Because of the greater speed of modern aircraft and the increasing complexity of air-traffic systems, air navigation is changing and breaking away more surely from its marine counterpart. This divergence means that navigational equipment designed for marine navigation is becoming less and less suitable for use in the air, and the special needs of air navigation are slowly gaining recognition. This paper concerns air navigation charts; its aim is to show the shortcomings of the charts at present in use, and to suggest a specification for a new style of chart that will meet modern requirements.

At the beginning it is well to define exactly what is meant by the word ‘Chart’. In I.C.A.O. terminology it is widely defined and includes amongst other things maps; but maps are a special case and their use is limited to visual flight. In this paper, therefore, the word is used in its older sense of a sheet upon which the actual navigation is performed.