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Aviation History
1963
1963 - 0723.PDF
696 FLIGHT International, 9 Mav 1963 Great Britain FLIGHT SYSTEMS Full-visibility Landing System The Miles group of companies (Old Shoreham Road, Shoreham-by-Sea, Sussex) have proposed and carried out preliminary design studies on a method of providing pilots with a direct visual representation of the runway in bad weather. Although at first sight the system appears unattractive, further investi gation shows the idea to have real possibilities when applied to either land- based airfields or aircraft carriers. Miles designers have themselves moved from incredulity to increasing confidence in the prospects, and already MoA, Royal Navy and US Navy interest has been aroused. The company state that they could produce a complete system for evaluation for £250,000. Pilots of both BEA and PanAm have expressed approval of the principle. The system involves a pictorial present ation in the cockpit of the view of a model of the airfield as seen by a television camera whose motion and position are slaved to those of the actual aircraft. Azimuth, range and elevation of the aircraft are derived from a tracking radar, and pitch, roll and heading attitude information is telemetered Television view of a runway model such as might be used in the Miles Full Visibility Landing System described here INDUSTRY International Flight Systems Products Company News The navigator's position in a Tu-104 ofAeroflot, showing Standard Telephones and Cables ILS/VOR units. Delivery of more than £250,000 worth of these units for Tu-I04s and //-/8s is almost complete from the aircraft to the ground station. The flight information is translated into camera movement by a conventional computer such as is used in flight simulators. For carrier applications, additional terms could be fed in to indicate carrier pitch and roll. Miles have considerable experience of designing and producing flight simulators, their latest being that for the Buccaneer; and they are in process of making a tank driving simulator for the Army. For this they employ a terrain model measuring 30ft x 10ft, equivalent to an area 9,000ft >. 3,000ft at a scale of 300 : 1. Simulation for a driver in an enclosed cabin is reported to be so good that "you can scrape along a wire fence without breaking it." It is prob able that the computer for a landing system would be analogue, but digital systems might later be employed. An airspeed of lOOkt would be simulated by camera move ment of 6in/sec and a 4 : 1 speed range could easily be accommodated. Miles have consulted radar manufacturers and have been offered 1cm tracking radars of the gun-laying type with a range accuracy of ±30ft and full performance in tropical rain at a range of 2|ml. The aerial could be sited either on the far end of the runway or at any suitable location on the airfield, radar offset being computed to derive position of the aircraft relative to the run way. The critical factor is lateral displace ment at touchdown on a carrier, which might have to be not more than 10ft. Detection of the aircraft centreline when the wing-span is greater than the runway width has also been solved, though Miles are not yet prepared to say exactly how. Telemetry sets of appropriate accuracy and capacity are readily available, and Miles estimate that a system for three channels (pitch, roll and heading derived from the autopilot) at i per cent accuracy could be produced simply, the airborne unit costing approximately £200. Similarly, the television transmission system, with a required range of five miles, should raise no problems, the airborne receiver again costing about £200. The display in the aircraft could take many forms besides the obvious one of a television tube somewhere in the pilot's direct field of view, but some work apparently remains to be done on minimum picture size and definition for any given application and cockpit size. Other methods include front- or back-projection on to transparent or opaque screens, an adaptation for television of the Rank Cintel type head-up display, use of hinged screens, flat transparent television tubes or a mon ocular system in which the picture is pro jected at infinite focus on to a half-silvered spectacle lens worn on the head. It might be possible in some instances to arrange the artificial picture to coincide with the outside view when the ground came in sight. Miles also state that a wide range of artificial symbols could be combined with the visual picture derived from the model, adding such information as height, glide- slope displacement and speed. Compared with such systems as Bendix Microvision, the Miles full-visibility system might well prove attractive as a monitor for automatic landing systems, especially since the airborne equipment could be relatively light and cheap. Equipment on the ground might be fairly diffuse and bulky, and the reliability aspects of an information chain incorporating a relatively large number of different elements would have to be very carefully considered. The psychological difficulty of landing a real aeroplane on a real runway according to a view of a model relatively remote from either does not stand up well to comparison, either in terms of remoteness or realism, with current conventional techniques. But reliability of anything like "10-7" standard might be difficult to produce in electro mechanical computing systems now used in simulators. Such questions apart, there seem to be no basically new techniques involved and no immediately apparent reason why the system should not work extremely well. It does use the pilot's eyes, which are his most natural and immediate sensors, and keeps him in the loop to make corrections to allow for very small errors. The simulator system would not have to take account of the flight characteristics of each type of aircraft. A standard optical and computing system on the ground could be quite easily matched with the model of any particular runway and changes in terrain or obstacles could be fairly easily incorporated. There is also the most interesting possi bility that the model could cover the taxi- ways and ramp areas of an airfield, providing guidance beyond the landing run. An additional application considered by Miles has been the berthing of large tankers at critical tide states in poor visibility.
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