"Virtual Fitcheck"

Virtual fittings for VIP aircraft cabins

When a new cabin is installed in a customer aircraft in the Completion Center of VIP & Executive Jet Solutions, up to now the "fitting" – or "Fitcheck" – has always followed the same procedure: the various elements of the cabin are designed in line with the customer's wishes in the mock-up center, built in the workshops and then installed in the customer aircraft by way of test fitting. Any problems are then documented and the best possible solutions are developed. After that all the elements are taken out again, adjusted and only then installed for good.

This Fitcheck on the real aircraft, a procedure established over the course of many years, is relatively time-consuming, ties up hangar space for a comparatively long time and accordingly is cost-intensive. With the aid of the results of the "Virtual Fitcheck" research project, for which a patent application has been filed, the old procedure has been not just amplified but effectively revolutionized. 

For more than two years engineering and IT staff of Lufthansa Technik AG have been working with representatives of five universities on this research project funded jointly by Lufthansa Technik and the Federal Ministry of Education and Research (BMBF) with the aim of shortening the process chain of the Fitcheck. The objective is to develop working techniques and methods that will ensure most of the components fit the first time around. This will mean that the fitted elements no longer have to then be removed, adjusted and reinstalled; instead, they will remain in the customer aircraft after the very first installation. The virtual test fitting has the effect of reducing to a minimum the number of changes required to the real components, thus reducing significantly the length of the aircraft layovers.

First of all a 3D image of the relevant aircraft type is created in order to represent the airframe and the systems. A digital mock-up (DMU) is then created on the computer, enabling all the components to be viewed in a faithful reproduction of the aircraft environment and any problems to be identified and rectified. In the course of this process the system detects errors and filters them out. For errors that the system cannot detect automatically, a checklist with about 10,000 different questions is available. Virtual reality is then used to detect as yet unknown error types.

The designers enter a twelve square meter glass cube (Cave Automatic Virtual Environment, CAVE) that serves as a projection room and faithfully reproduces the internal structure of every customer aircraft in three dimensions. The staff wear special glasses fitted with reflector spheres that are "tracked" by infrared cameras located on the ceiling. The system then uses the results to create 3D views for the employees, who move within the virtual world.

As all the data generated is mapped faithfully on a 1:1 basis, any problem areas can be investigated more closely and identified more easily than on the computer. Thus, in the CAVE one can see slanting cracks that are difficult to spot on the computer or in the model, for example, also maintenance access points that are too small. Such problems are barely visible on the computer, but in the CAVE they are immediately apparent.

All the additional data gained from CAVE flows into production, so that inaccuracies or errors in the design process can be avoided. In this way most of the virtually checked components only have to be precisely fitted and screwed into position once. Minor work and corrections can even be carried out on the installed cabin.

But promising as the Virtual Fitcheck is, at the end of the day this new work platform can only be as good as the knowledge that flows into it. Hence the success of this research project depends on a lot of input and constructive cooperation on the part of everyone involved. Now the priority is to transpose the knowledge gained from the project and establish it permanently in practice. And if in future other staff and layouts can be included in the project, the advantages of the Virtual Fitcheck can soon be put to use in many other areas of Lufthansa Technik.