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  1. How much time is required for an IRS alignment?
    Aproximately 10 minutes at mid-latitudes.
  2. When the IRS Mode Selector is placed from OFF to NAV position, what does the momentary illumination of the ON DC light indicate?
    The IRS alternate power source is available from the switched hot battery bus.
  3. To what extent are the magnetic variation limits stored in each IRS memory?
    73 degrees north, 60 degrees south
  4. What is the origin of the present position latitude and longitude used in IRS alignment?
    Latitude and longitude are selected from the database and entered by the crew.
  5. What is reequired for an IRS to automatically enter the NAV mode?
    A present position entry.

    A successful performance test.

    A successful reasonableness test.
  6. What information is provided by the IRS in addition to present position, heading and attitude signals?
    Ground speed, ground track & wind data.
  7. Which IRS entries are subjected to the reasonableness test?
    Latitude & Longitude
  8. If, at the beginning of IRS alignment, the present position entry in the IRS fails the reasonableness test and the same position is re-entered, what indication does the the crew see?
    The ALIGN light returns to steady ON.
  9. What condition may cause a reasonableness test failure when proper entry of present position has been accomplished?
    Aircraft has been moved to a different location with the IRS OFF.
  10. Which IRS entry or entries are cross-checked by the system performance test?
    Latitude only
  11. What causes IRS alignment to be lost inflight?
    Moving the selector switch to ALIGN.
  12. After entering the present position during alignment, what would indicate a reasonableness test failure?
    The ALIGN light flashes.
  13. What information is lost and cannot be restored when inflight alignment of an IRS is lost?
    Present position
  14. What are the normal electrical power sources for the IRS?
    The Standby AC bus for the left IRS & the No.2 Transfer bus for the right IRS.
  15. What is the IRS backup source of electrical power?
    Left IRS by the switched hot battery bus.

    Right IRS by the switched hot battery bus for 5 mins.
  16. What is indicated when two consecutive identical latitudes are entered into the IRS and they both fail system performance test?
    Steady ALIGN light extinguishes & FAULT light comes on.
  17. Which statement is correct concerning right IRS operation whil operating on aircraft battery power only.
    The right IRS will operate for 5 minutes on the aircraft battery.
  18. TRUE or FALSE

    The crew can never update the IRS position inflight.
  19. What does an illuminated IRS DC FAIL light indicate?
    The IRS backup power source is not available.
  20. TRUE or FALSE

    During the IRS initialization, if the reasonableness test fails, the ALIGN annunciator flashes. If the same wrong data is reentered a second time the ALIGN anunciator will continue to flash.
  21. TRUE or FALSE

    The pilot can update the current IRS latitude and longitude any number of times without delaying alignment as long as the IRS has not enered the NAV mode.
  22. TRUE or FALSE

    The IRS are the sole source of Attitude and Heading except for the Standby Compass and Standby Attitude Indicator.
  23. What does the IRS performance test check?
    The latitude entered by the pilot.
  24. Describe the IRS:
    If the IRS Alignment is lost in-flight, only Attitude and Manually entered Heading information is available.

    Only the Captain's (left) IRS will operate from the battery for more than 5 minutes.

    The present position entered during preflight must pass both a Reasonableness and System Performance Test prior to the IRS entering the NAV mode.
  25. During normal IRS Allignment, the momentary illumination of the "ON DC" annunciator indicates______.
    The "ON DC" annunciator illuminated to indicate that the IRS is capable of operating from its backup DC power source.
  26. What is the power source for the right IRS when AC Transer bus #2 is lost?
    Switched Hot Battery bus for a maximum of 5 minutes.
  27. Which of the following will cause a flashing ALIGN light on the IRS Mode Panel during alignment?
    No present position entry.

    Failure of the Reasonableness or System Performance Test.

    Aircraft movement during alignment.
  28. TRUE or FALSE

    During IRS alignment, NAV Database out of Date will cause a flasing ALIGN light.
  29. During normal IRS Alignment, the momentary illumination of the "ON DC" annunciator indicates______.
    A successful self test to indicate that the IRS backup DC power source is available.
  30. Which bus normally powers the left IRS?
    AC Standby bus
  31. When IRS alignment is lost inflight, all______features are lost for the remainder of the flight.
    Track and groundspeed
  32. During takeoff with flight director in the TOGA mode below 400 ft., roll commands are for:
    Maintaining aircraft wings level.
  33. What does an illuminated F/D master light indicate?
    Indicates which FCC provides logic to F/D & A/P modes.
  34. What ensures that both the CAPT and FO will have the same F/D VOR/LOC command guidance when the CAPT master F/D light is on?
    The same VHF frequency & course selection must be set on the CAPT and FO radios.
  35. How is the master F/D determined with no A/P engaged?
    The first F/D turned on.
  36. Both master lights on the Mode Control Panel are illuminated at the same time when:
    The GA mode is engaged below 400 ft.
  37. How is the F/D TO mode engaged?
    Place both F/D switches to ON & press either TO/GA switch.
  38. What are the F/D pitch commands during the takeoff roll?
    10 degrees nose down until 60 kts, then 15 degrees nose up.
  39. TRUE or FALSE

    When the FO is flying and ILS approach using the "A" autopilot, the APP mode will follow signals from the #2 NAV radio.
  40. When is the F/D Go-Around Mode armed?
    Below 2000 ft. AGL
  41. During a dual autopilot approach (A/P GA mode) which are the FMA and MCP indications when the GA mode is engaged?
    TO/GA is annunciated, IAS/MACH display blanks
  42. What is the initial F/D GA pitch command during a 2 engine missed approach?
    15 degrees nose up
  43. What A/T thrust is generated during a F/D GA when the TOGA button is depressed once?
    A/T engages in GA and advances thrust toward the reduced go-around N1 to produce a 1000-2000 fpm rate of climb.
  44. How can the F/D APP mode be disengaged after the localizer and glideslope have been captured?
    Press the TOGA switch

    Retune the VHF NAV sets

    Disengage the autopilot(s) and place both F/D switches to OFF.
  45. What causes the F/D command bars to bias out of view?
    Automatically at 50 ft. RA on an ILS approach.
Card Set
B737 navigation systems
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