FLUG REVUE August 2005: Engineering oursourcing gains momentum

August 2005

OUTSOURCING IS BECOMING MORE AND MORE THE NORM

By Matthias Gründer

Today it is not uncommon for engineering companies to independently develop and deliver finished products or prototypes to original equipment manufacturers (OEMs), vis-à-vis they see themselves as service providers. These include not just the aircraft manufacturers but also the producers of subassemblies and systems. “Originally the OEMs were somewhat reluctant to give such work to outside contractors,” says Harald Felten, head of Aviation at Ferchau Engineering in Bremen. “Initially they were only used to cope with peaks in demand. But today our services are taken for granted in the plans of the end manufacturers.” He cites a few examples of this.

For the A400M military airlifter, there is a requirement to develop systems for smoke warning, fire extinguishing and also for draining the cargo bay. In the latter case, this means that condensation and rainwater and also water that gets into the hold with the freight has to be taken outboard again, using drainage pipes. This requires that a pipe system is constructed out of thin-walled steel pipes; this must be designed specifically for the quantities of fluid that are to be expected and the drainage routes that will be available. Moreover, these thin pipes must not collide with any other systems under the floor of the hold.

The development engineers receive the documentation necessary for this from Airbus Military and determine from this the points at which fluid can be drained off. Finally the pipes are installed with a gradient of two degrees, so that the system functions virtually like a rain-water gutter.

The lines for the smoke detectors and the fire extinguishers with associated extinguisher bottles also have to be installed in such a way as to avoid collisions. However, unlike the drainage, these systems are mounted in the cargo bay ceiling, and here Airbus makes digital documentation available as well. The layout of the systems, allocation of space, choice of materials and attachment method are left entirely to the discretion of the engineering specialists.

Air conditioning tailored to customer requirements

Another area of work for the developers is air conditioning systems on board passenger aircraft. The cabin itself, toilets, galleys, video control centre and crew rest areas have to be ventilated and vented. To this end, the engineers prepare the plans and preliminary design and ultimately even take care of the customers. The latter usually decide themselves on how they want the seats arranged and the positioning of toilets and galleys. This means that the plans have to be modified specifically for each customer. In this way construction diagrams and parts lists are prepared for the system suppliers who will afterwards perform the installation work. Here the fitters are supported on-site and given regular training by the staff of the engineering company.

Staff in Ferchau's Structure Metallic department are tasked with calculations, dimensioning, optimisation and simulation for the construction process. In addition, analyses of complex structures are carried out on Airbus's behalf on the basis of three-dimensional computer models, drawings or existing finite element models. One example here is their involvement in the preliminary design of the A400M fuselage, in connection with which they were tasked with reducing the weight of individual components.

Meanwhile in the Structure & Composite Design department, floor panels are designed for the cargo bays of all the Airbus types. On the basis of an advance layout of the cargo loading system to be installed, the panel contours are arranged into a perfect fit around the loading system, while a design is developed for sealing the deck so that it is watertight. This work is time-consuming because the cargo bay extends over the entire length of the lower deck, yet the fuselage sections are being built by several different suppliers.

In another part of the company, staff are calculating the operating strength of metal structures for safety and security purposes. How many flights can be completed before any fatigue cracks appear on the fuselage? How will the cracking develop over time? On the basis of design and tension data, the life cycle of cracks and the pattern that such cracks follow over time can be calculated. The results of such analyses ultimately flow into the specification of the frequency of structural inspections.

Like all other aircraft, Airbuses have to undergo extensive testing prior to certification, and the installation of the equipment necessary for this (flight test installation) is also performed by engineers from Ferchau. Whether it is a matter of temperature measurements, determining the air pressure distribution around the wing profile or the air humidity in the cabin, the uptake of pressures, accelerations and loading on the structure, the specialists install the measuring transducer units and the necessary electrical cables for all these requirements.

While section 19 of the A380 megaliner is being built in Spain, the related hydraulic system is evolving in Bremen. This entails hydraulically connecting the trim spindle and attaching the horizontal and vertical tail units. Three-dimensional models are used to determine the interface points for retaining clamps and clamping blocks. The pipework is modelled using special CAD systems. Similar work has to be performed for the A400M.

In the Flight Physics area, there is a requirement for weight and balance calculations, that is, weight analyses of all the installed assemblies and systems, calculation of mass distribution and the centre of gravity of the cargo. These enable the loads acting on the structure to be accurately quantified. For the A400M, extreme loading conditions in special situations have to be worked out, as they might occur, for example, if pallets were to be air-dropped.

At Jigs & Tools, experts are working on the design of production resources that range from simple transport racks and small gauges through to complex jigs and entire construction sites for the assembly of fuselage sections. After design and the investigation of technical feasibility, the production resources “only” have to be procured from specialist companies on time and to budget.

Because so many suppliers are involved in the production of an Airbus, the Product Harmonisation section has an important role to play, as here product and system differences are identified, parallel development is avoided and as a result costs are reduced. One example here is special system mounting devices that are screwed in one country and riveted in another.

The service providers help to save costs and avoid duplication of effort

Such duplication would ultimately make it necessary for customers to hold larger stocks of spare parts, thus incurring higher costs. Thus they have succeeded in developing a flexible set of support clamps which can be attached to profiles of different sizes and be used on different aircraft types.

Finally, in addition to mechanics and electrical systems, expertise is also harnessed in the area of electronics. Here safety-critical systems are developed that include both the hardware and software and also the related test systems, taking into account customer-specific development processes.

All this work and even more is performed by specialists at Ferchau Aviation under contract to Airbus, and if one considers that numerous other engineering companies are working on other projects, it becomes clear just how many jobs the OEM in Toulouse has outsourced to “outside companies”. Without them, modern aircraft construction would be impossible, and the size of their contribution to the evolution of aircraft is growing steadily.

From FLUG REVUE 8/2005

Last updated 15 July 2005

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