Flight Management, Navigation

Question 1

(756) Recall what information is displayed by the IRS (Inertial Reference System) on the overhead panel.

Answer 1

IRS DISPLAY
 Displays track, groundspeed, present position, wind or
heading as controlled by display selectors or keyboard.

Note: Directions are referenced to true north.

Question 2

(756) Recall the entry required to complete IRS alignment. (2 methods of entry)

Answer 2

 Enter present position using the IRS MODE SEL keypad

 Enter present position in the FMS MCDU “SET IRS POS” boxes on the POS INIT page.

Question 3

(756) Recall the IRU(s) load shed after 5 minutes when the aircraft is operating on standby power.

Answer 3

At least one IRU remains powered on all aircraft.

Question 4

(756) Describe the meaning of both steady and flashing IRS ALIGN lights.

Answer 4

Steady White:

• Align mode
• Initial ATT mode
• Shutdown Cycle

Flashing
   - No position
   - Wrong Position
   - Aircraft moved during 
     alignment

Extinguished
   - IRS is not in align mode
or
   - With the mode selector in 
     NAV alignment complete

Question 5

(756) Recall the time required for IRS alignment:

Answer 5

 Full alignment: 10 minutes

 Fast realignment: 30 seconds

Question 6

(756) Describe the meaning of the IRS DC FAIL light.

Answer 6

 Illuminated (amber) –

-DC backup power for the related IRS has failed.

Question 7

(756) Describe the meaning of the IRS FAULT light.

Answer 7

 Illuminated (amber) – a system fault affecting the related IRS ATT and/or NAV modes has been detected.

Question 8

(756) Know the function of the IRS selector and switch positions.

Answer 8

 IRS Mode selectors
Rotate – controls the mode of the related IRS.
- Must be pulled out to move from the NAV position.

OFF –
- Alignment is lost.
-The ALIGN light illuminates for 30 seconds as the
system goes through a shutdown sequence.
- Realignment requires about 10 minutes while the
airplane is parked. Re-entry of present position
(Latitude and Longitude) is required.

ALIGN –
- Initiates an alignment when the aircraft is parked.
- Initiates a fast realignment if selected when the
system
was in the navigation mode.

NAV –
- Normal operational mode.
- Permits the system to enter the NAV mode after
completing alignment.
- Initiates a 10 minute alignment if selected from OFF.

ATT –
- Provides only attitude and heading information.
- Position and ground speed information is lost until the
system is realigned on the ground.
- When selected airborne, the ALIGN light illuminates
for
30 seconds while the system senses local level which
requires level flight.
- A magnetic heading input is required to initialize
heading output.
- The selector must be cycled through OFF to re-enter
the ALIGN or NAV mode.