Flight Management, Navigation

Question 1

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

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

Recall the IRU(s) load shed after______________ when the aircraft is operating on standby power.

Answer 3

5 minutes

Note: At least one IRU remains powered on all aircraft.

Question 4

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

Answer 4

ALIGN lights:
• Illuminated (white) –

• Steady – The related IRS is operating in the:
  ALIGN mode or
  The initial ATT mode or
  The shutdown cycle
• Flashing – Alignment cannot be completed due to IRS detection of:
  A significant difference between the previous position and last entered position or
  An unreasonable present position entry or
  No present position entry or
  Aircraft movement was detected during the alignment process.

• Extinguished –
The IRS is not in the ALIGN mode
or
With the mode selector in NAV, all IRS information is available and the alignment is complete,

Question 5

Recall the time required for IRS alignment:

Answer 5

• Full alignment: 10 minutes

* Fast realignment: 30 seconds

Question 6

Describe the meaning of the IRS DC FAIL light.

Answer 6

DC FAIL lights
• Illuminated (amber) –
-DC backup power for the related IRS has failed.

Question 7

Describe the meaning of the IRS FAULT light.

Answer 7

FAULT lights

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

Question 8

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.

Question 9

Recall the _____________ lights should be allowed to extinguish prior to either accomplishing a full alignment or selecting the battery switch to OFF.

Answer 9

IRS ALIGN