What is the use of flc mode?

[kb389]

So I'm not too familiar with autopilot and I've just about been able to get it to work(talking about the planes with the Garmin systems for the most part) , so I have observed that sometimes the flc will not turn on no matter what, I engage ap mode, then turn on flight director mode, and then try to turn on flc but it won't get turned on, and even when it does work sometimes it follows the flight path but sometimes it doesn't, my question is what is the difference between flight director, flc , nav , vnav? Also I have observed that whenever I turn on the back course mode then the plane always follows the flight path, so what should I do to correctly make the plane follow the flight path upon taking off? Just use the ap mode and flight director mode and turn back course mode?

I'm flying the citation longitude right now by the way.

Thanks

[Maki Nishikino]

https://aviation.stackexchange.com/questions/107/flight-level-change-or-vertical-speed-when-to-use-it

[Neo King Arthur]

I dunno why, but if I change the altitude using the selector knob and push the knob on the 787, it actually functions the same way as FLC..

Yet when I press FLC. it doesn't do anything..

[Malkuth]

Originally posted by Neo:

I dunno why, but if I change the altitude using the selector knob and push the knob on the 787, it actually functions the same way as FLC..

Yet when I press FLC. it doesn't do anything..

You have to change your speed. If you wanna dive.. Kill your throttle.. it will try to keep your speed, which with allow you to descent. Opposite if you want to gain altitude.

I just use VS mode though so much easier.. But the difference in Real Life is that VS you can over throttle and kill your plane engine.. (you have to control your engine speed in vs)

So think of it this way.
FLC will try to keep your speed.. But you have to adjust throttle for it to actually start to do that.
VS mode will just put you into a descent or Ascent you choose.. IE 1500 FPM.. But won't control your speed so it can kill you easier. EI Stall, or Overspeed.

[Neo King Arthur]

Originally posted by Malkuth:

Originally posted by Neo:

I dunno why, but if I change the altitude using the selector knob and push the knob on the 787, it actually functions the same way as FLC..

Yet when I press FLC. it doesn't do anything..

You have to change your speed. If you wanna dive.. Kill your throttle.. it will try to keep your speed, which with allow you to descent. Opposite if you want to gain altitude.

I just use VS mode though so much easier.. But the difference in Real Life is that VS you can over throttle and kill your plane engine.. (you have to control your engine speed in vs)

So think of it this way.
FLC will try to keep your speed.. But you have to adjust throttle for it to actually start to do that.
VS mode will just put you into a descent or Ascent you choose.. IE 1500 FPM.. But won't control your speed so it can kill you easier. EI Stall, or Overspeed.

Yeah, I know all that, which is why I find it strange that on VNAV and clicking the altitude knob after changing the altitidue, the auto-throttle manages itself to keep the same airspeed and only once it's stable enough on the airspeed, that's when the aircraft starts to descent. Which in my perspective it works as if it's on FLC.

But when I make the change in the altitude and press FLC, it doesn't do anything. The other way works too, if I want to climb, I keep it on VNAV change the altitude and press the knob. And it'll control the throttle to keep the airspeed as I climb. Again, behaving the same way as FLC.. but the FLC button itself doesn't do anything.

I've detailed this steps in my guide here on Steam. It may be a bug, but it still works (albeit in a different way than the way it should).

[HoloByteus]

FLC does seem to be redundant with the longitude since you have auto throttle but it's real useful on aircraft that doesn't. Before engaging FLC it helps to get a descend speed setup first, instead of trying to descend at 315Kts, try slowing down first in level flight then make alt changes.

I suspect trim values might also make FLC hunt more than it should. Sometimes it will work fine and in other flights it seems to thinks it's Chuck Yegar and either wanting to go to space or auger in. Zero trim out first I think might help prevent this.

I don't think VNAV is even working yet, it should pull alt settings from your FMS.