Flight Management - Navigation Flashcards
There are two FMCs with one FMC active and the other inactive. The active FMC accomplishes all flight management computing tasks. What happens if a system fault occurs in the active FMC?
The second FMC replaces the active FMC if system faults occur
The FMC determines present position from ADIRU, GPS, and navigation radios. What is the priority of navigation sources?
GPS-updated, navigation radios (when enabled), ADIRU (inertial)
What will cause the FMC to automatically provide inputs to reference all fight displays in true north and how is the change annunciated?
The FMC begins polar operations when computed aircraft position enters a polar region. Auto switching to a true north reference is annunciation by a flashing white box around the word TRU on the Navigation Display (ND)
When VNAV is armed for takeoff, the FMC updates the VNAV target airspeed to____ or the current airspeed whichever is higher up to____. VNAV engages at ____.
V2+15, V2+25
400 feet AFE
FMC Datalink communication system provides two−way communication between the FMC and airline operations. What information can be transferred?
Data can be uplinked from the airline system directly to the PERF INIT, TAKEOFF REF, DESCENT FORECAST, RTE, ALTN WX, and WIND pages
Independent left and right GPS receivers provide airplane position to the FMC. What indicates to the pilot that GPS is providing position data?
The symbol GPS is displayed as the FMC position update status on the Navigation Display (ND)
The ADIRU ON BAT on the overhead panel indicates what?
Internal power-up requires battery bus power. If electrical power is revoked the ADIRU is powered by the Hot Battery Bus and occurs when the switch is left on and all other power is removed from the aircraft. The horn in the landing gear wheel well sounds to alert personnel of the condition.
When the ADIRU is in the align mode, a new airplane latitude/longitude position must be entered on the CDU POS INIT page. What will result when an entry of a latitude and longitude that is not close to the position of the origin airport? What happens if a position fails the internal check twice?
The FMC displays the scratchpad message INERTIAL/ORIGIN DISAGREE and then the message ENTER INTERTIAL POSITION is displayed.
When the alignment is complete, the ADIRU enters the navigate mode and the airplane can be moved. What occurs when the aircraft is stopped for an extended period of time?
TheADIRU enters the realignment mode and refines the alignment until the aircraft moves again.
When can the ADIRU position be updated manually?
In the automatic realignment mode a new latitude/longitude position can be entered on the CDU POS INIT page.
The EICAS caution message NAV ADIRU INERTIAL displays when the ADIRU fails indicating SAARUisproviding backup information. How long can the SAARU provide heading information?
The SAARU supplies 3 minutes of backup heading based on ADIRU heading before failure.
From what sources do the ADIRU and SAARU receive air data and when are the sources considered valid?
Both the ADIRU and SAARU receive air data from the left, center and right pitot tube and static systems. Data is valid when two or more sources agree
Three ILS receivers are installed. How can they be tuned?
Normally tuned automatically by the FMC but can be manually tuned
What is required for FMC auto−tuning of the ILS receivers?
An ILS, or LOC backcourse approach has been selected on the active route and, the aircraft must be less than 50 NM from the top of descent, less than 150 NM from the landing runway threshold, or in the FMC descent mode.
Manual tuning of the ILS is possible when not inhibited. What inhibits manual tuning of the ILS?
The autopilot is engaged and the localizer or glideslope is captured
Only the flight director is engaged, the localizer or the glideslope is captured, and the aircraft is below 500 feet radio altitude.
On the ground, the localizer is alive, airplane heading is within 45 degrees of the localizer front course, and groundspeed is greater than 40 knots.
