Flight Management System Flashcards
The left and right GPS positions are displayed on POS REF page 3/3.
When the FMC is using GPS to update its position, it will be
displayed on the ND.
Should the ADIRU fail during flight, an EICAS caution message NAV ADIRU INERTIAL will be displayed along with the master CAUTION light.
In this situation, the FMC will now use
GPS only for navigation.
The Air Data Inertial Reference System (ADIRS) calculates airplane
altitude, airspeed, attitude, heading and position information.
The ADIRS supplies information to the display units,
Flight Management System,
flight controls, and engine controls.
The ADIRU is a fault-tolerant and fully redundant system supplying
the primary flight data, inertial navigation and air data.
Battery bus power is required during ADIRU initial power-up.
Before moving the airplane, a full alignment must be completed.
If electrical power is inadvertently removed from the airplane and the
BATTERY switch has been selected OFF, the ADIRU will still receive power
from
the hot battery bus.
The ON BAT light will illuminate.
Maintenance personnel will be alerted to this situation by the sounding of a
horn, located in the nose wheel well.
If the ADIRU is accidentally turned OFF in flight, system logic prevents the ADIRU from becoming unpowered.
If the ADIRU switch is turned OFF on the ground, it will
remain powered for a few seconds.
The scratchpad message INERTIAL / ORIGIN DISAGREE will display if the latitude / longitude position is not within
6 nm of the origin airport.
If an incorrect latitude / longitude is entered by the crew and the airplane senses
a disagreement to where it thinks it should be, the scratchpad message
ENTER INERTIAL POSITION will display.
The scratchpad message ALIGNMENT REINITIATED will display if a new present position entry fails twice.
This causes
a new alignment cycle to begin.
If the GPS position differs greatly from the entered ADIRU position, the scratchpad message NAV UNABLE RNP will display.
This is a rare occurrence and will rectify itself when the FMC reconciles the difference between the new
ADIRU position and the GPS position.
Each time the airplane is stopped for an extended period of time, the ADIRU will enter an automatic realign mode.
Position alignment will be refined until
the airplane starts to move again.
The ADIRU velocity and acceleration errors will be set to zero.
With the ADIRU in the automatic realign mode, a manual position update can be accomplished.
A new position can be entered on
POS INIT page 1/3.
NOTE: An ADIRU alignment cannot be accomplished in flight.
If the time between alignments is expected to exceed 24 hr, a position update is recommended.
When a ADIRU fault occurs, the SAARU will supply attitude data and will supply backup heading data for
3 min.
The heading is based on ADIRU heading prior to the failure.
After 3 min, heading data will be removed and a SET HDG prompt will be
displayed on the CDU POS INIT page.
The ADIRU and SAARU receive their air data from
the left, center and right pitot and static systems.
Two of these three air data sources must be in agreement before the ADIRU and
SAARU use the data.
There are 2 ADF systems installed on the airplane. Each ADF can be manually
tuned from
the NAV RADIO page on either CDU.
In the event of a dual FMC failure, the ADFs can be tuned using
the CDU ALTN NAV RADIO page.
There are 2 DME systems installed on the airplane. The DMEs, usually
autotuned by the FMC, may also
be tuned manually.
When the VOR portion of a VOR / DME is manually entered on the NAV RADIO page, the DMEs are considered to be tuned manually.
This does not inhibit FMC DME tuning.
Two DMEs are used by the FMC for position updates.
The FMC will tune DMEs as necessary for radio position updates.
This is seen on
POS REF page 2/3 displays the identifiers of the DME stations used for FMC position updates.
The DME / DME updates are usually more accurate than VOR / DME updates.
If the NAVAIDS have been inhibited on the REF NAV DATA page, the FMC
will be unable to tune specific DMEs.
In the event of a dual FMC failure, the VORs can be tuned manually using
the CDU ALTN NAV RADIO page.
Each DME tuned will be displayed on its own CDU.
NOTE: The only exception is if the ND mode selector is set to APP, the DME displayed will be that of the ILS.
The B777 has three ILS receivers which are usually tuned by the FMC.
They may also be manually tuned on the NAV RADIO page.
For ILS autotuning to occur, two conditions must be met.
he two conditions are: An ILS, LOC, back course, LDA (Localizer-type Directional Aid), or SDF (Simplified Directional Facility) approach must have been selected to the active route;
and the airplane must be within 50 nm from the Top of Descent, 150 nm of the landing runway threshold, or the FMC operating in descent mode.
To prevent clutter on the PFD, ILS autotuning is inhibited for
10 min after take-off.
This inhibit does not apply if a new approach is inserted into the active Flight Plan causing the ILS to autotune to the new approach frequency;
or
to subsequent take-offs and landings on the same flight (for example, touch-and-go or stop-and-go landings).
Unless ILS approach tuning inhibit is active, the three ILS receivers can be manually tuned from
the NAV RADIO page.
ILS approach tuning inhibit is active when:
The autopilot is engaged and either the localizer or glideslope is captured.
Only the flight director is engaged, and either the localizer or the glideslope is captured, and the airplane is below 500 ft Radio Altitude, or
on the ground,
the localizer is alive,
airplane heading is within 45 ° of the localizer front course,
and ground speed is greater than 40 kt.
Manual ILS tuning is again enabled when:
either TO/GA switch is pushed,
the autopilot is disengaged and both F/D switches are switched OFF, or
the MCP approach mode is deselected above 1,500 ft Radio Altitude.
n the event of a dual FMC failure, the left and center ILS receivers can be tuned from
and the right ILS receiver can be tuned from
the left CDU ALTN NAV RADIO page
right CDU ALTN NAV RADIO page.
In flight, with the mode selector in XPNDR, TA ONLY or TA/RA, the selected transponder activates
beacon and altitude reporting.
If transponder altitude reporting fails, the ALT SOURCE selector can switch the
source from the ADIRU (NORM) to
SAARU (ALTN).
On power-up, each radar sweep and when descending through 2,300 ft AGL,
the weather radar performs
several self tests.
In the event of an EFIS control panel problem, the weather radar can be
controlled from the EFIS OPTIONS page
on the CDU.
This is only to be used during non-normal operations.
The ND will display any operating modes and fault conditions.
Only when there is sufficient precipitation can the weather radar display turbulence.
Clear air turbulence
cannot be sensed by radar.
The 322 has a multiscan radar system designed for fully automatic operation.
It collects data from different scans and merges the information into a total weather picture.
Ground clutter is eliminated from the onboard software providing clutter free viewing of significant weather out to
320 NM.
In AUTO mode, multiple radar scans at pre-selected tilt angles detect short, mid, and long range weather.
The result is weather detection at all ranges and in all phases of flight.
Additional processing ensures data from a thunderstorm top within
5,000 ft of the aircraft remains on the radar display until it no longer poses a danger;
this enables flight around thunderstorms that may not be visible.
Tilt and gain inputs are not available when operating in AUTO.
The desired range in AUTO can be selected on the EFIS control panel.
When AUTO is initially selected, the radar first sweeps along the aircraft’s flight path.
This will ensure that weather in front of the pilots is immediately displayed.
Four subsequent sweeps are part of the initialization process to detect weather and ground clutter.
After approximately
16 seconds, the initialization is complete and the ND will show an optimized
weather picture with minimal ground clutter for any range selection.
The TEST switch tests the weather radar system operation without transmitting.
A test pattern and Predictive Windshear Systems (PWS) symbol display along
with any fault messages that result from the test provided
WXR is selected on any ND or PFD.
The TFR switch transfers other ND display selections to the related ND.
Note that selecting both TFR switches at the same time results in
the TEST mode and the test pattern displays.
WX displays weather radar returns. WX+T displays weather returns and threats within precipitation at the calibrated gain level.
Turbulence within 40 nm is displayed at all display ranges.
Note: that turbulence detection requires the presence of detectable precipitation. Clear air turbulence
cannot be detected by radar.
MAP displays ground returns at the selected gain level. Pushing and holding GC
displays ground clutter.
322 The enhanced features of this radar include
Threat Assessment, Predictive Overflight, Turbulence Display, and a Descent feature.
322
The Threat Assessment feature is active in AUTO with WX+T mode selected.
This feature combines data from vertical and horizontal sweeps to predict the presence of turbulence and hail in anvil and electrified stratiform clouds.
At altitudes above 25,000 ft threats display as
red speckled patterns in green or yellow regions,
indicating a threat in a cell and a region where aircraft-induced lightning may occur.
322 Predictive Overflight (POF) protection displays a cell growing into the flight path,
but not currently a threat. A POF display can be an indication of
clear air turbulence above a growing cell even if the visible cell may not reach the flight path.
POF displays as a red enclosure with red dots. POF is active only with AUTO and WX+T selected.
322 When operating in AUTO,
two-level turbulence detection displays severe turbulence with solid magenta areas while light-to-moderate turbulence areas display with magenta dots. Severe turbulence is for aircraft loads 0.3g or greater; light turbulence is for aircraft loads 0.2g or less.
magenta dots. Severe turbulence is for aircraft loads 0.3g or greater;
light turbulence is for aircraft loads 0.2g or less.
322 When operating in AUTO and WX+T,
threat assessment is operative for the descent profile.
It is not necessary to switch to
manual operation during descent.
322 Radar - Summary
In the event of a left or right CDU failure, the center CDU will automatically
take over the role of the failed CDU.
When alternate navigation is active, only
the left and right CDUs are used to tune navigation radios.
Left and right CDUs provide backup to the left and right EFIS control panels,
while the center CDU provides
EFIS control panel backup for a failed left or right CDU.
When an altitude entry is required it may be entered into the FMC as a
three digit (XXX), four digit (XXXX), five digit (XXXXX), or flight level (FLXXX) number.
Based on the transition altitude, the FMC will change the altitude or flight level entries into
the proper format. Some data lines may be further restricted.
Entry of three digits represents altitude or flight levels in increments of 100 ft. Leading zeros
are required.
A slash / on a CDU page is used for a data pair. Examples include wind direction / speed and waypoint airspeed / altitude constraints.
If both values of a data pair are needed, the slash is inserted between the values. The slash may not be required if it is possible to enter only one value of the pair.
If only the outboard value of a data pair is needed, the trailing or leading slash is not required, but may be entered before transferring to the data line.If only the inboard value of a data pair is needed,
the trailing or leading slash must be entered before transferring to the data line.
An INVALID ENTRY message normally displays if a required slash is left out.
If the manual entry is followed by an A, for example 390.0A, the ADF uses Antenna mode.
This mode optimizes audio reception and removes ADF bearing information.
The ADF L (R) Frequencies and Tuning Status Display tuning status (white) is adjacent to left and right ADF frequencies (cyan).
The ADF receivers require
manual tuning and operate in three modes.
Valid entries are XXX.X or XXXX.X, followed by A (ANT), B (BFO) or none (for default).
If the manual entry is followed by a B, the ADF is in BFO,
or Beat Frequency Oscillator mode. This is used for
audio identification of stations that transmit unmodulated CW signals.
The letter R indicates route autotuning.
The NAVAIDS for the active route are selected by the FMC.
The NAVAID is
the previous VOR or a downpath VOR within 250 NM of the aircraft position.
The letter M indicates manual tuning, which has priority
over FMC autotuning.
When a VOR approach is selected,
the FMC procedure autotunes the VOR frequency when the IAF / FAF is
sequenced. The inbound course is selected when
the approach contains a runway waypoint.
For radio position updates the FMC tunes DMEs as necessary.
Manually tuning a DME does not
inhibit FMC DME tuning.
TA ONLY and TA/RA are associated with
TCAS operation.
The WXR SYS switch selects the receiver / transmitter for operation.
In the L position, the radar antenna is stabilized by
the left and center Inertial Reference Units (IRUs),
while in the R position it is stabilized by the right and center IRUs.
When WXR is selected off on the EFIS control panel the pattern is removed.
It also is removed when
another mode is selected on the mode selector, or if an actual PWS alert is detected.
Weather returns along with turbulence are displayed by selecting WX/TURB. Ranges of 40 nm or less must be selected to display turbulence.
Clear Air Turbulence cannot be detected by radar since
the turbulence detection function requires the presence of detectable precipitation.
Ground returns, at the selected gain level, are displayed by
selecting MAP.
Selection of TO/GA starts the take-off phase. Thrust reduction for climb
terminates the take-off phase.
The approach phase begins when the first waypoint of the procedure sequences
or when the runway is the active waypoint and the distance to the runway is
25 nm or less.
The FMC climb mode will activate if a go-around is initiated.
Monitor for errors following:
activation of a new database,
power interruption
or ADIRU failure.
When on a route offset, active route waypoints sequence normally.
However, during transition to or from an offset route
greater than 21 nm,
the crosstrack limit is extended
to 200 nm.
When a waypoint is in the route more than once, certain route modifications
(such as DIRECT TO and HOLD) use the
first occurrence of this waypoint in the route.
If the engines remain operating between flights, a new cruise altitude entry is
required before the next flight to recalculate the proper vertical profile.
A new cruise altitude entry must be made if a climb to cruise altitude is
necessary after completing a descent.
This may be entered
on the CLB page.
DIRECT TO courses are segments of a great circle route.
If a DIRECT TO waypoint is entered on the LEGS page,
the arrival course at the waypoint.
the course above the waypoint before execution is
After execution, the course displayed is the current course to fly to the
waypoint.
As a result, these courses may not be the same.
Selecting the PURGE prompt removes all airports uplinked to
the ALTN LIST.
A conditional waypoint is not associated with a land reference; it is based on
a time or an altitude requirement.
An example of a conditional waypoint is when
reaching 3,500 ft.
ADIRU and / or GPS data is used on the ground to calculate
FMC present position.
When a TO/GA switch is pushed for take-off,
the FMC position is updated to the landing threshold,
or, to the position shift position, if one has been entered.
Note that this only happens with
GPS NAV OFF.
When the aircraft enters a polar region, a flashing white box around the word
TRU on the
ND indicates automatic switching to a true north reference has taken place.
When leaving the polar region, a green box is displayed around the word MAG
to indicate the change
from TRU.
An amber box appears around the word TRU if the heading reference is still in
true during
descent.
In the polar region, TRUE must be selected on the HDG REF switch when
operating the autopilot in other than
LNAV.
The airplane position symbol does not display while in ND plan mode and
flying
north of 82 °N or south of 82 °S.
Lines 2 through 4 left on POS REF page 2 display navigation system positions.
Bearing and distances displayed are from the FMC position to each
navigation system position.
Inertial and DME / DME updates cannot
be inhibited.
When it is armed for take-off,
LNAV will engage at or above 50 ft, provided it is within
2.5 nm laterally of the active route leg.
Normally, LNAV provides great circle course guidance between waypoints.
Conditional waypoints for altitudes and course intercepts are displayed on the CDU inside
parenthesis marks.
When latitude or longitude reporting waypoints are required,
they are entered as the full latitude or longitude followed by a dash
and the increment chosen to generate the
subsequent multiple waypoints.
In this example,
W005 - 10 adds waypoints starting at W005 in ten degree increments
from that point to the destination.
For an altitude constraint covering a range of altitudes two altitudes may be entered in either order.
The lower constraint is followed by the suffix A, with the upper constraint followed by the suffix B. Examples of such entries are shown here.
The altitudes and speeds for SPD TRANS and SPD RESTR on the DES page will be deleted if the altitude set in the ALTITUDE window is below those altitudes.
These restrictions must then be maintained by flight crew action.
VNAV will not transition to the approach phase when passing the first waypoint
of the approach if a waypoint located after the first waypoint of an FMC
database approach is
added and executed.
The FMC creates an E/D point when an arrival or approach procedure is
selected on the ARRIVALS page and incorporated into the Flight Plan.
This point normally coincides with
a final approach fix (FAF) or runway threshold.
Auto throttles off - Airspeed may decrease to the minimum maneuvering speed.
To stop the deceleration,
VNAV then commands the airplane to fly
below the path.
The pitch mode changes from VNAV PTH to VNAV SPD
if VNAV can no longer maintain the airplane within
150 ft of the path without further deceleration.
The scratchpad message DRAG REQUIRED will display if the speed increases
to more than 314 kt. This speed is
The aircraft may accelerate up to 15 kt above the speed on the SEL SPD line (maximum 319 kt,
VMO / MMO minus 15 kt.
10 kt below VMO) to maintain the path.
If more correction is required, the airplane may go up to 150 ft above the
desired VNAV path.
For any descent that starts before the calculated Top of Descent point, VNAV
will command a reduced rate of descent until
path interception.
On a missed approach, LNAV will engage above 50 ft Radio Altitude if the
autopilot is not engaged, and above
200 ft Radio Altitude if the autopilot is engaged.
A missed approach may be accomplished by selecting either TO/GA switch.
Driftdown
Set the MCP altitude at or below EO MAX altitude and execute the FMC modification to start the driftdown.
Another means of starting driftdown is to execute the ENG OUT modification. Then, set the clearance altitude, which must be lower than EO MAX, in the MCP and push the altitude selector.
Yet another method is to set the clearance altitude in the MCP, push the altitude selector; then, after the descent is established, execute the ENG OUT modification.
to execute the ENG OUT modification.
Then, set the clearance altitude, which must be lower than EO MAX, in the MCP and push the altitude selector.
set the clearance altitude in the MCP, push the altitude selector; then, after the descent is established, execute the ENG OUT modification.
GPS POS displays the GPS present position.
During preflight, it may not display due to
satellite availability, performance, or unfavorable geometry.
The page title is white when the route is active, and cyan when
the route is inactive.
MAX ANGLE displays the maximum angle of climb speed.
is not allowed.Manual entry
is not allowed.
Selection and execution above the engine-out maximum altitude displays
the ACT EO D/D page.
CLB DIR displays when a climb altitude constraint exists between the current
altitude and
the FMC cruise altitude.
Selecting CLB DIR deletes all waypoint altitude constraints
between the airplane altitude and the MCP altitude or FMC cruise altitude,
whichever is lower. FMC cruise altitude is not affected.
Engine-out VNAV climb guidance is available on the EO CLB page.
The EO
CLB page must be selected and
executed by the flight crew.
CRZ ALT displays if the cruise altitude is less than MAX ALT and displays
MAX ALT if engine-out cruise altitude is less than
cruise altitude. Manual entry is allowed.
MAX ALT displays the lower of maximum altitude at engine-out climb speed or
cruise speed.
Manual entry
is not allowed.
During the take-off roll, the autothrottle commands the thrust and the FMC
commands acceleration to between
V2 + 15 kt and V2 + 25 kt, based on the rate of rotation.
Setting an altitude below the current altitude in the MCP ALTITUDE window and pushing the ALTITUDE selector (more than 50 nm from a T/D) causes the cruise altitude to be set to the MCP ALTITUDE and the airplane to descend to the new altitude.
The CRZ page displays ACT ECON CRZ DES.
A calculated thrust value for an approximate 1,250 ft/min descent is set by the autothrottle. Pitch changes maintain the commanded cruise speed. Thrust levers can be
manually positioned to adjust the descent rate.
Selecting OFF displays ALL in both locations of the VOR ONLY INHIBIT line.
DME / DME position updating
is not inhibited.
OAT can be entered for any one altitude. The FMC calculates the temperature
for the entered altitudes
using the standard lapse rate.
An FMC position update can be accomplished on the
POS REF 2/3 page in
flight.
PROGRESS page three is used to enter data for
Required Time of Arrival (RTA). This may be entered or changed during
preflight or in flight.
Creating an RTA changes the CRZ page title to RTA CRZ. RTA
operates only in
cruise.
PROGRESS page four displays concise
RNP information.
Alternate airports display the identifier of the four alternate airports in ETA
order when airborne; and, in
distance order when on the ground.
The selected alternate is identified with an A or SEL to the right of the airport
identifier.
Usually, the closest alternate is selected and identified with A.
An airport will not be one of the four alternate airports if entered into the
ALTN INHIBIT line. One or two airports can be entered.
he FMC computes holding patterns with constant radius turns based on current
wind and
FMC commanded airspeed. The pattern size is limited to FAA or ICAO
protected airspace.
Holding
Strong winds or airspeed in excess of FAA or ICAO entry speeds may result in
the airplane flying outside the protected airspace.
Holding
teardrop entries use
a 40 degree offset angle
Lateral guidance directs the airplane to fly-by or fly-over the holding fix and to
remain
on the holding side of the inbound holding course.
Holding
The BEST SPEED line displays the best holding speed for the airplane gross
weight, altitude, and flap setting. Note that this speed may exceed
the ICAO limit speed.
In ALTN NAV
Navigation radios are tuned on the ALTN NAV RADIO page and related parameters display. Autotune is
not available.
The CDUs operate independently for navigation radio tuning.
VNAV is not available in ALTN NAV
In ALTN NAV
The left CDU tunes the left VOR, DME, ADF,
and left and center ILS. The right CDU tunes
the right VOR, DME, ADF, and right ILS.
In ALTN NAV
Waypoint speed and altitude restrictions are not displayed because performance data is
is not available
The center CDU is automatically selected after failure of
the left or right CDU.
If both FMCs fail, the CDUs retain Flight Plan waypoints except for
conditional waypoints, offsets, and holding patterns.
IN ALTN NAV
New waypoints can only be entered in
latitude and longitude.
This includes waypoints the flight crew has deleted from the copied route.
In ALTN NAV
The ADIRU supplies magnetic variation for present position.
Only the active waypoint course can be referenced to magnetic north.
All subsequent waypoint courses
are true courses.
The FMC must have continuous electrical power to operate.
When the electrical power is interrupted and returns,
the FMC restarts.
After restart, the performance data displayed on the PERF INIT page must
be re-entered.
The route previously in use is available but must be reactivated.
The AFDS modes shown here are inoperative after failure of the inertial
reference portion of the ADIRU.
LNAV / VNAV
TO/GA
LOC / GS
TRK HOLD / SEL
HDG HOLD / SEL
The navigation functions shown here are inoperative after failure of the inertial
reference portion of the ADIRU.
FMC VNAV pages
FMC Performance Predictions
ND wind direction & speed (wind arrow)
The PFD functions shown here are inoperative after failure of the inertial
reference portion of the ADIRU.
Flap maneuvering speeds
PFD heading
(this is operative when heading from standby is entered on pos init page)
autobrakes inop
If the ADIRU fails in a polar region, the EICAS message NAV ADIRU
INERTIAL displays and all
autopilot and AFDS roll modes fail.
The CDU POS INIT page displays the SET HDG prompt
3 min after ADIRU failure.
SAARU power-up is completely automatic at airplane power-up.
There are no SAARU
controls.
A software reset may occur while in single FMC operation.
The active route becomes inactive, the performance data is erased, and
LNAV and VNAV (if engaged) modes fail.
To regain FMC operation,
activate and execute the Flight Plan, enter the necessary performance data,
and engage LNAV and VNAV.
If the MENU page and the scratchpad message TIMEOUT RESELECT display,
the FMC is no longer
connected to the CDU.
Selecting the < FMC prompt connects the CDU to the FMC.
