In recent years there have been a number of accidents caused by aircraft flying into high ground. The aircraft were mostly on nonscheduled rather than scheduled flights. This has resulted in much publicity being given to such questions as the licensing of the operators, the sufficiency of the radio or radar carried, and the route-experience of the pilots. These questions are of course relevant, but there is one further question which ought to be investigated and which has received little attention: it is the adequacy or otherwise of the means employed to show relief on charts.

Under present policy the only picture of the relief is on topographical maps (Fig. 1), but it is on charts (Fig. 2) that the route and aids are shown. If the pilot is to check his safety-height in the air, he can do so only by coordinating the maps with the charts. This is cumbersome when he is pressed for time, and generally he does not do it; he flies on the charts using flight altitudes that have been pre-calculated, and the maps remain in the navigation bag unused.