ABSTRACT
Constraints and specialty requirements are discussed together because many constraints arise from the engineering specialties. However, specialty requirements may be either performance requirements or constraints. The human factors specialist has the responsibility for setting the requirements for flight crew ingress and egress during normal, abnormal, and emergency conditions. Touch requirements pertain to the physical interaction of the human with the equipment. The flight deck is the focal point of cognitive human factors requirements. All equipment is normally subject to the requirement to withstand the effects of single- and multiple-stroke lightning. The precipitation requirements specify the environments for rain, snow, hail, frost, and sleet which the aircraft must withstand. Weight is a requirement which generates much attention in the commercial aircraft industry. Maximum take-off weight is important from a performance point of view since it is a parameter in determining the take-off distance.
