmitted to parts of the plane’s composite structure, says Kay. 

Testing landing gear components is part of the job of Steve Raynes, head of the structures test centre at Filton. His team will simulate the load on landing gear fuse pins over tens of thousands of flight cycles. They test everything from individual fasteners, coupons, or material test samples, to winglets, right up to complete wings, for both new programmes and existing aircraft.

“The aim is very high reliability,” says Kay. For example, one measure is technical faults that cause a service to be delayed by 15 minutes. Very few flights are delayed for that reason, he says. “Of single-aisle aircraft, one is taking off or landing about every two seconds: to have two in 1,000 delayed because of technical reasons is phenomenal. It’s a great performance – but the airlines always want more.”

We clamber up and down ladders to see the test rigs in action, testing complete components such as sharklets, or smaller parts of airliner skin. Of the 16% improvement in fuel burn touted for the new-engine A320, about 4% might come from the winglet, and the remainder from the new CFM or Pratt & Whitney gas turbine. Winglets essentially ‘fool’ the wing into having a greater span, which cuts down on drag while allowing the plane to fit into the gate at an airport, which stands at a maximum of 38m for a single-aisle aircraft, says Kay. For the twin-deck A380, the plane had to fit into an 80m span, however. 

The test rigs feature a mixture of bespoke and off-the-shelf technology, and Filton’s sprawling complex of buildings also includes a wind tunnel. “There was a point when people were talking about computational fluid dynamics replacing wind-tunnel testing,” says Kay. “In the end, you have to validate the virtual model in reality.”

Raynes says that other methodologies for testing aircraft components are also under investigation, including digital image correlation and photoelasticity – a full-field technique for measuring stress and strain that relies on a material’s ability to bend light as it passes through it. Areas of strain on a given component show up as purple on an isochromatic map. “The idea is that you identify points of stress and strain and optimise your design accordingly,” he says. The photoelasticity phenomenon was first demonstrated by Scottish physicist David Brewster in the
early 19th century.

Among other tests being simulated are the deformation of aircraft wings in the event of a tyre bursting and fragments striking them. To carry out this type of work, the test centre uses strain gauges, which rely on many kilometres of cabling stretching back to a central control room. However, the centre is exploring wireless alternatives, says Raynes. The test system is powered by hydraulic fluid driven by high-
pressure pumps, which work at about 3,000psi (20.69MPa). Many thousands of loads on a component are simulated, mimicking its in-flight life. It is hoped that physical testing will correlate with finite element analysis models.

To simulate bird strikes or tyre impacts, the centre uses a compressed air ‘gun’. Samples might travel at 25m/s. “Test is a fast-moving environment,” says Raynes. Other experiments are less fast-paced: for example, monitoring crack deformation in a sample, where tiny saw-tooth marks are made and then allowed to grow. “We plot the deformation of the sample, and then enable the part to be designed with what we call ‘crack stoppers’ as well,” he says. Ultrasonic testing can be used to measure deformation in a material by timing how long it takes for an ultrasonics wave to travel back to an oscilloscope.

The process begins with testing the smallest possible item, or material ‘coupon’ sample, and works its way up to an entire wing, for example. Even if you know the fatigue life of a certain material, designing in features such as corners changes the way it performs under stress, says Raynes. “You need to verify the designer’s intentions. We are putting real aircraft loads on to be representative of flight conditions.” For example, landing-gear pins have to be sturdy but also sensitive. “The pins have to be strong enough to sustain the ultimate landing case but, should you ever get in a crash scenario, they have to detach safely. There’s only a 5% margin involved.”

As well as wireless connections to strain gauges, other applications of modern technology inform aspects of work at the Filton test site, including robotics. Kuka robots have been employed to test robotic techniques for composite lay-ups, says Raynes. 

Automation, for so long the province of the car industry, is beginning to make stronger inroads into aerospace, says Colin Mitchell, one of the engineers at Filton responsible for research and technology programmes. At the recent Mach machine tool show, for example, a robot specifically designed to deal with some of the intense manual work found in wing manufacture was demonstrated by Japanese company Fanuc, although it is not working with Airbus currently. “We are doing a lot of work with automation, mostly to assist the worker – not replace them,” says Mitchell.

Wings, for instance, require thousands of holes to be drilled. Today, semi-automated drilling units are used. But the end operator still has to position these using templates, before the drilling takes place. The speed and feed to the drill is controlled by the unit, but the positioning process could cause strain injuries for the operator, so “there is scope to improve quality”, he says. “Automation could play a part here in terms of positioning. Another area where it could help is in handling of large panels.”

The onus is on Airbus in ensuring that human beings and their potential robot co-workers get along on the shopfloor, says Mitchell. “We can’t just introduce robots into the worker manufacturing environment. We need systems where automation recognises the human element; mobile robotics have to be able to recognise a human as such as opposed to a stationary object, and take a different path. Even if a person walks toward them, it has to always move and change direction.”

Another key area of research for Airbus is the development of composites and methods of composites manufacture, where the primary driver is to reduce cost. The company is already flying additive-layer-manufactured (ALM) components on test aircraft. Its 3D printing innovation centre is based at Filton. But it will be a while before ALM components are used routinely, Mitchell believes. “It will be three to five years before such parts are being used in the mainstream.”

The entire industrial process at Airbus’s plant at Broughton in North Wales, which makes wings for every family of Airbus aircraft, is being reviewed, says Mitchell – because if capacity at the site could be expanded, then the work is out there. “Our advance orderbook is unprecedented in most industries. If we can make productivity improvements with an industrial system with a high degree of automation, we would consider it. We are very busy on single-aisle.”

Airbus is making around 40 single-aisle aircraft a month, but Kay believes the firm needs to ramp up to 50 or more to take advantage of demand. “We can anticipate a rate of 60 single-aisle aircraft a month in the future,” says Mitchell. Learning from the car industry will be important, so Airbus is looking at a partnership with a UK-based automotive OEM. 

Mitchell is involved in the new Catapult technology and innovation centres, which he compares favourably with Germany’s long-established innovation powerhouses, the Fraunhofer institutes. He is a member of the advanced design and manufacturing Catapult, and says he has been impressed by government commitments to the aerospace sector, including the Aerospace Technology Institute programme, which is worth £2 billion over the life of the next parliament. Airbus is already working with the institute on several projects, he says. “The government is starting to develop this in a strategic manner – and I don’t see that happening to the same extent elsewhere in Europe.” 

Key employer wins accolade for enterprise

Around 100,000 jobs are sustained by Airbus’s activities in the UK. Including those working for suppliers, more than 4,000 people are involved in design, engineering and business support roles in Bristol. Filton is responsible for the wing assembly and equipping of the A400M military transport, while Airbus’s production facility at Broughton, North Wales, assembles the wings for all Airbus civil aircraft.

The site at Broughton employs more than 6,000 people, primarily in manufacturing and engineering. After assembly, the wings for the A380 are transported by road and then river craft to Mostyn Harbour, where they are loaded on a ferry for transport to France. Broughton has also produced the De Havilland Comet and Mosquito. 

Airbus won a Queen’s Award for Enterprise in April. The company received the Queen’s Award for International Trade for ‘outstanding overseas sales growth over the last three years’. Aside from exports, the company was recognised by the awards panel for understanding and anticipating the future needs of customers and environmental issues. 

The British aerospace industry is recognised as being the second largest by value globally after that of the US. Airbus tries to locate as many operations as possible in US dollar-denominated economies, to insulate the firm against currency movements. Aircraft are priced in US dollars. Based on current orders, 10 years’ work is estimated to be in the pipeline for British aerospace firms. Initiatives to help British suppliers prepare for increasing global competition in the civil aviation market have been set up, such as Sharing in Growth, which is led by Rolls-Royce. Figures from aerospace and defence association ADS show a year-on-year increase in airline deliveries. April data revealed a record first quarter for aircraft deliveries in 2014, it says. In the first three months of the year, 302 single-aisle and widebody aircraft were delivered – a 35% increase on the first quarter in 2011, and 7.5% more than in the same period last year.

The figures put the global industry in a strong position, with experts predicting that the order backlog will continue to grow, says ADS. “The first quarter of 2014 has set a new record for aircraft and engine deliveries, offering a strong foundation for the year ahead and confirming significant UK growth for this global industry,” it said. 

“Aerospace manufacturers are working hard to respond to the current and projected increase in demand. The Aerospace Industrial Strategy and the Aerospace Growth Partnership are helping to secure investment in technology, skills and facilities to improve efficiency and access opportunities in markets around the world.”

Record interest in airshow 

Farnborough International has said it has confirmed a “record number of requests” to exhibit at the forthcoming airshow. As PE went to press, more than 70 aircraft were confirmed as part of the static line-up and a further 23 for the flying display.

The show, in Hampshire, will feature several Farnborough firsts, from the F-35 Lightning and Textron Airland Scorpion to classics such as the ME262 and the Spanish Navy’s Sea Harrier.

The theme for this year’s show is ‘100 years of aviation’. It will feature aircraft from every decade of the past century. A performance by the Great War Display team will commemorate the 100th anniversary of the start of the First World War.

A new feature of the static display will be the vintage aircraft collection tent.

The airshow runs from 14 to 20 July.