Thrust levers idle above/below 30000ft

[Budbud 227]

Hello,

 

I have a strange behaviour of the thrust levers on both the T7 and the NGX regarding the idle above and below 30000ft.

 

First to explain the situation, my config is a FDS Jetmax 737 configured throught fscuipc (registered) with "send to direct calibration" option.

In the FMC, I have setup to always override.

 

Now here is the thing.

When starting the descent above 30000ft, the thrust levers are not fully closed to the idle detent but rather kept a little above.

Bringing my thrust levers to idle and setting up "Never" to override in the FMC doesn't change nothing to the matter.

Pushing F1 or moving back and forth my thrust lever temporary brings the thrust levers in the sim to the idle detent but they immediately comes back to the position slightly above the idle detent.

It is like if the FADEC forced the thrust levers above idle until passing 30000ft.

 

Below 30000ft, the thrust levers are fully closed.

 

The difference in terms of "idle" thrust above and below 30000ft is not that much (few percents maybe, it is difficult to assess it as the idle thrust decreases automatically with the loss of altitude anyway), but is usually enough to get me off the VNAV path (especially on the NGX).

 

Before removing my fsuipc profile and do it again from scratch (which I would like to avoid if possible), could you please confirm that it is not the normal behaviour? I don't remember having seen that before and I thought that the thrust levers in the aircraft should be at the idle detent with the idle thrust managed by the FADEC?

 

I have also checked in the FCOM and couldn't find any reference to the 30000ft limit. 

I don't understand where that altitude comes from to trigger that difference in behaviour and why it is common to both the T7 and the NGX.

Could it come from fsuipc or anything else?

 

Thanks.

 

 

 

[downscc 1,327]

I don't recall the details but there is a difference between flight idle and ground idle.  Maybe this is PMDG trying to simulate flight idle?? Seems odd that it cuts off at FL300.  Staying on VNAV path in the NGX is not normally a problem... I never have a problem as long as my descent forecast is in the ball park.  You might have something else going on there.

[Budbud 227]

Well actually, once past 30000ft and the thrust levers fully closed, I don't have any issue to stay on the path, but on the T7, I have noticed that if I retard my throttles to idle at the descent, then first the thrust levers on the sim stay above the idle detend and then retard themselves to fully closed at 30000ft.

On the NGX, even with my throttles fully closed, I have to press F1 or move my throttles passing 30000ft to get the thrust levers fully closed.

If I forget to do so, then the thrust remains above the idle thrust and I get off path.

What is strange there is that I have not changed my config and I don't remember having had that problem before (but I might not have noticed that before ?).

The only thing changed was the updates of both the NGX and the T7. I can't tell if the problem started before or after the update though.

[downscc 1,327]

I always have my throttle override in HOLD only. I can still override A/T in SPD mode but it takes disconnecting A/T to do so... works for me.

[Budbud 227]

Throttle override to Always works fine except for that behaviour above 30000ft but I don't think it is related as I have tried with "Never" and it doesn't change nothing.

I will try to "hold only" the next time to see if it does the trick but I strongly doubt about it.

 

I think that once I get confirmation that the normal physical position for idle at any altitude is the idle detent (fully closed), my only solution will be to delete and recreate the fsuipc profile.

 

I won't uninstall/reinstall the PMDG's as they are already fresh installed after a complete reinstallation of fsx following a world texture bug.

[AirborneZed 168]

Could it be a form of flame-out protection? I assumed this happened because it's what you would see in the real world? Maybe it has to do with air pressure at altitude.

[kevinh 409]

Could it be a form of flame-out protection? I assumed this happened because it's what you would see in the real world? Maybe it has to do with air pressure at altitude.

No need for that in the real thing so why in the sim? Turbine engines don't flameout at idle. If there was a reason not to fully close the throttle during descent then the consequences of doing that should be simulated so you learn not to do it. Not an artificial limitation.

[Budbud 227]

I have done a new test this morning with the override setting in the FMC and no matter what I choose ("Never", "Only in hold mode", "Always"), the result is the same. 

So it is not coming from the throttle quadrant itself. The behaviour is triggered by something else.

Now I need to identify what could be in relation to the 30000ft limit.

Something in fsuipc or in the addons T7 and NGX.

In both case, I cannot see anything obvious.

 

I will proceed first with the fsuipc profile before sending a ticket to the support but if someone from PMDG could give an opinion on the matter I would really appreciate.

[scandinavian13 5,192]

 

 

I will proceed first with the fsuipc profile before sending a ticket to the support but if someone from PMDG could give an opinion on the matter I would really appreciate.

 

Unplug the TQ. Watch for the issue. If it disappears, then you know what it causing the issue. There are numerous oddities with assigning hardware through FSUIPC that can affect our products in ways outside of our control (and therefore, settings).

[Budbud 227]

Thanks. I will try disconnecting the yoke on the next flight but I was more asking if there was something obvious regarding the 30000ft with the aircrafts that I may have missed.

Upon your answer I guess no.

So I will keep testing (disconnecting yoke and rebuild a fsuipc profile).

[Budbud 227]

Ok I did some new tests yesterday.

I disconnected the yoke before the descent and it didn't change nothing to the behaviour so I suspected the issue to come from the aircraft.

 

Then, I disconnected the autothrottles as well and I didn't change nothing either.

 

So now I know that it doesn't come from my TQ nor from the autothrottle. 

I think remains only fsuipc or a bug both the T7 and the NGX at the same time (would be very strange).

I will keep you inform after rebuilt of the fsuipc profile.

[scandinavian13 5,192]

 

 

I think remains only fsuipc or a bug both the T7 and the NGX at the same time (would be very strange).

 

If it's affecting both the NGX and the 777, then it likely isn't either of them, and is something external, to be very honest.

[Budbud 227]

If it's affecting both the NGX and the 777, then it likely isn't either of them, and is something external, to be very honest.

 

Unless it would be something with the Boeing thrust logic that would be common to both and that would be related to 30000ft. But I have given up with that idea.

And as these two addons are the only installed for now in my fsx for now, I cannot compare with any other to see if that problem occurs with other addons.

 

Honestly, if it doesn't come from the fsuipc profile, I would live with it... It doesn't prevent me from flying them and after the numerous reinstall of fsx due to world texture bugs (mainly after uninstalling some sceneries), I don't feel like uninstalling either fsx or PMDGs once again.

[kevinh 409]

If it's affecting both the NGX and the 777, then it likely isn't either of them, and is something external, to be very honest.

What Romain is talking about is something that has been widely commented on in the forum, particularly in the NGX forum. Some people ignore it, others use the F1 key to squeeze a little more descent rate out of VNAV. It's seems to be part of the design relating to engine idle simulation in FSX. It certainly isn't a feature of the real aircraft.

 

It's definitely not FSUIPC as I see the same thing but only use FSX for input calibration.

[Budbud 227]

Hello Kevin,

 

Thanks for the info and sorry to have missed the posts already discussing that issue. I wouldn't have opened a new thread...  :ph34r:

In any case it answers my question.

 

Thanks also to Kyle for your help.