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FMC Question

Pro Member Trainee
lowensteinbs Trainee

Greetings all,

When you program the FMC, take off and turn on the autopilot using LNAV and VNAV, do you still need to change the altitude on the autopilot panel?
I have noticed as well that the flight level keeps changing in the FMC, so do you need to keep current with the FMC on the autopilot panel?

Any help with this matter will be highly appreciated.

Thanks in advance.

10 Responses

Pro Member First Officer
Mohit (Mc_GaNgStA) First Officer

Well, the FMC usually provides a guildeline on where you are to be. If you're using an FMC and ATC says climb and maintain FL290, then when you increase the MCP Altitude, the FMC asks confirmation and then you have to click on the EXE button to continue flying higher. It's a bit hard to explain this. Someone will give you a better description on what to do.

Pro Member First Officer
ARD-DC First Officer

lowensteinbs wrote:

Greetings all,

When you program the FMC, take off and turn on the autopilot using LNAV and VNAV, do you still need to change the altitude on the autopilot panel?
I have noticed as well that the flight level keeps changing in the FMC, so do you need to keep current with the FMC on the autopilot panel?

Any help with this matter will be highly appreciated.

Thanks in advance.

Which plane are you flying if I may ask?
I've been flying the LDS763 recently and if I am not mistaken, VNAV is limited to your alt. settings on the MCP.

VNAV won't be able to descend from cruise, for example, unless you change the altitude to your new desired flightlevel.

Pro Member First Officer
pilatflyr First Officer

it can, as it is labeled to descend as well, but I use FL Change and the alt hold to guide me backdown.

..that plane is just awesome

Pro Member First Officer
ARD-DC First Officer

It absolutely is! It's a dream to fly.

But - re. what you said about descends; looking at the manual it says:

In order for the aircraft tot begin an automated descend upon reaching the T/D, the MCP ALT must be set to a lower altitude. If the aircraft reaches T/D and the MCP ALT has not been reset, the AFDS enters ALT HOLD mode

..... Read

Back to the original post...(again if I am not mistaken 😉 -correct me if I am) the changes you need to make on the MCP ALT selector are at least:

Before Takeoff: set cruiselevel
- other altitude restrictions can be entered on the LEGS page of the FMC and VNAV will maintain those until passing the waypoint
Before TOD: set MCP ALT to MDA
- again any other altitude restrictions or holds can be entered in the LEGS page, and obviously you'll need to remain in VNAV mode until APP can be engaged.

Pro Member First Officer
pilatflyr First Officer

that's true.

VNAV can be used. for example, flying into LAX, i usually arrive on the SADDE6 transition to pickup the approach. I'll engage ALT hold, which is usually at 2,000 feet. That way the plane can't dip too low. Even though you might be following the purple line into the runway, you must be within range of the localiser before you can enable the APP hold. The localiser range is marked by those white dashed lines on the main display. Once you're at that point, hit LOC. that will keep the aircraft on the glideslope. then once you know it's working steady, enable the APP hold and all three autopilots and the plane will do the rest

Pro Member First Officer
to_coolguys First Officer

lowensteinbs wrote:

Greetings all,

When you program the FMC, take off and turn on the autopilot using LNAV and VNAV, do you still need to change the altitude on the autopilot panel?
I have noticed as well that the flight level keeps changing in the FMC, so do you need to keep current with the FMC on the autopilot panel?

Any help with this matter will be highly appreciated.

Thanks in advance.

1) Yes you need to set the altitude..This can be the cruise altitude , altitude mentioned in your SID/DP or the one assigned by ATC..

2) The flight level keeps changing because FMC calculates your FL's based on your current FL and your cruise altitude...Hence it would just show that with your current FL,your intended cruise altitude,etc what would your FL's be at those waypoints/fixes/etc etc...

Pro Member Trainee
lowensteinbs Trainee

Thanks for all the help everyone. I am flying the PMDG 737-700 and just getting used to it. It's an awesome plane to fly and makes the default FS planes look bad!!!

I have not flown a flight from point A to point B using the FMC yet, as I am still getting used to it.

While on the subject of going from point A to point B, is there a site that I can look at that will show me the jetways so that I can plot a "real life" route from one place to another?

Thanks again for all the help with the FMC. It makes a lot of sense and I look forward to trying it out.

Pro Member First Officer
pilatflyr First Officer

airnav.com i think might have some charts

Pro Member First Officer
ARD-DC First Officer

lowensteinbs wrote:

Thanks for all the help everyone. I am flying the PMDG 737-700 and just getting used to it. It's an awesome plane to fly and makes the default FS planes look bad!!!

I have not flown a flight from point A to point B using the FMC yet, as I am still getting used to it.

While on the subject of going from point A to point B, is there a site that I can look at that will show me the jetways so that I can plot a "real life" route from one place to another?

Thanks again for all the help with the FMC. It makes a lot of sense and I look forward to trying it out.

an easy one:
http://rfinder.asalink.net/free/

enter departure and arrival ICAO, choose low or high altitude and enter desired FL, leave SID/STAR checked (otherwise you may get first/last waypoints that do not connect to a SID/STAR) and it gives you the route in format FIX-AIRWAY-FIX at the bottom of the page which you can use for FMC naviation.

EHAM SID LEKKO UB31 WOODY UN872 KOVIN UY317 RESMI UN857 DIRMO UZ365 NARAK UN859 LOMRA UN727 ROCAN UN859 PUMAL STAR LEBL

http://www.navdata.at/ (amongst others)
contains a lot of links to published AIP's.

Pro Member First Officer
pilatflyr First Officer

do also note that if yu don't enter one, you'll have to make a transition to pick up the approach

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