FMS and Navigation Flashcards
FMS and Navigation
Which Air Data Module (ADM) sends its info directly to the IFSD ?
The CENTER ADM.
FMS and Navigation
If voted ADRS Air data is invalid, what is the next backup system ?
Backup Airspeed and Backup altitude information is sent to the PFDs.
Backup airspeed is based on AoA and data from the IRS.
Backup altitude is provided by GPS data.
FMS and Navigation
If Backup Airspeed and Altitude are invalid, what is the next backup ?
ISFD altitude and airspeed will be displayed on both PFDs.
FMS and Navigation
Can the IRS be realigned in flight ?
Yes, if GPS data is available.
FMS and Navigation
What is the IRS composed of ?
2 IRS each containing :
- 1 IRU (Inertial Reference Unit)
- 1 AHRU (Attitude Heading Reference Unit)
FMS and Navigation
In case of failure of the 3 FMCs, how can navigation be achieved ?
Through the Alternate Navigation feature of the TCPs.
It is accessed by pressing the NAV button on the TCP.
Alternate navigation data is displayed on the TCPs and the ISFD.
FMS and Navigation
What is ANP : Actual Navigation Performance ?
ANP is the FMS position accuracy.
It can be visualized as a circle that contains all possible computed aircraft positions.
The aircraft is assumed to be within this circle 95% of the time.
FMS and Navigation
When starting a descent before the computed TOD, by using the “descend now” prompt, what initial rate of descent will be commanded ?
Approximately 1250 ft/min.
The DESCEND NOW prompt is available until 50 NM from the TOD.
FMS and Navigation
When will the VNAV mode switch from VNAV PATH to VNAV SPD during descent ?
If more than 150 ft above or below the VNAV Path.
FMS and Navigation
When is ILS autotuning inhibited ?
For 10 minutes after take-off and during manual tuning.
FMS and Navigation
What is the difference between OPT and RCMD FLs on the VNAV CRZ page ?
The RCMD (Recommended) speed takes into account forecast winds and temperatures at cruise altitudes. The FMC evaluates FLs from 9000 feet below the current CRZ FL up to the max FL.
What is the function of the CDU Line Select keys?
• moves data from scratchpad to selected line• moves data from selected line to scratchpad• selects page, procedure, or performance mode as applicable• deletes data from selected line when DELETE displays in scratchpad
What is the purpose of the CDU Help Window?
Displays error/help messages to the crew.
If LEGS page 1/3 is displayed, which key(s) would you press to display LEGS page 3/3?
PREV PAGE Key once, or NEXT PAGE twice.
How is required entry of data that is mandatory for FMS operation indicated on appropriate CDU pages?
Boxes
What is indicated by “dashes” adjacent to line select keys on some CDU pages?
Data input is optional.
a. What colour are “not yet” executed flight plan modifications?b. What colour is used to indicate an active way point, speed or altitude?c. What colour are the input fields?
a. Black text on a white background.b. Magenta.c. Shaded gray.
a. How is a highlight box displayed?b. What actions can you make with a highlightbox?
a. Hovering the cursor over an active area of the CDU.b. An action may be performed such as data entry or line key selection.
What is the autotabbing feature?
To facilitate data entry during preflight, when data is entered into a field, the cursor automatically moves to the next appropriate entry field.
What does the CDU LEGS page entry W060-10 in the active line produce?
Adds waypoints starting at W060 in ten degree increments from that point to the destination
Define the E/D (end of descent) point.
• The E/D is located 50 feet above the runway threshold for all approaches except VOR approaches.• The E/D for VOR approaches is the missed approach point; which may be the VOR, runway waypoint or a named waypoint.• During cruise, an E/D is also created when an altitude constraint is entered on the LEGS page on a downstream waypoint.
Under VNAV control, what crew action is necessary for an automatic descent to commence at the T/D (top of descent) point?
Set the MCP altitude to below that of the aircraft.
During VNAV controlled descents, what target speed is normally commanded by the FMC?
Economy speed above 10,000 ft and 240 Knots below 10,000 ft.
On the CDU LEGS page, for example, how would you differentiate between an entry of FL230 and a speed of 230 Knots?
Speed must be following by a slash (/).
a. How many databases does the FMC contain?b. Which database is regularly updated every 28 days?
a. Three: Navigation, Option Settings and Performance.b. Navigation.
How many sets of navigation data are contained in the FMC?
Two.
After an electrical power interruption, the FMC will restart. What crew action is required to reactivate the route?
• Performance data displayed on the PERF INIT page must be re-entered.• Modify the active waypoint to activate LNAV.
At power up, how are the three FMCs designated?
Master (active), spare (standby) and backup.
What happens if the master FMC fails?
• The spare (standby) FMC automatically becomes active and assumes all FMC functionality in the event the master FMC fails.• The backup FMC then assumes the role of the spare FMC
a. What happens in the event of a dual FMC failure? b. What crew action will be required?c. Why may a software reset be required?
a. The third FMC automatically takes over in a single FMC configuration.b. The flight crew need store activate and execute the flight plan,and reselect LNAV and VNAV.c. This is a self-protection mode which prevents permanent loss of the FMC in the unlikely event the FMC is presented with an insoluble computation.
a. What functionality is lost if a triple FMC failure occurs?b. What navigational capability remains?
a. PFD mini-maps, ND map displays, CDU pages on the MFD and loss of both LNAV and VNAV.b. The TCPs provide the capability to enter a single Lat/Long waypoint. The TCPs then provide track, distance to go, and groundspeed for the entered waypoint.
a. How are the crew made aware of pending uplink messages via the CDU? b. What indications are there on the EICAS?
a. ACCEPT/REJECT or LOAD/PURGE prompts, FMC modification ERASE prompt or EXEC key, or when the page with the uplink is selected.b. An •FMC EICAS comms alert and a hi–lo chime.
What prompt appears on either the RTE or WIND page after the receipt of uplink data?
LOAD.
a. What prompts appear after the uplink has been loaded? b. Selecting either of these prompts does what?
a. The EXEC light illuminates and the ERASE prompt displays.b.• Selecting the EXEC key puts the modified data in the active flight plan and changes the page format to pre–uplink format.• Selecting the ERASE prompt removes the modified data and returns the page display to the pre–uplink format
What displays on the FMC COMM page to alert the crew of pending uplink messages?
The page line title displays UPLINK.
Which page is automatically displayed on the FMS CDU when electrical power is initially applied to the aircraft?
The IDENT page.
a. What is the sequence of pages used in the initial pre-flight check of the FMC?b. What supplementary CDU pages can be used during the pre-flight check?
a. IDENT, POS REF, RTE, DEPARTURES, NAV RAD, PERF INIT, THRUST LIM, TAKEOFF REF pages 1 & 2.b. ARRIVALS, RTE LEGS, ALTN, REF NAV DATA, VNAV, WIND.
a. Which CDU page allows you to change the method of FMC position updating?b. How could you verify that the FMC was using GPS-IRU updating?
a. POS REF page 2/4 (UPDATE/ARM prompt).b. Check FMC position line suffix (in brackets) on POS REF page 2/4.
POS REF page 2/4 displays the Required Navigation Performance and Actual Navigation Performance (RNP/ACTUAL). What EICAS caution displays if ACTUAL exceeds RNP?
NAV UNABLE RNP
a. Which CDU page displays the calculated positions of all three FMCs?b. What other functions does this page enable crews to do?
a. POS REF page 3/4.b. Enable or inhibit position updating modes used by the FMC.
a. What information is displayed on POS REF page 4/4? b. What capability does this page provide for the crew?
a. Displays the present position of individual navigation sensors in bearing/distance format from the Master FMC position.b. To remove specific sensors from the FMC navigation solution.
What change is there to the colour of the RTE page title when the route is activated and executed?
It changes from cyan to white.
What is the purpose of the RTE copy facility on the ROUTE page?
It copies the entire active route (RTE 1 say) into the inactive route (RTE 2).
Which CDU function key must be pressed to display the available SID’s?
DEP ARR – displays page to input or change departure and arrival procedures.
When checking the NAV RAD page on pre-flight, what action would you take (if any) if you saw a white ‘M’ between a VOR frequency and ident?
Press the DELETE key on the MFK, and line select to line 1L or R as appropriate (releases the VOR for automatic tuning).
What is the Cost Index (CI) used for?
It is used by the FMC to calculate the ECON CLB, CRZ and DES speeds.
a. Would a low CI result in a low or high ECON speed? b. What does a CI of zero produce as a speed?
a. A low ECON speed.b. Maximum Range Speed
What happens if an assumed temperature (SEL) is entered on the THRUST LIM page after the take-off speeds have already been accepted?
The takeoff speeds are deleted and the CDU help window message TAKEOFF SPEEDS DELETED is displayed.
What entry is required on the TAKEOFF REF page 1/2 before the FMC calculated stabiliser trim setting appears?
Centre of Gravity (CG) within valid range.
a. What information is entered in the RWY/POS line on the TAKEOFF REF page 1/2?b. Can the crew manually enter data onto this line if required?c. When is the RWY/POS update inhibited?
a. The selected take off runway, and TO/GA push distance from the runway threshold or runway intersection identification.b. Yes.c. When GPS is primary FMC navigation source
a. What appears on the TAKEOFF REF page 1/2 when the preflight entries are complete?b. Does it appear on any other CDU pages?
a. The line 6 header displays FMC PREFLIGHT COMPLETE in white letters on a green background.b. Yes, the PERF INIT and THRUST LIM pages.
a. During a VNAV climb, the profile is such that an altitude constraint will not be achieved; what CDU help message appears?b. Which CDU page displays the predicted error?c. How do you access this page?
a. UNABLE NEXT ALTITUDEb. The CLB page, ERROR at waypoint line. c. Selecting the VNAV function key.
Which CDU page, and line would you select to comply with an ATC request to maintain 240kts up to 8000 feet?
CLB page, SPD RESTR line.
On the CLB page, what is the significance of the parameters coloured magenta?
They are the current FMC commanded parameters.
If ATC stated that speed was unrestricted below 10,000ft, how would you climb at ECON speed?
Press DEL key (DELETE in scratchpad), line select DELETE into SPD TRANS line and execute.
During a VNAV climb, if the title of the CLB page is ‘ACT MCP SPD CLB’, how is speed being controlled?
From the AFDS Mode Control Panel (MCP) – by speed intervention.