This paper presents the design research for Human Engineering to modify a 747SP aircraft for the Stratospheric Observatory for Infrared Astronomy. It summarizes the work of the SOFIA Layout of Personnel Accommodations (LOPA) Team at NASA-Ames Research Center in developing the specifications and project documents to define the mission crew work areas, including consoles, equipment racks, and astronomer/experimenter work areas and facilities. It covers several key areas, including the Project's assumptions about the SOFIA personnel complement and the aircraft's operational scenarios, based upon a systematic comparison to the SOFIA's predecessor, the Kuiper Airborne Observatory (KAO), a modified C-141.The LOPA Team analyzed these complex assumptions, requirements and goals for improved Mission crew productivity to develop a Human Engineering Design Guideline. This Human Engineering Guideline follows a Crew-Centered Design Philosophy that takes four perspectives: crew members as occupants, crew members as individual operators, crew members as leaders, and crew as team members. This Guideline evaluates the role of automation in crew productivity. It suggests verification metrics through the design, development, and pre-operations phases of the SOFIA Program.A key product of the LOPA Team activity was to develop several candidate layouts of the floor plan and console arrangements. These layouts derived from four considerations: LOPA requirements, physical and operational constraints upon the LOPA design, an architectural adjacency analysis, and a SOFIA-specific set of architectural design guidelines.