The Army Avionics Research and Development Activity (AVRADA) is pursuing programs that would enable effective and efficient management of large amounts of situational data that occurs during tactical rotorcraft missions. The Computer Aided Low Altitude Night Helicopter Flight Program has identified automated Terrain Following/Terrain Avoidance, Nap of the Earth (TF/TA, NOE) operation as key enabling technology for advanced tactical rotorcraft to enhance mission survivability and mission effectiveness. The processing of critical information at low altitudes with short reaction times is life-critical and mission-critical necessitating an ultra-reliable/high throughput computing platform for dependable service for flight control, fusion of sensor data, route planning, near-field/far-field navigation, and obstacle avoidance operations. To address these needs the Army Fault Tolerant Architecture (AFTA) is being designed and developed. This computer system is based upon the Fault Tolerant Parallel Processor (FTPP) developed by Charles Stark Draper Labs (CSDL). AFTA is hard real-time, Byzantine, fault-tolerant parallel processor which is programmed in the ADA language. This document describes the results of the Detailed Design (Phase 2 and 3 of a 3-year project) of the AFTA development. This document contains detailed descriptions of the program objectives, the TF/TA NOE application requirements, architecture, hardware design, operating systems design, systems performance measurements and analytical models. Harper, Richard E. and Babikyan, Carol A. and Butler, Bryan P. and Clasen, Robert J. and Harris, Chris H. and Lala, Jaynarayan H. and Masotto, Thomas K. and Nagle, Gail A. and Prizant, Mark J. and Treadwell, Steven AIRBORNE/SPACEBORNE COMPUTERS; AIRCRAFT GUIDANCE; ARCHITECTURE (COMPUTERS); AVIONICS; COMPUTER SYSTEMS DESIGN; FAULT TOLERANCE; FLIGHT CONTROL; INFORMATION SYSTEMS; NAP-OF-THE-EARTH NAVIGATION; PARALLEL COMPUTERS; ADA (PROGRAMMING LANGUAGE); DATA PROCESSING;...