The problem as to which engine configuration—single or twin—is most suited to the close support/tactical strike class of aircraft has faced both designers and Air Force personnel for many years. The inherent human choice on safety grounds is two engines. But, many aircraft built today are powered by one engine and good reasons for this choice have been produced. The basic arguments for one engine are the lower initial cost and better maintainability.

A comprehensive view of the overall costs incurred by selecting one layout as opposed to the other is a rarity, and yet it is possible to produce a definite indication, albeit by a broad brush, as this paper will show.