Navigation and Surveillance Flashcards
Describe the DUAL operating mode of the Flight Management Guidance Computers (FMGCs).
❇️Dual:
▪ Normal mode of operation
▪ Both FMGCs are synchronized, meaning data entered into one Multi-Function Control and Display Unit (MDCU) is also transferred to the other FMGC (crosstalk).
Describe the SINGLE operating mode of the Flight Management Guidance Computers (FMGCs).
❇️Single:
▪ FMGC operating mode when it is the sole operating FMGC. The other FMGC has failed.
▪ Provides all related functions, with some limitations.
▪ Indications of a failed FMGC include:
• 1FD1 or 2FD2 in Column 5 of the FMAs, indicating that the flight directors are using the same FMGC as a source of guidance.
• OPP FMGC IN PROCESS message in MCDU scratchpad.
• MAP NOT AVAIL or SET OFFSIDE RNG/MODE messages on the failed side’s ND, depending on EFIS control panel settings.
Describe the Independent operating mode of the Flight Management Guidance Computers (FMGCs).
❇️Independent:
▪ Mode of operation is caused by a significant difference between the two FMGCs (Database validity).
▪ There is no synchronization of data between the FMGCs.
▪ Each FMGC is controlled by its respective MCDU.
▪ Indications include the INDEPENDENT OPERATION message in the scratchpad of both MCDUs and an illuminated amber IND light on the top of the MCDU cases.
What does the FMGCs navigation auto-tuning feature do?
▪ Provides localizer guidance during takeoff roll for runways served by an ILS.
▪ Automatically tunes VOR and DME stations enroute for position and orientation updating.
▪ Automatically tunes the ILS frequency for final approach guidance, when an ILS approach has been loaded into the flight plan.
What occurs when the STBY NAV key on the RMP is selected?
❇️When selected:
• Activates the STBY NAV (ILS, VOR and ADF) selector keys of the respective RMP.
• De-actives the auto-tuning capability of both FMGCs.
• The MCDU RAD NAV page is unusable.
• A green light illuminates next to the key indicating activation.
• An R appears next to the tuned VOR frequency.
How much time is required for a FAST ADIRS alignment?
▪ A FAST alignment takes 30 seconds to 3 minutes.
What is the function of the radar’s WX MODE selector knob.
❇️WX – Displays precipitation returns: ▪ Black – minimum/no intensity. ▪ Green – low intensity. ▪ Amber – moderate intensity. ▪ Red – higher intensity (saturation)
What is the function of the radar’s WX+T MODE selector knob?
❇️WX+T – Displays both precipitation returns and turbulence:
▪ Magenta represents turbulence.
What is the function of the radar’s TURB MODE selector knob?
❇️TURB – Displays only areas of turbulence in magenta.
NOTE: ND range must be set to 40 miles or less for the display of turbulence.
What is the function of the radar’s MAP MODE selector knob?
❇️MAP – Ground mapping mode:
▪ Black – water or radar shadows.
▪ Green – ground returns.
▪ Amber – man-made structures or high terrain.
What is the function of the radar GAIN selector knob?
▪ Allows for the control of the radar’s energy beam strength:
What is the function of the radar CAL (Calibrated) selector knob?
❇️CAL (Calibrated) – provides a predetermined beam power level.
Note: The CAL position may not always provide the optimum beam power setting for a given weather condition.
What is the function of the radar MIN to MAX selector knob?
❇️MIN to MAX - allows for manual control of the beam’s strength.
▪ MIN - greater beam strength than the CAL level.
▪ MAX - most powerful beam strength.
▪ When in the MIN to MAX range, MAN appears on the NDs.
NOTE: A manual GAIN setting is recommended above FL250.
What is the function of the GND CLTR SPRS switch?
▪ When placed to ON, eliminates the majority of ground clutter targets. ▪ Ground targets are displayed in magenta.
NOTE: The switch is spring-loaded to the OFF position and must be held in the ON position for ground clutter suppression
Recall the meaning of the radar’s Path Attenuation Compensation (PAC) indication.
❇️Radar attenuation has been detected (A yellow alert bar appears at the top of the NDs).
❇️The radar system is advising that additional weather targets beyond what is currently being displayed may be present but cannot be viewed.
▪ In order for a PAC alert:
• GAIN selector knob must be in CAL
• Intervening (currently displayed) weather must be within 80 NM of the aircraft. ❇️Pilot actions would be to increase GAIN selection.
