Getting to the heart of the material
Materials Engineering at Lufthansa Technik
The choice of materials for specific aircraft components plays a special role in aviation. Sometimes, there is no precise information available from the manufacturer on the material composition of components. In such cases, even the experienced colleagues in the specialist departments depend on the professional support of the Materials Engineering team in the Central Materials Technology division. The materials and metals specialists research, analyze, and classify even the most complex material structures, and they are available to advise and assist their colleagues from throughout the company at any time. They receive many request from within the company, and occasionally from outside. In some cases, a quick database search suffices, but in other cases the Materials Engineering team delivers in-depth literature on the special characteristics and behaviour or the material in question.
Many inquiries come from the departments dealing with landing gear, engine overhaul, electroplating, and the equipment workshops. They may need the German designation for steel from an international manufacturer, or perhaps they want to know what treatment and cleaning agents can be used on a particular type of steel or how to best apply a coating. If even the experts are not completely certain, they advise a comprehensive materials analysis and laboratory examination of the component in question. Smaller components, and material samples from larger components, are then examined in the plastics analysis or metallography labs to determine their exact composition and special characteristics.
Larger components may also be examined in the workshops or with mobile equipment directly at the aircraft. If, for example, localized overheating of an undercarriage component results in the paintwork melting, there is a danger that the material structure underneath will become brittle. The Materials Engineering experts will assess the affected component in situ using well-trained eyes, a flashlight, a magnificying glass and a portable microscope, after which they can recommend the best course of action. Precise analysis of damage to overheated steel components is possible with corrosion tests. Structure analysis is performed by taking a cast of the damaged area subjecting this to microscopic analysis in the laboratory. Once the damage has been precisely diagnosed, a decision can be made as to whether the component can be repaired or has to be scrapped.
Examinations and tests, some of them very extensive, can, for example, identify embrittlement, determine the composition of screw threads, distinguish between forged and cast components, and determine whether specific components have been surface-hardened or require machine processing. Components that have to be re-engineered, for example parts for the Junkers JU 52, the Lockheed Super Star, or undercarriage bushings for modern aircraft, are examined and analyzed in terms of physical and chemical characteristics by the materials experts and metallurgists, who conduct quality checks and make recommendations. The decision to use a component, however, is always in the hands of the responsible system engineer.
As well as information, advice, and procurement, the Materials Engineering team issue binding standard procedures which it publishes in the Lufthansa Technik Handbook PMT (Processes & Material Test Methods). Every three months there is an intense interdisciplinary discussion with the engineers who work with plastics and adhesives. The goal of this know-how platform is to gather all new findings together and present them in the PMT as a simplified and integrated Lufthansa Technik in-house standard. This also applies to cleaning procedures and crack inspections; the Materials Engineering team is not only available for assessment and advice, but also regularly hosts the "Cleaning Network" gatherings, facilitating targeted discussions between the specialist departments on all cleaning-related issues. This makes it possible to further intensify collaboration between Materials Engineering and the specialist workshops, and innovative cleaning processes can be presented.