FLIGHT MANAGEMENT - NAVIGATION

Question 1

1. 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?

Answer 1

1. The second FMC replaces the active FMC if system faults occur.

Question 2

2. The FMC determines present position from ADIRU, GPS, and navigation radios. What is the priority of navigation sources?

Answer 2

2. GPS-updated, navigation radios (when enabled), ADIRU (inertial)

Question 3

3. What will cause the FMC to automatically provide inputs to reference all flight displays in true north and how is the change annunciated?

Answer 3

3. The FMC begins polar operations when computed aircraft position enters a polar region. Auto switching to a true north reference is annunciated by a flashing white box around the work TRU on the Navigation Display (ND)

Question 4

4. 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 _____.

Answer 4

4. V2 + 15,
   V2 + 25
   400 feet AFE

Question 5

5. FMC Datalink communication system provides two-way communication between the FMC and airline operations. What information can be transferred?

Answer 5

5. Data can be uplinked from the airline system directly to the PERF INIT, TAKEOFF REF, DESCENT FORECAST, RTE, ALTN, and WIND pages.

Question 6

6. Independent left and right GPS receivers provide airplane position to the FMC. What indicates to the pilot that GPS is providing position data?

Answer 6

6. The symbol GPS is displayed as the FMC position update status on the Navigation Display (ND)

Question 7

7. The ADIRU ON BAT on the overhead panel indicates what?

Answer 7

7. Internal power-up requires battery bus power. If electrical power is removed 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.

Question 8

8. 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?

Answer 8

8. The FMC displays the scratchpad message INERTIAL/ORIGIN DISAGREE and then the message ENTER INERTIAL POSITION is displayed.
   The scratchpad message ALIGNMENT REINITIATED is displayed and the system begins a new alignment cycle. (Ref. 3-1.30.8)

Question 9

9. 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?

Answer 9

9. The ADIRU enters the realignment mode and refines the alignment until the aircraft moves again.

Question 10

10. When can the ADIRU position be updated manually?

Answer 10

10. In the automatic realignment mode a new latitude/longitude position can be entered on the CDU POS INIT page.

Question 11

11. The EICAS caution message NAV ADIRU INERTIAL displays when the ADIRU fails indicating SAARU is providing backup information. How long can the SAARU provide heading information?

Answer 11

11. The SAARU supplies 3 minutes of backup heading based on ADIRU heading before failure.

Question 12

12. From what sources do the ADIRU and SAARU receive air data and when are the sources considered valid?

Answer 12

12. 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.

Question 13

13. Three ILS receivers are installed. How can they be tuned?

Answer 13

13. Normally tuned automatically by the FMC but can be manually tuned

Question 14

14. What is required for FMC auto-tuning of the ILS receivers?

Answer 14

14. An ILS, or LOC backcourse approach has been selected on the active route and, the aircraft must be less that 50 NM from the top of descendent, less that 150 NM from the landing runway threshold, or in the FMC descent mode.

Question 15

15. Manual tuning of the ILS is possible when not inhibited. What inhibits manual tuning of the ILS?

Answer 15

15.
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.

Question 16

16. When is the ILS frequency automatically re-tuned?

Answer 16

16. The ILS frequency is automatically re-tuned when ILS tuning is enabled and new approach is selected on the CDU.