APPLICATION OF FLEET CREATION PROBLEMS IN AIRCRAFT PRE-DESIGN

APPLICATION OF FLEET CREATION PROBLEMS IN AIRCRAFT PRE-DESIGN Pavel V. Zhuravlev Faculty of Aeronautcal Engneerng, Moscow Avaton Insttute, Moscow, Russa Keywords: Passenger Arplane, Arcraft Fleet, Operatonal Effectveness, Arplane Famly Abstract Nowadays the competton on the passenger ar transportaton market becomes stffer wth each year. The market share that the Russan cvl avaton ndustry currently occupes on the global passenger arplane market s not very bg. However, the government of Russan Federaton plans to take measures for ncreasng ths share up to 10-15%. A number of new arcraft s planned for development and manufacturng to mplement ths dea. One of such new proects s the famly of MS-21 (MC-21) medum-and-short-range trunk-route arplanes. Irkut company plans to create a famly of these arplanes wth three versons. It s necessary to menton that the experence of Russan avaton ndustry n the creaton of trunk-route passenger famles s relatvely small compared to that of the Western arcraftproducng companes. The research concernng the problems of the evaluaton of the effectveness of trunk-route passenger arplane famly creaton was carred out both n Russa and abroad. However, such research dd not take nto the account the problems of operaton of these famles wthn the composton of mult-type arplane fleets. The paper adduces the fundamental prncples of the Methodology, whch was developed by ts author wth the purpose of takng the abovementoned factors of trunk-route passenger arplane operaton nto the account. The usage of the Methodology s llustrated on the example of evaluaton of varous varants of the short-and-medum range trunk-route passenger arplane fleet. 1 Problems and challenges One of the most mportant tasks of modern avaton desgners conssts n mnmzng the manufacturng costs whle caterng to the market needs. One of the ways of the soluton of ths problem conssts n creaton of the arcraft famles. Arcraft famly conssts of a number of versons, whch are created as a result of the modfcaton of the basc famly verson. All of the famly members (versons) are characterzed by a hgh degree of commonalty whle havng dfferent performance. Statstcs shows that the costs of creaton of a new verson le wthn 20-40% of the cost of the creaton of the basc verson for modfcaton (new arplane). Due to the constantly ncreasng costs and efforts, whch are requred for the development of new arplanes, t s mportant to evaluate ther future success at all desgn stages (especally the early ones). Such task can be accomplshed by the soluton of the fleet creaton problems [1, 2]. The current plans of Irkut company consst n manufacturng a famly of MS-21 arcraft, whch should consst of 3 versons wth the followng maxmum values of onboard passenger quanttes: 162, 196 and 210 (for MS- 21-200, MS-21-300 and MS-21-400 accordngly). However, accordng to the offcal nformaton [3], MS-21-400 (wth maxmum passenger capacty of 210) should be developed wth a new composte wng. The development of a new wng ncreases the cost of the proect by approxmately 50% and therefore such an arplane cannot be consdered as a verson of the famly and should be regarded as a new type of 1

PAVEL V. ZHURAVLEV arplane [4]. Therefore t s only possble to consder MS-21-200 and MS-21-300 as members of the MS-21 famly durng the fleet comparson. Also t s qute well-known that one of the key factors, whch determne the success of the new cvl arplane on the nternatonal market, s the postve experence of ts successful operaton at the domestc market (market of the country, whch manufactures the arcraft). Thus t s reasonable to evaluate the expedence of creaton of the MS-21 arplane famly from the pont of vew of carryng out the passenger transportaton wthn the cvl avaton system of Russan Federaton. 2 Problem statement and calculaton methods 2.1 Obectve functon for the problem of arplane famly desgn The arlne company ncome manly depends on the tcket prces. However, snce t s extremely hard to obtan the data concernng the proft margn of the company, the evaluatons of arplane operaton are normally carred out va the crtera of costs of carryng out the gven volume of passenger transportaton [5]. The evaluaton of the future arcraft proects accordng to the crtera of costs of carryng out the gven volume of passenger transportaton wth the created fleet s done accordng to the followng formula [1]: m m WS = mn FD ( a,{ x} ) = mn mn mn f ( a, x ) (1) m = 1 m a { D } = 1 x D W S s the obectve functon (the total expenses on transportng the gven amount of passengers over a gven perod of tme); W S s optmal value of the selected obectve functon; a s the vector of performance and parameters of the evaluated arplane of type (geometrcal parameters, aerodynamc characterstcs, performance etc.); a s the optmal vector of performance and parameters of the evaluated arplane of type (the vector, n whch all of the values of the performance and parameters are optmal); S s the msson (e.g. passenger ar transportaton program), whch should be fulflled; t s descrbed by the characterstcs from the {x} multtude; FD are the total expenses on carryng out the transportaton on the multtude of routes, whch are served by the type of arplane; m s the total quantty of arplane types n the fleet; {x} parameters, whch descrbe all mssons (routes, on whch the passengers are transported), whch are served by type of arplane; f( a,x ) are the costs of carryng out one flght on route by type of arplane; D s the multtude of routes, on whch the arplanes of type are assgned for carryng out ar passenger transportaton. To take nto account the absence or presence of a famly n the fleet t s necessary to keep n mnd that the ncrease of amount of the arplanes of the same type nfluences postvely the costs of mantenance, reparng and overhaul (MRO), spare parts, plot and mantenance crew tranng and so on. 2.2 Transportaton costs calculaton methods It was necessary to take the costs of fuel [6, 7], arport [8, 9] and ar navgaton charges, flght crew salares, on-board food prcng [10] and other expenses from the avalable modern statstcs to calculate the transportaton costs f( a,x ). The method for calculaton of the costs of carryng out one flght f( a,x ) was derved from [11]. The costs were dvded nto two groups: - drect operatonal costs, whch are proportonal to the volume of passenger transportaton and - ndrect operatonal costs, whch are proportonal to the number of flghts that should be carred out to fulfll the gven demand. 2

APPLICATION OF FLEET CREATION PROBLEMS IN AIRCRAFT PRE-DESIGN The MRO costs are changed and a dscount on the arplane prce s gven to take nto account the change (reducton) of operatonal costs wth the ncrease of the quantty of arplanes of the gven type or famly. The reducton of flght crew expenses s not consdered due to the absence of the approprate statstcs and methods. To evaluate the expedence of creaton of the MS-21 famly (MS-21-200 and MS-21-300) t s necessary to compare t to the arplane fleet, whch ncludes the same number of separate arplane types m (arplane types, whch do not belong to the same famly). In ths case t would also be possble to determne how the avalablty of a famly nfluences the operaton of an arcraft fleet. 2.3 Selecton of fleets (combnatons of arplane types) for comparson Irkut Company, whch s developng the MS-21 famly, has made numerous announcements that the man compettors of MS-21 are the Boeng 737 Next Generaton (B737NG) and Arbus 320 (A320) famles. Therefore t s reasonable to look at these famles for comparson. It s necessary to put all of the compared obects under smlar condtons to obtan proper results. Therefore each arplane would be consdered as havng a sngle-class passenger cabn wth maxmum possble number of seats. The arport requrements of the arplanes are also assumed to be smlar. B737NG famly conssts of 6 versons: B737-600, B737-700, B737-700ER, B737-800, B737-900, B737-900ER. However, B737-600 s much smaller than MS-21-200 and MS-21-300, whch does not allow consderng them as compettors. B737-700ER s the busness verson of B737-700. Thus t also cannot be consdered as a compettor for MS-21-200 and MS-21-300. A320 famly conssts of 4 versons: A318, A319, A320 and A321. All of those arplanes meet the requrements of the stated problem. However, t s obvous that A318 cannot compete wth the MS-21 famly nether n terms of maxmum passenger capacty nor n terms of flght range. The maxmum passenger capacty of A321 s too bg and ts flght range s too small. Thus t also cannot be compared wth MS-21-200 and MS-21-300. Thus the research was carred out for: MS- 21-200, MS-21-300, B737-700, B737-800, B737-900, B737-900ER, A319, A320. The followng rules were taken as the man ones durng the selecton of the compettor pars (competng fleets): 1) All compettor pars should dffer from the evaluated [(МS-21-200)+(МS-21-300)] par accordng to the descrbed below crtera by no more than 10% (Graphcal Method). The Graphcal Crtera s calculated as follows: 2S12 K = (2) S1 + S2 S 12 s the area of the geometrc fgure, whch s formed by the aggregaton of the flght envelopes of the evaluated and competng arplane pars; S 1 s the aggregated area of the flght envelopes of the evaluated [(МS-21-200)+(МS-21-300)] par, S 2 s the aggregated area of the flght envelopes of the competng par. Fg.1. Illustraton of the areas of two competng fleets. 2) It s necessary to compare the evaluated par wth several pars, whch nclude arplanes wth maxmum flght range and/or maxmum passenger capacty bgger and smaller than those of the evaluated par. Otherwse t s mpossble to put the compared pars nto equal condtons. 3) It s mpossble to determne the comparablty of the MS-21-200/MS-21-300 wth other arplanes based only on the Graphcal Method descrbed above. 3

PAVEL V. ZHURAVLEV Therefore an Analytcal Method was used as well. It conssted n evaluatng the sum of the percentage dfferences between the maxmum passenger capactes and flght ranges for each arplane. If ths sum does not exceed 30% t s possble to compare the analyzed arplane par wth MS-21-200/MS-21-300. Otherwse, ths par s excluded from consderaton. The dfference between maxmum passenger capactes (Analytcal Crtera of Passenger Capactes) s calculated as follows: NS N = ( 1) 100% (3) N MS 21 N S s the maxmum passenger capacty of the compettor arplane; N MS-21 s the maxmum passenger capacty of MS-21-200/MS-21-300 arplane. The dfference between maxmum flght ranges (Analytcal Crtera of Flght Ranges) s calculated as follows: LS L = ( 1) 100% (4) L MS 21 L S s the maxmum flght range of the compettor arplane; L MS-21 s the maxmum flght range of MS-21-200/MS-21-300. Fg. 2. Flght envelopes of the MS-21-200/MS-21-300 arplanes and ther potental compettors. Fg. 2 shows that the area of each transportaton dagram can be found as a sum of areas of a rectangle and a rectangular trapezum. The followng arplanes were determned as compettors (accordng to the Analytcal Crtera): for MS-21-200: А319, А320, B737-700; for MS-21-300: А320, B737-800, B737-900, B737-900ER. Thus the followng potental competng pars for [(МS-21-200)+(МS-21-300)] par can be constructed: [(А319)+(B737-800)]; [(А319)+(B737-900)]; [(А319)+(B737-900ER)]; [(А320)+(B737-700)]; [(А320)+(B737-800)]; [(А320)+(B737-900)]; [(А320)+(B737-900ER)]. The analyss accordng to the Graphcal Crtera shows that the followng compettor pars can be selected for [(MS-21-200)+(MS- 21-300)] fleet: - [(А319)+(B737-900)], - [(А319)+(B737-900ER)]. The frst par has smaller passenger capactes and flght ranges than those of MS-21 famly and the second one has bgger capacty and range values. Ths helps to balance the comparson out better. Snce the famly s compared to fleets wth two separate arplane types, t s mportant to properly capture the dfferences between them (and n partcular, reflect the changes n fleet operaton costs W dependng on the number of S operated arplanes of the same type and/or famly). 2.4 Dependence of the sellng prce on the quantty of the produced/purchased arplanes The arplane prce s reflected n the deprecaton expenses. Thus prce decrease also results n the decrease of transportaton costs f ( a, x ). The maxmum dscount, whch can be gven to an arlne company accordng to the avalable statstcs, s 30%. Such dscount can usually be obtaned for the purchases of 200 arplanes and more. Mnmum dscount apples 4

APPLICATION OF FLEET CREATION PROBLEMS IN AIRCRAFT PRE-DESIGN to purchases of at least 2 arplanes and s equal to 1-3%. Such dscount can attan 20% for average purchase of 40-50 arplanes. However, there are also exclusons. For example Aeroflot ordered 50 MS-21 arplanes wth an approxmate dscount of 22% [12]. Therefore based on the abovementoned data t s possble to buld an approxmate dependency of the arplane prce dscount on the amount of unts sold. The graphcal representaton of ths dependency s shown n Fg. 3 below. Fg. 3. Dependency of the dscount on the quantty of purchased arplanes. Ths dependency can be approxmated by the followng formula: C1 C N = (5) 0,06 N C N s the prce of one arplane when N arplanes of one type are purchased; C 1 s the catalogue prce of one arplane; N s the quantty of purchased arplanes. Thus t s possble to determne the dscount (%) on the prce of one arplane when N arplanes of one type are purchased by the followng formula: CN Dsc = (1 ) 100% (6) C It s mportant to pont out that such dscount Dsc wll be obtaned for all arplane versons wthn one famly. The total amount of the dscount would depend on the total quantty of the purchased arplanes N, whch belong to one famly. Ths s explaned by the fact that the manufacturer uses effectvely the 1 same facltes to produce varous versons of the same famly. 2.5 Adustment factors based on the experence of the SSJ-100 arplane creaton The frst flght of the frst MS-21 famly verson s planned for 2020. Rght now the proect s stll under development and only prelmnary data s avalable for evaluaton [3]. It would be extremely desrable to try and take the exstng experence of the recent arplane creaton n Russa nto account to ncrease the precson of such prelmnary estmatons. Ths can be done, n partcular, based on the data about SSJ-100 the new Russan shortrange trunk route arplane. Snce both arplanes were created at approxmately the same tme and under approxmately smlar condtons t s possble to assume that the experence of SSJ- 100 creaton can be used durng the evaluaton of the possble MS-21 future performance. Accordng to the avalable data [13], t s known that SSJ-100 came out 10% heaver and 20% more expensve than was ntally planned. Its fuel consumpton s also 11% hgher than planned (announced durng the desgn). At that the flght range and passenger capacty of SSJ- 100 remaned unchanged. Thus t s possble to ntroduce the followng adustment factors nto the calculaton of the total expenses of МS-21-200/МS-21-300 fleet on passenger transportaton W S : m ss s the adustment factor for the take-off weght of the МS-21-200 and МS-21-300 arplanes. m ss = 1.1; C ss s the adustment factor for the calculaton of the prce of the MS-21-200 and MS-21-300 arplanes. C ss = 1.2; F ss s the adustment factor for the calculaton of the fuel consumpton of the MS-21-200 and MS-21-300 arplanes. F ss = 1.11. The ntroducton of these factors nto the vector allowed us to carry out an addtonal parametrcal study. In partcular, f the values of these factors are taken as equal to 1, t s possble to estmate how much the fulfllment of 5

PAVEL V. ZHURAVLEV the announced requrements nfluences the compettveness of the created arplanes. 2.6 Method of assgnment of arplanes onto routes It s necessary to assgn one of the types of the arplanes wthn the fleet onto each route (lne) of the transportaton network {x}, on whch the fleet s carryng out passenger transportaton. Frst of all, t s necessary to allocate the multtudes of lnes, whch should be served by the evaluated fleets. It makes sense to only take amounts of passengers per flght that would ether be equal to or exceed 50% of the maxmum arplane capacty. Snce all arplanes should be n same condtons, t s necessary to take 50% of the mnmal maxmum passenger capacty among all compared arplanes (n our case t would be for A319 wth 145 passengers). All of the consdered arplanes fly over the dstances of more than 875 km n Russa. And none of them can fly onto the dstances of more than 6750 km except for MS-21-200. Snce all arplanes should be n equal condtons these wll be the lmts of the consdered flght ranges (above 875 and below 6750). The allocaton algorthm s the followng: 1) Flght envelops are bult for both arplane types n the fleet. 2) The startng requred quanttes of arplanes N are calculated. Those are equal to the quanttes of arplanes, whch are requred to carry out transportaton wthn the parts of ther transportaton dagrams, where the approprate arplane types are the only ones capable of transportng passengers. 3) In those parts of transportaton dagrams where both types can carry out transportaton, the requred arplane quanttes are splt between both types as 50%-50% (passenger-flow wse). 4) The dscount Dsc on the prce of the arplanes of each type s calculated. 5) The costs of transportaton f ( a, x ) are calculated for each arcraft type on each route based on the calculated dscounts and prces. 6) The calculated transportaton costs f ( a, x ) are compared and the arplanes wth smaller transportaton costs are assgned to the approprate routes (D are formed). On routes, where the costs of transportaton by smaller arplane are lower than those of the bgger one by no more than 10%, the bgger arplane type s selected. The tolerance zone of 10% from the total costs s due to the fact that t s not always possble to assgn the optmal type on each route n real operaton. Thus, f the dfference s suffcently small (<10%), there s an opportunty to assgn a non-optmal (e.g. bgger) arplane onto the approprate route. 7) The new requred arplane quanttes N are calculated and the process s repeated. When the new calculated requred quanttes dffer from the quanttes at the prevous step by less than 10% the algorthm stops and the quanttes stay fxed for further calculatons. Otherwse the process s repeated startng from step 4. 2.7 The results of comparson of the MS-21 famly arplane fleet wth the competng arplane fleets accordng to the proposed Methodology The followng results were obtaned durng the research (Table). All of the fleet operaton costs W S are shown n %, where 100% are the total fleet operaton costs of the А319/В737-900 par. 3 Conclusons The followng was accomplshed and obtaned durng the research: The research was focused on the development of the Methodology for evaluaton of mprovement of the trunk-route passenger arplane fleet effectveness due to the usage of arplanes, whch belong to one famly, durng ts creaton. The developed Methodology s versatle and can be used both at the stages of new arplane desgn as well as durng the strategc plannng of arlne company actvty. 6

APPLICATION OF FLEET CREATION PROBLEMS IN AIRCRAFT PRE-DESIGN The developed Methodology ncludes several orgnal Methods: - Method of selecton of potental competng arplanes; - Method of assgnment of varous types of arplanes for carryng out passenger transportaton onto the routes; - Method of takng the quantty of produced and purchased arplanes nto the account; - Method of takng the nfluence of the factors of the presence of a famly among the operated arplane types nto account; - Method of the correcton of evaluaton results, whch s based on the practcal experence of arcraft desgn. The developed Methodology was tested durng the evaluaton of the effectveness of the MS-21 arplane famly usage n an advanced arplane fleet, whch transports passengers wthn the Russan ar transportaton system: - the competng arplanes were dentfed (А319, B737-900, B737-900ER) and the comparson wth the usage of the developed Methods was carred out; - the Total Fleet Costs W S, whch are requred to carry out passenger transportaton on the forecasted transportaton network of Russan Federaton over a gven perod of tme, were selected and substantated as the Crtera for the Evaluaton of the Compettveness of the Arplane Fleets; - a parametrc study of the relatve nfluence of varous factors, whch are connected wth the desgn of new arcraft, on ther compettveness was carred out; - t was demonstrated that MS-21 famly can compete successfully wth ts declared compettors on the market, f the company that desgns t would be able to successfully attan the announced arplane performance; - the research has proved that the usage of the short-and-medum range arplanes of the MS-21 famly n the future fleet (nstead of ndvdual arplane types) would result n a benefcal effect durng the creaton of the fleet of advanced shortand-medum range arplanes. Table. Relatve change of the total fleet operaton costs dependng on varous condtons. For MS-21-200/MS-21- For MS-21-200/MS-21-300 n the 300 n the Compared A319/B737- area where A319/B737- area where Fleet 900 they compete 900ER they compete Alternatves wth wth A319/B737-900 A319/B737-900ER Wthout takng the quantty of 100% 95,3% 102,2% 96,8% arplanes nto the account Wth takng the quantty of arplanes 89,6% 85,2% 91,5% 86,6% nto the account Wth takng the quantty of arplanes and prevous development experence (SSJ-100) nto the account 89,6% 92,7% 91,5% 94,2% References [1] Pavel Zhuravlev. Desgn of passenger arplanes wth takng nto account ther operaton wthn the fleet. Presentaton at EWADE 2009 Workshop, Sevlla, www.mp.hawhamburg.de/pers/scholz/ewade/2009/ewade2009_ Zhuravlev_Pavel.pdf [2] Pavel Zhuravlev. Sgnfcance of modfcatons for development of passenger arplanes. Presentaton at EWADE 2011 Workshop, Naples, http://www.das.unna.t/ewade2011/presentatons/ Sesson_3/02_P_Zhuravlev_EWADE_2011.pdf [3] Famly of MS-21 arplanes advertsng brochure, Irkut Corporaton, 2007 [4] Zhuravlev P., Zhuravlev V. Sgnfcance of modfcatons for development of passenger arplanes, Arcraft Engneerng and Aerospace Technology, Vol. 84 Iss: 3, Bngley: Emerald Group Publshng Lmted, Guldford: Banner Managed Communcaton, Great Brtan, pp. 172-180, 2012. [5] Krauss M. Varantenentwcklungen be Verkherflugzeugen. PhD Thess. München: Technschen Unverstät München, Germany, 1997. [6] Mronenko P., Ekmovsk A. Money smells lke kerosene. Kommersant" newspaper 135 (4190), 2009 http://www.kommersant.ru/doc/1211697 7

PAVEL V. ZHURAVLEV [7] Avaton fuel prces n Russa grow agan. OlCaptal.ru., 2012 http://www.olcaptal.ru/konyunktura/176071.html [8] Vnukovo arport. Arport charges and tarffs. http://www.vnukovo.ru/rus/forarlne/charges#.ul0ksmdk-nb [9] Arport charges rates and ground servcng tarffs, whch are charged at the Sheremetyevo nternatonal arport. http://www.svo.aero/f/1/open_nfo/svo_stavk_aero portovyh_sborov tarfov_za_nazemnoe_obsluvan e.pdf [10] Feedng n the arplane. http://www.33ud.ru/forum/9/5---.html [11] Nechaev P.A., Samolov I.A., Samolov V.I. Compettveness of cvl arplanes. Integral estmaton. Textbook. Under the edtorshp of P.A.Nechaev Moscow: MAI, 2003 220 pp. [12] Aeroflot wll buy 50 MS-21 medum-range arplanes. V-EQUITIES Journal, 2011 http://www.vequtes.ru/%d0%bd%d0%be%d0%b2%d0%be %D1%81%D1%82%D0%B8%D0%AD%D0%BA% D0%BE%D0%BD%D0%BE%D0%BC%D0%B8% D0%BA%D0%B0NovostEkonomka.aspx?d=502 [13] Gel'man M. SuperJet-100 the tombstone of Russan avaton ndustry. Khrstenko and Pogosyan are the sculptors. Promyshlennye Vedomost, 5-6, 2012 http://www.promved.ru/artcles/artcle.phtml?d=227 7&nomer=76 7 Contact Author Emal Address The author emal address: pvzhuravlev@gmal.com 8 Copyrght Statement The author confrm that they, and/or ther company or organzaton, hold copyrght on all of the orgnal materal ncluded n ths paper. The author also confrm that they have obtaned permsson, from the copyrght holder of any thrd party materal ncluded n ths paper, to publsh t as part of ther paper. The author confrm that they gve permsson, or have obtaned permsson from the copyrght holder of ths paper, for the publcaton and dstrbuton of ths paper as part of the ICAS2014 proceedngs or as ndvdual off-prnts from the proceedngs. 8