Flight Management

Question 1

IRS ALIGN Light

When the light is steady white and flashing white

Answer 1

Steady- IRS is in ALIGN mode, initial ATT mode, or shutdown cycle

flashing: alignment can’t be completed due to IRS detection of:
- diff between previous and entered position or unreasonable present position entry
- no present position
- movement during alignment

Question 2

IRS FAULT light (amber)

Answer 2

-system fault affecting related IRS ATT and/or NAV modes detected

Question 3

IRS ON DC light (amber)

Answer 3

• related IRS operating on DC power from switched hot battery bus
• if on ground, the ground call horn in nose wheel well sounds (battery drain alert)_
• momentary illumination normal in self-test

Question 4

IRS DC FAIL light (amber)

Answer 4

-DC power for IRS not normal

Question 5

IRS alignement time varies from five to seventeen minutes. Time depends on what?

Answer 5

airplane latitude

Question 6

GPS light (amber)

Answer 6

1. failure of both GPS sensor units
2. indicates failure of single GPS sensor unit on recall
3. with single sensor failure, the light will extinguish when system recall is reset

Question 7

IRS mode selector (OFF)

Answer 7

• OFF:

- alignment is lost and electrical power is removed from the system after a 30 second shutdown

Question 8

IRS mode selector (ALIGN)

Answer 8

• OFF to ALIGN initiates the alignment cycle

- NAV to ALIGN updates alignment and zeroes ground speed error

Question 9

IRS mode selector (NAV)

Answer 9

• system enters NAV mode after complete alignment cycle and entry of present position
• in NAV, all IRS info is available to airplane systems

Question 10

IRS mode selector (ATT)

Answer 10

• provides only heading and attitude info
• attitude info is invalid until ALIGN light extinguished
• heading is invalid until actual magnetic heading is manually entered after ALIGN light goes out
• positions and ground speed info not available until irs is aligned on ground
• selector must go to OFF before reselecting ALIGN or NAV

Question 11

What normally powers the left IRS?

Answer 11

AC standby bus

Question 12

What normally powers the right IRS?

Answer 12

AC transfer bus 2

Question 13

If AC power is not normal, either or both IRS systems will automatically switch to what power source?

Answer 13

DC power from switched hot battery bus.

Question 14

How long will backup DC power supply the right IRS?

Answer 14

5 minutes if AC power is not restored

Question 15

The flight management system is composed of the following components:

Answer 15

1. flight management computer system
2. autopilot/FD system
3. autothrottle
4. IRS
5. GPS

FMS refers to joining these components to provide nav, guidance, performance mgmt

Question 16

How can you perform a fast realignment and zeroing of groundspeed error for the IRS?

Answer 16

select align and update PPOS and then reselect NAV

Question 17

IF the IRS loses alignment mid flight, NAV mode will be inop the rest of the flight. What will selecting ATT do?

Answer 17

allows the attitude mode to be used to relevel the system and provide attitude. it will take 30 seconds of straight and level unaccelerated flight. Can provide heading info if you manually enter mag heading