Navigation Flashcards
(16 cards)
What systems are used for navigation on the A320?
ADIRS, FMGC, GPS, radio navaids (VOR/DME/ILS), and standby instruments
How many FMGCs are there and how do they work?
Two — operate independently but usually synchronized; cross-talk enabled
What happens if one FMGC fails?
The other can manage both sides; can use the MCDU selector to display data on either side
How many MCDUs are there?
Three — CAPT, FO, and a third for maintenance or backup use
What does a GPS PRIMARY LOST message mean?
GPS is not available — FMGC reverts to DME/DME or IRS position
What does GPS PRIMARY provide?
Accurate position for FM navigation and RAIM monitoring
What does NAV ACCUR HIGH or LOW mean on ECAM?
Assessment of nav accuracy: HIGH means GPS or good DME/DME; LOW means degraded accuracy (IRS-only, etc.)
Can you shoot a GPS approach if GPS PRIMARY LOST?
No — RAIM and GPS PRIMARY required for RNAV(GNSS) approaches
How many VOR receivers are on the aircraft?
Two
How many ILS receivers are on the aircraft?
Two (LOC and GS each side)
What happens when VOR1 or VOR2 fails?
It is flagged and removed from ND display; backup selection available via RMP
How do you tune NAV radios?
Auto-tuned by FMGC or manually via RMPs if needed
When is manual tuning of NAV radios recommended?
During ILS approaches, especially in NAV RAW DATA review or if GPS PRIMARY is lost
What is the function of the RADIO NAV page in the MCDU?
Displays autotuned frequencies and allows manual input
What is the purpose of the DME HOLD function?
Allows holding a DME frequency while autotuning another VOR/ILS
Can the aircraft fly with a failed GPS?
Yes — using IRS/DME navigation and raw data; but limitations apply to RNAV procedures
