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Aviation History
1957
1957 - 0435.PDF
FLIGHT, 5 April 1957 Jet Transport Operation Problems A T.C.A. Appraisal—Part 2 LAST week we published abstracts from the first part of thenotable paper read recently by Mr. J. T. Dyment, chiefJ engineer of Trans-Canada Air Lines, before the Weybridge and London Airport branches of the Royal Aeronautical Society.Here we give further excerpts. In the first instalment the layout of airports for jet operationswas examined. Discussing the speeding-up of passenger handling on the apron, and complications caused by the jet-blast factor, Mr.Dyment considered that in cases where it was possible to do so, taxying the aeroplane straight into a nose dock attached to dieterminal building was the most desirable; where it was not prac- ticable to have the necessary servicing facilities in the terminalnose dock, the conventional method of taxying and swinging around and stopping near the terminal was most likely to be usedat the majority of airports. T.C.A. is considering the use of a mobile conveyor-belt unitsimilar to those used [continued Mr. Dyment] for loading and unloading high compartments, but the unit would comprise threebelts which could be moved sideways on the vehicle so each belt could be presented in turn to the baggage-compartment opening.The combined capacity of the three belts would hold the contents of one compartment. As soon as loaded, this unit would movequickly by its own power to the passenger baggage collecting point where it would discharge its load by die movable belts. The actualdistribution of the baggage to the passengers in a matter of seconds is not an easy problem, but the automatic self-serve method usedat the Los Angeles airport goes a long way towards clearing this particular problem. An intensive analytical study by the airline is sorely needed as towhat it is trying to accomplish and what it needs to achieve its objectives. A time-and-motion study of existing terminal pro-cedures and of mock-ups of proposed facilities, and greater fami- liarization of the architect with the day-to-day problems at aterminal, are all essential to evolve a design, or redesign that will be satisfactory for the coming traffic. It is obvious that many airport terminal buildings will have tobe remodelled immediately, or new ones built between now and 1960 or 1961, otherwise the building facilities will become thebottleneck in this modern era of mass high-speed transportation. In analyzing future requirements, provision should be made forcontinual expansion. It appears inevitable that, within the next twenty years, long-haul rail passenger traffic will become justabout extinct, at least on the American continent. Another small but important point in relation to terminal designis that, if the civil operators continue to use kerosine rather than JP-4 as a fuel, the building will have to be air conditioned, becausethe windows on the ramp side must be kept closed to keep the fumes out. The air-conditioning intake will also have to be wellshielded from the fumes. This problem need never arise if the airport authority, Customs,immigration and the airline officials work together to avoid it. I recall seeing over 450 passengers handled in 40 minutes at SanJuan, Puerto Rico, a few years ago and the speed of handling was due not to the number of officials but entirely to the enthusiasmand complete co-operative spirit that existed between the govern- ment airport manager, the head of Customs, the head of immigra-tion, and the Pan American Station manager. Everyone was imbued with the idea that no one must ever be able to accuse anyone atSan Juan with being slow or disinterested. They were the most efficient group I have ever seen, and demonstrated that the prob-lems can be solved. [When asked later for his opinion of London Airport's passenger-processing, Mr. Dyment said it was "justmarvellous."] Meteorological Requirements. The actual met. informationrequired for the forthcoming turbine era will be little different than it is today, but the penalty of not having the informationat the time it is required can impose a much greater economic penalty. Apart from the increased altitude band with which weare concerned, the new problems are to provide the airlines with a good knowledge of the velocity and boundaries of jet streams,the location and intensity of gust areas, and the ambient tempera- tures from sea level to 45,000ft. Safety will be more adversely affected than it is today, becauseof the greater speed of jet transports, unless met. offices get together and issue the same weather information about a particu-lar area from all points. Right now, operators using different met. sources for planning flights, substantially along the sametrack at approximately the same time, may file inconsistent 437 Artist's impression of a DC-8 in T.C.A. livery. flight plans because the information provided by these sourcessometimes differs. As a result, initial separation between aero- planes may be incorrectly assessed. It is essential that measuresbe taken to ensure accuracy and uniformity in the forecast information provided.The larger the fuel reserve that must be carried to cover deviations due to changes in forecast weather, the greater will bethe cost. It must be remembered that 26 gallons is equivalent to a passenger in weight, yet will fly the aeroplane for onlyone minute. Accuracy in forecasting is thus even more important than today. There is no place in air transportation where the payload canbe as easily affected as it can by calling up more fuel reserves. At the present time T.C.A. plans to start its DC-8 servicescarrying 7,900 lb of fuel reserve solely as a route factor. Such a reserve is in addition to the normal reserve of 9,600 lb for onehour's holding and 9,000 lb for diverting to an average alternate. There is one redeeming feature about jets—the elapsed timebetween when the forecast is made and when the weather is encountered can be almost halved from that of today. Because the fuel penalty involved in a missed approach (about2,000 lb) or a diversion to an alternate airfield is so great (9,000 lb), it is essential that terminal forecasting of visibility under marginalconditions be most accurate. It is still not possible for a ground station to tell a pilot the actual visibility range he will have as heapproaches a runway. Some device is needed to measure "slant visibility." Air Traffic Control. Many believe this to be the toughestproblem facing air transportation today. The introduction of jet transports into service will make it worse. Because of the speed of the new jets (or even current aero-planes), dependence on visual flight conditions to avoid collision is entirely inadequate. Airborne collision warning radar hasbeen found impracticable to date, with little hope of improvement on the basis of present knowledge. Planning an A.T.C. systemmust, therefore, not count on aeroplanes avoiding each other through the use of any airborne equipment alone. It is hopedthat efforts will continue to solve the problem of airborne col- lision radar, because when perfected it will provide a monitoringback-up device similar to that provided by G.C.A. during regular I.L.S. approaches for landing. The most difficult A.T.C. problems occur in the areas whereaircraft converge or are climbing and descending, and that is what a jet aeroplane does best. It does not like to fly for long at a con-stant altitude. It wants to climb as it burns off fuel. This accentuates the problem for A.T.C. For maximum efficiency, a turbojet aeroplane would like totake off and climb in an unrestricted manner, as quickly as pos- sible, to its initial cruising altitude of around 30,000ft (preferablyclimbing in the direction of its destination). It would then like to continue to climb slowly (drift-up) as it burns off fuel duringcruise. At the appropriate point, depending on the distance to the destination and the altitude, it would like to descend atconstant Mach Number straight into a landing. Any deviation from this ideal flight plan costs additional fuel.However, it is obvious that both traffic and adverse weatiier con- ditions will dictate departures from it. The desire is that anydeparture from it will be a minimum. The type of departure having the least adverse effect on fuel would generally be one in alateral direction. Since both lateral and vertical separations will be required, itis essential that improved altimeters be developed with much
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