using FMC with ATC?

[Guest monkey]

Okay, heres the deal...I understand how to use the FMC but using it with ATC is confusing to me. For example, T/D point that the FMC has calculated starts before FS2004 ATC clears me for descent. If I stay the cruise alt and wait for ATC the FMC says "screw you I'm not waiting any longer" and I lose VNAV. Do I descend at the FMC T/D point or wait for ATC? The same problem occurs with stepped descents that are different to what the FMC has calculated. Surely this can't be right!?Any ideas?

[Guest Robin.B]

If you insist on flying with the FS ATC, then what I would do is disconnect VNAV and carry on with ALT Hold until the ATC tells you to start descending. From that point you would have to use V/S and ALT Hold controls to get you down.

[michal 44]

I strongly suggest you get yourself one of those popular DVDs that show how pilots manage their climbs/descends in Boeing aircraft. Yes, you have to KNOW your airplane very well, its MCP modes and be able to follow any ATC instructions and get the job done. Pilots do ASK controllers to let them start descend if they think time is ripe or if denied such request must apply drag if their descent comes late. And yes, there may be number of steps, turns on the way down. There is very little chance in the real world that your descent will be exactly as FMC calculated it to be. So don't count on staying in VNAV PATH for very long. Pilots are not known to complain to controllers that "I can't do that because I don't know how to reprogram my FMC or how to use autopilot".Michael J.WinXP-Home SP2,AMD64 3500+,Abit AV8,Radeon X800Pro,36GB Raptor,1GB PC3200,Audigy 2http://www.precisionmanuals.com/images/forum/747400.jpg

[Guest tmetzinger]

When you're in VNAV and working with ATC, as Michael says, what ATC wants you to do will generally not match up with the pre-calculated path, so you need to be flexible.If you're given a descent before your TOD point, you should dial in the new altitude to your MCP (so you won't descend below it), and then start a descent in one of three autoflight modes.You can stay in VNAV by going to the DES page and selecting DES NOW, this will start a shallow descent until the calculated path and your actual path coincide, then it will resume an idle-thrust descent.You can select a LVL CHG descent, and the throttles will roll to idle and the aircraft will pitch to the MCP selected speed.You can also select a VS descent and use the vertical speed - 2200 or so FPM is about normal for an idle clean descent at .74 mach or 280 KIAS.

[Guest tmetzinger]

When you're in VNAV and working with ATC, as Michael says, what ATC wants you to do will generally not match up with the pre-calculated path, so you need to be flexible.If you're given a descent before your TOD point, you should dial in the new altitude to your MCP (so you won't descend below it), and then start a descent in one of three autoflight modes.You can stay in VNAV by going to the DES page and selecting DES NOW, this will start a shallow descent until the calculated path and your actual path coincide, then it will resume an idle-thrust descent.You can select a LVL CHG descent, and the throttles will roll to idle and the aircraft will pitch to the MCP selected speed.You can also select a VS descent and use the vertical speed - 2200 or so FPM is about normal for an idle clean descent at .74 mach or 280 KIAS.

[michal 44]

>I understand how to use the FMC but using it with ATC is>confusing to me.I might add this. Understanding FMC is not enough, you have to know how FMC interacts with the MCP/AP. You may practice climbs/descents first withouth ATC by experimenting on your own. One of the best way to gain in-depth understanding of the aircraft is to "play" with it. Having a simulator has tremendous advantage - it is often better than any tutorial or 1000 page manual. Also do you really understand FMC that well? Are you able to switch to a different approach/runway or even change destination airport while in flight? You can compile the whole list of problems/exercises like that and practice.Michael J.WinXP-Home SP2,AMD64 3500+,Abit AV8,Radeon X800Pro,36GB Raptor,1GB PC3200,Audigy 2http://www.precisionmanuals.com/images/forum/747400.jpg

[McCrash 3]

This is a great thread. I have just learned a lot. Thanks to all.