Questions tagged [vnav]

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7 votes
1 answer

Why did autopilot switch to CWS P on a LNAV/VNAV approach, and why didn't it reduce descent rate to comply with CDU alts when VNAV was re-engaged?

We were performing an NDB approach the other day due to the ILS being unserviceable. We are flying a 737-800, FMC Update 14.0 (“common VNAV”) We were using LNAV and VNAV as our roll and pitch modes ...
tedioustortoise's user avatar
3 votes
1 answer

How do one "force" VNAV climb mode through a set altitude constraint?

Let's say I'm flying out of EGPH, there is a first altitude constraint at 6000ft automatically set by the FMS. After departure, I will engage my VNAV to climb on profile. VNAV will hold at 6000ft no ...
Hinapilot's user avatar
2 votes
2 answers

How to deal with both a speed and an altitude crossing restriction while in VNAV PTH descent (Boeing 737NG)?

Suppose you are in VNAV PTH descent and are approaching the IAF for your Approach, The IAF has both an altitude crossing restriction and a speed restriction. Assume that your VNAV PTH descent is at ...
Stamatis Vellis's user avatar
2 votes
2 answers

What does "transition of glideslope intercept waypoint" mean in the 737 FCOM?

In the Boeing 737NG FCOM, I've read this statement: VNAV mode is terminated by any one of the following: selecting another pitch mode glideslope capture reaching end of LNAV route transition of ...
Arcil Tralleis's user avatar
1 vote
1 answer

Does a VNAV PTH descent need the Forecast Descent winds?

If VNAV PTH, contrary to VNAV SPD, maintains a given path angle, depending on the CI chosen, and not a given Speed, then in my mind winds shouldn't affect it, since they would only cause the Vertical ...
Stamatis Vellis's user avatar
0 votes
2 answers

When do the LNAV and VNAV NPS pointers appear in the PFD of a B737NG?

I am pretty sure the LNAV NPS pointer should appear from after takeoff, if LNAV is armed. But I am not sure about the VNAV NPS pointer. A VNAV climb is based on Speed, not Path, so I assume there is ...
Stamatis Vellis's user avatar
2 votes
2 answers

How does one resume a VNAV climb in a B737 NG after being instructed to level off at an altitude below the Cruise altitude?

I am referring to a Boeing 737NG. Assuming I am on a VNAV climb but I am instructed by ATC to climb only to an altitude lower than my FMC Cruise altitude. After leveling off, how do I resume my VNAV ...
Stamatis Vellis's user avatar
4 votes
1 answer

What is the difference between Level Change and ALT INTV during VNAV descent?

I'm confused between the two. During descent for 737 PMDG, I usually start a descent via ALT INTV, but sometimes the plane doesn't response to ALT INTV but responds to LVL Change instead. I need help ...
Billcoke's user avatar
8 votes
2 answers

What is the benefit of having baro-VNAV in addition to a WAAS GPS?

On Cirrus' 2015 aircraft page, they advertise Baro-VNAV capability in the new model. Having never done an LNAV/VNAV GPS approach (only LNAV or LPV), I'm wondering: when would I actually use it, if I ...
Mike's user avatar
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