Flight Management And Navigation Flashcards
During climb out on the RAMBL6 from DAL
departing runway 31L, ATC issues a climb and
maintain 17,000’.
How would you delete the hold down over NNOLN
without using the FMC?
Each selection of ALT INTV deletes the next altitude
restriction if the MCP altitude is beyond the next
altitude restriction.
Note: The use of the ALT INV Switch does not affect
speed restrictions on the FMC LEGS page
You are in VNAV cruise at FL380 100 miles
from TOD and ATC issues a descent clearance to
FL240.
How would you initiate an early descent?
The use of early descent is recommended for VNAV
PATH descents prior to the TOD.
To initiate an early descent, use the following
procedure.
FMC:
1. Set the clearance altitude limit in the MCP.
2. Select the DES page.
3. Select the DES NOW> prompt (LSK 6R).
4. Press the EXEC function key. The MOD DES
page changes to ACT and the descent is initiated.
How would you initiate a cruise descent when
greater than 50 miles from TOD?
ALT INTV (when greater than 50 NM from T/D point
and MCP altitude is at or above an FMC altitude
constraint):
1. Set the clearance altitude limit in the MCP.
- Push ALT INTV. The ACT ECON CRZ page
changes to ACT CRZ DES and the descent is
initiated.
When initiating a cruise descent, the FMC calculates
ECON speed for the new altitude. For example,
ECON cruise Mach at FL 410 = 0.772. ECON cruise
Mach at FL 310 = 0.648. Mach 0.648 is unacceptably
slow at FL 410.
CAUTION: A cruise descent may result in a new
ECON speed that is unacceptably low for the current
altitude. Avoid the use of a cruise descent for large
changes in altitude.
Are there any additional considerations for the
MAX regarding VNAV descents?
VNAV Descent Prediction Anomaly
• FMC performance predictions are periodically
recalculated automatically to better account
for changing environmental conditions. These
performance prediction recalculations may
result in additional computing time. As
a result, an updated prediction could provide
a new path when the aircraft is already in its
descent phase.
• When this occurs, a 600 to 800 ft VNAV path
discrepancy may result. Based on the
prediction outcome, the aircraft can find itself
below or above the idle descent path.
• If below the idle descent path, the FMC
provides guidance to the enhanced Digital
Flight Control System (DFCS) to command a
1,000 fpm descent until VNAV path intercept.
If above the idle descent path, the FMC may
find itself in late descent where the guidance
mode pitch command switches to VNAV
SPD. Flight Deck Crew intervention may
be required to re-establish path tracking.
What does the illumination of a flashing IRS
ALIGN light indicate?
Alignment cannot be completed due to IRS detection
of:
• Significant difference between previous and
entered positions or an unreasonable present
position entry.
• No present position entry.
• Excessive motion of aircraft during the
alignment period. If two consecutive entries of
the same position do not pass the second
internal position test, the FAULT light
will illuminate.
During flight below FL220 you observe a
DSPLY SOURCE message on the primary flight
display. Will the autopilot and/or flight director be
affected?
Yes, below FL220 available autopilot modes and flight director commands will be affected depending on phase of flight and which autopilot is engaged.
When VNAV is engaged when will VNAV
automatically switch from VNAV PTH to VNAV SPD?
When the airspeed exceeds the top of the VNAV
Speed Band
What does the lower limit of the VNAV Speed
Band in the PFD trigger?
Lower limit will trigger autothrottle wakeup
After performing the Immediate Action Steps,
QRC, and QRH for an Airspeed Unreliable, what
resource would you go to that can help determine
your pitch and thrust settings as you continue with the flight?
Refer to the Flight with Unreliable Airspeed table in
the Performance Inflight chapter of the QRH.
What are the costs/benefits of a derated thrust
takeoff and climb?
Reduced thrust takeoffs lower EGT and extend
engine life. They are used whenever performance
limits and noise abatement procedures permit.
Use of derated climb thrust reduces engine
maintenance costs but increases total trip fuel.
What speed does VNAV command at the all
engine acceleration height if the VNAV Climb page is
not manually programmed and speed intervention is not selected?
With VNAV armed for the climb phase, VNAV
commands acceleration to the following:
• Last MCP speed (V2) + 20 kt until acceleration height.
• The flap placard speed minus 5 kt.
• 230 kt or less, when leading-edge flaps are not fully retracted.
• 250 kt with flaps retracted.
• The active target speed.
• Waypoint speed constraints.
• The speed restriction associated with the origin airport, whichever is more restrictive
You are on an arrival and given holding
instructions due to weather at your destination.
How does entering an EFC on the FMC HOLD
page affect arrival fuel?
Entry of the EFC time will help optimize FMC
performance computations. Computation of
destination fuel assumes that departure from the
holding fix will occur at the EFC time
How does the FMC calculate Hold Available
time?
Displays available holding time in hours + minutes
remaining if destination is to be reached with
planned fuel reserves as entered on PERF INIT
page.
