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Aviation History
1951
1951 - 1335.PDF
FLIGHT CIVIL AVIATION . . . this sort of traffic in recent months are now wholly committedelsewhere. Smaller aircraft such as Dakotas and Vikings are also busy on either Government or tourist work for the next fewmonths, and on only a few isolated dates are they available for the open market. A similar situation obtains for flights within Europe, where nocharter company has aircraft to offer, and the fixing of charters with American operators is also out of the question. Another reason for the shortage of Yorks is that the BritishGovernment recently directed that all passenger aircraft of B.O.A.C.'s charter section should be "frozen," for the timebeing, to cope with a possible evacuation from Persia. It has even been intimated that a certain number of B.O.A.C.'s scheduledservices might have to be cancelled in order to make additional aircraft available for this purpose. Other charter companiesoperating aircraft suitable for such work have also been warned to stand by. Several operators have submitted tenders for long-term troopcontracts to take place this summer, and until their offers are either accepted or rejected they are not free to undertake normalcommercial commitments. Many flights which had been pre- viously fixed have now had to be either cancelled or postponedfor an indefinite period, as no one is in a position to say how long the present emergency is likely to last. The charterers have thusbeen placed in a very embarrassing position. It is impossible to provide foreign replacement aircraft for fixtures already made,and even if replacements were available it would in many cases be impossible to make these arrangements under the same con-ditions and rates agreed for the original fixtures. Although the charterers have naturally accepted the situationas being the result of what might prove a national emergency, some surprise is felt that the charters for such an airlift willapparently not be handled through the medium of the Baltic Exchange. ALL-WEATHER APPROACHESP ART of the nineteenth annual meeting of the Institute of theAeronautical Sciences, held recently in the United States, was devoted to a symposium on Ail-Weather Flying—designed tobring to the notice of I.Ae.S. members the fact that, in general, pilots consider that their own views on this subject have been toooften overlooked. One of the main features of the symposium was a film, ofexceptional merit, dealing with the much-discussed topic of approach lighting and runway markings. The film, a project ofthe Air Transport Association and the American Airline Pilots Association, is, in fact, an edited version of films made indepen-dently by the Landing Aids Experimental Station (California) and the Sperry Gyroscope Company. Over fifty scenes areincluded of actual bad-weather approaches, some of them under- taken in visibility as low as 150ft and with zero ceiling. The filmis said by those who have seen it to go a long way towards bringing the problems connected with low visibility landings within thegrasp of non-flyers, who would otherwise only begin to understand some of the difficulties involved by actually doing cockpit dutyduring the procedures. It occurs to us that many members of our own air-transport industry would be interested in this film, andit might be a good idea for some responsible organization such as the M.C.A. or G.A.P.A.N. to try to borrow it. In the film itself, the main design-requirements for satisfactoryapproach-lighting systems are specified and the various sequences either emphasize the need for, or show the benefits of, meetingthese requirements. The design factors are listed as follows: Identification—the approach lights should be easily identifiablefrom the greatest possible height in bad weather. Alignment—no mental interpretation should be required to define the runwaycentre-line. Distance-remaining Indication—a visual indication should be incorporated in the approach zone to warn the pilot ofthe imminence of the runway threshold (this indication should be visible under the poorest conditions). Threshold Identification—threshold lighting should be positive and distinctive and should include a properly illuminated overrun area which uses differentlighting from the runway itself. Glare Elimination—none of the lights used should be capable of blinding the pilot. Contrast—atthe threshold both red and green lights should be used (red for the overrun area, and green to mark the beginning of the runway);in addition, bold painted markings should be provided on the runway surface to distinguish the concrete from grass verge.Runway Lighting—runways should be evenly illuminated, with no blind soots, and the lights should be equally visible even whenthe aircraft is off to one side of its correct line, or high on the approach. Shots from the film emphasize that the surest method ofavoiding mis-identification appears to be the use of condenser FIRST TASTE : A visit paid to Wales last week by the new Minister of Civil Aviation, Lord Ogmore—to confer with his countrymen of the Welsh Air Advisory Committee—recalled a much earlier aeronautical incident in his career. Over 30 years ago, as Mr. David Rees-Williams, he flew as a passenger in an Avro 504K belonging to the Welsh Aviation Company. Lord Ogmore (in the centre of this photograph, taken at the time) recollects that the aircraft had to make an exceptionally steep climb over a stone wall at the end of the small field from which—in • typical joy-riding fashion—it was operating. discharge lights combined with a single row of fixed burning units. The condenser lights are powerful enough to penetrate several hundred feet of fog, yet the high-speed flash is too rapid to affect the eye. The phenomenon by which airports equipped with approach lights on the port side occasionally had lights knocked down on the starboard side of the runway is also demonstrated. This has been found to result from an optical illusion in which the pilot, aligning himself to land by the aid of the approach lighting only, appears to be on a collision course with the port lights. Broken runway lights prove that the pilot has followed the normal tend- ency to turn slightly to starboard. The use of centre-line lighting is recommended to ensure correct alignment. The film demonstrates, also, the pilot's general preference for the "centre-line and single crossbar" method of gauging the remaining distance to the threshold. Approaches to Idlewild using unfiltered slope-line lights give adequate proof of the need for eliminating the glare factor. Again, although the use of red filters is seen to eliminate glare, the resultant decrease in intensity proves the need for condenser discharge units. A "before and after" sequence emphasizes the benefits of painting distinctive markings at the ends of the runway. Night approaches at La Guardia have been photographed to show the confusion often produced when low-powered directional runway lights are used. They are shown for comparison with the wide-angle lights of uniform intensity used at Idlewild, which outline the runway clearly and give good speed and directional information. The ensuing discussion touched upon the relation between electronic and visual landing-aids. From it there emerged/the fact that, although automatic landings have been made, they have in most cases proved to be extremely rough. Experiments are now in hand to develop a flare-out system, although in this connection it was pointed out that the advantages gained would cost rather dearly in respect of the weight of such additional equipment as sensitive altimeters. It was the view of the panel that the cal- culated risk in automatic landing devices currently available could not be accepted for airline operations. Some details were also given of a new radar air traffic control system which is being evolved by the Air Co-ordinating Com- mittee. This will use long-range radar roughly to space aircraft approaching the terminal area in order to place them on final approach with proper sequencing. It is hoped by this means to eliminate "holding" procedures completely, and to speed-up airport landing rates from forty movements per hour (as obtain- able with the use of the present equipment) to 120 per hour in the near future. The usefulness of airborne radar was another subject discussed. A spokesman for the pilots expressed the opinion—which, he said, was shared by many of his colleagues—that airborne radar would someday be as important as engine and landing gears.
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