Aircraft Design: Synthesis and Analysis - part 10 doc

This equation is truly valid only for aircraft with cruise Mach numbers of about 0.85. However, speed differences of 10 to 20% will affect the IOC by only 2 to 4%. Higher block speeds reduce the IOC. For other ranges the IOC is corrected by using the ratio of IOC($/n.mi) / IOC 1000nm ($/n.mi) from Figure 16. The latter is derived from the same data as Fig.15. Figure 16. Breakeven Load Factor To break even at distance, d , with a yield of $y /passenger-rnile, the revenue must equal the sum of the direct and indirect costs: N* LF * d *y = DOC * N * d + N * LF * ($/pass) indirect where DOC and ($/pass) indirect are taken at distance, d ; N = number of pass. seats. LF is the breakeven load factor. Substituting: LF breakeven = d DOC / [y d – ($/pass) indirect ] Total operating costs may be used in a complete airline system analysis in which each city-pair is studied to determine total traffic, required schedule frequency, load factors, total income, total costs and profit. Simpler presentations of the effect of costs may be shown in the form of passenger load required to pay the DOC as shown for the B707-320B and the B747 in Figure 17. Another type of analysis determines the break-even load factor, the load factor required to cover the total costs. Figure 18 shows this type of analysis for the DC-10, B747, DC-8-62, and the B727-200. All three of these economic analyses require establishing not only operating costs but also the yield, the average passenger fare per mile. The yield varies greatly with route and is generally different from the basic fare as airlines now determine fares based on the day of the week, when the ticket is purchased or whether the traveler will stray over a Saturday night. Figure 17. Figure 18. AIR TRANSPORT ASSOCIATION of America STANDARD METHOD OF ESTIMATING COMPARATIVE DIRECT OPERATING COSTS OF TURBINE POWERED TRANSPORT AIRPLANES December 1967 - PREAMBLE The following data represents a modification to the 1960 revision of the Air Transport Association Standard Method of Estimating Comparative Direct Operating Costa of Transport Airplanes. Since it is doubtful that new transport airplanes will be powered by reciprocating engines and the overwhelming majority of the passenger miles are now being flown with turbine powered airplanes, this revision is confined to the turbine powered airplanes. It is considered that, with proper adjustment to the crew costs and the maintenance labor rates to account for the changing economic situation from 1960 to 1967, the 1960 revision is still valid for airplanes powered by reciprocating engines. In addition to new methods of determining costs and new values for many of the basic parameters, the formula has been extrapolated to include the Supersonic Transport. The formula is not considered to be applicable to rotary wing or V/STOL aircraft. PREFACE The first universally recognized method for estimating direct operating costs of airplanes was published by the Air Transport Association of America in 1944. The method was developed from a paper, “Some Economic Aspects of Transport Airplanes,” presented by Messrs. Mentzer and Nourse of United Air Lines, which appeared in the Journal of Aeronautical Sciences in April and May of 1940. The basis of this method was taken from statistical data obtained from airline operation of DC-S airplanes and was extrapolated to encompass the direct operating costs of larger airplanes which were then coming into the air transport picture. In 1948 it was determined that the 1944 method of estimating direct operating costs fell short of its goal due to rising costs of labor, material, crew, and fuel and oil. Consequently, the Aix Transport Association reviewed the statistical data which were then available, including four- engined as well as twin-engined airplane data, and in July 1949 published a revision to the 1944 method. The ATA method was again revised in 1955 for the same reasons as above and also to introduce the turboprop and turbojet airplanes. The 1960 revision revised the predictions on turbine powered airplanes based on experience gained to that date. The formula has again been revised to bring it up to date and an effort has been made to make it easier to use, yet at the same time more meaningful to its basic purpose — comparing airplanes. The formula has been extrapolated to include the Supersonic Transport. This revision has been prepared with the assistance of an ATA working group consisting of representatives of the ATA member airlines and prime airframe and engine manufacturers. The assistance of this group is gratefully acknowledged. INTRODUCTION The objectives of a standardized method for the estimation of operating costs of an airplane are to provide a ready means for comparing the operating economics of competitive airplanes under a standard set of conditions, and to assist an airline operator and airplane manufacturer in assessing the economic suitability of an airplane for operation on a given route. Any system evolved for these purposes must essentially be general in scope, and for simplicity will preferably employ standard formulae into which the values appropriate to the airplane under study are sub-stituted. Clearly these formulae, seeking to give mathematical precision to complex economic problems, by their very nature can never attain this aim completely, but it can be closely approached by ensuring that the method quotes realistic universal averages. Data derived from this report is intended to forecast a more or less airplane “lifetime average” cost and cannot necessarily be compared directly to actual cost data for an individual airline. These individual airline costs are dependent upon many things which the formula does not take into account. These would include, but not be limited to, fleet size, route structure, accounting procedures, etc. Particular care must be taken in comparing airline short term operating cost statistics to data derived from this report. Airline maintenance scheduling is such that heavy maintenance costs (overhaul) may not be included for a particular fleet during a short term period such as one year. In comparing data derived from this formula with actual reported data it should be noted that some carriers may capitalize certain costs. The capitalized cost would then be reported in depreciation or amortization cost figures. The formula is further based on the assumption that the carrier does its own work. Actual reported data may include work by outside agencies. These formulae are designed to provide a basis of comparison between differing types of airplanes and should not be considered a reliable assessment of actual true value of the operating costs experienced on a given airplane. Where data are lacking, the user of this method should resort to the best information obtainable. Operating costs fall into two categories — Direct and Indirect Cost, the latter dependent upon the particular SeTvice the operator is offering although in certain particulars, the Indirect Costs may also be dependent upon and be related to the airplane’s characteristics. This method deals with only the direct operating costs with one exception. As maintenance burden is required to be reported to CAB as a Direct Cost, it is included in this formula. For data relating to estimation of Indirect Cost the following reference is provided: “A Standard Method for Estimating Airline Indirect Operating Expense” Report (to be) published jointly by Boeing, Douglas and Lockheed. DIRECT OPERATING COST EQUATION The following pages present the detailed Direct Operating Cost Equation. The costs are calculated as a cost per airplane statute mile (Cam); however, can be converted as follows: Block Hour Cost = Cost/Mile * Vb = Cam * V b Flight Hour Cost = Cost/Mile * Vb * tb / tf = Cam * Vb * tb / tf Where tb = Block time (hours) Tf = Flight time (hours) Vb = Block speed (mi/hr) BLOCK SPEED For uniformity of computation of block speed, the following formula based upon a zero wind component shall be used: Vb = D / (Tgm + Tcl + Td + Tcr + Tam) Where Vb = Block speed in mph D = CAB trip distance in statute miles Tam = Ground Maneuver time in hours including one minute for takeoff = .25 for all airplanes Tcl = Time to climb including acceleration from takeoff speed to climb speed Td = Time to descend including deceleration to normal approach speed Tam = Time for air maneuver shall be six minutes (No credit for distance) = .10 for all airplanes Tcr = Time at cruise altitude (including traffic allowance) = [(D + Ka + 20) – (Dc + Dd)] / Vcr Dc = Distance to climb (statute miles) including distance to accelerate from takeoff speed to climb speed. Dd = Distance to descend (statute miles) including distance to decelerate to normal approach speed. Vcr = Average true airspeed in cruise (mph) Ka = Airway distance increment (7 + .015D) up to D = 1400 statute miles = .02D for D over 1400 statute miles NOTES: 1. Climb and descent rates shall be such that 300 FPM cabin pressurization rate of change is not exceeded. In the transition from cruise to descent the cabin floor angle shall not change by more than 4 degrees nose down. 2. The true airspeed used should be the average speed attained during the cruising portion of the flight including the effect of step climbs, if used. 3. Zero wind and standard temperature shall be used for all performance. RESERVE FUEL Fuel reserve shall be the amount of fuel required to do the following: (These are in excess of minimum Federal Aviation Regulations and are representative of airline operational practices. This excess is not related to safety requirements). Subsonic Airplanes Domestic (1) Fly for 1:00 hour at normal cruise altitude at a fuel flow for end of cruise weight at the speed for 99% maximum range. (2) Exercise a missed approach and climbout at the destination airport, fly to and land at an alternate airport 200 nautical miles distant. International (1) Fly for 10% of trip air time at normal cruise altitude at a fuel flow for end of cruise weight at the speed for 99% maximum range. (2) Exercise a missed approach and climbout at the destination airport, fly to an alternate airport 200 nautical miles distant. (3) Hold for :30 at alternate airport at 15,000 feet altitude. (4) Descend and land at alternate airport. Supersonic Airplanes Domestic and International (1) Fly 5% of trip air time at cruise altitude at supersonic cruise speed at a fuel flow for end of cruise weight. (2) Exercise a missed approach and climbout at the destination airport and fly to the alternate airport 200 nautical miles distant. (3) Hold :20 at 15,000 feet over the alternate airport. (4) Descend and land at the alternate airport. Flight to Alternate Airport (All airplanes) (1) Power or thrust setting shall be 99% at maximum subsonic range. (2) Power setting for holding shall be for maximum endurance or the minimum speed for comfortable handling, whichever is greater. (3) Cruise altitude shall be the optimum for best range except that it shall not exceed the altitude where cruise distance equals climb plus descent distance. BLOCK FUEL Block fuel shall be computed from the following formula: Fb = Fgm + Fam + Fcl + Fcr + Fd Where Fb = Block fuel in lbs. Fgm = Ground maneuver fuel based on fuel required to taxi at ground idle for the ground maneuver time of 14 minutes plus one minute at takeoff thrust or power. F cl = Fuel to climb to cruise altitude including that required for acceleration to climb speed. Fcr = Fuel consumed at cruise altitude (including fuel consumed in 20 statute mile traffic allowance and allowance for airway distance increment Ka). Cruise altitude shall be optimum for minimum cost with the following limitations: (a) Cruise distance shall not be less than climb plus descent distance. (b) Cruise climb procedures shall not be used. (c) A maximum of two step-climbs may be used. Fam = Six minutes at best cruise procedure consistent with airline practice (no credit for distance). Fd = Fuel required to descend including deceleration to normal approach speed. 1. FLYING OPERATIONS a. Flight Crew Costs (Figure 1) These costs were derived from a review of several representative crew contracts. Based on this review, yearly rates of pay were arrived at which were used with welfare, training, travel expense, and crew utilization factors to produce the crew cost equations herein. Domestic Subsonic Airplane with Two-man Crew Turboprop Cam = [ .05 (TOGW max /1000) + 63.0] / Vb Turbojet Cam = [ .05 (TOGW max /1000) + 100.0] / Vb Domestic Subsonic Airplane with Three-man Crew Turboprop Cam = [ .05 (TOGW max /1000) + 98.0] / Vb Turbojet Cam = [ .05 (TOGW max /1000) + 135.0] / Vb Domestic Supersonic Airplane with Three-man Crew Cam = [ .05 (TOGW max /1000) + 180.0] / Vb International Subsonic and Supersonic Airplane with Three-man Crew Add 20.00 to term in brackets [ ] for domestic operation with three-man crew Additional Crew Members (All Operations) [...]... 34.5 - 41.0 73 7-6 00 36.0 - 44.0 73 7-7 00 41.5 - 49.0 73 7-8 00 51.0 - 57.5 73 7-9 00 53.5 - 61.0 74 7-4 00 167.5 - 187.0 74 7-4 00 Combi 177.5 - 197.0 75 7-2 00 65.5 - 73.0 75 7-3 00 73.5 - 81.0 76 7-2 00ER 89.0 -1 00.0 76 7-3 00ER 105 .0 - 117.0 To the left is a range of 1999 prices for inproduction airplanes The difference between the high and low prices is a function of the configuration and special features options... fuel, and so forth The 1999 prices include the reset of our prices in July 1998, incorporation of optional features to basic, and escalation from 1998 to 1999 *Note that the BBJ price is for a "green A/P" and excludes interior completion costs All prices are in U.S dollars and are in millions 76 7-4 00ER 115.0 - 127.0 77 7-2 00 137.0 - 154.0 77 7-2 00ER 144.0 - 164.0 77 7-3 00 160.5 - 184.5 MD-80 42.0 - 49.0... (Ct + 0 .10 (Ct – Ne Ce) + 0.40 Ne Ce ) / (Da U Vb) a Where: Da U Ct = Total airplane cost including engines (dollars) Ce = Cost of one engine (dollars) Ne = Number of engines = Depreciation period (years) = Annual utilization — block hours/year (See Figure 4) 1999 Airplane Prices Airplane Model Price (millions $) 71 7-2 00 31.5 - 35.5 73 7-3 00 40.0 - 46.5 73 7-4 00 44.0 - 51.5 73 7-5 00 34.5 - 41.0 73 7-6 00... 92.7 93.6 94.0 95.4 96.7 98.6 99.1 101 .6 103 .1 106 .4 108 .7 112.9 115.2 119.1 120.2 123.1 124.3 127.3 130.7 138.5 143.9 155.4 158.6 166.3 168.2 174.3 179.6 186.1 191.5 202.9 211.5 229.9 242.5 258.4 266.8 281.5 284.3 292.4 295.5 303.5 308.8 315.5 320.1 327.4 325.3 331.1 337.7 345.7 350.8 360.9 368.8 377.6 91.7 92.7 92.9 94.2 94.5 96.8 97.2 99.4 100 .0 103 .4 104 .2 109 .0 109 .8 115.7 116.3 120.8 121.3 124.7... 92.2 92.5 93.3 93.6 94.9 96.0 98.5 98.7 101 .0 102 .3 105 .7 107 .1 111.6 113.9 118.1 119.4 122.4 123.8 126.6 128.6 136.6 141.5 153.0 157.2 164.6 167.1 173.3 177.1 184.5 188.4 200.9 207.1 225.4 236.4 253.9 263.2 279.9 283.4 294.1 293.2 302.6 306.6 315.3 317.4 325.5 327.5 330.5 334.4 345.3 347.4 360.1 364.1 376.2 92.3 92.6 93.5 93.7 95.1 96.3 98.5 98.9 101 .3 102 .8 106 .1 108 .0 112.2 114.5 118.5 119.8 122.6 124.0... 91.7 92.1 92.1 1964 93.0 1965 94.6 1966 97.9 1967 100 .5 1968 104 .8 1969 110. 7 1970 116.9 1971 122.1 1972 125.7 1973 135.1 1974 149.9 1975 162.8 1976 171.9 1977 183.3 1978 197.8 1979 221.1 1980 249.4 1981 276.5 1982 292.8 1983 300.3 1984 313.0 1985 323.5 1986 328.6 1987 342.7 1988 356.6 1989 373.1 92.1 92.6 93.2 93.6 94.8 95.4 98.1 98.6 100 .7 102 .0 105 .1 106 .7 111.2 113.3 117.5 119.2 122.2 123.2 126.2... T /103 ) Ne = Labor manhours per flight hour (turboprop) KFCe = (0.3 + 0.03 T /103 ) Ne = Labor manhours per flight cycle (jets and turboprop) T = Maximum certificated takeoff thrust, including augmentation where applicable and at sea level, static, standard day conditions (Maximum takeoff equivalent shaft horsepower at sea level, static, standard day conditions for turboprop) RL Ne Labor rate per man-hour... 115.0 - 127.0 77 7-2 00 137.0 - 154.0 77 7-2 00ER 144.0 - 164.0 77 7-3 00 160.5 - 184.5 MD-80 42.0 - 49.0 MD-90 49.0 - 56.5 MD-11 132.0 - 147.5 MD-11 Combi 144.5 - 162.0 Business Jets* 35.25* Product Information More Information Customer Services Search Boeing Home| Commercial Copyright© 1999 The Boeing Company - All rights reserved title: Consumer Price Index Data subtitle: from US Bureau of Labor Statistics... design About the PASS variables PASS: Program for Aircraft Synthesis Studies This document describes the input and output parameters for the PASS program, including the variable name, units, and a description of each variable Input Variables 1 weight.maxto (lbs) The design maximum take-off weight For the cruise range computation, we assume the take-off weight is equal to this maximum value 2 sref (ft^2)... controlstype () 1= aerodynamic, 2 = part power, 3 = fully powered controls 58 clhmax () CLmax of horizontal tail 59 addclimbtime (hr) Additional time required to climb (See climb notes) 60 flapdeflection.to (deg) Take-off flap deflection 61 flapdeflection.landing (deg) Landing flap deflection 62 slatdeflection.to (deg) Take-off slat deflection 63 slatdeflection.landing (deg) Landing slat deflection 64 maxextrapayload . 81.0 76 7-2 00ER 89.0 -1 00.0 76 7-3 00ER 105 .0 - 117.0 76 7-4 00ER 115.0 - 127.0 77 7-2 00 137.0 - 154.0 77 7-2 00ER 144.0 - 164.0 77 7-3 00 160.5 - 184.5 MD-80 42.0 - 49.0 MD-90 49.0 - 56.5 MD-11 132.0. 73 7-5 00 34.5 - 41.0 73 7-6 00 36.0 - 44.0 73 7-7 00 41.5 - 49.0 73 7-8 00 51.0 - 57.5 73 7-9 00 53.5 - 61.0 74 7-4 00 167.5 - 187.0 74 7-4 00 Combi 177.5 - 197.0 75 7-2 00 65.5 - 73.0 75 7-3 00 73.5 -. type of analysis determines the break-even load factor, the load factor required to cover the total costs. Figure 18 shows this type of analysis for the DC -1 0, B747, DC- 8-6 2, and the B72 7-2 00.