Navigation/Display Transfer Switches

Question 1

IRS transfer switch
Both on 1
Normal
Both on 2

Answer 1

• enables selection of the opposite Inertial Reference System (ADIRU) in the event of attitude or compass failures
  BOTH ON L
• switches the gyro source (attitude and heading) to left IRS
  NORMAL
• left flight instruments source is left ADIRU
• right flight instruments source is right ADIRU
  BOTH ON R
• switches the gyro source (attitude and heading) to right ADIRU

Question 2

FMC transfer switch
Both on L
Normal
Both on R

Answer 2

NORMAL
- left FMC controls CDUs and provides input to the autothrottle system
- dual operation is enabled, meaning the right FMC is synchronized with the left FMC
BOTH ON L or R
- operation is identical to single FMC operation
- all functions are controlled by the selected FMC

Question 3

VHF NAV transfer switch
Both on 1
Normal
Both on 2

Answer 3

• changes the source of the data that the DEUs use for the nav displays
• the switch transfers the following data: DME, ILS/GLS, VOR, and MCP course
• enables selection of opposite VHF NAV receiver/MMR in the event of receiver failure

BOTH ON 1
- the DEUs use MMR 1 as the source for the Capt’s and FO’s display

NORMAL
- MMR 1 supplies data for the Capt’s display and MMR 2 supplies data for the FO’s display

BOTH ON 2
- the DEUs use MMR 2 as the source for the Capt and FO’s display

Question 4

DISPLAY SOURCE SELECTOR
AUTO
ALL ON 1 or 2

Answer 4

• controls the Display Electronic Units (DEUs)
• there are 2 DEUs
• the display source selector lets you select the DEU that controls the displays

AUTO (if there are no failures)

• DEU 1 controls Capt outboard, inboard, and upper DUs
• DEU 2 controls FO outboard, inboard, and lower DUs
• when a DEU fails the other DEU supplies data to all 6 DUs

ALL ON 1 or ALL ON 2

• DEU 1 or DEU 2 controls all 6 DUs
• DSPLY SOURCE appears on both PFDs below speed tape / EFIS-MAP - above both altimeters

DSPLY SOURCE message

• indicates a CDS fault
• only one DEU is supplying display information to all 6 DUs

Question 5

a failed DEU can be identified by

4

Answer 5

• both EECs go to ALTN mode (both EEC ALTN lights illuminate)
• the absence of hydraulic pressure indication on failed side
• the speed limit flag visible on failed side
• the minimum maneuver speed and stick shaker band removed from airspeed indicator on failed side

Question 6

DISPLAYS CONTROL PANEL
Both on 1
Normal
Both on 2

Answer 6

• controls EFIS Control Panels

BOTH ON 1
- Captain’s EFIS CP controls Captain’s and FO’s DUs

NORMAL
- left EFIS CP controls Capt DUs and right EFIS CP controls the FO’s DUs

BOTH ON 2
- FO’s EFIS CP controls Captain’s and FO’s DUs