Flashcards in Navigation Deck (13)
How is the primary position provided to the FMC?
Hybrid GPS Inertial position by the IRS.
What is the indication of invalid voted data from the ADRS?
- EICAS “NAV AIR DATA SYS”
- Backup airspeed and altitude is displayed (AOA SPD & GPS ALT)
What is the indication of invalid voted and backup data from the ADRS?
ISFD altitude and airspeed is displayed.
How is the IRS powered?
Primary power by the respective instrument bus, secondary by the hot battery bus.
How is a failure of both IRU's indicated?
EICAS "NAV IRU"
How is a position provided in the event of failure of both IRU's?
Hybrid GPS inertial position from the AHRU's.
What is the significance of EICAS "NAV INERTIAL SYS"?
Failure of IRS (IRU's & AHRU's).
How is a position and attitude information provided in the event of IRS failure?
GPS position sent directly to FMC, ISFD attitude information to PFD. (SGL SOURCE ATTITUDE)
What is the significance of EICAS "NAV AIR DATA SYS"?
Loss of voted ADRS data to displays. Backup data provided by AOA SPD and GPS ALT.
ISFD data my be unreliable.
What is the significance of EICAS "NAV AIRSPEED DATA"?
Loss of voted airspeed data to displays. Backup data provided by AOA SPD. ISFD airspeed data may be unreliable.
When is the ILS autotuned?
- Appropriate approach selected to the active route.
- Within 50nm from TOD, 150nm of landing RWY, or FMC in descent mode.
When is ILS tuning inhibited?
- A/P engaged or F/D on and LOC or G/S captured, or
- HUD Takeoff mode active for 5 seconds on the ground.