IRS

Question 1

What is the function of the ALIGN position of the IRU Mode Selector?

Answer 1

quick realignment (30 secs in comparison to 10 mins for full) removes sensor errors when selected from NAV mode

Question 2

How do you accomplish a fast alignment of the IRS?

Answer 2

Turn IRS Mode Selectors to Align and enter PPOS on CDU

Question 3

What does the IRS ON Battery (BAT) Light mean when displayed on the Overhead Maintenance Panel?

Answer 3

IRS on backup electrical power (APU hot batt bus)

Question 4

Explain what happens when alignment of the IRS is lost in flight?

Answer 4

• Nav mode inoperative for remainder of flight
• ATT gives attitude information

Question 5

What happens if the center IRU is operating on DC power?

Answer 5

Shuts down after 5 mins