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Aviation History
1958
1958-1- - 0241.PDF
FLIGHT, 15 August 1958 CIVIL AVIATION ... tive—as those who followed United's medium jet procurementmay recall. Each is priced, without engines, at about $3m. There will be much confusion about American's decision to call the 720by its previous designation 707-020; actually this is a more precise definition of what is no more than a lighter version of theshort fuselage 707-120. First flight of the 600 will be in August, 1960: this will be followed by 8£ months' tests; and deliveries willbe made as from June, 1961. American's lease-back arrangements with the engine-manufac-turers, reported last week, will reduce American's capital com- mitments by $80m. Cost of the G.E. and P. and W. leases, accord-ing to Aviation Daily, is based on amortizing engines over seven years, plus interest payable to the banks who will buy the enginesfrom the makers (or from special subsidiaries). American will have an option to buy the engines at residual value, which will notbe less than 10 per cent of first cost. American will overhaul the G.E. and P. and W. engines themselves; under the Allison lease(five year amortization), the makers will do overhauls. Mr. C. R. Smith, American's president, says that the new fleetwill not require any additional financing: whether finance will be required later will, he said, "depend upon earnings, which willdepend on the authorization of adequate fares by the C.A.B." He then declared, in so many words, that the leasing arrangement hadbeen made on the assumption that fares would be increased. SAFARI COMPETITION PUBLICATION of B.O.A.C.'s annual report for 1957-58 hasstressed the growth of "serious competition" from the Safari services operated jointly by Airwork and Hunting-Clan. Theperiod in question—April 1957 to March 1958 inclusive—was one in which B.O.A.C. were not alone in having severe difficulties toface. Throughout the early months of 1957 the Suez aftermath was felt by critical payload cuts resulting from the need for theSafari Vikings to avoid Egyptian territory. And the Vikings were only replaced by Viscounts on East- and Central-African routes inOctober and on West-African routes in January. As total Safari capacity remained unchanged, and as the bulk of Safari trafficmoves in the (British) summer months, October to February being the slack period, the effect of Viscounts was not significant.According to last July's Ministerial pronouncement on the Safari services, capacity would be pegged at a fixed level of total Britishcapacity (i.e., the sum of all seats offered on B.O.A.C. and on Safari services). This device succeeds in limiting Safari traffic even morethan appears: by operating on charter many services on behalf of dominion and colonial airlines, the Corporation can derive benefitfrom the carriage of traffic while causing an apparent drop in total "British capacity," thus limiting the growth of Safari capacity. THOUGHTS ON AIRCRAFT REPLACEMENT "POLLOWING an article in The Times on the future of the-*• British aircraft industry, a letter appeared in the corres- pondence columns over the name of Mr. Eoin Mekie, chairmanof Silver City, indicating that the article had made "no mention of the likely fate of thousands of relatively modern airliners fac-ing premature obsolescence" and had taken little account "of the financial position of the airlines upon whom the future of the com-mercial aircraft manufacturers depends." Mr. Mekie explained that "a slight recession in air travel was coupled with a glut offast modern piston-engined airliners about to be made obsolescent by the introduction of jets ... ordered because airlines feared thattheir competitors would have the edge on them if they too did not order jets . . ." Because "the aircraft industries of the U.S.and Britain are causing airliners to be obsolescent long before they have worked for a reasonable proportion of their useful lives,"Mr. Mekie suggested that "governments concerned must face up to the situation of paying ever-increasing subsidies to the airlines,or the airlines must combine so as to prevent themselves from becoming bankrupt." Surprisingly, replies soon came not from manufacturers butfrom operators. Mr. F. Laker, managing director of Air Charter, endorsed the idea of inter-airline agreements, suggesting that thereplacement problem "could well be dealt with by I.A.T.A." Lord Douglas of Kirtleside, chairman of B.E.A., admitted that"there is a lot with which I agree . . . about longer depreciation periods for the new types of civil aircraft... I raised (this subject)some weeks ago at a meeting of the Executive Committee of I.A.T.A. and intend to raise the matter again at the I.A.T.A.annual general meeting at New Delhi next October." To another correspondent, Mr. J. L. Jones, "it seems operators are forcedto deny passengers the benefit of cheaper fares which might result from the continued use of obsolescent aircraft, while on the otherhand the cheaper fares made possible by operating up-to-date equipment are not being allowed to the passengers." In a final summing up, Mr. Mekie emphasized that "thepossible reduced operating costs of a new type of aircraft can usually only show a hope of reduced fares if it is purchased afterall depreciation has been written off the type which it replaces." 245 KINDLY LIGHT "D ESEARCH by the Royal Aircraft Establishment into landingxv accidents, particularly those where undershooting of the run- way has been the cause, has brought some interesting facts to light.It has been shown on the landing simulator at Farnborough that under certain conditions of weather or terrain it can be extremelydifficult for a pilot to recognize an undershooting danger until he is very low. The phenomenon has been quite clearly established andthe "recognition height" has been found to be only about 100ft above ground level. When undershoots do occur, it is usuallybecause of a combination of circumstances rather than because of pilot error—for instance, an unsettled G.C.A. approach or smallI.L.S. approach error coupled with rough air, a cross wind, haze or any of a multitude of other factors. And although the incidenceof undershoot accidents is only about once in three million land- ings, the number of accident-free undershoots is very much higher.In about a quarter of all landing accidents, investigation has shown no defect in the aircraft or its equipment; what has gone wronghas frequently been ascribed to pilot error, but may in fact have been due to inefficient visual-approach indication. It is not hard to see that as approach speeds rise and sinkingspeeds consequently become higher (reductions in the generally standard 3 deg glide-path angle are still only at discussion stageand in many cases may be very difficult to achieve) the position will deteriorate unless something positive is done. What is required isa clear and constant indication of absolute reliability that the air- craft is on the glide-path; it is apparent that G.C.A. directions canbe given fewer times over a given distance as approach speeds rise, and a device to supplement I.L.S. information as the threshold isapproached can also be very valuable. Operational trials are now in progress on two new methods ofvisual glide-path indications; the Australian Cumming/Lane system comprising wing bar lights which, when in alignmentindicate that the correct glide-slope is being followed, and the R.A.E.-Calvert visual glide-path indicator. The latter has beeninstalled by the M.T.C.A. at Blackbushe (it became operational on July 14) and at Aberdeen, Prestwick, Belfast and Liverpool. The elements of the system are illustrated in the accompanyingphotograph. It consists of two bars, about 30ft wide, spaced about 50ft from the runway edge at the fore-and-aft limits of the pre-scribed touch-down area (say 500ft from the threshold and 500 to 1,000ft apart). Each light consists of a sealed-beam lamp of highintensity—about 50,000 candles—the upper half of which is covered by a red filter. To avoid the condensation and colour-mixing troubles prevalent with amber-green-red glide-path indica- tors, no lens is used and the light shines through a "pin-hole" slot.For maximum safety a battery of three lights is used each side of the runway and the system appears as a square-box of four light-sources when the aircraft is correctly aligned with the glide-path. As only red and white lights are used, the inter-zone colour ispink, and the possibility of incorrect colour-mixing cannot occur. Another advantage over earlier point-source systems is that thelight pattern is easy to distinguish and the I.L.S. glide-path centre line is bracketed by a correct approach path of finite width rightdown to touchdown. Indication of position is given by both fore- and-aft bars showing red if the aircraft is too low, both white if itis too high and the near bars white and the far bars red (overshoot- ing the first threshold marker, undershooting the second) if theaircraft is correctly aligned on the glide-path. The bars also pro- vide roll guidance at touchdown. The visual range is considered to be at least two miles by dayand 8-10 miles by night, when it is dimmed by a factor of ten. Both A.A.I. systems have been discussed by an I.F.A.L.P.A.study group. Opinions are divided, but it was agreed that pre- mature standardization on either might result in installation delays. A model in Shell-Mex House, London, shows the fundamentals of the R.A.E.'s visual glide-path indicator (see text). The operator is pointing to the model of the three-bar light; its actual size is indicated by the arrow on the right. Red and white colours only are used.
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