At the tripartite conference held in Eastbourne in May 1964 by this Institute, the French Institute of Navigation and the Deutsche Gesellshaft fur Ortung und Navigation, it was agreed to set up a representative working group to study the environment and its influence on the navigation systems to be chosen for supersonic transport aircraft, and to clarify the governing parameters. The early work of the group was necessarily hampered and delayed by a lack of reliable data on the probable performance of S.S.T. aircraft and on their manoeuvring capabilities and limitations. Flight trials with Concorde may suggest some modification of figures given in this paper.

The group has now completed its work and a report will be published by the Deutsche Gesellshaft für Ortung und Navigation. In addition to the two sections on meteorological factors and air traffic control, which appear to be of more general interest to readers and are included in an abridged form in this issue of the Journal, the complete report also covers the probable performance characteristics of S.S.T. aircraft and a review of available navigation systems. The temperature frequencies discussed in section 4 are illustrated in a paper by Wehry published in July 1968 (Journal, 21, 277) and will be reproduced in the final report. The Chairman of the group was Dr. Karl Karwath.