Flight Mangagment and Navigation Flashcards
What information do the IRSs provide?
position, ground speed, and attitude data.
Are they dependent on, or independent of, external navigation aids?
independent.
How is the GPS activated and what does it provide data for?
Auto activation. Independent geographical position to the FMC and time data to clocks.
With the FMC SOURCE select switch in NORMAL, which FMC is primary and what does it control?
Left, controls CDUs and auto throttle.
Describe the criteria for airports included in the nav database
One runway > 5000 ft long, 100 ft wide
When using the Auto throttle system, how are reference thrust limits calculated, how is thrust equalization
maintained?
By the FMC commands. FMC commands thrust equalization through the electronic engine controls
Where do the FMC’s receive their inertial data from?
FMCs receive inertial data from their on-side ADIRU
What does the FMC use to determine position?
GPS or inertial reference data or navigation radio position
If GPS data is not available, how does the FMC calculate present position?
IRS
FMC position updates from navigation sensor positions are used in what priority order?
GPS, DME x2, VOR DME, LOC DME, LOC
How does the FMC calculate a descent path during a VNAV PTH descent?
From BOD backwards, using Alt and Spd constraints, winds and A/Ice use
How can you further reduce a derated takeoff?
The N1 LIMIT page is used for assumed temp takeoff. Fixed takeoff and climb thrust derates may be
selected
What is the lateral navigation intercept criteria?
Anytime <3nm from FMC lateral course. >3nm must be <90 degree intercept, Intercept before valid
waypoint
When does IRS position and ground speed information become available and up to how long could it take?
In Nav mode, between 5-17 mins to align
What does an ALIGN light (white) on the IRS panel indicate?
IRS is in Alignment phase
What does a flashing ALIGN light (white) on the IRS panel during preflight indicate?
Bad or No position, Fault
If IRS AC power has failed, how long can the right IRS operate?
5 mins
If a system fault affecting the related IRS ATT and/or NAV modes has been detected, what indication will you
get?
Fault light
On the Boeing 737-NG, how many GPS receivers are installed?
2
What will happen if both ON DC lights (amber) lights illuminate?
. Both switch to backup DC power from the Switched Hot Battery Bus, IRS 1 powered for 60 mins, IRS 2
powered 5 minutes
What could cause the call horn in the nose wheel well to sound while the aircraft is on the ground?
IRS is on battery power
If position information while programming the FMC CDU on the ground is contradictory, what indication, if any,
will alert the crew to this?
Flashing White Align Light
