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.3.4-432R LONGITUDE – Displays the longitude of the navaid, waypoint,airport (reference point), or runway threshold entered in 1L
.3L
MAG VAR or LENGTH – The header displays MagneticVariation (MAG VAR) from true North when the identifier is anavaid. The magnetic variation is for the navaid.If the identifier in 1L
is a runway, this field displays the runwaylength and the header displays LENGTH.For any other entries in 1L
, this field and header lineremain blank.3R ELEVATION – This field displays the elevation of the navaid,airport (reference point), or runway threshold entered in 1L
.Waypoint entries in 1L
causes the field and header line at 3Rto remain blank.4L
NAVAID INHIBIT – This field displays dash prompts initially.4R The pilot may inhibit, or blackball, up to two VORs, VOR/DMEs,VORTACs, or DMEs contained in the nav data base, from FMCradio updating. This is done by using the NAVAID INHIBITfields in 4L
and 4R . Once a valid entry is made, the enterednavaid is inhibited from use by the FMC for radio updating.Entry of a different navaid over an existing entry re-enables theexisting identifier and inhibit the newly entered navaid.Overwriting or deleting an entry clears the previously selectednavaid and removes the inhibition of the navaid. Selections areautomatically cleared at flight completion or long-term powerinterrupt.NOTE: Navaids blackballed from this line are not inhibited fromroute tune, manual tune, or procedure tune capability.Entry of a navaid identifier on this line inhibits the useof the whole navaid for navigational updating.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.3.4-445L
VOR ONLY INHIBIT – Initially dash prompts are displayed5R in this field. The pilot may inhibit up to two VORs containedin the nav data base for navigational updating. Only the VORportion of the navaid is inhibited from use by the FMC forupdating. Entries are cleared at flight completion. Deleting oroverwriting an entry clears the previous navaid and removesthe inhibition.NOTE: VORs inhibited from this line are not inhibited fromroute tune, manual tune, or procedure tune capability.If the inhibited VOR is paired with a DME, the DME isnot inhibited from being autotuned or from being usedfor DME/DME mode position updating.6L
<INDEX – Pressing this <INDEX prompt displays the INIT/REF INDEX page.6R VOR/DME NAV – When the INHIBIT> prompt is displayed,pushing 6R inhibits VOR/DME radio position updating andchanges the prompt to ENABLE>. When the ENABLE> promptis displayed, ALL is displayed in 5L
and 5R in SMALL font.This overwrites any existing navaid identifier displayed in 5Land 5R .The INHIBIT> prompt is the default display, and the displayreturns to this default at flight completion and long-term powerinterrupts.NOTE: The VOR/DME NAV function does not affect DME/DME radio position updating.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.3.4-45STEP: 6R INHIBIT> promptG3641-21-093#Figure 3.4-28REF NAV DATA – ENABLE>6R ENABLE> – Selection of the ENABLE> prompt at 6R enablesVOR/DME updating, returns the prompt to INHIBIT> andreturns 5L
and 5R to dash prompts.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.3.4-463.4.8 SELECT DESIRED WPT The SELECT DESIRED WPT (Waypoint) page is automaticallyaccessed when an ambiguity occurs in the entry of a nav data basefix, such as, multiple waypoints, NDBs and VORs existing with thesame identifier. The SELECT DESIRED WPT page is displayed toallow the pilot to select the desired nav data base fix.Displayed waypoints are generally displayed by increasing distancefrom the aircraft. However, if the entry is made on the RTE or RTELEGS pages, the waypoints are displayed by increasing distancefrom the fix prior to the entry position.CAUTIONIf the entry is distance ordered from the aircraft and aircraftposition is not valid, the waypoints appear in the order theyare stored in the Nav Data Base.Selection of a waypoint is made by pushing the adjacent line selectkey, either left or right. Line selection results in returning to the pagefrom which this page was accessed. The selected desired waypoint isinserted where the pilot had previously attempted to do so.If more than six non-unique identifiers exist, the remaining fixes maybe accessed using theNEXTPAGE orPREVPAGE mode keys. Failure to select a fixcancels the entry.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.3.4-47STEPS:A. Type NN in SPB. 1L
on the REF NAV DATA pageG3641-21-094#Figure 3.4-29SELECT DESIRED WPT – Page 1/2STEP:NEXTPAGE orPREVPAGEG3641-21-095#Figure 3.4-30SELECT DESIRED WPT – Page 2/2B747-400 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.3.4-48Identifier/Fix TypeThe fix identifier and fix type are displayed in the header lines. Fixtypes may be any of the following:APRT ILS NDB MLSWPT ILSDME VOR VORTACTACAN MLSDME LOCFrequencyThe fixes which are navaids, the frequency is displayed in1L
through 6L
as appropriate.PositionThe position of each of the fixes is displayed in the 1R through 6Rdata fields.CAUTIONIf the desired navaid waypoint is stored in the FMC underits NAME rather than its coded identifier it will not appearon the SELECT DESIRED WPT CPU page at all. A moredistant, probably undesired navaid, will appear at the top ofthe screen.Before executing the selection at the top of the screen,extreme care should be taken to compare the LAT/LONtaken from the Nav Data Base against the LAT/LON shownby the chart and check that the proposed routing shown onthe map display looks reasonable.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.3.4-493.4.9 DESCENT FORECASTS The DESCENT FORECASTS page is used to enter forecast windsand the altitude where thermal anti-icing is turned on to moreaccurately define the descent path. The page is access via theFORECAST> prompt at 5R on the DES page, which is page 3/3when the VNAV
mode key is selected.STEPS:A. VNAVB.NEXTPAGE to display DES page 3/3C. 5R FORECAST> promptG3641-21-096#Figure 3.4-31DESCENT FORECASTS PageThe pilot enters the appropriate descent forecast winds by typing thewinds in the SP and pushing a line select key. The forecast valuesmay also be uplinked if ACARS is available.1L
TRANS LVL – The Transition Level (TRANS LVL) for thedescent phase of flight defaults to FL180. The value may bechanged by pilot-entry. The value changes automatically whenentering a destination or arrival procedure with a stored transitionlevel, if a pilot-entry has not already been entered.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.3.4-50This field is used to change descent FMS-MCDU displaysbetween FLs and feet. Deletion of the transition level is notallowed.2L
ALT – The wind Altitude (ALT) line permits entry of descent3L
wind altitudes in standard altitude format. An altitude which is4L
equal to one of the altitudes in 2L
through 5L
is not permitted,5L
that is, only one wind direction is allowed for a given altitude.The delete function selected into fields 2L
through 5Lcauses the ALT and WIND DIR/SPD fields to return to dashprompts.6L
<OFFPATH DES – Pushing the <OFFPATH DESCENTprompt displays the OFFPATH DES PAGE.1R TAI/ON ALT – The Thermal Anti-Ice (TAI) field is for a pilotentered altitude below which the use of thermal anti-ice isexpected to be used. The FMC performance function uses theTAI altitude to make adjustments in the descent profile for amore cost-effective and accurate descent. Deletion of a pilotentered value returns the field to dash prompts.2R WIND DIR/SPD – The pilot-entered wind direction and speed,3R which correspond to the altitudes displayed in 2L
through 5L
,4R and displayed in fields 2R through 5R . Valid entries consist5R of a wind direction and speed separated by a slash ( / ). Winddirection is entered in true and is a three-digit value. Valid windspeed entries, in knots, consist of one- to three-digit valuesranging from 0 to 250.Leading zeros are optional for speed but required for winddirection. Initial entries must consist of both speed and direction;however, subsequent entries may be partial and only theentered portion is changed. A wind direction only entry must befollowed by a slash ( / ).6R DES> – Pushing the Descent (DES>) prompt at 6R returnsthe display to the DES page.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.3.4-513.4.10 Altitude Intervention Altitude intervention is the function of incorporating the MCP altitudewindow and knob-push operation with the FMC VNAV flight planningfor “heads-up” operation. For cruise, altitude intervention allows thepilot to raise or lower the current cruise altitude without using theMCDU and without confirmation using theEXECkey.3.4.10.1 Cruise Altitude Modification If the MCP altitude is set to an altitude above the current cruisealtitude, pressing the altitude knob changes the current cruisealtitude to the MCP selected altitude.If the MCP altitude is set to an altitude below the current cruise altitudebut above the first descent constraint, and the aircraft is greater than50NM from the top-of-descent point, the cruise altitude is lowered tothe MCP selected altitude. If the aircraft is within 50NM of the top-ofdescent, an early descent is initiated consisting of a 1250 fpmdescent until the descent path is intercepted.3.5-1B747-400 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.3.5 DESCENT The FMS Descent (DES) phase of flight begins when the aircraftdeparts the CRZ ALT at the T/D or begins the deceleration segmentprior to reaching the T/D. The DES phase extends to the lastconstraint in the descent, known as the End-of-Descent (E/D) point.The descent path is computed starting at the E/D and projects up tothe cruise altitude. The descent vertical path is calculated to satisfydecelerations, configuration changes, altitude and airspeedconstraints, forecast winds, preselected descent speeds and otherconstraining factors.The FMS creates a deceleration segment at the T/D point when thecruise speed is greater than the descent speed. An accelerationsegment is created also to meet speed constraints during thedescent.A descent path can be one of two types. The first type is an ECONDescent in which the path is constructed for an optimal descentspeed, subject to defined airspeed/altitude constraints. The secondtype is a SEL SPD Descent where the path is constructed to fly a pilotentered speed and still subject to defined airspeed/altitude constraints.The descent speed is maintained until the intermediate decelerationpoint when the aircraft begins to slow to the speed transition altitude,or speed restriction altitude airspeeds. The FMS default is a speedtransition of 240 kts (a 10 kt buffer so as not to exceed 250 kts) below10,000 ft. The aircraft decelerates to 240 kts upon reaching theintermediate deceleration point prior to 10,000 ft.
The FMC continuously updates the appropriate deceleration distancefrom the destination to slow to approach speeds. The approachphase normally begins at the last descent constraint in the flight plan.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.3.5-23.5.1 DES Page The DES page is accessed by pressing VNAVmode key when thedescent mode is active. If the descent mode is not active then theDES page 3/3 of the vertical navigation pages is displayed by eitherpressingNEXTPAGE orPREVPAGE after the VNAVkey has been selected.The DES page is used by the pilot to evaluate or revise the descentpath. Available speeds are economy and selected speeds. The DESpage is blank with DES as the title only when there are no altitudeconstraints below the cruise altitude.STEP: VNAVG3641-21-097#Figure 3.5-1ACT ECON DESPage Title•
Displays the active descent speed. XXXKT if target is a fixedspeed, M.XXX if target is a fixed Mach, or ECON if target iseconomy speed which is based on cost index set on PERF INITpage.•
MCP SPD is displayed if speed intervention is selected on the MCP.•
LIM SPD is displayed if controlling to a limit speed, such as flapplacard.•
END OF DES is displayed when E/D waypoint is reached if notfollowed by a climb segment.3.5-3B747-400 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.1L
E/D AT – The End-of-Descent (E/D) AT line displays thealtitude and waypoint with the lowest altitude constraintpropagated from the LEG page. Figure 3.5-1 shows thedescent ending at the threshold of runway 34 at YSSY.If no constraint exists, the page is blank with DES as the pagetitle. If the E/D constraint is a window constraint the loweraltitude is displayed. The altitude may be followed by “A” at orabove, “B” at or below, or an altitude window.2L
SPD LINE – The speed line displays the command speedused above all waypoint speed constraints, speed restrictions,and speed transition altitudes.Speed and/or Mach may be entered by the pilot and when it isentered the line title changes to SEL SPD if done manually.The aircraft flies the constraint speed or the current performancespeed, whichever is less.The flight scenario displays an ECON speed of 306 at thisstage of the descent into Sydney.3L
SPD TRANS – The Speed Transition (SPD TRANS) displays10 knots less than the nav data base speed limit at thedestination airport to ensure that the speed limit is not exceeded.The displayed value is 240/10000 and is automatically shownif a different value is not in the data base for the destination.If aircraft is below the SPD TRANS altitude the field is blank.Deleting this field causes the aircraft to fly an economy orselected speed if not limited by a waypoint constraint or speedrestriction.4L
SPD RESTR – The Speed Restriction (SPD RESTR) line isdisplayed if a valid speed retriction has been entered and thespeed restriction altitude has not been crossed. The data fieldcontains the restriction speed followed by the speed restrictionaltitude.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.3.5-4The altitude must be below the cruise altitude and above theE/D constraint in 1L
and below the current aircraft altitude.The Calibrated Air Speed (CAS) must be less than the CASspeed of the first remaining descent segment and be in therange of 100 to 400 kts. Speed restriction entries that conflictwith the speed transition causes the speed transition displayedin 3L
to be blanked. If an entered speed restriction is thendeleted, a blanked speed transition may be redisplayed.1R AT – This is the waypoint constraint line that displays the nextdescent waypoint constraint. Constraints entered on a RTELEGS page by procedure selection or pilot-entry.The constraints can be deleted here at 1R or on the RTELEGS page. The label line may also display HOLD AT (nameof fix), AT VECTORS or AT (INTC).5R FORECAST> – Selection of this prompt displays theDESCENT FORECAST page.6R DES LINE – The Descent (DES) line may display the DESNOW> prompt or the Descent Direct (DES DIR>) prompt.DES DIR> – The Descend Direct (DES DIR>) is displayedwhen the descent is active and an altitude constraint exists inthe flight plan between the current altitude and the E/D.Selection of the DES DIR> prompt results in the illumination oftheEXEC. Selection deletes all descent constraints above theMCP altitude window and initiates a descent to reach the MCPaltitude. Upon reaching the MCP altitude, the vertical guidancefunction captures the computed vertical path for the selectedmode of descent and meet any remaining descent constraints.This is illustrated in Figure 3.5-2.3.5-5B747-400 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.E/D40006000T/DDES DIREXECUTED(MCP ALT = 4000)G3641-21-098#DIRECT DESCENT (DES DIR)INITIATED BY:1. DIALING CLEARANCE ALT2. PRESSING ’DES DIR’3. EXECRESULTS IN:1. DIRECT DESCENT TO MCP ALT2. THROTTLES DORMANT10,000Figure 3.5-2Descend Direct Vertical PathDES NOW> – The Descend Now (DES NOW>) prompt isdisplayed on the descent page when the aircraft is not in activedescent. Pushing 6R with the DES NOW> prompt illuminatesthe
EXECkey. Pressing theEXECkey subsequent to pressingDES NOW activates the displayed descent profile.Selection of DES NOW> deletes all climb and cruise constraints and initiates an early descent, that is a descent beforereaching the computed top-of-descent. The vertical path,which is illustrated in Figure 3.5-3, consists of an approximate1250 fpm descent rate until reaching the computed path. Theautothrottles go into Throttle Hold (THR HOLD) mode uponreaching the 1250 fpm descent rate to allow the pilot to readjustthe throttles to change the rate of descent. Upon intersectingthe original descent path, the vertical guidance function capturesthe computed vertical path for the selected mode of descent.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.3.5-6EARLY DESCENT (DES NOW)INITIATED BY:1. DIALING CLEARANCE ALT2. PRESSING ’DES NOW’ OR PRESSING THEALTITUDE KNOB IF WITHIN 50NM OF T/D3. EXECRESULTS IN:1. 1250 FPM DESCENT (APPROX)2. THROTTLES DORMANT(UNTIL REACHING NEW T/D,OR TARGET ALTITUDE)DISPLAYED T/D WHENFORCED TO INITIATEEARLY DESCENT10,000E/D4000G3641-21-099#NORMAL T/D (LOCATED AT THEBEGINNING OF THE DECELERATIONSEGMENT IF ONE EXITS)T/DFigure 3.5-3Descend Now Vertical Path6L
<OFFPATH DES – The Offpath Descent page is displayedwhen this prompt is pushed.3.5-7B747-400 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.3.5.2 OFFPATH DES Page The OFFPATH Descent (DES) page displays information relevant toa clean or speed brake descent direct to a defined point.This page can be accessed by using the DES page or the DESCENTFORECAST page and pushing the <OFFPATH DES at 6L
.STEPS:A. VNAVAccess DES pageB. 6L
<OFFPATH DES promptG3641-21-100#Figure 3.5-4OFFPATH DES PageRev 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.3.5-81L
DES TO – The Descend To line displays the End-of-Descentpoint propagated from the DES page. This line also permitspilot-entry of any valid nav data base waypoint. Pilot-entriesmay be deleted causing the descent fix to return to the DESpage propagated fix.The center field displays the direct distance to the waypointin 1L
.When the aircraft altitude is within 150 ft of the altitudedisplayed in 1R , the display defaults to the new End-ofDescent point propagated from the DES page or to box prompts.2L
Speed Line – The ECON or SEL SPD label is displayed withthe appropriate speed in the field. Mach and/or speed can beentered. A pilot-entered speed causes the label to change toSEL SPD. Whenever SEL SPD is displayed, an ECON>prompt is displayed in 5L
.3L
SPD TRANS – The Speed Transition (SPD TRANS) displayedis the transition speed and altitude propagated from the DESpage. This data may be deleted on either the DES page or thispage. Deletion causes this field and header line to blank onboth pages and illuminates theEXECkey. Once deleted, thespeed transition is only redisplayed by entering a new cruisealtitude above the nav data base stored altitude.The field automatically displays 240/10000 if a different valueis not in the nav data base. Deleting causes the aircraft to flyECON or SEL SPD if not limited by a waypoint constraint orspeed restriction.4L
SPD RESTR – The Speed Restriction (RESTR) line displaysdashes before a pilot-entry is made. It permits entry of a speedlimit at an altitude higher than E/D altitude. When transitioningto the limiting speed, dashes are again displayed. The headerand field blank when a valid E/D target is not displayedin 1L
.3.5-9B747-400 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.5L
ECON – ECON is displayed only when SEL SPD is displayedin 2L
.1R SPD/ALT – The speed/altitude displays the restriction for thefix in the DES TO line.2R CLEAN CIRCLE – This displays the distance from the aircraftto the clean idle descent path displayed in 2C. “Clean” represents the energy circle with no speed brakes, flaps, or geardown which allows the pilot to reach the constraint flying directto the fix displayed in 1L
.Prior to reaching the clean circle the descent can be madewithout losing excess energy. Once the clean circle is crossed,some degree of drag or path extension is necessary to meetthe entered constraint. A negative distance is indicated whenthe aircraft has passed the clean energy circle.3R DRAG CIRCLE – The drag circle displays the distance fromthe aircraft to the computed top-of-descent point at the currentaltitude for a full speed brake idle descent. The computeddescent path is calculated direct to the fix displayed in1L
, crossing the fix at the speed and altitude displayed in2L
through 4L
.“Drag” represents the energy circle with full speed brakesapplied, no flaps or gear extended, which allows the airplaneto make the constraint at the offpath descent fix. The distanceto the drag circle is not displayed until the aircraft has crossedthe clean energy circle. The constraint speed and/or altitudecan not be met once the aircraft has entered into the drag circle,without additional drag or path extension.5R FORECAST> – Selection displays the DESCENTFORECAST page.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.3.5-106R DISPLAY – In the field, the SELECT ON> or SELECT OFF>prompts are activated by the 6R key.With the SELECT ON> prompt, the clean circle is displayed onthe ND. After the aircraft penetrates the clean circle the dragcircle is displayed.SELECT OFF> prompt selection removes the energy circlesfrom the ND.3.5.3 A ARRIVALS RRIVALS Page The ARRIVALS page is used to select the desired Standard TerminalArrival Route (STAR) or profile descent, approach and transitionsstored in the nav data base. Leaving and returning to the ARRIVALSpage results in a display of all items.When using theDEPARR key to access the ARRIVALS page, and lessthan 400NM from the departure airport or less than halfway along theactive route, whichever is less, arrivals for the departure airport aredisplayed. Otherwise, arrivals for the destination are displayed.The flight scenario to Sydney (YSSY) is used to show the ARRIVALSpage. Since the duration of the flight is well over halfway, theARRIVALS page is accessed directly by selection of theDEPARR key.
STEP:DEPARRG3641-21-101#Figure 3.5-5YSSY ARRIVALS PageRev 1 12/963.5-11B747-400 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.Page TitleThe page title displays the arrival airport identifier and route number.The scenario displays YSSY Arrivals and RTE 1.1L
STARS – The Standard Terminal Arrival Routes (STARS)/Profile Descent lines are listed for the YSSY airport. If NONEis displayed, as it is in this case, then there are no STARS inthe nav data base.If STARS are listed, pushing the desired line select key selectsa STAR. Once selection is complete a <SEL> is displayedbeside the selected arrival procedure. All other arrivalprocedures are no longer displayed and transitions for theselected procedure are displayed.Selecting a procedure deletes any previously selectedprocedure.6L
<INDEX – This prompt allows selection of the DEP/ARR index.1R APPROACHES – A complete numerical list of approachesand a complete list of the runways contained in the nav database for the arrival airport are listed under Approaches header.Selection of an approach is made by pushing the adjacent lineselect key. The selected approach is then indicated by <SEL>or <ACT> labels. Figure 3.5-6 illustrates the selection of ILS34.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.3.5-12STEP: 3R YSSY Arrivals page 1/3G3641-21-102#Figure 3.5-6YSSY ARRIVALS – ILS342R TRANS – The approach Transitions (TRANS) for a selectedapproach are now displayed in the right data fields beginningin 2R on page 1. Selection of an approach transition is madeby selecting the adjacent line select key. The selected approachtransition is indicated by <SEL>.The flight scenario selects no approach transition.6R APPROACH INTERCEPT> – An approach intercept fix isdisplayed in flight when an arrival runway or procedure isselected or is in the active flight plan. Selection of theAPPROACH INTERCEPT> prompt selects the intercept leg tothe approach fix or runway.It displays a waypoint or approach course for the selectedapproach or approach transition. The waypoint sequencesalong the approach route as the flight progresses.The field is blank if no arrival runway or procedure has beenselected, or exists in the active flight plan. The field is blank forthe ARRIVALS page if the arrival airport displayed does notmatch the selected approach.Rev 1 12/963.5-13B747-400 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.Following selection of the APPROACH INTERCEPT> prompt,the RTE LEGS page is displayed and the creation of a flightplan modification with the intercept approach fix as the activeflight plan waypoint, with a defined intercept course TO the fix.The LEGS page displays the routing with the approach interceptfix waypoint as the active waypoint. The intercept in-boundcourse to the fix is the same as the course outbound from thefix to the next fix/runway in the procedure.For runway only selections, the intercept course is the same asthe nav data base runway heading.The RTE COPY and ABEAM waypoint prompts are notdisplayed on the RTE LEGS page following selection of theAPPROACH INTERCEPT> prompt. Any previously existingflight plan waypoints are deleted.NOTE: If a transition exists between a STAR and an approach,it is entered into the arrival route automatically onceboth the STAR and the approach/Initial Approach Fix(IAF) have been selected.The YSSY ARRIVALS page shows the C134 INTC> prompt locatedat 6R for the approach intercept to the ILS34.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.3.5-14STEPS:A. 6R YSSY ARRIVALS page.B. Display changes to MOD RTE 1 LEGS page.C.EXECG3641-21-103#Figure 3.5-7ACT RTE 1 LEGS – C134The intercept leg into C134 is now the active leg in the flight plan. Ifthe aircraft is not on the intercept heading an appropriate messageis displayed, “NOT ON INTC HDG”.Approach Intercept Function – Additional InformationThe approach intercept function selection is enabled for the following:•
All published and tailored approaches defined in the nav data basefor the selected destination airport.•
All runway selections with a VFR Approach for the selecteddestination airport.•
All runways with an entered Runway Extension Fix distance for theselected destination airport.•
Arrivals with only the runway selected at the destination airport.Rev 1 12/963.5-15B747-400 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.The default approach fix is determined as follows:•
For published and tailored approaches, the default approach fix isthe first fix for the selected approach.•
For runway selections with a VFR approach, the default approachfix is the FMC created final approach fix for the selected runway.•
For runway selections with an entered Runway Extension Fix, thedefault approach fix is the FMC created runway extension fix for theselected runway.•
For runway only selections, the runway is considered the defaultapproach fix.CAUTION The Approach Intercept Function autotunes the ILSfrequency for the new approach ONLY if the ILS tuningmode is Auto. If the ILS tuning mode is Manual, thenautotuning is inhibited.3.5.3.1 VFR Approach A runway can be enabled for VFR approach capability by airlineselection in the nav data base, based upon compatibility with obstacleclearance limits or procedural requirements. The VFR APPR> promptis displayed when a runway is selected without an approach and hasbeen VFR-enabled in the nav data base.VFR APPR provides path generation for LNAV and/or VNAV guidanceto the entered runway as an aid to the pilot during a VFR approach.The FMS creates a path in line with the runway centerline beginningat a point 50 feet above the runway threshold and extending upwardat the specified flight path angle until it intercepts a plane 2,000 feetabove the runway threshold.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.3.5-16The flight path angle has a default value of 3° but can be variedbetween 2.4° and 3.7° by pilot-entry. The path then extends level fromthe intersection point at 2,000 feet above runway threshold to a point8NM from the runway threshold. This point is identifed as the FinalApproach Fix, FAXXX where XXX is the designated runway. Thisprofile is illustrated in Figure 3.5-8.
8 NMFAXXX2000 FTRWXXXPREVIOUSWAYPOINTCONSTRAINTTHRESHOLD 50 FTFPAG3641-21-104#Figure 3.5-8VFR Approach ProfileGuidance is given to arrive at the Final Approach Fix at a speed of 170kts, along the path to the 50-foot point above the runway threshold.The speed can be varied by the crew through the speed interventionmode or by line selecting the desired speed.3.5.3.2 Runway Extension Runway extension fixes are pilot-defined waypoints which are in linewith the runway centerline at a specified distance. When a runway isselected, without an accompanying approach procedure, a runwayextension distance may be entered into 3R “RWY EXT / – –.–NM”on the destination airport arrivals page. Valid entries are one- or twodigit distances (NM), optionally followed by tenths, ranging from 1.0to 25.0. Upon entering a distance, the FMC creates a flight plan fixalong the runway centerline at the entered distance. The fix is namedRXYYY where YYY is the designated runway, for example RX34.3.5-17B747-400 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.The purpose of creating the Runway Extension Fix when a runway isselected is to provide for entry of an end-of-descent target for VNAVguidance, particularly when radar vectoring is expected. VNAVoptimizes the descent to arrive at the Runway Extension Fix, inposition for final approach, regardless of vectoring. VNAV guidancealso results in descent to the required crossing altitude followed bylevel flight at the specified speed.3.5.4 Descent Profile The default descent profile is an economy descent to 10,000 feetfollowed by a 240 kt CAS speed descent. The pilot may, however,change the default descent profile by entering any speed and/oraltitude restrictions required to meet ATC clearances. If the airplanereaches the limit speed, such as an unforeseen tailwind, the aircraftdeparts the vertical path (VNAV PATH mode) and command a speedtarget (VNAV SPD). The DRAG REQUIRED and THRUSTREQUIRED messages are displayed to advise the pilot of speedchanges required to maintain the descent path. Figure 3.5-9 illustratesa descent profile.DRAG REQUIREDMESSAGE DISPLAYEDIF AIRPLANE REACHES AIRSPEEDLIMIT, AIRPLANE LEAVES PATHAT NEAR LIMIT SPEED (VNAV SPD) TAILWINDT/DECON SPDDECEL SEGMENT240 KT4000A10,000 FT170/1800E/DT/CG3641-21-105#MISSEDAPPROACH ALTVNAVPATHVNAVSPDVNAVPATHFigure 3.5-9Descent ProfileB747-400 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.3.5-183.5.5 Altitude Intervention Altitude intervention is the function of incorporating the MCP altitudewindow and knob-push operation with the FMC VNAV flight planningfor heads-up operation. For descent, altitude intervention allows thepilot to delete constraints, perform altitude level offs, and resumedescent.3.5.5.1 Constraint Deletion If the aircraft is actively descending, the pilot may dial the MCPaltitude window to an altitude below the current altitude and deletedescent constraints. Each time the MCP altitude knob is pushed thenext descent constraint below the current altitude and above the MCPaltitude is deleted.3.5.5.2 Altitude Level Of Off/ f/ Resumption If the altitude window is set to an altitude between the current aircraftaltitude and the end-of-descent constraint, the aircraft levels off at theMCP altitude. The descent may be resumed by dialing the altitudewindow to a lower altitude and pressing the altitude knob on the MCP.Rev 1 12/963.6-1B747-400 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.3.6 APPROACH The approach section describes the reference information availablefor approach. This information consists of the APPROACH REF pageand Navigation Radio tuning on the NAV RADIO page.3.6.1 APPROACH REF Page The APPROACH REF page is accessed by pressingINITREF when theaircraft is airborne or via the <APPROACH prompt on the INIT REF/INDEX page.The APPROACH REF page provides data relative to theapproach profile.STEP:INITREFG3641-21-106#Figure 3.6-1APPROACH REF – YSSYRev 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.3.6-21L
GROSS WT – The Gross Weight (WT) line displays FMCinstantaneous computed aircraft gross weight, or a pilotentered gross weight value. Manually entered gross weight isreplaced by instantaneous computed gross weight upon leavingthe page.The weight is displayed in thousands of pounds or metric tons,based upon the kilogram PERF FACTORS option code.Pilot-entered gross weights to 1L
are for approach referencespeed computation only and does not affect the airplane grossweight or the values displayed on the PERF INIT page.4L
Runway Length Line – The origin or destination airport andrunway are displayed in the 4L
header. The orgin runwayinformation is displayed until the aircraft is more than halfwayto the destination or the aircraft is more than 400NM from theorgin runway, at which point the destination runway informationdata is displayed.
The 4L
data field contains the runway length in feet andmeters. The flight scenario illustrates this by displaying alanding in YSSY on runway 34 which is 12,999 feet long or3962 meters long.NOTE: No data can be entered, selected, or deleted from 4Land the display is cleared at flight completion.6L
<INDEX – Pushing it displays the INIT/REF INDEX page.1R FLAPS/VREF – The reference speeds (VREF) for up to three2R flap settings can be displayed in 1R through 3R . The refer3R ence speeds are computed from the performance data baseon the gross weight in 1L
. If the performance data basecontains less than three flap references, fields 2R and/or 3Rare blank. Although these VREF values are not displayed onthe speed tape, they may be down-selected and entered into4R to provide a speed tape reference. Entry and deletion offields 1R through 3R are not permitted.Rev 1 12/963.6-3B747-400 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.4R FLAP/SPEED – The field initially displays dashes until data isentered. The pilot may enter a speed or flap setting/speed toindicate which speed is to be used for landing.The 30°/136 kt was selected in 4R for the YSSY landing usingthe following steps on the APPROACH REF page.STEPS:A. 2R down-selects into SPB. 4R up-selects information from SPDeletion of a pilot-entered value returns the display to dashesat 4R .6R THRUST LIM – Pushing this LSK displays the Thrust Limit(LIM) page.3.6.2 Radio Tuning The radio tuning function is handled automatically by the FMC, ormay be operated manually using the radio tuning control panel on theNAV RADIO page. Tuning capabilities are provided for VOR, ADF,ILS, and MLS receivers. In the event of FMC failure, radio tuning ishandled by the MCDU using pilot-selected stations or frequencies.Additional information on Degraded Performance is in Section 4.3.6.3 NAV RADIO Page The NAV RADIO page is accessed by pressingNAVRAD mode key, whenthe FMC is the tuning source. The purpose of the NAV RADIO pageis to display current radio information and provide tuning capability forTACAN, VOR, ADF, ILS, and MLS receivers.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.3.6-4STEP:NAVRADThis step displays a typical NAV RADIO page with the TACAN tuningfeature disabled.G3641-21-107#Figure 3.6-2NAV RADIO Page1L
VOR L/VOR R – The VOR frequency information for the cur1R rently tuned stations is displayed in 1L
and 1R respectively.Valid entries are VOR and non ILS DME station identifiers orVOR frequencies or identifier (frequency)/course.Tunes the associated DME frequency in the respective radio.The field displays frequency, identifiers, and the tuning status.The tuning status are indicated by the following:•
“A” – Auto. The navaid has been selected by the FMC forthe best position updating geometry.•
“M” – Manual. The displayed station or frequency is pilotentered.•
“R” – Route. The FMC selected navaid is the next VOR,previous VOR, or a downpath VOR on the active route andwithin 250NM of the current aircraft position. This feature isonly operational when enabled on the PERF FACTORSpage.3.6-5B747-400 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.•
“P” – Procedure. The FMC selected navaid is required bythe active flight plan procedure.•
All tuning status symbols are displayed in SMALL font.•
Deletion of a manual tuned frequency and/or station resultsin the corresponding channel reverting to autotuning in bothFMCs and the corresponding VOR course being cleared.2L
CRS/RADIAL L/R – The VOR Course (CRS)/Radial line2R displays VOR course and radial for the selected VORs. Validentries are course or VOR identifier (frequency)/course.The VOR course may be entered when a course or dashes aredisplayed. Course information is not displayed for autotunednavaids. Deletion of field 2L
or 2R while a course is displayedclears the displayed course.The actual VOR radial received from the corresponding VORreceivers are displayed in 2C. If a VOR radial is invalid, thecorresponding radial display is blank. Entries or deletions arenot possible.3L
ADF L/ADF R – ADF tuning information is displayed in 3L3R and 3R . Frequency display is followed by BFO or ANT for thecorresponding tuning modes of BFO or ANT. For the ADFmode, no suffix is displayed, and it is also the default mode.Valid entries are three- or four-digit values optionally followedby a decimal point and tenths-digit. Entries are allowed intodash prompts or over existing ADF frequencies. The ADFfrequency may optionally be followed by “A” to indicate ANTmode, or by “B” to indicate BFO mode. Likewise, if the currentmode is BFO, “A” may be entered without a frequency tochange the mode to ANT. If the mode is either ANT or BFO, adeletion causes the mode to return to ADF (no suffix displayed).Any other attempt to delete an ADF frequency is not allowed.NOTE: ADF frequencies are NOT tuned automatically. Thefrequency must be manually entered.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.3.6-64L
ILS – MLS – Valid entries displayed in 4L
are ILS frequencyand front course, or front course with frequency alreadyentered, or the MLS channel and azimuth, depending on whichis being used.The display is initialized to PARK. When an ILS, LOC, BackCourse approach or an ILS/LOC runway is entered in the activeflight plan, the appropriate frequency/course is displayed inSMALL font with a caret followed with PARK This displaybecomes active when the aircraft is within 200NM of the topof-descent or the aircraft is more than halfway along the activeroute, whichever represents the lesser distance to destination.When a valid frequency is manually or autotuned, PARK isremoved and the frequency/course display appears in LARGEfont. The pilot may select the SMALL font display in order tomanually tune the ILS.The FMC autotunes the ILS/MLS associated with the activeflight plan destination runway when the aircraft is within 50NMof top-of-descent or within 150NM direct distance of therunway threshold (whichever is greater) or when active indescent.Remember PARK indicates that the ILS tuning is not active, itis in a standby condition waiting for the proper conditions tobecome active.The tuning status following the frequency/course is “A” forautotuning, “M” for manual tuning , and “PARK” for selected butstandby condition.
NOTE: Autotuning will NOT override manual tuning and deletionof a manual tune frequency allows autotuning.3.6-7B747-400 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.ILS receivers are inhibited from manual or automatic tuningwhen any of the following conditions occur:•
An autopilot engaged and either the localizer or glideslopeis captured.•
No autopilot engaged and a flight director engaged, eitherlocalizer or glideslope captured, and the aircraft is below 500feet RA.•
On the ground and localizer is alive, with airplane headingwithin 45 degrees of localizer front course, and groundspeed greater than 40 knots.NOTE: Autotuning is inhibited for ten minutes after takeoff.6L
PRESELECT – The tuning preselect fields in 6L
and 6R6R allow the pilot to preselect an entry for any field on the NAVRADIO page. This preselection process allows the pilot to prestore an entry prior to actually making the tuning change. Oncepreselected, the entry may be down-selected into the SP andthen entered in the appropriate field on the NAV RADIO page.Valid entries are any valid tuning entry.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.3.6-83.6.4 Autotuning The autotuning portion of the FMC navigation function reducescockpit workload required to tune navigation stations. The FMCcalculates its position in a manner that yields the most accurateposition. Autotuning, in conjuction with the IRS system, selectsposition updating in the following order of preference:•
IRS/LOC or IRS/MLS (on approach only)•
IRS/DME/DME (RHO-RHO)•
IRS/DME/VOR (RHO-THETA)•
IRS onlyThe autotuning (radio update) mode is indicated in the lower rightcorner of the ND in MAP and MAP CTR selections. The followingabbreviations are used on the ND:•
DD for DME/DME updating•
VD for VOR/DME updating•
LOC for Localizer updating3.6.4.1 DM DME/ E/ DME DME/DME (RHO-RHO) updating uses the distance values obtainedfrom two DME stations and the navigation data base stored positionsfor the stations to triangulate the airplane position. The FMC selectsthe two best DME/DME pairs from the nav data base (based ondesired geometry with the airplane) and tunes the stations in four ofthe directed-scan DME channels. The scanning function of the DMEradios is used to validate signals from DME stations prior to tuning.3.6.4.2 VO VOR/ R/ DME VOR/DME (RHO-THETA) updating uses the distance and bearinginformation from a single VOR/DME station. The bearing and distanceinformation, along with the nav data base stored position for thestation, are used to calculate the aircraft position.Rev 1 12/963.6-9B747-400 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.3.6.4.3 IL ILS/ S/ MLS ILS updating uses the localizer centerbeam to update the aircraftposition. ILS/MLS autotuning is only available on approach, and onlywhen the active flight plan destination runway and approach procedureis appropriate for the ILS/MLS station. In addition, autotuning onlytakes place when the aircraft is within 25NM (direct distance) of thelocalizer, or within 10NM of the approach leg if it is less than 40NMfrom the runway.Section 44-1Use or disclosure of the information on this page is subject to the restrictions on the title page of this document.ADVANCED FLIGHTPLANNINGThis section contains, Waypoints, FMC Waypoint Abbreviations,Polar Operations, Holding Patterns, and Use of Wind Information inthe FMC.4.1 PILOT PILOT--DEFINED W WA A AYPOINTS YPOINTS Waypoints are specified as: navigation data base waypoints or pilotdefined (non-nav data base) waypoints.Pilot-defined waypoints include the following:•
Place Bearing/Distance•
Place Bearing/Place Bearing•
Along Track•
Latitude/Longitude•
Course IntersectionGenerally, waypoints are entered in the SP, then moved to thedesired location by pressing the appropriate LSK. If a waypoint entryis line selected in an invalid format, the “INVALID ENTRY” messageis displayed. If a waypoint entry referring to an identifier is not presentin the nav data base line selected, the message “NOT IN DATABASE” is displayed.4.1.1 PBD/PBD and PB/PB Waypoints entered as a Place Bearing/Distance (PBD) or PlaceBearing/Place Bearing (PB/PB) are identified by the first threecharacters of the entry followed by a two-digit sequence number.Example:SEA330/10 becomes SEA01SEA330/OLM020 becomes SEA024 ADVANCED FLIGHT PLANNING4-2Use 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 4.1.2 Along Track Along track waypoints are entered using the waypoint name followedby a slash ( / ) and minus (–) sign or no sign, then the mileage offsetfor the newly defined waypoint. The created waypoint is then insertedover the original waypoint. The distance offset must be less than thedistance between the original waypoint and next (positive value) orpreceding (negative value) waypoint. Latitude and longitude waypointscannot be used to create along track waypoints.Example:ELN/25 would be 25 miles after ELN on the present route.ELN/–30 would be 30 miles before ELN on the present route.4.1.3 Latitude/Longitude Waypoints entered as a latitude and longitude are displayed in aseven-character format. Latitude and longitude waypoints are enteredwith no space or slash between latitude or longitude entries. Leadingzeroes must be entered. All digits and decimal points (to one-tenthminute) must be entered unless the latitude or longitude is in fulldegrees. Example: N47° W008° would be entered as N47W008 anddisplayed as N47W008. Example: N47°15.4" W008°3.4" would beentered as N4715.4W00803.4 and displayedas N47W008.Latitude or Longitude reporting waypoints are entered as latitude orlongitude followed by a dash, then the increment chosen for themultiple waypoints. Example: W060-10 adds waypoints starting atW060 in ten-degree increments from that point to the destination.The entry must be made on a RTE LEGS page on the line prior to thefirst desired reporting point. Normally, this entry is made on the activewaypoint line and proper sequencing is performed by the FMC.Rev 1 12/964-3B747-400 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.4.1.4 Airway Crossing Fixes Airway crossing fixes are entered as a five-character waypoint nameor by entering consecutive airways on the RTE page. In the lattercase, the display is an X followed by the second airway name. Forexample: entering J70 on the VIA line of the RTE page causes boxprompts to display opposite on the same line. Leaving the boxprompts empty and entering J52 on the next VIA line, directly belowJ70, causes the FMC to compute the intersection of the two airwaysand replace the boxes with the waypoint identifier, XJ52.4.1.5 Summary of Pilot Waypoint Construction Table 4.1-1Pilot Waypoint ConstructionTYPE OFWAYPOINTCDU PAGE ANDVALID ENTRYINVALIDENTRYEXAMPLESNavigationData BaseRTE or LEGSNavaid, Airport,Waypoint, RunwayNOT INDATA BASENavaid: BAE, TOTNBAirport: YSSYWaypoint: AUGERRunway: RW30RRTE or LEGSNavaid, WaypointRunway Fix, LOM,MM, Lat/LongDEN090/70OBK274/61Place Bearing/DistancePlace Bearing/Place BearingRTE or LEGSNavaid, WaypointLat/Long, DistanceGreater than 700 NMFrom Either FixORD125/CGT097SFO360/CCR090Latitude/Longitude RTE or LEGSLeading ZerosRequiredIf Lat or Long ContainsMinutes, Both Lat andLong Must HaveTrailing ZerosN45W165N3728.0W13309.0N3750.0W12500.0Along TrackWaypointLEGSWaypoint Must Existon LEGS Page.(-) is Prior toWaypointCannot Coincide orExtend BeyondAnother ExistingWaypointSFO/-35DEN/30CrossingLat or LongLEGSRoute Crossesthat Lat/LongRoute Does NotCross the Lat/LongW123, N05IntervalLat or LongLEGSRoute Crosses thatLat or LongAn Interval Greaterthan 20 DegreesW130-5S05-10AirwayIntersectionRTEAirways thatIntersectAirways thatDo Not IntersectVIA TOJ70J70J204LWTXJ204MLSG3641-21-108#Rev 1 12/96
4-4Use 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 4.2 CONDITIONAL W WA A AYPOINTS YPOINTS Conditional waypoints are automatically entered in a route as a resultof selecting a procedure on a DEPARTURES or ARRIVALS page.Conditional waypoints cannot be manually entered. These waypoints indicate when an event occurs and are not at a geographicallyfixed position.There are five types of conditions: passing an altitude, flying aheading to a radial or DME distance, intercepting a course, andheading vectors. Altitude and course intercept conditional waypointsare displayed on the MCDU inside parenthese ( ) marks.The legend VECTORS on a LEGS page denotes a conditional legunder ATC heading instructions. When released from ATC vectorcontrol, the FMS uses LNAV HEADING HOLD to intercept the active leg.4-5B747-400 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.180 HDGTO1000 FT140 HDGTOABC 180CDEABC180280310 FORVECTORSTO CDE20 NM090 HDG TO 20 DMEFROM ABCBCD020 HDGTO INTC340 TO BCDG3641-21-109#oooooooooFigure 4.2-1Conditional Waypoints4-6Use 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 4.3 FMC ABBREVIA ABBREVIATIONS TIONS Waypoints located at un-named runway-related fixes are identifiedby adding a two-letter prefix to the runway number. The followingabbreviations are used with the runway number if a single approachexists to that runway:A (+ an alpha) Step Down FixBM Back Curve MarkerCF Final Approach Course FixIF Initial Approach FixFA VFR Approach FixFF Final Approach FixOM Outer MarkerMM Middle MarkerIM Inner MarkerRX Runway Extension FixRW Runway ThresholdMA Missed Approach Point (not runway)MD Minimum Descent AltitudeTD Touchdown Point Inboard of ThresholdExamples:(ILS 28L)CF28L, FF28L, RW28LRev 1 12/964-7B747-400 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.The following abbreviations are used with the runway number ifmultiple approaches exist to that runway (parentheses under thewaypoint type are included to compare with abbreviations above):WAYPOINT TYPE NDB (N) MLS RNAV
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 4.4 POLAR OPERA OPERATION TION This section identifies operation unique to the polar region for themagnetic/true reference and for the IRS mode.4.4.1 Magnetic/True Reference Selection of magnetic or true reference is normally selected by theHDG TRUE/NORM switch located above the upper EICAS display.However, the reference is automatically changed to true, independentof the position of the HDG TRUE/NORM switch, when the aircraft isoperating in the region above N73° or below S60° latitude. Uponleaving this region, the heading reference is again determined by theposition of the HDG TRUE/NORM switch. When operating in the truereference mode, bearing information entered by the pilot is assumedto be a true bearing reference.4.4.2 Polar IRS Navigation This section describes FMC navigation using the IRS when enteringor leaving the polar region. For the purpose of navigation, the FMCposition is considered to be in the polar region if its latitude is greaterthan 84°, or if its latitude is greater than 83.5° after having beengreater than 84°.When the computed aircraft position enters the region above N84°,or the region below S84°, each FMC downmodes from the triple-mixIRS position to a single IRS position. The “SPLIT IRS OPERATION”message is displayed to inform the pilot the FMC has changed fromtriple-mix to split IRS position updating.Each FMC selects the corresponding valid IRS. For the left FMC, theorder of selection is left, center, and right. For the right FMC, the orderis right, center, and left. The IRS selection may be checked on thePOS REF page. The two IRS positions chosen are those exhibitingthe least distance between them following comparison of each IRSposition with the other two.4-9B747-400 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.The FMC navigation function gradually changes the computed FMCposition from the triple-mix position to the single IRS position toprevent sudden position jumps. Ultimately the FMC position is equalto the single IRS position. The rate at which the position difference iseliminated is chosen to minimize aircraft maneuvers and map “jumps”while still ensuring all differences are eliminated upon reaching thepole for the worst case condition of flying directly North or South atmaximum ground speed.When the computed aircraft position of both FMCs is between N83.5°and S83.5° latitude, the FMC returns to triple-mix IRS positionupdating. There is no instantaneous change in either FMC positionwhen returning to triple-mix mode. Any differences existing betweenthe mixed IRS position and either FMC position is washed out at thesame rate used for previous 84° latitude crossing.If the triple-mix is not available (i.e., only one or two IRUs are valid),the “SPLIT IRS OPERATION” message is displayed. The POS REFpage indicates the single or triple-mix IRS position.If there is a detected IRS failure while the FMC position is greater than89° North or South latitude, the FMC position immediately becomesthe IRS position.4-10Use 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 4.5 HOLDING P PA A ATTERNS TTERNS This section is an in-depth look at holding patterns and how the FMCcomputes and calculates the holding pattern.4.5.1 Types of Holding Patterns There are three types of holding patterns:1. Patterns terminated by reaching a specific altitude (referred to asaltitude terminated).2. Patterns terminated by crossing the hold fix the first time afterentering the hold (referred to as fix terminated).3. Patterns terminated manually (referred to as manually terminated).All three types may exist in terminal area procedures extracted fromthe navigation database and thus can be accessed by the pilot. Onlymanually terminated holds may be created via the FMC HOLD page.Altitude terminated and fix terminated holds cannot be created via theFMC HOLD page.The altitude for altitude terminated holds is an AT or ABOVEconstraint; therefore, altitude terminated holds only occur in climb.The FMC remains in the holding pattern until the AT or ABOVEconstraint is met. If the aircraft is already at or above the specifiedaltitude upon reaching the holding fix, the hold is not flown. Uponreaching the altitude constraint, the FMC enters the exit armed state,adjust the holding pattern size to provide the shortest route to the holdfix, and exits the hold the next time the hold fix is crossed.Fix terminated holds are allowed in all flight phases but are usuallyencountered in descent. This type of hold consists of only one loop(or partial loop) around the pattern and the FMC exits the hold uponcrossing the hold fix the first time after entering the hold. No specialdisplays are used to alert the pilot the hold is terminated.4-11B747-400 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.Manually terminated holds are allowed in all flight phases. The pilotmust manually terminate this hold by selecting line 6R (EXIT HOLDprompt) on the FMC HOLD page. Upon selecting line 6R , the FMCenters the exit armed state, adjusts the holding pattern size to providethe shortest route back to the hold fix, and exits the hold the next timethe hold fix is crossed.If a direct-to is executed while in any type of hold, the FMC exits thehold immediately.4.5.2 Creation and Modification of Holding Patterns Pilot-generated holding patterns are created on the ACT RTE HOLDpage which can be accessed by selecting the HOLDmode key on theCDU. If a hold does not already exist in the flight plan, this actiondisplays the ACT RTE LEGS HOLD AT page which allows the pilotto specify a desired fix for the hold by entering the fix in line 6L
or todefine a present position hold by selecting line 6R (PPOS prompt).If one or more hold(s) already exists in the flight plan when the HOLDmode key is pressed, the ACT RTE HOLD page is displayed whichshows the characteristics of the nearest hold in the flight plan. Thepilot may access the ACT RTE LEGS HOLD AT page, by selectingline 6L
(NEXT HOLD prompt). If more than one hold exists, the pilotmay access the next nearest hold in the flight plan by selecting theNEXTPAGE key.Line 1L
of the hold page displays the fix at which the hold is defined.The holding quadrant and radial are displayed in line 2L
of the holdpage. The quadrant abbreviations are N, NE, E, SE, S, SW, W, NW.Line 3L
of the hold page defines the inbound course and turndirection of the hold. For manually terminated holds, the inboundcourse defaults to the leg course of the leg preceding the hold fix andthe turn direction defaults to right. The holding pattern’s straight legsize is defined by either its length or the time spent flying wings level.Line 4L
defines the leg time and line 5L
defines leg distance. Legtime and leg distance are mutually exclusive; an entry in either erasesthe value in the other. The FMC defaults to leg time. The leg timedefaults to 1 minute at or below 14,000 feet and 1.5 minutes above14,000 feet. The altitude used to compare to 14,000 is determined asfollows:
