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Aviation History
1947
1947 - 2024.PDF
576 FLIGHT NOVEMBER 2OTH, Light and Ultra-Light from Italy retractable nosewheel undercarriage * and two IsottaFraschini Delta engines of 800 h.p. each. All-up weight, 19.360 1b; cruising speed, 192 m.p.h. Reggiane Re. 2005.—A wartime fighter with DB605engine. Piaggio P.108CT.—A transport development of thePiaggio P. 108 four-engined bomber. Piaggio P. 135.—This twin-engined high-wing monoplane has a retractable nosewheel undercarriage and is powered by two Wright Cyclones. The cruising speed is 198 m.p.h. and the range 1,365 miles. Piaggio P. 136.—A twin-engined gull-wing amphibian. Piaggio P. 137.—A 4-seater resembling the French Courlis and powered with a Franklin engine of 215 h.p. Breda Zappata B.Z. 308.—With four Bristol Centaurus engines this large transport weighs 88,180 lb, and in "Atlantic" condition has a maximum range of 3,100 miles. The maximum speed is 353 m.p.h. THAT 3,000 HOURS PER [Concluded from page 571.) tration. In particular, fuel and operations usually repre- sent between 45 per cent and 55 per cent of the total costs. On the average airline, depreciation of flying equipment, on a five-year basis, is unlikely to exceed 6-9 per cent of the total annual expenses. If, then, the aircraft are made to do more work, the major cost of fuel and operations will automatically in- crease in proportion. Maintenance costs are likely to increase at a greater rate, and traffic and administration probably at rather a lower rate, the precise amount depend- ing on the state of the organization before the increase in work and the extent of extra sales work required. Depre- ciation of ground equipment is likely to remain more or less constant, b'tit there will be a proportionate increase in the maintenance costs of such equipment. Thus it may be expected that if the rate of work of an aircraft fleet is increased from a medium to a very high figure, the cost will increase approximately in proportion. Thus, if revenue can also be made to increase to the same extent, it will obviously pay the operator to increase his utilization rate. This is, however, most unlikely, as one of the first results of intensive use of aircraft is that, instead of operating services when the prospective passen- ger wants to travel, it usually becomes necessary to fit the extra operation into the maintenance and operating programme at the most unpleasant times. Furthermore, there is the certain decrease in punctuality and regularity. Let us now consider the case of an air transport concern corning (incredibly!) gross profits of, say, 10 per cent per annum. If, by an increase in utilization of aircraft rates, the total operating costs are increased by 25 per cent, "it becomes necessary to increase the revenue by not less than 23 per cent in order to earn the same gross profits. Although, under present conditions, most airline com- panies have a back-log of waiting passengers, under more normal circumstances additional traffic to this extent would indicate a phenomenal effort. If new routes are undertaken with the additional flying hours available, the chances of high load factors are small, except where specially favour- able circumstances prevail. It seems rather unlikely, therefore, that such an increase in revenue could readily be achieved, particularly when coupled with an almost certain falling-off in load factor consequent upon a deterioration in punctuality and un- popular operating times. One other factor is worthy of consideration. Most air- lines have a steady loss of aircraft, for one reason another, of something like 5 per cent of their units ev one to two years. In addition, there is nearly always some- thing under repair for minor damage. When the first aircraft is lost, it is usually possible to readjust the utilization rate and the organization and carry on as before. This may even be possible after the second loss. Thus an operator who has commenced operations with a fleet of 20 aircraft and a utilization rate of perhaps six hours a day, finishes a five-year depreciation period at a rate of 6§ hours a day. Another operator who starts operating at a rate of 10 hours a day may simply have to cancel a proportion of his services, as his organization is likely to be at full stretch from the beginning. The solu- tion of this difficulty by replacement of lost units through adequate insurance is frequently impracticable. Aircraft soon become obsolete, from the manufacturer's point of view, and, even if the aircraft remains in production, much time may be lost between the placing of an order and the delivery. The utilization rate and the flexibility factor are, to some extent, dependent on the type of service operated. Short- distance, high-frequency services will permit a higher utili- zation rate than low-frequency, long-distance services, and allowances should always be made for such matters. In general it may be said, therefore, that— (1) The rate of utilization of aircraft should be fairly high but not the absolute maximum possible, as it is essen tial to have some flexibility of operation. (2) Lack of flexibility is likely to result in adverse pub- licity because of a resultant lower standard of punctuality and regularity, together with unpopular times of opera- tion. In addition, maintenance costs will be higher. Thus the net result may be a reduction in mean load factor with a possible reduction in gross profits. FOR CORPORATION CIRCLES : Three helicopters flying at the B.E.A. demon- stration at Westland's airfield, Yeovil. Leading is an Irv'm Bell, followed by two Westland Sikorsky SSIs.
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