This paper reviews various environments established by the aircraft gas turbine itself, by the aircraft, and by new aircraft engine specifications within which fuel and control systems must operate. Emphasis is on the design requirements placed on controls to assure satisfactory operation in these environments. The influences on design choices and the demands for special testing are discussed for several components. As its objectives, the paper identifies specific areas which may prove troublesome as controls are designed to meet the new requirements. Recognition of potential problem areas is suggested as a first step toward successful design.