This SAE Aerospace Recommended Practice (ARP) is broken into various categories for convenience and ease of identification. It is the purpose of this recommended practice to provide certain criteria for the design and selection of stairways, for the boarding of passengers aboard an aircraft. The criteria presented are limited to those factors which affect the safety of the passengers and are coordinated, where applicable, with the practices of the architectural profession, with respect to the design of stairways. The recommended practices are applicable to both mobile variable-elevation type stairways and to fixed-elevation stairways of the type built into an aircraft fuselage.