Boeing 747-400 Flight Management System Pilot’s Guide
Boeing 747-400 Flight Management System Pilot’s Guide**** Hidden Message ***** Boeing 747-400 Flight Management System Pilot’s GuideThis Honeywell FMS Pilot’s Guide was written as a training aid to theoperation of the Flight Management System in the B747-400 aircraft.In no case will this guide be used as an authorized check list orprocedural aid replacing FAA or other certifying authority approvedflight manuals or check lists. Contact Honeywell Flight OperationsPrograms Pilots at 602-436-1446 with any aircrew related questions,problems, or comments.Pilots using the avionics system described in this document arerequired to maintain Lateral and Vertical Situational Awareness at alltimes through the use of current and approved en route, sectional,and other topographical and navigational charts. The avionics systemherein described is designed to aid pilots in enhancing navigationalprecision. However, pilots are advised to use all flight followingtechniques normally employed, to insure that a valid mental pictureof the topography and desired route is maintained at all times.Helping You Control Your WorldC28-3641-21-01December 1996Printed in U.S.A.©1996 Honeywell Inc.Rev 1 12/96PROPRIETARY NOTICEThis document and the information disclosed herein are proprietarydata of Honeywell Inc. Neither this document nor the informationcontained herein shall be reproduced, used, or disclosed to otherswithout the written authorization of Honeywell Inc., except for trainingon recipient's equipment.NOTICE – FREEDOM OF INFORMATION ACT (5 USC 552) ANDDISCLOSURE OF CONFIDENTIAL INFORMATION GENERALLY(18 USC 1905)This document is being furnished in confidence by Honeywell Inc.The information disclosed herein falls within excemption (b)(4) of 5USC 552 and the prohibitions of 18 USC 1905.Use or disclosure of the information on this page is subject to the restrictions on the title page of this document.B747-400 FMS PILOT’S GUIDE LR-iList of Revised PagesPAGE NO. REV STATUSTitle Page Rev 1 12/96Proprietary Notice— 3/94Table of Contents FMS PILOT’S GUIDEiUse or disclosure of the information on this page is subject to the restrictions on the title page of this document.PAGE1 PILOT OVERVIEW .......................................................1-12 FLIGHT MANAGEMENT ...............................................2-1/22.1 GENERAL OVERVIEW ..........................................2-1/22.2 FLIGHT DECK CONFIGURATION ........................2-52.3 SYSTEM INTERFACES .........................................2-72.4 FLIGHT PHASES ...................................................2-82.5 OPERATION ..........................................................2-112.5.1 Dual Mode ...................................................2-112.6 FUNCTIONS ..........................................................2-132.6.1 Navigation....................................................2-132.6.2 Performance ................................................2-162.6.3 Guidance .....................................................2-172.6.4 Thrust Management ....................................2-192.6.5 Flight Displays .............................................2-202.7 SOFTWARE AND DATA BASE ............................2-222.8 MULTIPURPOSE CONTROL DISPLAY UNIT ......2-242.8.1 Display Functional Areas ...........................2-262.8.1.1 Display ..........................................2-262.8.1.2 Lines Select Keys (LSK) ............... 2-272.8.1.3 Brightness (BRT) Control .............2-272.8.1.4 Annunciators .................................2-272.8.2 Alpha Numeric Keys ....................................2-282.8.2.1 Slash Key......................................2-282.8.2.2 Space Key ....................................2-282.8.2.3 Plus/Minus Key .............................2-29TABLE OF CONTENTSiiUse or disclosure of the information on this page is subject to the restrictions on the title page of this document.B747-400 FMS PILOT’S GUIDE 2.8.3 Function Keys ............................................2-292.8.4 Mode Keys ................................................. 2-312.8.5 Page Formats and Data Labels .................2-332.8.6 Data Entry ..................................................2-362.8.6.1 Button Push Processing ............... 2-362.8.7 Navigational Display (ND) Symbology .......2-372.8.8 Initial Power-up Operation .........................2-402.8.9 Flight Management System Terminology ..2-403 FLIGHT OPERATIONS .................................................3-13.1 FLIGHT DATA .......................................................3.1-13.2 PREFLIGHT ..........................................................3.2-13.2.1 Aircraft Identification .................................. 3.2-23.2.2 INIT/REF INDEX........................................3.2-63.2.3 Position Initialization ..................................3.2-83.2.4 Position Reference ....................................3.2-143.2.5 Flight Plan Route Entry.............................. 3.2-163.2.6 Departure Selection ...................................3.2-243.2.6.1 SID and Departure Runway Entry 3.2-263.2.7 Route Discontinuity ....................................3.2-293.2.8 Flight Plan Route Activation ......................3.2-323.2.9 Performance Initialization ..........................3.2-343.2.10 Thrust Limit Data .......................................3.2-403.2.10.1 Thrust Lim Page – Airborne ...... 3.2-433.2.11 Takeoff Data Entry ....................................3.2-443.3 TAKEOFF/CLIMB ..................................................3.3-13.3.1 Autothrottle Takeoff ...................................3.3-13.3.2 Climb Phase .............................................. 3.3-23.3.3 CLB Page ..................................................3.3-23.3.4 Climb Profile ..............................................3.3-83.3.5 Climb Performance Change ......................3.3-93.3.6 RTE LEGS Pages ..................................... 3.3-103.3.6.1 RTE DATA ....................................3.3-113.3.6.2 Climb Airspeed/Altitude3.3.6.2 Constraints....................................3.3-163.3.6.3 Rules for Airspeed/Altitude3.3.6.3 Constraints....................................3.3-18iiiB747-400 FMS PILOT’S GUIDE Use or disclosure of the information on this page is subject to the restrictions on the title page of this document.3.4 CRUISE .................................................................3.4-13.4.1 CRZ Page ..................................................3.4-13.4.1.1 Route Copy ...................................3.4-53.4.1.2 Abeam Points ...............................3.4-73.4.1.3 Direct-To/Intercept Course ...........3.4-123.4.2 PROGRESS Page .....................................3.4-173.4.3 Altitude Step Points ...................................3.4-233.4.3.1 Optimum Steps .............................3.4-233.4.3.2 Planned Steps ..............................3.4-243.4.4 Lateral Offset Route ..................................3.4-263.4.5 Holding Patterns ........................................3.4-283.4.5.1 RTE 1 LEGS – HOLD AT – Page .3.4-283.4.5.2 MOD RTE 1 HOLD Page ..............3.4-293.4.5.3 ACT RTE 1 HOLD ........................3.4-343.4.5.4 Holding Pattern Guidance ............3.4-353.4.6 FIX INFO Page ..........................................3.4-373.4.7 REF NAV DATA Page ...............................3.4-413.4.8 SELECT DESIRED WPT ..........................3.4-463.4.9 DESCENT FORECASTS ..........................3.4-493.4.10 Altitude Intervention ...................................3.4-513.4.10.1 Cruise Altitude Modification ........3.4-513.5 DESCENT .............................................................3.5-13.5.1 DES Page ..................................................3.5-23.5.2 OFFPATH DES Page ................................3.5-73.5.3 ARRIVALS Page .......................................3.5-103.5.3.1 VFR Approach ..............................3.5-153.5.3.2 Runway Extension ........................3.5-163.5.4 Descent Profile ..........................................3.5-173.5.5 Altitude Intervention ...................................3.5-183.5.5.1 Constraint Deletion .......................3.5-183.5.5.2 Altitude Level Off/Resumption ......3.5-183.6 APPROACH ..........................................................3.6-13.6.1 APPROACH REF Page .............................3.6-13.6.2 Radio Tuning .............................................3.6-33.6.3 NAV RADIO Page ..................................... 3.6-33.6.4 Autotuning .................................................3.6-83.6.4.1 DME/DME .....................................3.6-83.6.4.2 VOR/DME .....................................3.6-83.6.4.3 ILS/MLS ........................................3.6-9Rev 1 12/96ivUse or disclosure of the information on this page is subject to the restrictions on the title page of this document.B747-400 FMS PILOT’S GUIDE 4 ADVANCED FLIGHT PLANNING .................................4-14.1 PILOT-DEFINED WAYPOINTS .............................4-14.1.1 PBD/PBD and PB/PB ................................4-14.1.2 Along Track ...............................................4-24.1.3 Latitude/Longitude .....................................4-24.1.4 Airway Crossing Fixes ...............................4-34.1.5 Summary of Pilot Waypoint Construction ..4-34.2 CONDITIONAL WAYPOINTS ................................ 4-44.3 FMC ABBREVIATIONS ..........................................4-64.4 POLAR OPERATION .............................................4-84.4.1 Magnetic/True Reference ..........................4-84.4.2 Polar IRS Navigation .................................4-84.5 HOLDING PATTERNS .......................................... 4-104.5.1 Types of Holding Patterns .........................4-104.5.2 Creation and Modification ofHolding Patterns ........................................4-114.5.3 EFIS Display of Holding Patterns ..............4-124.5.4 Calculation of Holding Pattern Size ...........4-134.5.5 Deceleration Segments .............................4-14 4.5.6 Holding Pattern Entry Types...................... 4-144.5.7 Holding Pattern Guidance in Climb ...........4-154.5.8 Holding Pattern Guidance in Cruise ..........4-154.5.9 Holding Pattern Guidance in Descent .......4-164.6 FMC FLIGHT PLAN WIND USAGE ......................4-174.6.1 Entry and Propagation of Forecast Winds 4-174.6.2 Effect of Flight Plan Modifications onWind Propagation ......................................4-204.6.3 Mixing of Measured Winds with FMCPropagated/Forecast Winds ......................4-224.6.4 Step Climbs ...............................................4-234.6.5 Using the Step Climb Feature toEvaluate Wind Trade .................................4-24vB747-400 FMS PILOT’S GUIDE Use or disclosure of the information on this page is subject to the restrictions on the title page of this document.5 BACKUP FUNCTIONS ................................................. 5-15.1 EFIS CONTROL PANEL .......................................5-15.1.1 EFIS CONTROL Page ..............................5-25.1.2 EFIS OPTIONS Page ................................ 5-55.2 EICAS CONTROL PANEL ....................................5-75.2.1 EICAS MODES Page ................................5-75.2.2 EICAS SYNOPTICS Page.........................5-85.3 STANDBY NAVIGATION ......................................5-105.3.1 IRS LEGS Page.........................................5-115.3.2 IRS PROGRESS Page ..............................5-125.3.3 ALTN NAV RADIO Page ...........................5-156 FMS-MCDU MESSAGES ..............................................6-16.1 MCDU ALERTING MESSAGES ...........................6-26.2 MCDU MESSAGES...............................................6-47 ADDITIONAL INFORMATION ......................................7-17.1 COST INDEX ........................................................ 7-17.2 MAINTENANCE PAGES ....................................... 7-37.2.1 MAINTENANCE INDEX Page ...................7-37.2.1.1 <CROSS LOAD ............................7-47.2.1.2 PERF FACTORS ..........................7-57.2.1.3 IRS MONITOR .............................. 7-9APPENDICESAPPENDIX A Index ..............................................................A-1APPENDIX B Abbreviations & Acronyms.............................B-1APPENDIX C List of Illustrations..........................................C-1tHIS PAGE WAS INTENTIONALLY LEFT BLANK.Section 1 PILOT OVERVIEWThe Honeywell B747-400 Flight Management System (FMS) PilotGuide is oriented to the operation of the Honeywell Flight ManagementSystem installed on the B747-400 aircraft.This automated system integrates sensors, systems, and displays toprovide economy with a minimum workload. The Flight ManagementSystem (FMS) offers the pilot substantial assistance in devising theflight plan. The FMS software was developed by Honeywell to meetthe unique systems design specifications of Boeing. While optimizingthe flight plan for winds and operating costs, it fills in the details,suggesting the most economical climb profile, cruise altitude, airspeed,step climb, and desecent. If the pilot elects the automatic flight mode,the Flight Management System (FMS) guides the aircraft throughoutthe entire flight plan, from takeoff through landing. Additionally, theFMS attempts to provide the lowest possible cost for the flight whileattempting to satisfy all operational constraints that are imposed onit. The key roles of the system are performance and arrival predictions.While fuel consumption is a major component of cost, other factorsare taken into account. These include flight and ground crew wages,costs of late arrival and other factors determined by the operator.Thus, a Cost Index (CI) is determined by the operator and the FlightManagement Computer (FMC) uses this Cost Index to develop anoptimized flight.The Honeywell Flight Management functions include: navigation,performance and optimization, flight planning management, managedguidance computation, and information display management.1-1Use or disclosure of the information on this page is subject to the restrictions on the title page of this document.1 PILOT OVERVIEW1-2Use or disclosure of the information on this page is subject to the restrictions on title page of this document.B747-400 FMS PILOT’S GUIDE This guide is organized to:1. Provide a general Flight Management Computer System(FMCS) overview.2. Step through FMS operation as it could be used inairline operations.3. Provide in-depth information about system functions.Several appendices provide reference information useful inunderstanding this guide.The Pilot’s Guide is written to provide the information necessary tooperate the Flight Management System (FMS) in most operationalmodes. Used with a training device, the pilot gains sufficient knowledgefor in-flight use of the system. The guide contains details sufficient toanswer the majority of questions generated through system use.The reader should know that every effort has been made to ensurethe accuracy of published information. Questions about currentsystem operation and configurations should be directed to HoneywellB747-400 Engineering or the Honeywell Technical Pilots.This manual is intended as a guide and does not supersede Boeing,any certifying authority, or any airline approved procedures. It iswritten for system familiarization only. Section 2 FLIGHT MANAGEMENT2.1 GENERAL OVER OVERVIEW VIEW The Flight Management System (FMS) provides a means via theMode Control Panel (MCP) on the glareshield and the MultipurposeControl Display Unit (MCDUs) for the pilot to enter a flight plan, selectvarious flight control modes, and enter other necessary flight data.Flight progress is monitored through the Multipurpose Control DisplayUnit (MCDU) and the Electronic Instrument System (EIS).After data entry, the Flight Management Computer System (FMCS)aids the pilot by reducing the workload in flight planning, navigation,performance management, aircraft guidance, and monitoring of theflight progress to ensure optimum efficiency and effectiveness (seeFigure 2-1).Use or disclosure of the information on this page is subject to the restrictions on the title page of this document.2-1/22 FLIGHT MANAGEMENTB747-400 FMS PILOT’S GUIDE Use or disclosure of the information on this page is subject to the restrictions on the title page of this document.G3641-21-024#2-3Figure 2-1Flight Management PurposeG3641-21-024#THE FLIGHT PLAN ROUTE IS ENTERED ANDFUEL PLANNING DATA IS COMPUTED.CAPTURES AND TRACKS THEASSIGNED FLIGHT PLAN ROUTE.COMMANDS SPEED AND THRUSTFOR OPTIMUM FUEL ECONOMY.AIRPLANE LEVELS OFF AND CRUISESAT THE MOST ECONOMICAL SPEED.OPTIMUM ECONOMY CLIMBING TOA HIGHER ALTITUDE AS THE CRUISEPROGRESSES.PROVIDES CONTINUING GUIDANCEALONG THE FLIGHT PLAN ROUTE,INCLUDING GREAT CIRCLE ’’DIRECT""ROUTES.CONTINUOUS EVALUATION ANDPREDICTION OF FUEL CONSUMPTIONALONG WITH RECLEARANCE DATA.AN ACCURATE TOP OF DESCENT POINTFOR A CABIN REPRESSURIZATIONAND A COST EFFICIENT DESCENT.FUEL-SAVING IDLE THRUST DESCENTTO THE DESTINATION AIRPORT.AUTOMATICALLY COMPLIES WITHSPEED AND ALTITUDE RESTRICTIONS.PROVIDES THE TRANSITION TOTHE AUTOMATIC LANDING SYSTEM.AIRCRAFT DELIVERED AT PROPERAPPROACH SPEED.THE PILOT IS ADVISED OF THEPROPER LANDING SPEED.NAVIGATION INFORMATION ISDISPLAYED ON THE MOVING MAPDISPLAY.B747-400 FMS PILOT’S GUIDE Use or disclosure of the information on this page is subject to the restrictions on the title page of this document.2-4After data entry, the FMCS generates the optimum flight profile fromorigin to the destination airport. The system provides automaticaircraft guidance along the defined path while computing and displayingcurrent and predicted progress along the flight plan (see Figure 2-2).ORIGARPTDEPARTUREPROCEDURES(RWY, SID, TRANS)ENROUTEARRIVALPROCEDURES(APPR, STAR, TRANS)MISSEDAPPROACHPROCEDURESDESTARPTLATERAL FLIGHT PLANSTEP FLCRZ FLSTEP CLBSPEED LIMITDECELERATEGLIDESLOPEACCELALTCONSTR(AT)RWYACCELALTSPD CONSTRTHR REDRWYALTTAKEOFFCLIMB CRUISEDESCENTAPPROACHGO AROUNDTHRREDG3641-21-001#T/CT/DWAYPOINTALT CONSTR(AT OR BELOW)VERTICAL FLIGHT PLANFigure 2-2Flight Management System ProfilesTo perform these functions, the FMS automatically tunes the navigationradios and sets courses. The courses are not constrained to navaidradials. The system provides automated enroute and terminal areaguidance along defined procedures including Standard InstrumentDepartures (SIDs), Standard Terminal Arrival Routes (STARs),holding patterns, and procedure turns. It also provides guidance to avertical path, which honors defined altitude and speed, and can flylateral offsets to the defined path. In addition, the FMS computespredicted arrival times and fuel consumption along the flight planroute and to the flight’s destination.B747-400 FMS PILOT’S GUIDE Use or disclosure of the information on this page is subject to the restrictions on the title page of this document.2-52.2 FLIGHT DECK CONFIGURA CONFIGURATION TION The Flight Management System (FMS) consists of two FlightManagement Computers (FMCs),which are installed in the avionicscompartment and two Multipurpose Control Display Units (MCDUs),also referred to as a CDU, installed in the left and right sides of theforward pedestal. A third CDU not related to the FMS is installed in theaft pedestal. Refer to Figures 2-3 and 2-4.Figure 2-3Flight Deck ConfigurationB747-400 FMS PILOT’S GUIDE Use or disclosure of the information on this page is subject to the restrictions on the title page of this document.2-6Figure 2-4Flight Deck LayoutB747-400 FMS PILOT’S GUIDE Use or disclosure of the information on this page is subject to the restrictions on the title page of this document.2-72.3 S SYSTEM YSTEM INTERF INTERFACES ACES Both Flight Management Computers (FMCs) are highly integratedwith other aircraft avionics for both input and output data. The FlightManagement System (FMS) interfaces with the Autopilot FlightDirector System (AFDS) through the Mode Control Panel (MCP) andFlight Control Computers (FCCs). The left and right FMCs computeindependently; however, they “cross talk” with each other.The FMC integrates information from air data, inertial reference,radio navigation, engine and fuel sensors, optional weight andbalance system, an internal navigation data base, and crew-entereddata. Command data for lateral and vertical guidance is supplied tothe Flight Control Computer (FCC) and thrust commands to theautothrottle servo for automatic guidance.These multiple sources of information, from which the FMS receivesinformation, are illustrated in Figure 2-5. Correct aircraft, engine anddata base configuration may be confirmed on the Control Display Unit(CDU) Identification (IDENT) page on aircraft power-up. PILOTFMCG3641-21-002#INTEGRATEDDISPLAYSYSTEM(ND & PFD)CENTRALMAINTENANCECOMPUTERELETRONICENGINECONTROLSINERTIALREFERENCESYSTEMDIGITALCLOCKAUTOPILOTFLIGHTDIRECTORSYSTEMMODECONTROLPANELDATABASELOADERILS/MLSVOR DME ADFOFFSIDEFMCWEIGHTANDBALANCECOMPUTERFUELQUANTITYINDICATINGSYSTEMAIR DATACOMPUTERFLIGHTCONTROLCOMPUTERELECTRONICINTERFACEUNITAUTO-THROTTLESERVOMCDUFigure 2-5Flight Management System InterfaceB747-400 FMS PILOT’S GUIDE Use or disclosure of the information on this page is subject to the restrictions on the title page of this document.2-82.4 FLIGHT PHASES Figure 2-6 illustrates a typical Flight Management System (FMS)profile from the preflight phase at origin airport, to the rollout phaseat the destination airport. In addition to Vertical Navigation (VNAV)guidance and Performance (PERF) modes, the FMS supplies LateralNavigation (LNAV) guidance to follow waypoints along the predefined route.SPEED LIMITALTITUDECONSTRAINTACCELERATIONALTITUDETHRUSTREDUCTIONALTITUDESTEPCLIMBEARLYDESCENTTOP OF CLIMBINITIAL CRUISEFLIGHT LEVEL TOP OF DESCENTSPEED LIMITALTITUDECONSTRAINTFLAPSEXTENDEDDESTINATIONORIGINPREFLIGHTPHASETAKEOFFPHASEAPPROACHPHASECLIMBPHASECRUISEPHASEDESCENTPHASEG3641-21-003#LATE DESCENTFigure 2-6Typical Flight Management System ProfileThe pre-defined route may be divided into a number of FMS declaredflight phases to include PREFLIGHT, TAKEOFF/CLIMB, CRUISE,DESCENT, AND APPROACH.PREFLIGHT – In this phase the FMS is initialized. A flight plan maybe either recalled from the navigation data base by company routedesignator or departure/destination ICAO code identifier, or enteredwaypoint by waypoint (strung) on the ROUTE (RTE) page, oruplinked via Aircraft Communications Addressing and ReportingSystem (ACARS). B747-400 FMS PILOT’S GUIDE Use or disclosure of the information on this page is subject to the restrictions on the title page of this document.2-9During the preflight phase the following events are accomplished:•
Check of airplane and engine models in the Performance DataBase, and a check for an active Navigational Data Base.•
Inertial Reference System (IRS) alignment.•
Entry of origin, destination, cruise altitude, flight number, andcost index.•
Entry of fuel data and zero fuel weight.•
Entry of flight plan route, runway, Standard Instrument Departures(SIDs), transition and waypoint, revisions to include speed andaltitude.•
Selection of economy or pilot-entered flight phase speeds.•
Confirmation or entry of takeoff “V” speeds.•
Entry of thrust reduction/acceleration altitudes, assumedtemperature for derated thrust performance, and engine outacceleration altitude.•
Confirm auto tuning of navigation radios for departureTAKEOFF – This phase extends from initial thrust application to thethrust reduction altitude where takeoff thrust is normally reduced toclimb thrust. Lateral Navigation (LNAV) and Vertical Navigation(VNAV) are normally armed before takeoff. The LNAV engages if theairplane is above 50 feet, and within 2.5 nautical miles of the activeroute leg. The VNAV engages above 400 feet with the PerformanceInitialization (PERF INIT) page complete. The thrust reduction underthese conditions are automatic at the thrust reduction altitude.CLIMB – This phase extends from the thrust reduction altitude tothe Top-of-Climb (T/C). The T/C being the point where the aircraftreaches the cruise altitude entered on the Performance Initialization(PERF INIT) page. The Vertical Navigation (VNAV) and Performance(PERF) modes provide guidance for accelerating the aircraft whenabove the speed transition and speed restriction altitude. The modesobserve airspeed and altitude constraints that are stored in thenavigational data base or inserted by the pilot.Rev 1 12/96B747-400 FMS PILOT’S GUIDE Use or disclosure of the information on this page is subject to the restrictions on the title page of this document.2-10CRUISE – This phase extends from the T/C to the Top-of-Descent(T/D). Cruise could include step climbs as well as en route descents.The Flight Management Computer (FMC) calculates the optimumstep climb point. A step climb requires setting a new altitude target onthe Mode Control Panel (MCP) and initiating a climb thrust pilotselection. En route descents are initiated by setting a new altitudetarget on the MCP and reinserting a new Cruise Altitude (CRZ ALT)into the Control Display Unit (CDU).DESCENT and APPROACH – These phases start from the T/D, orby the pilot initiating a descent via Flight Level Change (FLCH), or viaVertical Speed (VS). The FMC calculates the appropriate point for thestart of descent and initiates the descent automatically if the ModeControl Panel (MCP) altitude has been lowered and VNAV and LNAVare engaged. VNAV guidance can be used to transition onto the ILSapproach, or to fly an entire non-precision approach. If a missedapproach becomes necessary, LNAV and VNAV modes may againbe engaged, in order to automatically fly the Missed ApproachProcedure (MAP).After landing and engine shutdown, the FMC goes through a “flightcomplete phase”, clearing the active flight plan in preparation forreinitializing. In addition, some of the data entry fields reinitialize todefault data values.Rev 1 12/96B747-400 FMS PILOT’S GUIDE Use or disclosure of the information on this page is subject to the restrictions on the title page of this document.2-11 2.5 OPERA OPERATION TION The Flight Management System (FMS) provides LNAV, VNAV, andPerformance (PERF) speed control functions to the Autopilot FlightDirector System (AFDS) through targets or steering commands tothe Flight Control Computers (FCCs).Flight Management Computer (FMC) generated data, commands,data base information, performance data, and stored information(routes, waypoints runways, and navaids) are displayed on theMultipurpose Control Display Unit (MCDU). Each flight mode has itsown page(s). Other available functions are aircraft status(identification), initialization, radio navigation (radio tuning),performance (takeoff, climb, cruise, descent, approach, go-aroundand climb/approach), data (position monitor), progress, fuel prediction,route data, route, and standby navigation.The FMS is operable when electrical power is applied to the aircraft.Both FMCs monitor power supply levels to detect supply transientsif either short or long duration interrupt FMC operation, but result inthe retrieval of enough previously stored data to recover completelywithout affecting FMS operations.2.5.1 Dual Mode The FMS supports dual, single, and standby operational modes. Dualmode is the normal operating state of the FMS.When operating in dual mode, both FMCs independently processpilot entries on both Multipurpose Control Display Units (MCDUs).Each FMC makes its own computation and exchanges the variousprocessed data through cross talk buses for the purpose of comparisonand validation to ensure the information is consistent between FMCs.If a discrepancy occurs in this exchange of information, aresynchronization process is automatically initiated to regain consistency between the FMCs. The Built-In Test Equipment (BITE)function records the cause of any resynchronization or other error forlater analysis. This BITE information/status is not accessible by the pilot.B747-400 FMS PILOT’S GUIDE Use or disclosure of the information on this page is subject to the restrictions on the title page of this document.2-12The FMC Master Selector switch is use to select the FMC, either leftor right, to provide information to the Flight Control Computer (FCCs),the Electronic Engine Controls (EECs), and for tuning the VHFnavigational radios.In the dual Flight Management Computer System (FMCS)configuration, the left FMC is designated as the Multipurpose ControlDisplay Unit (MCDU) Button Push Master FMC. This means buttonpush messages coming from either MCDU are first to be processedby the left FMC. This means the left FMC decides which buttonpushes should be executed and in what sequence to control theMCDU to FMC communications link. The left FMC in turn sendsbutton push messages and other information to the right FMC, whichis designated as the slave FMC. Each FMC processes the buttonpushes and updates its own MCDU.B747-400 FMS PILOT’S GUIDE Use or disclosure of the information on this page is subject to the restrictions on the title page of this document.2-132.6 FUNCTIONS The Flight Management Computer (FMC) part of the FlightManagement System (FMS) performs navigation, performancecomputations, and flight planning for the pilot. The guidancecalculations are accomplished using a navigation data base and aperformance data base responding to Multipurpose Control DisplayUnit (MCDU) input from the pilot.2.6.1 Navigation The FMS provides the capability to enter data and complete thealignment of the Inertial Reference Units (IRUs), compute position,provide an accuracy level assessment, and provide radio navaidselection.Position and velocity information from the IRUs are combined withrange and bearing information from VHF Omni-Range (VOR) andDistance Measuring Equipment (DME) stations, respectively, to forman accurate and stable estimate of the aircraft’s position and velocity.The primary mode of operation is to combine range from two DMEstations (corrected for slant range error), and position and velocityfrom the three IRUs. If the aircraft is below 12,500 feet the FMCautotune is searching for the best DME/DME pair that comes closestto intersecting the aircraft at an angle between 30° and 150°. Above12,500 feet, the best pair shall be the pair that comes closest tointersecting at an angle of 90° with respect to the aircraft position. Asthe aircraft progresses along its route, the FMC uses a currentestimate of the aircraft’s position and the stored navaids in the database to tune the VOR/DME receivers to the stations that yield themost accurate estimates of position.The data base contains information on the class and figure of meritof the available navaids. The class of a navaid is defined as VOR,DME, VOR/DME, VORTAC, TACAN, ILS, ILS/DME, LOC DME,LOC, or MLS. Figure of merit (reception quality) is based on theusable distance and altitude of the station relative to the aircraft.These criteria are established by the FAA and other regulatoryauthorities. B747-400 FMS PILOT’S GUIDE Use or disclosure of the information on this page is subject to the restrictions on the title page of this document.2-14The prioritized radio navigational modes for the Flight ManagementComputer System (FMCS) to determine its position are:•
IRS/LOC or IRS/MLS (Mode inhibited if RNAV or VOR approachprocedures is in the active flight plan)•
IRS/DME/DME•
IRS/DME/VOR (collocated)•
IRSThe criteria used for FMC selection of navaids for the internalcalculation of a radio-derived aircraft position is illustrated in a typicalexample (see Figure 2-7). The example shown indicates that twofrequencies are being tuned by the FMC. They are SY 115.4 andMSO 115.3. In this case, SY is used for display of the bearing anddistance to the next waypoint; MSO and SY are used for FMC internalcalculation of the aircraft’s present position from VOR/DME data. TheFMC has automatically selected MSO and SY because these stationsmeet the figure of merit distance requirement and in addition, theyintercept the aircraft position at an included angle which is closest to90° compared to other available navaids.B747-400 FMS PILOT’S GUIDE Use or disclosure of the information on this page is subject to the restrictions on the title page of this document.2-15A336UPMANS32 11.1E153 17.2212o034oS31 23.3 E151 24.6115.3 MSOMT. SANDONS33 56.7 E151 10.3115.4 SYSYDNEYDG3641-21-004#100oRADIOPOSITIONRADIOPOSITIONFigure 2-7FMC Navaid Autotune FunctionEach FMC independently computes the IRS position as a weightedaverage of all three Inertial Reference Units (IRUs). If any latitude orlongitude data from one IRU differs from the previous average by 30Nautical Miles (NM) or more, that IRU is not used for the remainder ofthe flight. An IRS can also be eliminated if the North-South or EastWest velocities differ by more than 20 knots, and if this occurs the IRUagain is eliminated for the remainder of the flight.The navigation function also computes true and magnetic track,vertical flight path angle, drift angle, and magnetic variation.The FMCs do not update the IRSs at any time, and only use theaverage IRS position exclusively for navigation when DME and/orVOR data is not available. When this occurs, after a short delay, theIRS NAV ONLY message is displayed on the MCDUs. The relativeFMC position to the IRS positions is maintained until valid radioupdating is again received.B747-400 FMS PILOT’S GUIDE Use or disclosure of the information on this page is subject to the restrictions on the title page of this document.2-162.6.2 Performance The Flight Management System (FMS) performance modes optimizethe aircraft’s vertical profile integrated with the lateral profile. Thisfunction includes both flight plan predictions and flight optimization.To develop an optimum flight path, the FMS determines the mostEconomical Climb (ECON CLIMB) and Economical Descent (ECONDES) speeds, the optimum target Mach for Cruise (CRZ), optimumflight level, and an optimum top-of-descent from cruise to destinationairport. These predictions are periodically updated as the flightprogresses, incorporating aircraft performance and ground speed.An economy profile results in an economical climb, cruise, anddescent speed/Mach target which is calculated to obtain the minimumoperating cost per mile traveled en route based on the entered CostIndex (CI). A CI of Zero is equivalent to Maximum Range Cruise(MRC) because time related cost is not considered and therefore,fuel efficiency is the only consideration. A Minimum Time speed/Mach may be obtained when the CI is set to 9999 (producingmaximum flight envelope speeds).Pilot-entered speeds, such as speed requests from Air TrafficControl, may alter the strategy for a flight segment with the enteringof specific speed/Mach targets for Climb (CLB), Cruise (CRZ), andDescent (DES) phases of flight. These speeds are subject to flightenvelope limits.The computed speed target value is output to the vertical guidancefunction which generates the required pitch commands to maintainthe desired Calibrated Airspeed (CAS) or Mach. The thrust targetvalue is used by the Thrust Management Function (TMF) for use asa thrust setting parameter in those control modes for which speed iscontrolled through the elevator and as an initial thrust setting parametervalue when in cruise. For the cruise portion of the flight, the optimumCAS or Mach is computed and thrust commands are sent by theautothrottle to maintain speed. For descent, a vertical path is computedbased on a defined End-of-Descent (E/D) waypoint. The vertical pathaccounts for such parameters as: wind, temperature, number ofoperating aircraft engines, engine anti-ice, intermediate waypointRev 1 12/96 B747-400 FMS PILOT’S GUIDE Use or disclosure of the information on this page is subject to the restrictions on the title page of this document.2-17altitude and/or speed constraints and the airspeed restriction belowthe speed transition altitude (250 knots below 10,000 feet, FAArules). Ideally, an idle thrust optimum airspeed descent profile isflown. However, airspeed may be varied or thrust added to remain onthe path to accommodate unforeseen wind conditions, or for trackingthe vertical path between altitude constraints.Without the autothrottle or autopilot engaged, the pilot can manuallyfly the optimum speed schedule by referring to the MultipurposeControl Display Unit (MCDU) and to the airspeed bug on the speedtape on the Primary Flight Display (PFD).Performance solutions are generated only when the gross weight,cost index, target altitude, and a route have been entered into theFMS. Vertical Navigation (VNAV) can only output valid verticalguidance if performance initialization is complete.2.6.3 Guidance The guidance function implemented as part of the Flight ManagementSystem (FMS) provides commands for controlling aircraft roll, pitch,speed, and engine thrust. Fully automatic, performance-optimizedguidance along flight paths in two or three dimensions are availablein LNAV and VNAV. These modes are coupled to the Flight Director(FD) and/or the autopilot and autothrottle via the Mode Control Panel(MCP). LNAV and VNAV may be used separately or together. LNAVprovides lateral guidance, and VNAV provides vertical guidance andspeed/thrust control. Air Traffic Control constraints may be insertedalong the flight plan route, thus allowing path and performanceguidance to the three dimensional profile, when LNAV and VNAV areflown together.Lateral Guidance – This function is provided by a primary flightplan with automatic route leg sequencing and route leg updating. TheLNAV guidance function compares the aircraft’s actual position withthe desired flight path and generates steering commands to theautopilot and flight director. This causes the aircraft to fly along thedesired path. Direct guidance from the aircraft’s present position toany waypoint is also available. LNAV can only be engaged when aroute has been activated and executed through the MultipurposeControl Display Unit (MCDU).B747-400 FMS PILOT’S GUIDE Use or disclosure of the information on this page is subject to the restrictions on the title page of this document.2-18Vertical Guidance – This function encompasses the takeoff, climb,cruise, descent, and approach phases of the flight plan. The flightplanning capability of the FMS includes means to enter publisheddeparture, arrival, and approach segments and individual waypointsthat include speed/altitude and time constraints. These constraints,as well as the entered cruise altitude and cost index, define thevertical profile for which the FMS provides guidance. The enteredprofile may be modified at any time to comply with Air Traffic Control(ATC) requests.The outputs of the vertical guidance are pitch commands to the FlightControl Computers (FCCs) and thrust commands to the autothrottleservo motor. For unconstrained vertical paths (most climbs), theFlight Management Computer (FMC) generates pitch commands tocontrol speed consistent with the performance management modeselected. The pitch commands are based on the difference betweenthe actual CAS or Mach and the target CAS or Mach computed by theperformance management function. During intermediate level-offs inclimb, or in cruise, or when tracking the descent path, pitch commandsare generated to maintain the desired path or altitude.When the speed is controlled on the elevator, (vary the rate of climbto control speed), the autothrottle is commanded to maintain a targetN1/EPR setting, (for example, climb thrust, hold or idle). However,when the path is controlled on the elevator, the autothrottle iscommanded to maintain the target CAS, Mach, or idle.B747-400 FMS PILOT’S GUIDE Use or disclosure of the information on this page is subject to the restrictions on the title page of this document.2-192.6.4 Thrust Management The thrust management function of the FMC controls the autothrottles.The autothrottles provide full-time automatic thrust control from startof takeoff through landing and rollout or go-around.The system uses the FMCs to directly control the throttles formaximum fuel conservation without having to send commands toanother computer.An autothrottle switch, thrust mode switches, and indicators on theAutopilot Flight Director System (AFDS) Mode Control Panel (MCP)are used for autothrottle control. The FMC operates the throttle servoin response to manual mode request selection by the crew from theMCP, or to automatic mode requests from the FMCs when VerticalNavigation (VNAV) is engaged.The FMC computes and displays thrust limits for all modes, andcontrols full-throttle operation to provide maximum thrust withoutexceeding engine operating limits.The Thrust Management Function (TMF) calculates a referencethrust based of existing pressure altitude and ambient temperaturedata from the Air Data Computer (ADC) for the following modes:< TO Takeoff< TO 1 Takeoff 1< TO 2 Takeoff 2< TO B Takeoff Bump< D-TO Assumed Temperature Takeoff< CLB Climb< CLB 1 Climb 1< CLB 2 Climb 2< CRZ Cruise< CON Continuous< GA Go-Around