AbstractThis paper presents the underlying ideas and methodology of constructing a cyclic duty line to meet economically the daily staffing requirements for apron crews. The focus is on the formulation of basic patterns (the building blocks of the duty line) for the purpose of allocating days off, and on the assignment of shifts to working days on this duty line. The pattern determination is formulated as an integer programming problem whose special structure affords a quick and efficient solution. A procedure is provided for shift assignment. An illustrative example is also included.