In 1965, following the Eastbourne Conference, the British, French and German Institutes of Navigation formed a Working Group to make a study of the environment in which the supersonic transport will operate and of its implications for the navigation of such aircraft. The Group's initial task has been one of education, largely through discussion of a series of papers submitted to it. Some of the papers considered have already been published in the Journal (Vol. 19) and a further selection is published below. Table I was contributed by Mr. G. E. Beck. The illustrations to these papers have not all been reproduced.

1. Atmospheric Conditions. It will be useful to distinguish between different kinds of atmospheric influences on supersonic aircraft operations. They may be classed as follows:

(a) Sporadic effects near the ground

(b) Sporadic effects in the free atmosphere

(c) Effects on sonic boom

(d) Effects of atmospheric ozone

(e) Permanently effective atmospheric parameters, such as temperature, density and wind.