Autopilot keeps disengaging...

[rmeier 473]

I'm not sure if this topic has already been posted...I tried to do a search but could not find any relevant information.

Just purchased/installed the PMDG 777. So far, I haven't been able to enjoy a flight yet...the Autopilot keeps disengaging for no apparent reason. Prior to purchasing/installing the PMDG 777, I had the MS-FSX controllers disabled for all my aircrafts and used FSUIPC exclusively for yoke, pedal and throttle control (all CH products). I've read there may be issues with the PMDG T7 using FSUIPC. I've disabled my FSUIPC controls (programming) for the T7 and I've gone back to the MS FSX controllers for this aircraft.

This did not help the problem.

I do have REX WX engine running (with no sudden wind shifts I can tell) and the A/P still disengages randomly. I have intentionally left my "hands off" the yoke controller and the A/P still disengages. This problem is happening at a rate of 5-7 times over a ten minute period.

I'm not sure what the problem is, but, it has made this aircraft "unflyable" without the autopilot.

Any ideas? I haven't had problems with any other aircraft using my configuration including the "old" LevelD 767, Flight1 Mustang, Majestic Dash 8 Q400 and many others. This problem seems specific to this new PMDG.

Any help would be greatly appreciated!!!

[777simmer 117]

One way to disengage the AP is by using the aileron, elevator or rudder.

All it needs is a little deflection and you will override the AP which will then disengage.

 

Maybe your controls are sending out little spykes and that causes the disconnect.

 

One thing to try is by going opintonthe PMDG FMC and turn the "realistic AP engagement" feature off.

I think this wil engage the AP anytime you push the AP button, even if you are still applying aileron/elevator or rudder.

And vice versa, it should not disengage the AP when one of your controls happens to send a signal.

 

The other thing I can think of would be to go into FSUIPC and put a tick mark in.....not sure what it is called...."elliminate spykes" or so.

[rmeier 473]

Hello 777Simmer!

Thank you for your suggestions! I'll try to go back and find that feature in the FMC to apply (unselect) the realistic AP engagement...I must have missed that.

Last night, I disabled the FSUIPC wind gusts/turbulence etc and ran FSX without Rex Wx and the autopilot performed without issue for a 2700 nm flight.

My issue appears to be either a conflict with FSUIPC or Rex Essential w/Overdrive. I haven't narrowed it down yet.

I would like to keep this sim as realistic as possible...at $90 I hope to keep/utilize all the design features!!! I'd hate to think this bird won't fly in real weather!

Again, thank you for your suggestion!

Rob

[rmeier 473]

Same result...

So I tried another flight with Rex Essential and the A/P continues to repeatedly disengage. Running without Rex and I don't seem to have a problem. I deselected the "realistic A/P engagement" in the FMC and tried another flight with Rex...same result, the A/P continues to repeatedly disengage (even with the FMC select disengaged).

For my system, there appears to be a conflict of some sort with PMDG 777 and Rex Essential w/overdrive. Anyone else seeing the same thing? (I'd hate to fly without this weather add-on.)

Any other suggestions would be greatly appreciated.

[777simmer 117]

You can try removing the FSUIPC.ini from the modules folder.

This will rebuild a new .ini file when FSX is started, but all your joystick settings will have been deleted.

So make a backup of the .ini file so that if it was not the cause you can use it again.

 

While you are at it, you might as wel update FSUIPC to the latest version.

 

A new FSUIPC.ini file has solved many strange unexplanable problems!

(it is also recommended in the PMDG intro guide)

[scrunge49 3]

I'm not sure if this topic has already been posted...I tried to do a search but could not find any relevant information.

Just purchased/installed the PMDG 777. So far, I haven't been able to enjoy a flight yet...the Autopilot keeps disengaging for no apparent reason. Prior to purchasing/installing the PMDG 777, I had the MS-FSX controllers disabled for all my aircrafts and used FSUIPC exclusively for yoke, pedal and throttle control (all CH products). I've read there may be issues with the PMDG T7 using FSUIPC. I've disabled my FSUIPC controls (programming) for the T7 and I've gone back to the MS FSX controllers for this aircraft.

This did not help the problem.

I do have REX WX engine running (with no sudden wind shifts I can tell) and the A/P still disengages randomly. I have intentionally left my "hands off" the yoke controller and the A/P still disengages. This problem is happening at a rate of 5-7 times over a ten minute period.

I'm not sure what the problem is, but, it has made this aircraft "unflyable" without the autopilot.

Any ideas? I haven't had problems with any other aircraft using my configuration including the "old" LevelD 767, Flight1 Mustang, Majestic Dash 8 Q400 and many others. This problem seems specific to this new PMDG.

Any help would be greatly appreciated!!!

 

Hi rmeier,

 

I had exactly the same problem, I eventually traced it to my flight yoke, it was sending out spikes. Despite using FSUIPC to try to smooth out the spikes I still have issues, this was only my experience but it does seem similar to your issue. Like you I only have problems with the PMDG aircraft ( 777 much more so).

 

Hope you get it sorted

[777simmer 117]

You guys do know there is a specific feature in FSUIPC that smooths out the spykes right?!

 

And I am NOT talking about the wind/gusts/turbulence feature that the OP mentioned!

[scandinavian13 5,192]

Additionally, the easiest way too confirm or rule out hardware issues is to take off, put the plane on autopilot, and then remove your hardware (unplug it).  If the issue then goes away, it's the hardware.

[rmeier 473]

Thanks for the additional thoughts on this subject gentlemen. I did delete/rebuild the fsuipc.ini file as suggested in the manual...no effect seen (sim continued to disengage the A/P).

The last move I made was to make two changes in the Rex winds configuration manager...I lowered both the turbulence and shear on the slider bars from 3 to 1...so far, 1 for 1 satisfactory flights (no A/P failure)!

[Cfoley 4]

I am having a similar problem.  I am learning to fly the PMDG 777 and working on becoming familiar with it and reading the tutorial manual (which I printed and it is getting really dogeared now).  After I take off, and with my airspeed at 250 knots and about 1500ft or higher,  I will engage the A/P after retracting the flaps.   But as soon as I let go of the joystick,  the A/P disengages and the plane pitches almost to 45 degrees skyward and into a stall.  I will take control of the joystick and push down, and select the A/P, but as soon as I let go, the A/P disengages again.  I turned off the "realistic A/P engagement" in the FMC, but it did not work, still the same issue.  I have the PMDG 747 and the A/P works fine, but not with the 777.   I have made some practice take offs before and the A/P did not disengage, but now it is constant and can't seem to figure what to do to fix it.   Any ideas what else may be causing it?

[Fabo 213]

I suppose that change of joystick position triggers the disconnect. Try letting go of the joystick first, then connect the AP

[777simmer 117]

You should first TRIM the arplane so it hold them 250kt.

Thereafter engage the AP.

 

As it is, with how the FBW works at the moment (PMDG are working on a fix), this means you just make corrections with your joystick a few times untill the nose stays where you want it. You can try to TRIM the airplane for speed with the TRIM switches, but that can make things worse (out of trim) untill the system is fixed.

 

When the airplane is in trim you should be able to let go of the joystick and airplane will still stay at 250kt and should follow the flight path (climb) you want.

Once you have let go of your joystick, now press the AP switch.

With no input coming from your joystick I cant see how the nose would go up to 45 degrees pitch.

 

 

PS since you said you are still learning,....this all only works if you have been flying manually while following the correct AFDS modes!

What you are flying manually must be the same as what you have set for speed and modes in the AP panel if you dont want the AP to deviate from you current flight path.

As in, when you fly 250kt during a climb, you should (for example) be following the FD in FLCH or Vnav mode with 250kt speed set!

If something is set differently (like 210kt in the window instead of 250kt, or VS mode instead of FLCH or Vnav), then when you engae the AP, it will try to achieve what is set (i.e. pitch up to reach 210kt).

[martin-w 3,235]

Thanks for the additional thoughts on this subject gentlemen. I did delete/rebuild the fsuipc.ini file as suggested in the manual...no effect seen (sim continued to disengage the A/P).

 

The last move I made was to make two changes in the Rex winds configuration manager...I lowered both the turbulence and shear on the slider bars from 3 to 1...so far, 1 for 1 satisfactory flights (no A/P failure)!

 

 

 

 

 

You should consider using ASN, instead of REX weather. All wind shift issues gone. Awesomely realistic weather.

[Cfoley 4]

So far nothing worked.  The plane AP will not hold the plane keeps pitching upward.  I tried the AP before letting go of the stick, but it will not engage.  It only engages when I am pushing slightly downward on the stick.  I am also having difficulty understanding the tutorial on trim and how to set it to the airspeed in the FMC.  I can the trim manually and brought it down to 2.5 before take off, but it did not work either.  I noticed after take off and during the AP disengage problems,  the trim is at 6.

.

[CaptCraig 226]

Looks like it's broken then.  Burn it.