Table of Contents
Ensuring safe operation is a never-ending task when dealing with aircraft engines, making damage prevention a special challenge. Problems are assumed to have multiple causes rather than just a single one. Specific damage prevention is based upon knowledge of damage-causing influences and their interplay. Analysis of these causes is required in order to prevent damage and accidents. The experience and knowledge gained in this process are first used by engine manufacturers in the design of new parts, then realized in the production process, ensured by quality control, proven by testing, and then maintained during routine maintenance and repair. A high degree of practical experience in a broad range of technical fields is necessary in order to recognize the large variety of possible causes and analyze them with sufficient accuracy. This begins with the knowledge of technical vocabulary and investigation methodology, and also includes an understanding of the operating behavior of the engines and their components, as well as the technical relationships between these.
One of the most frequently underestimated qualities is the experience necessary in order to investigate and solve problems and damages, which is required for their prevention. This kind of experience is gained most intensively through direct practical experience, the content of which must be understood. Recreated examples accompanied by a visual impression are of special importance. For this reason, this wiki makes extensive use of visual depictions of damages, problems, and processes, pairing these with actual examples cited in the original documents. Even if one has sufficient knowledge of general functions and operating behaviors, when it comes to the evaluation and solution of engine problems, it is extremely advantageous if one already has extensive experience with the affected engine type. Every engine has its own special weaknesses, which are not infrequently related to design principles unique to the specific manufacturer.
However, it is not necessarily beneficial for the individuals directly responsible for the development of an engine, such as designers or testing engineers, to be in charge of damage analyses. It can not be guaranteed that they would be able to detach themselves from some of their favorite design aspects. This can result in mere treatment of the “symptoms”, rather elimination of the actual root problem. This in turn means that more steps are required in order to solve the problem, which costs a great deal of time, money, and prestige. On the other hand, no changes should ever be made without first conducting a sufficient damage analysis. Because the safety of engines, as well as that of many other complex machines, necessitates an evolutionary approach that constantly draws on experience with the specific technology and components, changes will take place in seemingly incremental steps. Every alteration that is not evolutionary, or that goes too far beyond the horizon of experience, is accompanied by the risk of new damages and decreases in safety.
The first five chapters are part of a work that is intended to cover all aspects of turbine engines that are relevant to safety, although the author is aware that the incredible variety of problems makes completeness impossible. In addition, this wiki is written for professionals and avoids an especially scientific approach, which is why the following approach was chosen: Problems are accompanied by descriptions of actual related incidents, and the technical backgrounds are then dealt with either in separate chapters or in direct connection with the problem. This gives the reader the opportunity to use a certain (albeit limited) degree of experience in order to consider the effects in the context of a problem analysis.
In order to aid in the prevention of damage and problems, the chapters which deal with specific topics are intended to provide recommendations or measures for damage prevention. These are generally limited to procedural recommendations. Use of the reference works listed for each chapter will put the reader in a position in which he or she is able to find necessary details independently.
In order to keep the depiction of examples as objective as possible, the sources of cited text are given, and the original texts are rendered as accurately as possible with the exception of names of companies and individuals. This is in order to ensure that no unjustifiable conclusions are drawn with regard to the quality or ability of specific manufacturers. The original text is followed by comments which are the opinions of this author. This is intended to enable the reader to understand and critically evaluate the examples.
The first five chapters begin by introducing general problem areas, the methodology of fact collection (investigation), and the description and analysis of damages.
The central theme is the effect of environmental factors on engines and the damages these can cause. These are primarily foreign object damages, as well as damages due to erosion, corrosion, and weather.