NAVIGATION Flashcards
What battery backs up the IRS if the AC POWER fails?
APU BATT
What is the longest the IRS can go without full alignment?
18 hours
Where you can find time to remain for alignment for the IRS?
Top left corner of ND
What degree of error will give you the IRS POS/ORIGIN DISAGREE message on the FMC?
Position >6nm from origin airport
How long does alignment wait after IRS motion stops?
30 sec
What does the IRS do above 84N or 84S?
Goes into SPLIT IRS OPERATION:
Each FMC connects to a different IRU. This could also happen if there are large differences between IRU’s
BAT ON (IRS maint panel)
IRS running on bat power, horn sounds
> IRS AC CENTER, LEFT, RIGHT
IRU AC power has failed
> IRS D.C. LEFT, RIGHT, CENTER
IRS operating on AC power only, no backup
IRS LEFT, RIGHT, CENTER
All power to IRS Is lost, alignment lost and cannot be restored for the flight for navigation , however it can be used for basic attitude info.
If you see IRU (C) on the Capt ND, what does that mean?
FMC auto switched to IRU CENTER. For heading data
The PFD still uses the left IRU so you must switch IRU to left
IRS MOTION
Airplane motion detected during alignment
> SINGLE SOURCE ILS
Both PFD using the same ILS source
Two ILS systems failed
Be careful with monitoring
> TRANSPONDER L,R
Transponder is failed
IRS CENTER, LEFT, RIGHT
IRU fault occurs
> GPS
Both GPS receivers are failed
> GPS LEFT, RIGHT
One GPS receiver has failed
ILS ANTENNA
An ILS receiver does not use the correct antenna
Failed to switch when gear was lowered
> FMC MESSAGE
An alert message in the CDU scratchpad (see QRH)
> FMC RUNWAY DIS
Airplane not on the FMC origin runway when takeoff is attempted
ADS-B FAILURE
One or more of these occurs:
ATC reports ADS-B Out is lost or degraded
> GPS left is shown and left xpndr selected
> GPS RIGHT is shown and right xpndr selected.
FMC LEFT, RIGHT
If a single FMC fails, can you still use the auto throttle?
An FMC is failed
Yes
What does PARK mean on the NAVRAD ILS tuning page?
ILS receivers are untuned
This is displayed til 200 MN from TOD or more than halfway to the destination.
After that it loads the fest ILS freq with Park til it is tuned auto or man
When does auto tune happen for the arrival navaid?
50nm from TOD
150nm from threshold
FMC changes to descent mode
It will show a “a” when auto tuned
When a < it means you can manually tune the frequency “M” appears