Bringing it back to earth

Patrick Wack / CAPA Pictures / Safran
Patrick Wack / CAPA Pictures / Safran

With aircraft getting ever larger, the landing gear required to get them back on the ground are growing with them, creating unique challenges in their design and manufacture as Mark Venables explains.

Located in southwest England, the Gloucester facility of Safran Landing Systems has been at the forefront of landing gear technology for over 75 years, dating from the innovative solutions of its founder, Sir George Dowty in the Thirties, with the development of the first internally sprung wheel, to the advanced landing gears of the world’s most modern aircraft.

Today, the 51,000m2 facility on a site of 100,000m2 employs approximatively 1,200 people. Activities include total capability from concept to in-service support including design, development, test, production, processing (heat treatment and surface finishing) assembly, commercial and product support for landing gears. The Gloucester test facility entails a Centre of Excellence in landing gear development, including extensive capability for strength, fatigue, drop endurance, environmental testing and system integration.

The facility is home to numerous landing gear programmes including Airbus single aisle main landing gears (A320, A321 and A319), Airbus A330 main landing gears, Airbus A350 main landing gears, Boeing 787 main landing gear truck beam, and Eurofighter Typhoon main landing gear.

Assembly of an A330 landing gear in Safran Landing Systems’ Gloucester facility

Going super-size

But pride of place at the Gloucester facility goes to the huge main landing gear for the A350-900.

“The A350-900 main landing gear is an excellent example of concurrent engineering between the Integrated Programme Team (IPT) in Gloucester and Safran Landing Systems’ global manufacturing operations,” begins Nigel Woodford, executive vice-president for programmes at Safran Landing Systems. “The main gear components have been produced across the company’s manufacturing facilities in Bidos in France, Montreal in Canada and Suzhou in China with the final assembly carried out at our new A350-900 landing gear production area at Gloucester.”

Currently, the facility produces eight systems a month on the A350-900 but as in all industries there are peaks and troughs with this month’s target up to ten.

“We manufacture on a flowline; it’s a pulse line not a continuous movement line that you’d see on car production,” Woodford says. “But we integrate the A330 and the A350 landing gears on the pulse line so that we will launch a 350 and then another 350, then a 330, then a 350, and they run them down the line. It’s a balanced takt, so it pulses every so many hours, and at the end of the process, it’s complete.

“We have the ability to adjust the takt; the takt is set to meet the requirements across the different derivatives that go through that pulse line. But when the rates were going up we looked at compressing the takt to be able to support it. The other thing, of course, with the pulse line is you do have the ability to look at different shift patterns to go from two shifts to three shifts to four shifts, if you’ve got surge requirements.

“We work on a pallet assembly so you mount the main component, which is the main fitting, then you’ll assemble the shock absorber, the bogie beam and all the other bits and pieces as it moves down the line to complete the assembly and the test. One of the biggest challenges we faced was the size of the components that required specialist hoists, cranes, as well as custom-built fixtures to hold some of the bigger items.”

The facility is working towards the end game of just-in-time assembly, but for now they carry stock to ensure there are no hold ups.

“One of the key elements is working with the supply chain, making sure that it is robust and capable of supporting our needs,” Woodford explains. “If you look at automotive, they are probably further on down this road. There are things we can learn from the automotive industry in terms of improving the flow and the supply chain activities to make sure that we get to that next level of efficiency.”

Testing times

Located in-house is the Gloucester test facility where the full range of tests are carried out as Woodford explains: “We obviously design the landing gear ourselves and that involves the usual engineering test disciplines. But at Gloucester we carry out strength tests, fatigue tests, endurance tests and drop testing to make sure of its energy capability way before it goes onto an aircraft. The fatigue test is a longer activity, it takes more time, but we’re way in advance of anything that is in service.”

When it comes to challenges, it is no surprise given the current cash-constrained world of commercial aviation that cost is top of the list.

“Of course, cost is the biggest pressure we are under but that is followed closely by ensuring repeatability. As you can imagine, you’re picking up a three and a half tonne billet of steel that’s been forged. You’re putting that up on a machine and you’re machining it. But manufacturing a component once you’ve got the capabilities, you’ve got the equipment to be able to handle it, it’s fine.”

One of the main tools that the automotive sector has adopted in their cost-saving quest is standardising parts but that is not an option for landing gears.

“Every landing gear tends to be a unique solution,” notes Woodford. “You can strive for some commonality when it’s within a family, but very rarely do you end up with commonality. The big elements of the landing gear are always unique. It depends on the airframe structure, what you’ve got to mount to, the height that’s required to get the clearance for the engines; is it wing mounted, is it body mounted?

“For the big gears, it tends to be a straight strap, but if you look at a A330 it is a single side brace, for the A350 it is a twin side brace as it is with the Boeing 787. It depends on the airframe, the structure, you’re designing the solution to fit that particular aircraft.”

A people based solution

Despite the advanced technology employed, Woodford is keen to emphasise that the successful end product is all about a very skilled and motivated workforce.

“We have a good engineering team and we have a global engineering team,” he concludes. “Like all companies, we have our skills and skills development and we monitor and use processes to identify what skills are required and develop people to fit those gaps. Particularly important is to make sure we have a succession plan in place.

“Are we having problems in recruitment? Generally, I’d say no. It is a very specific industry, but we’ve got a lot of people that have been with the company a long time, and we continue to work on people development. The people are key to the business and making sure that we’ve got the right people with the right skillset, and that we are creating and developing them in the right way, is critical to our success.”

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