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Aviation History
1948
1948 - 1683.PDF
OCTOBER 7TH, 1948 FLIGHT 437 Some Economic Factors in Civil Aviation JS.OM 22,500 30,000 17,500 15,000 12,500 10,000 7,500 5,000 2.500 ft Tottl Reserve* Pre-fljfht and tot»I flight fuel •Howance* it 100% and could be varied with the time of year on certain routes to meet fluctua- tion in wind and traffic. The target regularity was the minimum regularity of take-off which could be accepted for satisfactory schedule operation, and a figure of 95 per cent had been taken as a reasonable objective. The variables are such that eleven points modify the apparent regularity and influence the actual regularity achieved. They are: (a) The effects of cruising procedure onthe payload/range characteristics of the aircraft. (b) Fluctuations in traffic in relation tofrequency—influencing the fuel load which can be carried. (c) The effect of passenger load factoron booking payload—again modify- ing the fuel load. (d) Possible variation in cruising heightto gain more favourable winds on particular occasions. (e) The influence of navigational tech-niques on effective route winds, particularly the development of"pressure pattern" navigation, which alters the shape of the" effective headwind probability curve.'" (f) The effect of mechanical unreliability—both of the aircraftand of ground services, such as radio aids. (g) Meteorological influences, other than wind, which cause delaysor diversions, e.g., fog, ice, snow on runways, and so on. (h) Traffic congestion in the circuit, causing delays or diversions,(i) The distance which has to be covered to the alternates and the possibilities of route diversion. . ;•' (j) The human element and the allowances which have to be-•':..' made for variation in operating performance on the part of aircrews. (k) The number of landings made during a given utilization— (each landing increases the possibility of delays). : The booking payload can be allowed to change over different seasons in sympathy with fluctuations of seasonal traffic demands and with varied frequencies; as a result a lower booking payload may be feasible in the most adverse season, and in consequence an improved seasonal regularity may be possible. The lecturer also spoke of the importance of the development of pressure pattern navigation which was "the application of the technique of the trade winds to the air." Summarized, the booking payload was the total payload available after fuel had been taken on board for the " pre- flight allowances," for the "flight allowances," for the necessary reserve and for the completion of the flight cruising at height against the wind component which in a typical analysis was not exceeded on 85 per cent of occasions in the worst season. Ideally, the booking payload should be closely related to capacity payload lor economy on the scale. Typical total allowances and reserves—Orion I. FlXED ANNUAL COSTS (Independent of hours flown and miles covered) 1 Amortisation of airframe. 2 Amortisation of engines. 3 Amortisation of pro- pellers. 4 Amortisation of radio. 5 Insurance of aircraft. 6 Interest on caoital n- vested in aircraft. 7 Engineering base over- heads. 8 Amortisation of ground equipment. 9 Interest and insurance of ground equipment. 10 Salaries and, pensions of administrative staff. 11 Headquarters accom- modation. 12 Administrative office ex- penses. 13 Accommodation at out stations. 14 Technical development and flying training. 15 Advertising and publicity. 16 Traffic and sales. 17 Total Fixed Costs. HOURLY CRUISINGCOSTS (Direct flying costs incurred over the full utilisation period at the rate of cost incurred while cruising at operating height) 18 Fuel consumed cruising at height. 19 Oil consumed. 20 Maintenance of airframe (cruising). 21 Maintenance of engines (cruising). 22 Maintenance of propellers. 23 Maintenance of radio. 24 Salaries and expenses of cockpit crew. 25 Salaries and expenses of cabin crew. 26 Insurance of crew. 27 Insurance of passengers. 28 Air service for passengers and crew. 29 Total Hourly Cruising Costs. TAKE-OFF & LANDINGCOSTS (Additional costs associated with each landing and take- off cycle, from operating height to operating height) fuel and 30 Extra - to - cruising used on take-off climb. 31 Extra-to-cruising main- tenance of airframe. 32 Extra-to-cruising main- tenance of engines. 33 Extra-to-cruising main- tenance of propellers. 34 Extra-to-cruising main- tenance of radio. 35 Landing fees. 37 Out station operation. 38 Total Take-off and Landing Costs. Three-heading breakdown operating costs. The actual sold payload* was, he said, the booking payload modified by the application of the achieved load factor. Operating Costs Having established the operatingperformances tor a range of aircraft, the meaning of their performances interms oi operating costs and revenue possibilities remains to be determined.Can a flight irom "A" to "B" in prevailing wind conditions and with apractical scale of overheads, be per- formed economically? And if so, whatare the typical ligures for an annual operation? In the opinion of the lecturer theiewas only one satisfactory way of assess- ing likely economic results from par-ticular aircraft operating over particu- lar routes. That was to analyse theoperating costs and the revenue poten- tials over a full year, taking intoaccount the essential parameters ol overheads, stage length, achieved blocktime, utilization and number of air- craft in a fleet. It had already beenestablished that the cost of aircraft operation depended largely on three things: — How much the aircraft is used in a year (utilization).How long it flies between landings (stage length, cruising speed and wind), and To what extent it is saddled with overheads (administra-tive efficiency). Revenue, on the other hand, depends directly on theamount of payload which can be attracted per mile. The costs incurred can therefore be divided into:— (a) Those annual costs which arise irrespective of hoursflown. (b) Costs which are dependent directly on hours flown (e.g., fuel and oil). (c) Costs associated directly with take-off and landings (e.g., station costs, landing fees, etc.). Mr. Masefield submitted that operating costs fell more naturally under three independent heads rather than under the heads of direct and indirect costs familiarly quoted. The three heads were: I. FIXED ANNUAL COSTS—independent of hours flown or miles covered. II. HOURLY CRUISING COSTS—the direct flying costs per hour of utilization, at the rate of cost incurred when cruising at operating height. III. TAKE-OFF AND LANDING COSTS—depending onthe average stage lengths flown in a defined period. Thev are the extra costs associated with each landing and take-offcycle over and above the costs associated with cruising height. The totals of operating costs summed under these, heads depend directly on the overhead expenses, the hours flown and the number of landings madein a year. With the addition that revenue is governed by the miles covered and the load factorachieved, the fundamental conception is stated. In- dividual airlines have their own methods of esti-mating operating costs. The lecturer said that he was attempting to set down a realistic method ofcompiling estimates on a generalized basis readilv applicable to any aircraft, the results of whichwhen combined with parallel estimates of revenue would be comparable rather than quantitative fordifferent types of aircraft. The costs governed by the various influences could be divided into 38items. Returning to- the breakdown of known costs forthe six airlines, and making allowance for a slight unbalance on the high side due to two of theoperators, it could be estimated that fair figures for the respective totals per ton of gross weightfor piston-engined aircraft in the present state of scheduled airline development was:—Fixed Costs—£i-5°° Per annum; Hourly Costs—£1 15s per hour flown; Take-off and Landing Costs—£4 10sper operating cycle of landing and take-off. (To be continued) °< n TO.
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