757_Engines.docx - 9'“ 3-757:22 System Description...

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Unformatted text preview: 9'“ 3-757 :22; System Description Lccsticn ct System Components Introduction Twc Pratt and Whitley 203? engines are instaled on 1118 Boeing ?5T. Tile 203? eng'ne: I inctrpcratesvariabie pitchstatcruanesandautcrraficsurge bieedvahrestc ensure: - good starting dlaraderistbs pius . surge andstalsfree cperatbnthrcughcutfl'lea'rcrafi fiighternreicpe. I isatwin rctcr,axa|fbwturbc1an with: - high ccmpressicnand - high bypass rafic. Thetwc rctcrsare rned'lanicely 'ndependent. I The N1 {or low pressure rctcr1mrlsists cfa: - fan - ccrrpresscrsecfim and - turbinesecficrl. I The N: {or high pressure rotor} - ccnsistscfa ccmpresscrandturbine secficrlscnly. - dl'iVflS-ti'fl engine atxnesscries. The airdriuanstarterccnnectstc the N2 rctcr. I Hun-Hamill Tile L Dr R ENGSTATOR message 'ndicetesa fauit with the variable pitch statcrvanes. Operation Thrust lever mmemmt, changes tcthe airccndific rIing packccntrci cr rec'rculaficrl fan, cr changestc file engines-Ming anti-ice may cause errg'ne f'arnecut. " B-757 “0:12.12: Engine Oil System Introduction The FEW 203? vol system consists cf an oil tank, mgina-dr'rvan Di pump, Di fitar and a Fuel-oil heat amhangar. This ihst rates 1119 engine oil system schemafic. @ua ENGINE 3-757 .527: Engine Oil fists-m [continued] lCIIiI pressure on Quantity Operation The oi llbritafiorl system isa non-pressure regulated system and hasa wide range of "normal‘ operafirlg oll pressures. Oil pressure is displayed on file lower EIGAS so'een {erlg'ned'lsplayseleotedl‘lasa digital value and I.lia a polnteron a I.mrlitalscale. The usable oll quantity, measuredforeach erlg'ne oi tank: I is displayed on file associated 0i Quanfity Dis-pay on file EIGAS Seoorldary Display Asfileerlg'ne is started, a quantity ofoi wil shifi tothe engine bear'ng and gear box oorrparfinent, arld wil not return to file tank unfil file engirle issl'lut down. The ollsystemis pressurized byfile erlgine-driuenollpump. This pumpisdriyen direcfiy bythe M2 rotorsooll pressure wilyary wifil erlg'ne RPM. In addition, ollquanfityarld oi temperature wiltendtoyaryirnrerselyw'rtherlghe RPM sudl filat, asRF'M isirlcreased, quanfityarld temperature decrease, arld as RPM is decreased, quanfityarld temperature irlcrease. Theollpassesfilroughanollfiterwl'lere oontam'nantsare removed. Elouldfileollfiter beoorne saturated wifil oontam'nants, oi wilautomafically bypass file filter. Priortofile oi bypassirlg file filter: I file EGAS message Lor ROIL Fl LTER wil appear Next, file oil flows through file Fuel-oil heat exchanger. Fuel is used as file heat s'nll, oool'ngthe oil and luam'l'rlg file fuel. The oil pressure lssensed dowrlsfieam oFfile fuel-oil heat exchanger. Elould file oi pressure drop below T0 psi: I file respecfiue Lor ROIL PRESS light will iIum'nate and file EIGAS message L or R ENG OIL PRESS wil appear ThenI file eng'ne bearirlgsarld gear box oorrparfinentareocoled arld lubricated byfile oi. The temperature offile oi is measured after file gear boxarld is sl'lownonthe EGAS OilTemperat'ure Display. F'nally, the oil is returrled to file olltanlt. " B-757 SITE: Engine Fuel System Introduction The fuel systemmneiets DfSp-erend Engine fuel halves, mgine-dr'rven fuel pump, fuel-oil heat exchanger, fuel mnlml unit and fuel spray mules. This ihst'etes file engine fuel system schemefic. g... ENGINE 3-757 :3: Engine Fuel System [continued] Operation Sup-rand Engin- Valves Fuel Filter Fuel urlderpressure issuppiedtothe engirle from purrps'ntj'le fuel tanks. The fuelfrst fbwstj'lrough aSpar'Ualue before additional pressure is added bytlle low pressure stage ofti'leengine-driuen fuel pump. Thefueltj'lenfiowstj'lroughafuelroill'leatexchanger,wl'lichoontIolstiletemperatureof the fuel and than passes ti'lrougha low pressure fuel fiter. F'nal fuel pressure isgenerated byti'le high pressure stage ofti'le eng'ne-drilren fuel pump priorto ‘lZl'Ifl fuel entering ‘lZl'Ifl Fuel Control Unit The FCU oorrtrolstlle amount offuel flowto meet 111833531:qu ti'anst requirements The fuelthen flows ti'lroughthe Engine Value arld fnallytothe spray nozles 'n ‘lIl'fl oon'bustl'on chan'bers. The Spar Valve, located attlle rrts'n fuel tank, omtrolsthe flow offuel from ti'letanltto theerlg'lle. The Erlg'lle Valve, located inthe Fuel Control Unit, controls tl'lfl flow offuel going to ‘lZl'Ifl spray nozzles inthe oombustl'on chan'bers. The Engine and Spar Valvesare opened orclosed bythe FuelContIol switch. F'ul'nga Eng'ne Fire switch w'iI also dose boti'l Imatures The Engand Spar Value fights will: I iIuminate momentarily whenthe value is 'n transit I rerrts'n ihn'l'natedwheneverthe I.filltresdo rlot agree withti'le Fuel Control switch or ‘lIl'fl respectjue Fire switch position - Alsoa EICAS message L {R15F'AR VALVE or LiR} FUEL VALVE willappear. Fuel is filtered bya filter with bypass tapabiitjes. If ‘lZl'Ifl filter beoornescloggedwifl'l oontan'l'rlates, fuel wiI bypass the filterallow'ng unfiltered fueltoenterthe Fuel Control Unit Tile EICAS advisory message L {WEN-G FUEL F|LT willappear when affected engine fiter oontan'l'natl'on approacllesa level sufficient to cause filter bypass. I enab'ceng'ne operation and fameout may oocur due to fuel contamination " B-757 “SITE: Engine Fuel System [continued] Fuel Control Unit The FuelCcnficl Unit schedules fuel flow: I to meeterlgirle fianst requiremenlsesdictated b‘ftl'fl filmst lever pesificnerld I specificerlghecperstbns, hccnjuncficnwifilfile ElecficnicErlghchnficl {EEG} . The EEG ccntrclsfile metered fuelsrld prenentseng'ne initsfrcm being exceeded. The FuelCcnficl Unit wil mechanically l'rn'rt N2 rotor speed to 1%. Fuel Flaw Sensors messurefuel flcwtc fileerlg'nes: I fills wahre lsshcwn on file ElGll-‘G Fuel Flew Disphy I fills i'lformeficn istrarlsm'rtted to file FMGerld used wifil cfiler fuel quantity measurements-to calcuhte fuel used and fuel rerrls'n'ng @ua ENGINE B -757 3.1le Engine Controls Introduction ul- spa S-tlinss The erlg'ne ti'anst iselecti'onicallvoonti'oled. Thn.lst Lever movementserlds electrical signalsto the Electronic Engine CDntl'Dl. The EEG ti'len operates ti'leerlg'ne Fuel Cm‘lIDl Unit. Allfuel conti'olsare mounted onti'leoenterconsole. Theerlg'ne fuel control system has separate m1trols-Forstart'l1g,t'orlnardthn.lst, and reverse ti'lrust. A lockout provision 'n the thrust lever assembly mecha nitalv prevents simultaneous actuation ofbothforlnard and reversethrust. There are two engirle idle speeds: I m'I1'rnumidIe . usedforallgrourlrzloperationarld - allphasesoffiightexoept approacharld hrld'ng I approach idle - useddur'ngapproachandlandirlg Tile idle speed setting irlcreasesfrom m'n'rnum to approach when ti'le gear is downor the fiapsaresetto 25 or3fl and is rra'ntairled unti 5 seoondsatitertomhdom to Faciitate a fasteraooeleration forgo-around or reverse ti'lmst operation. Afier ti'le5 seoorld delay the approach idle speed reuertsto n'l'nimum idle to halt: minin'l'zethe hrlding roll. In-fiight, when engirle anti-ice is tumed on: I ti'le idle speed setlirlg also automatically irlcreasesto the approach setlirlg to maintain higher idle speeds during icing oorlditiorls Forward Thrust Leversare providedtooontrol erlg'ne forward ti'lrust requ'rementsfrom idle to rrmrimum power. Tile Rteverse Thrust Leversare used to command reverserdeplcvment immeven I ti'le Forward Thn.lst Levers must be atthe idle position To mrnmand more than idle reverse tilrust: I ti'le t'an sleeve rllust have moved pastti'le interlock position Tostolvti'le reverser: I ti'le Rteverser Thrust Lerner is retumed to tile ful down, stowed position @ua ENGINE 3-757 413:: Electronic Engine Control Introduction Operation The Electronic Engine GonfioHEEGl‘lsystem: I provides M1 and M2 ouerspeed protection but does not provide EG'I' mortunpentull protection I omfinumslymputesl'rnitEF‘R - which wil be achieved atful forward fianst lever posifion - disphy'ng it asadual-an'ber rad'al on file EF'Rdispiay. The EEG isadualyoomposed oftwo channels: a primaryanda secondary. Boll channel: I is 'ndependently capable ofoontroling file engine I oo-nta'ns logic [EIEIZI ‘oonfi'oi parameters‘ to regulate eng'ne tthst The EEG also I'rnits nlex'rnum reverse filn.|st_ Boll EEG is powered: I when fileeng'ne is operat'ng - bya dedicated pernlenent magnet alterTlator-[F'MAL 'ndependent ofaircraft elect-helpmer. I for maintenance purposes - bysdeofingtheALTN posifionofthe EEC MAINT POWEstitchlocatedonfile aooessu'ypanel. The printer}: channel uses EF'R, N1 or Nzasconfiol parameters, while file seoondary d'lannel uses N1 or Nzonly. Normaloperafion isdesignedto use pr'nlarychannd 'nthe EF'RoontIolmode. Alfinughonlyone dlannelisinoonfidatanyfime, bothchanndsareacfiveallthefime, floss-checking each ofilert'ort'aults and otmpar'ng engine illetoorlzlitionswifil file A'r Datacullputerinputs. Ed'l EEG channel has its nun separate inputst'or most offile parameters. Should file EEG detecta fault in one or more offile inputsto file channel in control, it wil automatically use file input from file channel filat is not 'n omfid. This is termed ‘resouroe sharing‘ and is designed to keep file EEG in file highest control mode. In additionto resouroeshar'ng, inofil 'Ilputsofa parfimhrparameterare notavailable, file EEGcan synfilesize manyofthese 'nputsfromofiler parameters For example, N1 spaedcan be synfilesizad from stpeed in orderto lteep file engine n.|nn'|1g inthe N1 oonfiolmode. @ua ENGINE 3-757 :3; Electronic Engine Control [continued] EPR “ODE H1 HOD-E H2 HOD-E Engin- Stator Van-s Hon-nonnll Normally, file EF'R modeoonfiolsfileeng'ne. Rated filrustoocursatspecil’icfilmst lever positions. The autofilrottle satsfile requ'red filrLlst Via oorrrnands from file Thrust Management lIiiomputer. Iffile EEC is not provid'ng adequate parameters to ma'ntain EF'RoontIol, file EEC wil automatically revert to file l‘tl1 mode. M1 mode is usme 'I1dicated by file loss of EF'R dispblyon ECAS. Shouldtlle parameters necessary tbr N1oonfio|infile primary dlannel be unavailable, the EEGlnIIIautorrafitaIyswitchtotlle nexthigllestoonfiol mode.Tlliscan be 'I1eifiler tile prirraryorseoond dlannel, wi'liclleuer is better capable ofconfioling file engine. Operat'ng 'n eifiler of filese bacltup control modes results in some loss ofoonfiol. Autcmnathswitcllingfrom prirraryto seoondarycllannelwilalso oocurwi'len file eng'ne is shutdown infiigllt. Subsequentengine shutdowns and restartswilaltemate between the prirraryarld seoorldary dlannels. Iffile EEG is not provid'ng adequate parametersto rra'ntain N1oontIol using eifilerof the two: EEC channels I flnNlellIlfllS-LISEIZI byfile EECtocontrolfianst I file ENG- IJMIT PROT ligllltand associated EGAS message ENG UM PROTwiI appear indicat'ng filat file EEG has reverted to Nzconfiol I autorraficfilmst imit protection is notayaiblble I eng'ne aooelerafion and deoelerafion dlaraoterisfics rray be altered I filn.lst is controlled in a manrler simiar to oonyerltionalfuel oontIols I takeoffis notaufilorized Sahara] stages offile high pressure compressor stator Ilanesare posifiorled byfile variable stator vane actuator which isconfi'olled by file soc. The variable posifion'ng improves oorrpressor performanoeand halos preuent compressor surge. Ifbofil cllannelsoftlle EEG are urlable tooonfioltlle stator vane actuator, tile EGAS message Lor R Eng STATORappears. Any filmst lever movementon file affected engheorcllangestotlle pneurrafic bleed systemt'ora'roondifionhgorfilermalanfi-ioe may cause engine t'ailJre. Iffile eng'ne t'ailsand file L or R ENGSTATOR message rema'ns displayed, restart is not possible. @ua ENGINES B-757 Eli: Thrust Reverse System Introduction and] engine is equipped withe hfdreulbaly operated fan sir reverser. Hydraulic: pressure forthe operation thi‘lfl left end righteng'ne thmst reverser mes from file iefiend right hydreuiosystem respeofiureiy. Loss tieithersystem rendersits respective reverserimperefive. Thrust reverseroperefim isfor ground use onif. This Hlustretes the thrust reverser 'n fl'le stunned, unlocked and reverse positions. FIXED m! was Elm LHK ®ua ENGINE 3-757 :12: 1hrust Reverse System [conti nued] Operation '3'le Unintentional Sulliv- lllovllnlnt Tlle reversethrust lever may be raised onlylvhen: I file assoc'ated filrust lever is at file idle position I file aircraft ison file ground Afi rnovementoffile reverser sleeves: I exposest'ocedcascadeuanesand I closes blocker doors red'rectirlg file flow offana'r t'onnardfilrough file vanesto produce reverse filmst Asfile reverse filrust lever is raised to file interlockstop: I file autofilrotfie disengage, ifenclaged I file assoc'ated isoblfion value opens alblving hydraulic: pressure to unlock and extend file reverser sleeve afi toward file reverse filn.lst position I file reversethrust annunc'ation RE‘vlappears above each EF'R dis-phy 'I1 amber when file reverser is unlocked arlcl 'n transit totlle deployed position When file sleeve is full afi arlcl file interlock releases I file reverse lever rray be raisedtothe rrax'rnum reverse posifion I file EGAS annuno'ation REV changes oolorfrom amber to green I aI forward filn.lst reference displaysare inhibited When reverse filmst is no longer required, rnov'ng file reverse leverforlvard and down tothe reverse idle detent sclledules fuelfiolv for n'l'nimum idle operafion. Furfiler movement offile lever to file fulldolvn positioncausesfile: I reverser sleeve to retract to file stowed arlcl locked posifion I file ECIASannunc'ation RE‘v" changes backto amberlvl'liethe reverser is in-transit toward file retracted position I appicafion oft'orlvard filn.lst is restricted byan 'llterlock system lvllie file reverser sleeve isin-transit When file reverser sleeve isstovued, fileamber REV annunc'ationdisappears. Eadl filmst reverser is automatically protected against unintenfionai reverse filn.lst by an autostollv feature in file filn.lst reverse system. lfan unoorrl'narldedthn.lst reverser unlock is sensed, hydrauic polner isautorraficaly applied tostolvthe reverser. Adisagreernent betlneen file Flteverse Thrust Lever posifion and file reverser sleeve position causes: I file EGAS message L {R} REV ISLN VAL toappear iFon file ground. Fort'aults detected above SD knotsor in-fiight, file message is 'I1hibited unfil at‘ter larld'ng. 9'“ 3357.131: Engine 1tl'ibratipn fists-m Intro-dilution Tile Airborne "vibration Monitoring equipment maybe most useful: I asatrend monitor'ng program when periodic readingsare recorded during stabiized tthst settingsto detect significant vibration changes ouera period of time I in detecting potential eng'ne probiarns Vibration lIiIhraracteristic are uniqueto each eng'ne and monitoring isaffected by instalationand 'I1stIumentation, and can varvfrom eng'neto engine. Tile Boeing ?5?eng'ne vibration monitor'ng system provides: I continuous monitoring oftha state ofbablnoa oftha engines rotors I a vibration displayto alert the crew to higher than nom'ral eng'ne vibration levels Honihring Each eng'ne hasona acoalarometerwilh dual picltupsatseparate frequencies {i.e. low frequeno'esfor N1, high frequeno'esfor N21 The piclt-upsareoonnected througha signal conditioner andtraclcing fiiterto the vibration display on the lower ECAS. Thus the signal from the accelerator is fiitered 'nto separate frequencies which represent eng'netraclted vibration tbrthe M1 and M2 rotors. Vibration is displayed on lower EICAS: I as part ofSecu'lzlarv Eng'ne Indications I together with atraclt dispblyoftha rotor with the highest vibration level tbreach engine Forthis reason, WA prooedurescall tbr Secu'lzlarv Engine lnditatJ'onsto be dispblyed at al tJ'mes dur'ng fight. Operatioml Hot- lIBer'ta'n engine rraifunctJ'onstan result 'n airframe vibration from awirlzlnilirg engine. Asthea'rcraft transifionsfrom cruise to blnd'ng, there can be muit'pla, narrow regions ofaitituda and a'rspaeds wheretha vbratjon level can baoorna severe. In general, a'rframa vbratjonscan best be reduced bydesoending and reducing airspeed. HcI-mlerlrerI ifafterdasoand'ngand reduc'ng a'rspeedI the existing vbratjon level is unacceptable, and if it is 'rnpractJ'calto further reduce airspeed, the vibration level may be reduced toa previous, lower level bvaslight increase in airspeed. " 3-757 3:: Engine Start This ilustratas 1119 engine start sdlamafic. FUEL GDNTHDL @ua ENGINE 3-757 :3: Engine Stan: [continued] Introduction Operation fiborhd Starts Airfrom H13 prlaun'latiodum is Llsad to pomrHIa air drivan start3r. Tl13souro3 ofair may b3 from a ground souroa, H13 AF‘U or H13 oH13r mnnirlg 3rlg'l13. F'usl1'ng in and rotaHrIg H13 start s3l3otorto H13 GND posiHon: I opansHlastartvalva I 3rlgagasH13 a'rdr'nrm start3rto H13 N2 spool I olosas H13 3rlg'l13 bl33d air valva if it is opan As H: rotaHon aoo3l3rat3s,n1ovir|g H13 Fual CDI'IlIDlS-Wl‘lficll to RUN: I op3r1s H13 spar and 3rlg'l13 fualvaluras I This albws fual to flow totl13 fL13| control unit. I aot'nratas H13s3l3ot3d lgniHon I Tl13 iglniHon s3l3ctor may b3 usan to s3l3ot BOTH, or3iH13rtl13 #1 or#2 lgnitaris}. Normally only or13 lgnitar is usad fixground startor orossbl33d 'nfight starlswhia boH1ignit3rsara Llsadforwirlzln'l'l starts. At approxirrataly 50% N2: I H13 Engirla Start s3l3-otor autorrchaIy moms to H13 AUTO posiHon I ‘l'l13start3rauton'latioally outsoutarld, I T113 start valura dosas stopping H13 flow of airto H13 start3r. This anwsH13 3rlg'l13 bl33d I.uralIlra to mova to a positionthat agr33sw'rthH13 Engirla Bl33d Air switch. lfH13 start oyola is not aLrtomaHoally taiTn'I1at3d at 50% N2: I H13 Erlg'na Start s3l3otorrnL1st b3 manual}: rrmadtothaAUTO orOFF posiHon to t3n11'rlat3 start3roparaHon. Tl'13 folbwirlg oould b3 r3ason foranab-ortad start I low duct prassura hightaihuirlzls dansa fual VBPDfS-Bifil'tmg from H13taipip3 highiniHal fual flow int3rruptionoffu3lor igniHon G: 3-75? .3411 Controls and Indicators Looatlon of Control and Indloators Inhuducfion THsihstratosfl'lofi'ght dooklmflthnofEnghont’ds-mdlmioator. ...
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