15 Miscellaneous Design Considerations

15.1 Overview

Although the main tasks of the aircraft configuration are now completed, there are other topics of interest that require understanding of design. This chapter is an overview of the impact made by technological advances that must be considered at the conceptual stages to arrive at a “satisfying” design. It offers an understanding of specialized topics, some of which may appear out of context during the conceptual phase, but they do contribute to aircraft design. The aircraft external geometry is not affected by these considerations (unless a radical approach is taken); however, there could be weight and cost changes. The semi-empirical weight equations in Chapter 8 are sufficient and can be modified with improved data. In the industry, a more accurate weight estimation is required to reflect the changes affected by the topics discussed in this chapter.

A detailed study is beyond the scope of this book. Most academic institutions offer separate courses on some of the topics, such as aircraft structure, associated materials, and aircraft systems. Some of these topics sometimes escape attention because the undergraduate curriculum is already full with the main aeronautical subjects. Conceptual aircraft design is not only producing a geometry capable of meeting performance specifications; it also involves early thinking about environmental issues, safety issues, materials and structures, human interface with the flight deck, systems considerations, and military survivability issues that affect aircraft weight and cost. Therefore, whereas there is nothing to be altered on the finalized and substantiated configuration thus far obtained, it is beneficial for readers to appreciate the role of these varied topics. Some of the emerging scenarios are new and have yet to be implemented. It is important that newly initiated readers have a sense for what is required by these topics, which may be developed during a second term of coursework.

Environmental and safety issues must comply with standards specified by the FAA (United States), the EASA (Europe), and the ICAO (international). The differences among the agencies are minor. Military aircraft requirements are governed by MILSPECS/DEF standards. Aircraft doors (including emergency types) and environment standards, regulated by the FAA and the ICAO, also are described in this chapter.

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