Flight Managment, Navigation Flashcards
How many GPS receivers are installed?
Two
Left and Right.
2 GPS sensors in the MMR (multi mode receivers) get satellite signals, left and right. The GPS’s are independent and each provide accurate raw GPS position to FMC, ADIRU and other systems
Raw GPS is the GPS nav and timing data sent to onboard GPS sensors without any mixing or filtering from other systems
Are IRS outputs independent of external navigation aids?
Yes, IRS outputs are independent of external navigation aids.
What is indicated by an ALIGN (white) light (steady) on the IRS panel?
When operating in either the:
*ALIGN mode
*Initial ATT mode, or
*Shutdown cycle.
What is indicated by a flashing ALIGN (white) light on the IRS panel?
Alight can not be completed due to:
*Significant difference
between previous and
entered positions
or
*an unreasonable present
position entry,
or
*no present position entry
“No position
Wrong position
Incorrect entry”
What does an illuminated FAULT (amber) light on the IRS panel indicate?
A system fault affecting the related IRS ATT and/or NAV modes has been detected.
What does the illumination of an ON DC (amber) light on the IRS panel indicate?
The related IRS is operating on DC power from the switched hot battery bus (AC power not normal).
*If this occurs while the aircraft is on the ground, the call horn in the nose wheel sounds, providing an alert that a battery drain condition exists.
How long can the right IRS operate without AC electrical power?
Backup DC power to the right IRS is automatically terminated if AC power is not restored within 5 minutes
How long does a full IRS alignment take?
5-17 minutes
depending on aircraft latitude
What is Automatic Navigation Realignment (ANR) and when does it activate?
When a fast realignment is initiated or the aircraft parks after a flight and remains motionless for at least 7.5 to 15 minutes with the ADIRU’s still in NAV mode and valid GPS data available, the ANR mode will perform a complete realignment automatically.
What does illumination of the ILS (amber) light on the IRS panel indicate?
*Indicates a failure of both ILS sensor units.
*Ill’ of the ILS (amber) light during a Master Caution Recall indicates a single ILS sensor has failed.
Do the FMC’s operate independently?
Yes
The (FMS) is comprised of the following components:
*Flight Management Computer System (FMCS)
*Autopilot/Flight Director
System (AFDS)
*Autothrottle (A/T)
*Inertial Reference
Systems (IRS)
*Global Positioning
System (GPS)
Each of these components is an independent system, and each can be used independently or
in various combinations.
Where do the FMC’s receive their inertial data from?
Usually, the FMC’s receive inertial data from their on-side ADIRU
(Air Data Inertial
Reference Unit).
If the on-side ADIRU malfunctions or it is in the ATT or ALIGN mode, the FMC uses the data from the other ADIRU.
More Info*
The Air Data Inertial Reference Unit (ADIRU) combines the Air Data Reference System (ADR)
and the Inertial Reference System (IRS) into a single unit.
How is FMC position data calculated with the loss of GPS inputs?
FMC uses the IRS position as a reference. When the IRS is the only position reference, the FMC applies an automatic correction to the IRS position to determine the most probable FMC position.
How is takeoff thrust reduced from maximum takeoff thrust?
Takeoff thrust less than full rated thrust may be achieved by using an assumed temp that is higher than the actual temp
Where does the FMC receive fuel quantity information from?
From the Fuel Quantity Indicating System (FQIS) and from the engine or from manual entries into the MCDU.
The fuel quantity source is selected on PROG 5/5 page. Selections include TOTALIZER (default) and CALCULATED.
What criteria must be met for LNAV engagement?
*LNAV engages when
laterally within 3 nm of
the active route leg.
* If outside of 3 nm, LNAV
engages if on an intercept
heading of 90 degrees or
less and the intercept will
occur before the active
waypoint.
