A New Approach to Altimetric Zonal Control of Aircraft: A Proposal Based Upon the Removal of the Zonal Height Control Function from the Altimeter to a New Instrument Known as the Zonal Height Meter

WHILE flying within the control zone of an aerodrome, and also on long‐distance flights, aircraft are subject to altimetric height control procedures which, particularly near major aerodromes, arc becoming steadily more important as the density of air traffic increases. These procedures, although extremely important, arc based wholly on improvised techniques of adjusting the ground‐pressure scale of the pilot's sensitive altimeter, which, although admirable as a flight instrument, is not particularly well‐suited to such new functions. Further, the procedures may themselves be criticized, firstly for overelaboration in the required aerodrome operational control and secondly for the resulting overall reduction in accuracy of the altimeter's indications, in relation to its potential capability for indicating heights above Mean Sea Level, and hence safe terrain clearance operating heights.