The modern aero engine is one of the most sophisticated machines currently produced by man. Its design, manufacture and repair necessitate the use of the latest knowledge and techniques, and development in one form or another continues throughout its service life.

Despite this high technical content, the fundamental requirement of the industry is to run on a sound economic basis. Often, however, this objective is lost in the equally demanding requirements of flight safety, or meeting over optimistic dates and of keeping up with competition in a multiplicity of other ways.

Much has been written about the initial development of engines up to type approval. This paper proposes to go beyond that and to describe some of the problems which arise during manufacture and operation, to emphasise the frustration and fury of an operator who has to unload 100 passengers and find them hotel accommodation—at his expense—in some outlandish part of the world because of a leaking oil pipe, and to highlight the need for repair techniques which are economical and simple.