ABSTRACTThe tragic loss of an Air India jetliner off the coast of Ireland on June 21, 1985 resulted in an operation that illustrated the state‐of‐the‐art systems and techniques used in deep ocean integrated positioning and navigation. The aircraft debris was spread over a 30 mi2stretch of ocean, in depths of over 6,700 ft. The search and recovery effort required the use of both subsea and surface‐based navigation equipment for accurately logging the positions of hundreds of pieces of debris.A microcomputer‐based integrated navigation system (called ALLNAV), engineered, built, and operated by Eastport International, was used as the primary navigation system. ALLNAV was used for positioning the SCARAB Remotely Operated Vehicle, working on the seafloor, and the support ship, JOHN CABOT, above. With the integrated navigation system processing both acoustic positioning data and radio positioning data, the lat/long locations of all located debris were determined.This paper will address the requirements of, and equipment and techniques used for, subsea integrated navigation. The application of integrated navigation equipment on the Air India operation will be used as a cas