Flight Management, Navigation

Question 1

Explain the function of the FMC source select switch

Answer 1

BOTH ON L or BOTH ON R:
- selects left or right FMC for all FMC operations

NORMAL:
- left FMC controls CDUs and provides input to the auto throttle system
- right FMC operates in synchronization with left FMC
- maps display composite information from both FMCs

Question 2

Explain the function of the VHF NAV transfer switch

Answer 2

BOTH ON 1 or BOTH ON 2:
- transfers VHF navigation source to selected receiver

NORMAL:
- VHF navigation from default receiver. In the event of a receiver failure, this switch must be manually positioned to one of the other positions (no auto function)

Question 3

Explain the function of the IRS transfer switch

Answer 3

BOTH ON L or BOTH ON R:
- switches all attitude and heading to selected IRS

NORMAL:
- attitude and heading information from default IRS. In the event of an IRS failure, this switch must be manually positioned
to one of the other positions (no auto function)

Question 4

Explain the meaning of the amber FMC P/RST alert light on the fwd panel

Answer 4

An alerting message exists for both CDUs

Question 5

Describe the alert associated with failure of a single FMC

Answer 5

• If the right FMC fails, the FMC alert light and the FMC message light will illuminate. The message SINGLE FMC OPERATION
  will be displayed in both scratchpads
• If the left FMC fails, the FMC alert light will illuminate. The MENU page will appear on both CDUs

Question 6

Explain the alert associated when ANP exceeds RNP

Answer 6

If ANP exceeds the displayed RNP value, the UNABLE REQD NAV PERF-RNP message will be displayed on the CDU scratchpad. ANP and RNP annunciations on the MAP display turn amber. When in the approach environment an additional amber UNABLE REQD NAV PERF-RNP will be displayed on the MAP display turn

Question 7

Explain the meaning of the CDU messages DRAG REQUIRED and DES PATH UNACHIEVABLE displayed during a VNAV PATH descent

Answer 7

• The CDU message DRAG REQUIRED is displayed when airspeed is 10 kts or more above FMC target speed
• The CDU message DES PATH UNACHIEVABLE is displayed if the FMC determines that the planned descent profile cannot
  be accomplished

Question 8

Describe how to enter VNAV speed/altitude restrictions into the FMS

Answer 8

• All speed restrictions are considered by the FMC as “at” restrictions, unless modified by the pilot
• When modified by the pilot:
  • “At or above” airspeed restrictions are entered with a suffix letter A (250A/)
  • “At or below” airspeed restrictions are entered with a suffix letter B (200B/)
  • Mandatory airspeed restrictions are entered without any suffix
  • “At or above” altitude restrictions are entered with a suffix letter A (220A)
  • “At or below” altitude restrictions are entered with a suffix letter B (240B)
  • Mandatory airspeed restrictions are entered without any suffix

Altitude restrictions that are between two altitudes re displayed with the lower limit first, followed by a suffix letter A, then the upper limit, followed by a suffix letter B

Question 9

Explain the meaning of a flashing ALIGN light on the IRS mode selector unit (ISDU)

Answer 9

• No present position entry
• Unressonable present position

Question 10

Explain the meaning of an illuminated GPS light on the IRS mode selector unit (ISDU)

Answer 10

• Indicates failure of both GPS units
• Indicates failure of a single GPS unit when Master Caution recall is initiated

Question 11

Describe the commanded acceleration after takeoff when VNAV is engaged

Answer 11

• Last MCP speed (V2) + 20 kts until acceleration height
• If an engine failure is detected, target speed will be last MCP speed (V2) + 20 kts if the airplane is at that speed or greater,
  or the existing speed if the airplane is between V2 and V2+20
• The flap placard speed minus 5 kts
• 230 kts or less when LE flaps are not fully retracted
• 250 kts with flaps retracted
• The active target speed
• Waypoint speed constraints, or the speed restriction associated with the origin airport, whichever is more restrictive