This report describes the thesis "Concept development of jet engine inspection plugs" carried out in the spring of 2008. The work was carried out in the department of product definition at the company Volvo Aero in Trollhättan.

The objective of the work was to develop concepts on a "Volvo-unique" inspection plug. The work is part of Volvo Aero's focus on proprietary (self-developed) technologies.

Inspection plugs can be found on virtually all aircraft engines and gas turbines. They are used during inspections with fiber optics carried out at regular intervals during engine operation. Since the inspection plugs are screwed in and out many times during the life of an engine, it is important that the management (the installation and dismantling) is simple. It is also very important that the plugs are properly fixed in position to prevent them from loosening during operation.

The focus of the work was to develop proposals on how the fastening and fixing of plugs could be designed to simplify the management and have good and simple locking.

The procedure during the work was to first study the theory and the methods that could be relevant to use. The development was carried out according to the first three steps of the systematic construction methods. These steps include product specifications, concept generation, evaluation and selection of concepts, and development of selected concept. During the implementation, a number of tools and methods, including QFD, FMEA and decision matrices were used.

Out of 14 developed concepts, two were chosen for comparison with the leading rival. Both developed concepts turned out to outscore the competitor and the big difference was the cost of production. One of the concepts was considered to have a couple of advantages over the other and was consequently chosen for further development.

Geometry, manufacturing, materials, sealing and skew were the focus areas of the development. CAD models were made of the various construction ideas that were identified and one fundamental inspection plug was recommended for further construction.