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Aviation History
1960
1960 - 0573.PDF
FLIGHT, 22 April 1960 573 Air Transport as a "System" A rLEA FOR SOME NEW THINKING .... by J. E. D. WILLIAMS WHEN primitive Man made himself a club it was probablyfor his own use. He was the manufacturer and theoperator. As civilized society developed, the manufac-turer and the operator separated, and simple communication failure prevented functional design. A classic example is kitchenequipment: the wealth amassed by its manufacturers means that thev never have to use it themselves. This type of failure is easilyovercome by direct communication between operator and designer; in the aviation industry the principle is widely appre-ciated, even if not always faithfully applied. Care must, however, be taken to distinguish betweencommunication failure and development failure. Communication failure could not, for example, be blamed for the bad design of thetoilet in one aircraft in which the writer recently flew, for it is presumed that the designer was an experienced operator of suchdevices in general. Development failure occurs because the operating characteristics of the product are imperfectly under-stood before it is committed to operation. In the manufacture of aircraft and engines, the correct principles are of necessity nowso widely applied that optimum development, in a purely engineer- ing sense, is a technology in its own right. The same cannotgenerally be said of the equipment put in aeroplanes. From seats to sophisticated electronic devices, development failure is toocommon. In this respect British manufacturers have an unfortunate reputation which is not always unmerited. These problems of communication and development are com-mon to all manufacture in civilized society and are fairly easy to solve once the problems are understood. A more subtle difficultyis the definition of the operational requirement. Defining the Requirement In transportation the most striking examples of this difficultyare to be found in navigation. From Roman times (and perhaps earlier) navigators have had ideas about latitude-determinationat sea, but accurate longitude-determination had to wait for Harrison's clock, which was proved effective in 1762.Thereafter latitude and longitude could be separately determined at sea provided the sky was clear at the right times. Theastronomical position-line was not to be invented until the nine- teenth century, and then almost empirically, by a practicalnavigator who was lost! The essential concept of the position- line would have been perfectly elementary to the mathematiciansof the preceding two centuries, and communication was well established. Navigation had been one of the purposes of the RoyalSociety and even Newton had interested himself in its problems; indeed, it had given a major impetus to mathematical andastronomical studies in those centuries. The reason for this strange omission by whole generations of scientists is simple: noone invented the astronomical position-line because no one knew it was needed. No one asked loudly or insistently enough, "Whatis navigation for?" Fascinating historical parallels are to be found in some of thediscussions at IATA and ICAO conferences, or in the system philosophy of certain navigation systems currently marketed. Itis interesting to note that while some clever navigation devices flourish or wilt according to the effectiveness of this pressure groupor that, the radio compass is a device that was instantly recog- nized and accepted. The reason it is still nearly universal is that,for the first time in air navigation, the operational requirement was squarely met. The radio compass did not do the job well enough,but it did do the right job. In the simple case of the position line the hidden assumptionson the operational requirement could have been detected if people at that time had been aware of the danger. In the most sophis-ticated modern problems this ceases to be true unless the statement of the operational requirement is so general as to be useless. Thecore of the difficulty in advancing air transport technology is that any statement by an operator of his requirements for one systemmust contain intricately interrelated assumptions on the finished design of many other interacting systems if it is to guide thedesigner. The difficulty is not fully appreciated. One has heard manufacturers express disappointment (atIATA's annual technical conferences for example) that in such difficult areas as the navigation/ATC/communications complexthey can get no clear statement of the operational requirement. This is naive. Operators express their operational requirementsm terms of the systems they have. Henry V may have stated an operational requirement for sharper arrowheads before Agincourt,out he could not have specified 20mm cannon. The familiar concept of "weapon system" design opens the way WIDELY known as an authority onair-transport operations and equip- ment, "Jed" Williams is consultantto a number of international airlines. Among his best-known papers are"Navigational Aspects of Turboprop Operation on the North Atlantic"(1958), and "Britannia—An Opera- tor's Report" (1958) to advanced technological solutions to operational problems. Onedoes not specify the requirement in terms of current systems, but ideally goes back to the ultimate requirement, and starts designingfrom there. In current practice one no longer decides to build a faster bomber; design an aircraft in isolation from the rest of "thesystem"; fasten on whatever seem to be the most suitable engines, armament, navigation and communications equipment indepen-dently designed by other people for unspecified vehicles; fill any remaining space with bombs; and finally hand over the result tomilitary operators for any odd job they see fit. Nowadays airframe, engines, navigation (sometimes called guidance) and weapons aredesigned as components of a weapon system. This concept of systems as components of systems, the ultimatesystem satisfying the requirement, is easy to understand but difficult to apply. The formal development of a "general method"of operations-requirement analysis and system-design will be an advance of historical importance—perhaps the first step towardsa general theory of the solution of practical problems. So far the only really complicated problems to which system-design has been applied concern weapons. With present methods it seems to the outsider (who pays for it) that one essentialingredient of effective weapons systems design is money, in incredibly vast quantities. It also appears (to the outsider) thatthere must be some other essential ingredient, as yet undefined, because some results indicate that money alone is not sufficient.Clearly, to contemplate a design for air transport as a system is meaningless because a system must have a defined function.From the news pages of Flight one gathers that the operational requirement is to keep flags flying, political planners planning,members of trade unions employed, manufacturers in business, and so on. There is actually a minority which thinks that theobject is to provide a service to people who want to travel about. In the real world—where one wretched traffic right may be amatter for a Cabinet decision—this aspect sometimes appears inconsequential. Even if air transportation is not a system, the vehicle and itsoperating environment (airportSj ATC, ground operations, etc.) do form one. The technical requirement can be stated in termsof economics, performance and safety. A design for this system is impractical at present, but it may become necessary sooner thanwe think. A preliminary design study might start with a survey of the component sub-systems in current use, examining theirpurpose and the way in which they fit the requirement. Where the fit is found to be poor it might be inquired whether simplecommunication or development failure have occurred, or whether the operational requirement is misunderstood. The design ofbasic components is limited by the state of the an; the design of our component systems is limited by our failure to know what isthe state of the other chap's an. [A further article will consider the requirement for a navigation lairtraffic control I communications system.] THE PRINCIPLES OF DRAWING Know How to Draw, by Max Millar. B. T. Batsford Ltd, 4 Fitzhardinge Street, London Wl. Price 12s 6d. Illustrated. WE recently reviewed (March 4) a book on drawing aircraft. InMax Millar's book the drawing of aeroplanes is touched upon only briefly; but aeroplanes are just as subject as anything else—oftenmore so—to the basic rules of draughtsmanship, and here those rules are explained and illustrated with extraordinary clarity. Theauthor is no mere dilettante; he has had 40 years' experience as senior editorial artist of Iliffe & Sons Ltd, and all readers of Flight,The Autocar and other Iliffe journals will be familiar with the cut- away and other drawings which Mr. Millar and his staff regularlyexecute. As might be expected, the book has a slight bias towards the drawing of technical subjects, and therefore it is one that theyoung illustrator in industry will find helpful, especially as there is also a short section on the principles of pictorial printing.
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