This report provides a detailed description of the wake vortex prediction algorithm used in the Demonstration Version of NASA's Aircraft Vortex Spacing System (AVOSS). The report includes all equations used in the algorithm, an explanation of how to run the algorithm, and a discussion of how the source code for the algorithm is organized. Several appendices contain important supplementary information, including suggestions for enhancing the algorithm and results from test cases.Robins, R. E. and Delisi, D. P. and Hinton, David (Technical Monitor)Langley Research CenterALGORITHMS; PREDICTION ANALYSIS TECHNIQUES; WING TIP VORTICES; AIRCRAFT WAKES; AIRCRAFT APPROACH SPACING; COMPUTER PROGRAMS; SOURCE PROGRAMS; ARCHITECTURE (COMPUTERS)...