Return this book on or before the Latest Date stamped below. University of Illinois Library - 7 1959 ***MK i -4 19* AUG f- >A OCT 2 SSlI {964 5EC AUG 2 -.75 fC 1 6 197% APR li 964 N 08 1982 HAft 2 8 1985 L161— H41 ,..■,.■■■■ M UNIVERSITY OF I LLINOIS Operating Costs of a Light Aircraft Fleet HtVl*' itftO t*o\s AERONAUTICS BULLETIN NUMBER 10 UNIVERSITY OF ILLINOIS INSTITUTE OF AVIATION Leslie A. Bryan, Ph.D., LL.B., Director Bernice Schrader, A.M., Editor UNIVERSITY OF ILLINOIS BULLETIN Volume 50, Number 14; September, 1952. Published seven times each month by the ty of Illinois. Entered as second-class matter December 11, 1912, at the post "Hi"- al LJrbana, Illinois, under the Act of August 24, 1912. Office of Publication, 358 Admini (ration Building, Urbana, Illinois, BY LESLIE A. BRYAN Director, Institute of Aviation University of Illinois Operating Costs of a Light Aircraft Fleet A CASE STUDY ^E LIBRARY OF THE NOV 13.. ■3¥ ILLINOIS PUBLISHED BY THE UNIVERSITY OF ILLINOIS, URBANA 1952 FOREWORD THIS MONOGRAPH is the tenth in a series of bulletins on aviation subjects issued from time to time by the Institute of Aviation. It concerns* the operating costs of light aircraft in a specified situation and is an addition to the informa- tion available on aircraft operating costs. Estimates of the probable costs of light aircraft operations, even when made by the best informed persons, may be proved incorrect in the light of subsequent events. Consequently, the Institute decided to make a retrospective survey of the period from February 1, 1948, when a new cost system was initiated, until February 1, 1952. Because of their interest to operators, to industry, to private flyers, and to business executives, the results of the survey of the actual costs of operating the individual light airplanes included in the University of Illinois fleet during that period are made available in this bulletin. Many of the same aircraft were included in a shorter cost study, Aeronautics Bulletin Number Seven, published three years ago. The author gratefully acknowledges the assistance given him by Mr. David A. Gillespie, Supervising Accountant, Business Office, and by Mr. Jesse W. Stonecipher, Chief Pilot, and Mr. Forrest L. Lancaster, Aircraft Maintenance Engineer, Institute of Aviation, all of the University of Illinois. In this monograph, as in all publications of the Institute, the author has had complete freedom to express his opinions, understanding that he assumes sole responsibility therefor. Leslie A. Bryan, Director July, 1952 o./D INTRODUCTION The University of Illinois, through its Institute of Aviation, operates a fleet of aircraft for routine student flight training and also for the trans- portation of University faculty and staff members on University business. Forty-six of the aircraft which were included in the fleet during the period covered by this study were light aircraft. Each weighed under 3,200 pounds gross and was equipped with a single engine which delivered between 65 and 220 horsepower. Since the Institute desired to recoup the cost of operating the fleet, particularly for those airplanes which were used primarily in the faculty and staff charter service, a retrospective study was made of the operating costs of the aircraft for the period from February 1, 1948, to February 1, 1952. The results of the study are presented in three tables. Table 1 gives an outline history of each aircraft. Table 2 shows the actual costs of fuel, oil, and maintenance on a per flight-hour basis. Table 3 shows the flight- hour costs of other items charged to each aircraft and also the total operating costs per flight-hour of each aircraft for the period studied. These tables gave the University the opportunity to draw certain con- clusions concerning the operation of its own fleet of aircraft. They may be of help in methodology and in other ways to operators who are able to adapt the figures to their own businesses or circumstances. Although the results of the study represent the cost of operating the University of Illinois fleet during the period in question, no validity for universal application is claimed for the figures. They may have very little application or usefulness to another operation. Some items which have been included as costs might be questioned, and others, particularly hangar rent, which have been excluded would be included under other conditions and circumstances. Also, the amount of flight time for some of the aircraft on the list is so small that their costs are of questionable statistical value. It should be borne in mind, also, that the per flight-hour light aircraft operating costs decrease rapidly as the flight utilization of the airplane increases and that the utilization of University aircraft is, in general, above average. EXPLANATION OF COST ITEMS Fuel and Oil The costs for fuel and oil on each airplane represent the actual ex- penditures for these items, exclusive of a negligible amount of gasoline purchased on cross-country trips which could not be assigned to indi- vidual aircraft. Such purchases, however, were too few to make any appreciable difference in the fuel cost totals. Relatively little oil (average about one quart) was added between the complete oil changes which, according to the established policy for University aircraft, were made in each of the aircraft after every twenty-five hours of flight time. Additional facts which should be noted in connection with the figures are, first, that the standard fleet operating procedure calls for the use of decreased throttle on the take-off after breaking ground, as well as a cruising speed approximately one hundred r.p.m. less than that recom- mended by the engine manufacturer, and second, that most of the gaso- line consumed came out of the University's own tanks and had been purchased at bid prices with an average saving of several cents a gallon over retail prices. The fuel used was, in all cases, eighty octane aviation gasoline. Direct Maintenance Costs Airplane maintenance costs include expenditures for all labor and material used in the maintenance and repair of the individual aircraft, including minor accident repairs, major engine overhauls, and rebuilding of airframes. Labor costs per flight-hour averaged approximately $1.31 for 1948; $1.43 for 1949; $1.53 for 1950; $1.74 for 1951; and $1.89 for 1952. Charges for material were at actual cost to the University, possibly ten to twenty per cent less than retail prices. In the aggregate, however, the airplane maintenance expense is un- doubtedly higher than average since twenty-five-hour, fifty-hour, seventy- fivc-hour, as well as the required one-hundred-hour inspections, and annual inspections were run under general instructions to err on the side of safety and to keep the equipment on an "as good as new" basis and, where possible, above the minimums required by the Civil Air Regulations. Only experienced aircraft and aircraft engine mechanics were em- ployed. A ratio of one mechanic to four aircraft was maintained. The average maintenance cost per flight-hour on aircraft of less than one hundred horsepower was $1.08. Shop Overhead Maintenance The shop overhead maintenance was computed to be $1.38 per flight- hour and was applied uniformly to all aircraft on the basis of the total flight-hours of each. The salaries of the aircraft maintenance engineer, the shop foreman, the machinist, the stockroom clerk, and the secretary — all of whom devoted practically one hundred per cent of their time to the upkeep of the fleet — were totaled in the overhead. Included also were the labor and material costs of repairing airplane and engine parts which were then stored in the stockroom for future use. Shop Equipment Depreciation To determine the depreciation of shop equipment, the inventory maintained by the University Purchasing Division was reviewed with the Aircraft Maintenance Engineer, and the total value was depreciated on a ten-year basis. For the period in question, the amount of depreci- ation was computed to be sixteen cents per flight-hour. Insurance The University acts as self-insurer of its own fleet of aircraft as far as hull insurance is concerned. The fact that the total expense of repairs to damaged aircraft amounted to only 13.03 cents per flight-hour seems to indicate that this policy is wise. With respect to public liability and property damage insurance, the University has a statutory limitation on liability of $2,500 and then only in case of negligence. Hence, it is conceivable that personal liability in excess of that figure might accrue to pilots of University aircraft. To protect employees against such remote contingencies, insurance is carried under which the insurance company waives the right to use the statutory defense. The cost per flight-hour was 11.48 cents. The bodily injury coverage limits are $50,000 and $250,000, and the property damage limit is $50,000. Linemen's Salaries Linemen are on duty at the University Airport twenty-four hours a day, seven days a week, to service the University fleet as well as transient aircraft using the field. In order to have two linemen on duty during the day and one at night, the services of seven are required. For purposes of this study, it was assumed that the linemen devote about two-thirds of their time to servicing transient aircraft and one-third to University airplanes. On this basis, the total linemen's salaries allocated to this study amounted to slightly over fifty-six cents for each flight-hour. Aircraft Depreciation The University depreciates its flight equipment on the straight flight- hour basis, although there are several other methods. So far this method has worked satisfactorily. It is especially useful and reasonably adequate in cases of greater-than-average annual aircraft utilization. The Univer- sity aircraft annually are flown more than twice the national average number of hours for light aircraft. The aircraft depreciation figures shown in Table 3 are those being used at the present time. Average Costs From the figures shown in Tables 2 and 3, it is possible to arrive at average costs for the various types of aircraft in the fleet. The average per flight-hour costs were as follows : Seventeen Aeroncas 7AC's, on the basis of 25,949.3 hours flown, $5.07; seven 1 Cessna 140's, on the basis of 6,037.6 hours flown, $6.22; two Cessna 170's, on the basis of 1,458.6 hours flown, $8.83; five 2 Beechcraft Bonanzas, on the basis of 3,810.4 hours flown, $12.64; and four Boeing A75NTs, on the basis of 1,812.1 hours flown, $10.08. 1 These had 90-horsepower engines. Cessna 140 NG 89707 was not included because it had an 85-horsepower engine. 2 Beechcraft 35 NG 80460 was not included in totals because no record was kept of fuel and oil purchased on cross-country flights. TABLE 1. UNIVERSITY OF ILLINOIS LIGHT AIRCRAFT FLEE1 ' OPERATED i DURING COST STUDY FEB. 1, 1948 TO FEB. 1, 1952 Type NC No. Date Pur- chased New or Used Hours on Plane When Purchased Hours as of 2/1/48 Hours as of 2/1/52 Hours Flown During Study Aeronca 7AC 82993 4-46 New 1688.3 2928.3 1240.0 Aeronca 7AC 82994 4-46 New 1766.8 2883.0 1116.2 Aeronca 7AC 82995 4-46 New 1820.7 3539.5 1718.8 Aeronca 7AC 82996 4-46 New 1 660.6 3516.7 1856.1 Aeronca 7AC 82997 4-46 New 1643.4 3310.0 1666.6 Aeronca 7AC 83427 5-46 New 1653.0 3166.4 1513.4 Aeronca 7AC 83428 5-46 New 1736.8 3257.0 1520.2 Aeronca 7AC 83429 5-46 New 1597.1 2988.6 1391.5 Aeronca 7AC 83430 5-46 New 1615.4 3529.2 1913.8 Aeronca 7AC 83431 5-46 New 1722.2 3457.7 1735.5 Aeronca 7AC 1536E 9-46 New 1363.5 2630.8 1 267.3 Aeronca 7AC 1537E 9-46 New 1330.3 2697.3 1367.0 Aeronca 7AC 1538E 9-46 New 1463.7 3166.1 1702.4 Aeronca 7AC 1539E 9-46 New 1432.9 3438.9 2006.0 Aeronca 7AC 1540E 9-46 New 1389.4 3196.1 1 806.7 Aeronca 7AC 1541E 9-46 New 1203.6 3122.6 1919.0 Aeronca 7AC 84008 9-50 Used 721.7 721.7 930.5 208.8 Cessna 120 89546 6-46 New 1449.1 2357.0 907.9 Cessna 120 89623 6-46 New 1401.4 2043.1 641.7 Cessna 140 89707 6-46 New 1261.3 1456.3 195.0 Cessna 140 2301V 3-48 New 1 897.3 1 897.3 Cessna 140 2324V 3-48 New 1531.2 1531.2 Cessna 140 9411 A 6-49 New 846.2 846.2 Cessna 140 941 3A 6-49 New 1219.9 1219.9 Cessna 140 5688C 12-50 New 157.9 157.9 Cessna 140 5690C 12-50 New 205.7 205.7 Cessna 140 1112D 12-50 New 179.4 179.4 Cessna 170 9058A 4-49 New 962.8 962.8 Cessna 170 1313D 1-51 New 495.8 495.8 Beechcraft 35 80460 6-47 New 213.1 556.3 343.2 Beechcraft A-35 720B 9-48 New 1258.3 1258.3 Beechcraft A-35 752B 11-48 New 1003.0 1003.0 Beechcraft B-35 5213C 10-50 New 706.0 706.0 Beechcraft B-35 5233C 11-50 New 597.1 597.1 Beechcraft C-35 622D 7-51 New 246.0 246.0 Taybrcraft BC-65 27460 4-46 Rebuill 612.0 717.7 105.7 Piper PA-20 7733K 11-50 New 312.1 312.1 Piper PA-12 4185M 12-47 New 795.5 795.5 Stinson 150 97692 10-46 New 927.8 1426.3 498.5 Ercoupe 415-C 99272 6-46 New 791.1 1244.8 453.7 Ercoupe 415-C 86979 5-46 Used 69.9 570.7 866.4 295.7 Boeing A75N1 51443 10-45 Used 1765.5 2515.4 3012.3 496.9 Boeing A75N1 57843 2-47 Used 3455.5 3885.7 4595.2 709.5 Boeing A75N1 64079 6-46 Used 1735.0 1735.0 2211.6 476.6 Boeing A75N1 64078 10-46 Used 1459.0 1899.5 2028.6 129.1 Seabee RC-3 1 6717K 2-48 Used 63.8 65.8 116.7 50.9 TOTALS 9,270.4 43,137.3 86,805.2 43,667.9 Total flight time and use of this airplane is not sufficient for accurate indication of operational cost. 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O) "O Q c ol 1 .2 .2.1 s ■D O a co o 4= °l £ g | , Q'n(NO>o | ooooo(Ncs O'O'ttiO'-O'tOiOOOi-N^'OnO'tSiOCDtOiOK ->o ^d ir> >d c> oo co en CN CN CN ^ uS K <> O C> 00 C> C> O CN <— ' I0i0ir>u->000000000>OW">00000000 KKKKuoioooOOpoocsCNiOOOOOOOO r-' ^ ^ ^ o n* 0>0>000>0>0>0>0>0>0«0<0-00'0 , ©ND»ONDN3»0 nnfoconnconronconnfococotoconnncon ooooooooooooooooooooooo conncocococococorocococorocococincocococon <0«0<0«0^«0*0^ ,> , 0^^^ , , , , 0'0 , , , r 0'0 OOOOOOOOGOOOOOOOOOOOOOOOOOOOOOOOOOOOOOGOOOOOOO conconcocococonncococococoncoconcoconco O O "ONOK l OOCO^KOCOCOOCN ^f U-> K O — OcocopooojioKw^CNcoOKOjco CN CO' CN IT) ■** CO* ^' CO CO CN CO* CN ■"<* ^* "*' CO CO CO o >o CN < OcoioOKK ,s t''tKhvK -COC>r-iO--^CN(N^fOCNtrlO)'0(NC>tCOOO>- ^>0'Oi-0( , )OOinNNNKK'-KO«0'-N'•— C0KK l O l O > 0CNNN'OO00lO«O'O , 0'O •O IT) IO "O "9 COCOCOCO U (J u u u u o o CO CO o o o a. a. < < < < CO CO CO 0.0.0)00)0)0) 0«-«-03 3 CCCCo >■ rl S. = 8 8 ' 5 * 5 ' 5 ' 5 ° o .=■ .2- «= t: ii O O o o co »— O.O.COLULUCOCQCQCOCO THE INSTITUTE OF AVIATION, established in 1945 as the Institute of Aeronautics, is operated as the administrative agency responsible for the fostering and correlation of the educational and research activities related to aviation in all parts of the University. Other functions include aca- demic instruction, flight training, management of the University of Illinois Airport, and aeronautical research. In connection with the latter function, the Institute issues two types of publications . . . first, a group of reports on research results, and second, a series of bulletins on aviation subjects of an extension service nature to the citizens of the State. The following publications have been issued: Bulletin One: Municipal Airport Management, Leslie A. Bryan, 1947. (Out of print) Landscape Planting for Airports, Florence B. Robinson, 1948. Labor Relations in the Air Transport Industry Under the Amended Railway Labor Act, E. B. McNatt, 1948. Airport Zoning, J. Nelson Young, 1948. (Out of print) Evaluation of the School Link as an Aid in Primary Flight Instruction, A. C. Williams, Jr., and Ralph E. Flexman, 1949. Lightplane Tires on Turf and Concrete, Leslie A. Bryan, 1949. Light Aircraft Operating Costs, Leslie A. Bryan, 1949. Evaluation of the School Link and Special Methods of Instruction in a Ten-Hour Private Pilot Flight-Training Program, Ralph E. Flexman, William G. Matheny, and Edward L. Brown, 1950. Flight by Periscope: I. Performing an Instrument Flight Pattern; the Influence of Screen Size and Image Magni- fication, Stanley N. Roscoe, 1951. Operating Costs of a Light Aircraft Fleet, Leslie A. Bryan, 1952. Publications of the Institute of Aviation will be sent free of charge upon request. Bulletin Two : Bulletin Three : Bulletin Four: Bulletin Five : Bulletin Six: Bulletin Seven : Bulletin Eight: Bulletin Nine Bulletin Ten 1 1 "ISS* UNIVERSITY OF ILLINOIS-URBANA 3 0112 005630444 "■■■M 11 1 +a ;::•.::::' ;;.,:: :•:•;:: . i