Part II: Approach Guidance

Extract

The success of inter-city transport helicopter operation will depend on the ability to fly between small sites in city centres with good regularity. Any compromise, such as moving the site to the outskirts of the city or only being able to fly in fine weather, will destroy the advantage of the helicopter over other forms of transport. During the past decade there has been considerable progress in the improvement of helicopter flying qualities so that it is now possible to specify equipment which will enable a helicopter pilot to control his machine in all visibilities and most conditions of turbulence. Further developments in ice protection will enable the basic helicopter to be cleared as an airworthy vehicle for all-weather flight. However, there still remains the problem of navigation, which becomes particularly acute for the final instrument approach. Existing equipment, in particular the Decca Navigation System, can probably meet the case for aerial navigation at altitude, but to fly down an approach to low altitudes into a restricted site demands a higher standard of accuracy and reliability than is offered by any currently available equipment. This paper only deals with the blind approach down to a height of the order of 200 ft. above the landing pad. To extend this to blind landing would require an even higher degree of accuracy and reliability, which does not seem to be justified until some actual operational experience of a simpler blind approach system has been gained to establish whether or not there is a real need for blind landing. A blind approach system which will permit a cloud break height of 200 ft. to be followed by a visual approach and landing on ground lighting should offer at least as good a standard of weather regularity as is currently achieved by fixed-wing aircraft.