Flight Management, Navigation

Question 1

Explain the function of each position of the IRS MSU(mode selector unit)
OFF
ALN
NAV
ATT
What's prohibited

Answer 1

OFF - turns off after 3 sec delay
ALN - powers up IRU and performs BITE check. During which ON BAT shows for 15 sec. After BITE check. IRU enters align sub mode until switched to NAV. Full alignment takes 2.5 to 10 minutes
NAV - norm position. If selected prior to alignment sequence the IRU will do the seq automatically. When completed the ALIGN lights will extinguished. EFIS altitude and HDG data will be displayed
ATT - selects back up attitude mode. Can be selected in flight when partial IRU failure (indicated by fault on MSU) when either IRS is in att mode autoland inhibited. Heading updates are required for the failed system

Question 2

Explain the meaning of each advisory light on the IRS control panel
ALIGN
ON BAT
BAT FAIL
FAULT

Answer 2

ALIGN - (white) IRU in align mode. Flashes if position data not entered after align complete or incorrect data entry
ON BAT - (Amber) IRU is operating from back up battery
BAT FAIL - (Amber) bat voltage less than required
FAULT - IRU has detected problem in it align mode and navigation modes

Question 3

Explain what the altitude range arc (green arc) indicates during a climb or decent

Answer 3

When intersected with the track line, predicts the point where the reference altitude will be reached at current vertical rate

Question 4

Recall how the active waypoint is displayed on the ND in the MAP/PLAN mode and on the MCDU

Answer 4

The active waypoint is the first waypoint displayed on the legs page. The active waypoint is magenta on the map display.

Question 5

Recall how to accomplish a downmode alignment(quick alignment).

Answer 5

Selecting ALN from NAV provides a 30 sec. downmode alignment(quick align) which zeros all computed velocity errors and updates heading accuracy.