Aircraft systems - Auto Flight

Question 1

When is VNAV not able to be selected?

Answer 1

In APP mode (captured) either ILS approach or IAN approach

Question 2

When does VNAV activate on takeoff?

Answer 2

400ft

Question 3

What happens in VNAV SPD (pitch) mode?

Answer 3

AFDS commands pitch to hold target SPD

A/THR operates in THR REF, THR, IDLE or HOLD mode as required

Question 4

What happens in VNAV PTH pitch mode?

Answer 4

AFDS commands pitch to maintain target ALT or the VNAV PTH

A/THR maintains SPD (SPD) or IDLE/HOLD/SPD on descent

Question 5

What happens in VNAV ALT pitch mode?

Answer 5

AFDS commands pitch to maintain MCP selected ALT (lower than FMC in CLB) or (higher than FMC in descent)

Question 6

When to select MAP ALT on approach when using VNAV?

Answer 6

At least 100ft below MAP ALT when in VNAV PTH (to prevent a level off)

Question 7

When to select Gear down / F20 and final flap in VNAV / IAN app?

Answer 7

GD + F20 2-4nm before descent profile

Final flap at GP capture or beginning final decent path.

Question 8

How to deactivate VNAV?

Answer 8

Selecting another vertical mode :

TOGA, FLCH, VS, FPA, ALT HOLD, GS or IAN app mode engaged