GPS / ADIRS / NAV

Question 1

Why are the wind heading and arrow different?

Answer 1

Wind Heading is displayed in true while the arrow displays in magnetic.

Question 2

What does ADIRU 2 power?

Answer 2

FO PFD, ND and lower ECAM

Question 3

What are the 4 reasons fora IRS IN ALIGN memo?

Answer 3

M inute: 1 minute to alignment countdown but still not aligned

M easure: FROM airport is not current position

M emory: shutdown position different than present by 1 degree lat or long

M otion: when tugged during alignment, will restart alignment process in 10 minutes

Question 4

How many Ring Laser Gyros are on board?

Answer 4

9

1 per axis per IR

Question 5

What are the pilot inputs to the ADIRS?

Answer 5

Baro Reference Selectors

ADIRS Control and Display Unit (CDU)

(MCDUs) Multifunction Control and Display Units

Question 6

What does GPS PRIMARY mean?

Answer 6

GP-IRS position is accurate and used by FMS

Question 7

What are the inputs for ADIRU 2?

Answer 7

FO angle of attack

FO Total air temperature

FO pitot and static systems

Uses 3 ADMs

Question 8

How long does a fast realignment take and how do you accomplish?

Answer 8

30 seconds, Switch all ADIRS knobs to NAV - OFF - NAV

Question 9

What are the inputs for ADIRU 3?

Answer 9

Standby angle of attack

CA Total air temperature

Standby pitot (1) and static (2) systems

Uses 2 ADMs

Question 10

When is the only time the aircraft is navigated by a ground station?

Answer 10

When APPR is pressed for an ILS approach or LOC is pressed for a LOC approach

Question 11

How is GPS data calculated?

Answer 11

Through 2 Multi Mode Receivers (MMRs) which then send data to the ADIRUs. MMR1 =ADIRU1&3 MMR2=ADIRU2

Question 12

What is the MMR hierarchy?

Answer 12

On-side position

ADIRU3 position

Off-side position

Question 13

What are the inputs for ADIRU 1?

Answer 13

CA angle of attack

CA Total air temperature

CA pitot and static systems

Uses 3 ADMs

Question 14

How many accelerometers are on board?

Answer 14

9

1 per axis per IR

Question 15

How is MIX IRS re-calibrated in-flight?

Answer 15

While in flight using MIX IRS position, FMS recalculates position based on DME/DME or VOR/DME and applies the BIAS to the FMS position. The MIX IRS position is never changed only the FMS position.

Question 16

When GPS is lost and FMS is working off MIX IRS, what realignment take place during takeoff.

Answer 16

During takeoff, the FMS knows the location of the runway threshold and corrects the MIX IRS position when TOGO power is applied.

Question 17

When GPS is lost how is position information calculated?

Answer 17

After alignment, the 3 independent IRs calculate present position. The FMS then take the average as the MIX IRS position.

Question 18

What are the portions of the (ADIRUs) Air Data and Inertial Reference Units?

Answer 18

(ADR) Air Data Reference :
-Pitot/Static info

(IR) Inertial Reference:

• Gyro type info (attitude and heading)
• position

Question 19

How does ADIRS calculate present position (PPOS)?

Answer 19

Calculated hybrid position using GPS and IRS positions

IRS position only if GPS fails

Radio Navigation

Internal NAV Database

Question 20

What systems use the ADIRS data?

Answer 20

(EIS) Electronic Instrument System
(FMS)
Engine computers
Flight Control computers
Warning Computers

Question 21

What does ADIRU 1 power?

Answer 21

CA PFD, ND and upper ECAM

Question 22

What does the IR (Inertial Reference) supply data to ?

Answer 22

Airspeed trend

Attitude Indicator and BEta Target (slip/skid)

Instant VSI

Heading

All ND info (except TAS)

G load meter

Question 23

What does the AD (Air Data) supply data to ?

Answer 23

Airspeed

Altitude

Backup VSI (amber boarder around VSI)

TAS

Total Air Temp (TAT) and Saturated Air Temp (SAT)

Question 24

What does ADIRS consist of?

Answer 24

3 separate (ADIRUs) Air Data and Inertial Reference Units