AOM VOL 1

Question 1

The Flight Management Guidance System (FMGS) contains the following units:

Answer 1

• Two Flight Management Guidance Computers (FMGC)
• Two Multipurpose Control and Display Units (MCDU)
• One Flight Control Unit (FCU)
• Two Flight Augmentation Computers (FAC)

Question 2

Each FMGC is divided into two main parts.
* The Flight Management (FM) part controls the following functions:

Answer 2

• Navigation and management of navigation radios.
• Management of flight planning.
• Prediction and optimization of performance.
• Display management.

Question 3

Each FMGC is divided into two main parts.
* The Flight Guidance (FG) part performs the following functions:

Answer 3

• Autopilot (AP) command
• Flight director (FD) command
• Autothrust (A/THR) command

Question 4

What do the ADIRS supply?

Answer 4

Each ADIRU is divided in two parts, either of which can work separately in case of failure in the other:
- The ADR part (Air Data Reference) which supplies barometric altitude, airspeed, mach, angle of attack, temperature and overspeed warnings.
- The IR part (Inertial Reference) which supplies attitude, flight path vector, track, heading, accelerations, angular rates, ground speed, and aircraft position.

Question 5

Which sensors feed information to the ADIRS?

Answer 5

Four types of sensors:
- pitot probes (3)
- static pressure probes (STAT) (6)
- angle of attack sensors (AOA) (3)
- total air temperature probes (TAT) (2)

These sensors are electrically heated to prevent from icing up.

Question 6

What is the ATT mode of the ADIRS?

Answer 6

IR mode supplies only attitude and heading information if the system loses its ability to navigate.

The heading must be entered through the MCDU and has to be reset frequently (about every 10 minutes).

During the flight, if the IR mode selector is set from NAV to ATT or NAV to OFF, the NAV mode is lost for the remainder of the flight.

Question 7

In regards to the ADIRS, what does the ON BAT LT signify?

Answer 7

The ON BAT light comes on in amber when the aircraft battery supplies at least one IR. The ON BAT light also comes on for a few seconds at the beginning of a complete IRS alignment. The light does not come on in the case of a fast alignment.

Note: When the aircraft is on ground and if at least one ADIRU is supplied by aircraft batteries: - An external horn sounds
- The ADIRU and AVNCS light comes on amber on the EXTERNAL POWER panel.

Question 8

Briefly describe GPS on the A320.

Answer 8

Worldwide, 24 satellites broadcast accurate navigation data that the aircraft uses for precise determination of its position.

The aircraft has two independent GPS receivers. Depending of the aircraft configuration, each receiver:
- Consists of a GPS Sensor Unit (GPSSU), or
- Is integrated in the Multi Mode Receiver (MMR). The GPS 1 receiver in MMR 1, and the GPS 2 receiver in MMR2.

The GPSSU or the MMR processes the received data, and transfers them to the ADIRUs. Then each ADIRU performs the GP-IRS hybrid position calculation. FMGCs use this hybrid position.

Question 9

How does the A320 handle GPS receiver failures?

Answer 9

• In case of failure of one GPS receiver: All ADIRUs use the operative GPS receiver.
• In case of failure of ADIRUs:
  
  • If the ADIRU 1 fails, ADIRU 3 is supplied by the GPS receiver 1, and ADIRU 2 is supplied by the GPS receiver 2.
  • If the ADIRU 2 fails, the ATT HDG selector has to be set to F/O 3 in order to maintain Side 1 and Side 2 segregation. In this case, the ADIRU 3 will be supplied with GPS receiver 2.
  • If two ADIRUs fail, the remaining ADIRU is supplied by its own side GPS receiver.

Question 10

Compass Limitations

Answer 10

Because of the location of the APU power on contactor in the cockpit, the APU start sequence may disturb the compass reading.

Question 11

ISIS Limitations

Answer 11

When leveling the wings after performing a small turn of a small bank angle, the displayed roll attitude may temporarily be incorrect by a few degrees.

The system must be reset after 350 h of continuous electrical supply using the “ATT RST” pushbutton.

Question 12

How is the ISIS powered?

Answer 12

The ISIS is connected to the DC ESS BUS as well as the HOT BUS 1.

Question 13

What does the ISIS receive information from?

Answer 13

• ILS or MMR 1
• ADIRU 1
• ADIRU 3
• Standby Pitot
• Standby Static

Question 14

How does automatic tuning of navaids work?

Answer 14

In normal operation, the FMGC tunes navaids automatically, with each FMGC controlling
its own receivers.

If one FMGC fails, the remaining one controls both sides receivers.

Question 15

How does backup tuning of navaids work?

Answer 15

If both FMGCs fail, the Flight Crew can use the RMPs (Radio Management Panels 1 and 2) on the pedestal for back up tuning.
- The CAPT RMP controls VOR 1 and ADF 1 (if installed).
- The F/O RMP controls VOR 2 and ADF 2. (if installed)
Either RMP controls both ILSs (provided “STBY NAV” is selected on RMP 1 and RMP 2). RMP 3 (if installed) is not used for navaids tuning.

Question 16

How are the data from the radio altimeters usually displayed?

Answer 16

Normally the CAPT PFD displays the RA1 height and the F/O PFD displays the RA2 height. If either radio altimeter fails, both PFDs display the height from the remaining one.

Question 17

What is the purpose of the DMCs?

Answer 17

Three identical Display Management Computers (DMC) obtain data from the different sensors and computers, and send it to the display units. The display units then generate and display the applicable images. Each DMC has a single DMC channel, and can simultaneously supply one PFD, one ND, and both ECAM display units (E/WD and SD).

Question 18

What is the purpose of the SDACs?

Answer 18

The two identical System Data Acquisition Concentrators (SDAC) acquire data, then generate signals. Some of these signals go to the three DMCs, which use them to generate displays of system pages and engines parameters. Others go to the flight warning computers, which use them to generate ECAM messages and aural aural alerts.

Question 19

What is the purpose of the FWCs?

Answer 19

The two identical FWCs generate alert messages, memos, aural alerts, and synthetic voice messages. For this purpose they acquire data:
* Directly from aircraft sensors or systems to generate red warnings.
* Through the SDACs to generate amber cautions.

The ECAM display units display the alert messages generated by the FWCs. The FWCs also generate. * Radio altitude callouts.
* Decision height callouts.
* Landing distance and landing speed increments

Question 20

How does the ECAM display a primary failure?

Answer 20

As a boxed title.

Question 21

How does the ECAM display a secondary failure?

Answer 21

By placing a star in front of the title of the affected system.

In the case of ELEC EMER CONFIG, the secondary failures are inhibited.

Question 22

After a go-around, if the aircraft does not climb above _____ ft RA, the landing memo appears only below _____ ft RA during the subsequent approach.

Answer 22

2,000 ft RA, 800 ft RA

Question 23

What is the ECON Speed Range?

Answer 23

In descent mode with ECON/AUTO SPD mode active, these two thick lines replace the selected speed symbol. It shows the upper and lower limits, calculated by the FMGC.

• The upper speed is target speed + 20 knots, limited to VMAX or VMO -3 knots or MMO -0.006, whichever is lowest. If a speed limit or a speed constraint applies, the upper margin is limited to ECON SPD + 5 knots.
• The lower speed margin is the target speed -20 knots, limited to green dot, F, S, or VLS, whichever is the highest.