B787 #11 Flight Management, Navigation

Question 1

How long do the IRS’s take to align?

Answer 1

7-10 minutes at mid latitudes and up to 17 minutes at high latitudes.

AOM 11.20.5

Question 2

When will LNAV engage during takeoff?

Answer 2

When armed on takeoff, LNAV engages at or above 50 ft, when laterally within 2.5 nm of the active route leg.

AOM 11.31.14

Question 3

During a GOAROUND when will VNAV and LNAV be available?

Answer 3

VNAV can only be activated when the airplane climbs above 400 ft radio altitude.
If LNAV path is available, LNAV automatically activates:
- above 50 feet radio altitude when autopilot is NOT engaged
- above 200 feet radio altitude when autopilot IS engaged.

AOM 11.31.41

Question 4

Approximately what vertical speed rate will be achieved when the DESCEND NOW prompt is selected on the FMC before reaching the planned descent path?

Answer 4

1250 FPM

AOM 11.42.37