Autopilot Problems

[Doug Johnson 0]

Since the latest update to MSFS the autopilot cannot hold altitude and the speed hold mode in climb and descent is totally non-functional.  I have tried to reset the aircraft using the instructions in the FAQ section.  Altitude hold is always off by a few hundred feet and sometimes strays further and triggers a warning.  

 

Any suggestions? I have a lot of time in this aircraft and everything worked well until the latest update.  This is a very frustrating experience.  

[pawel-d 11]

Well, I'm not sure I observe the same things you have, but I also experience some AP issues.

For me, the AP is unreliable in regards to keeping altitude. I did a few simple test flight - mainly low level flying, simple AP modes - HDG and ALT.

I just fly at let's say 3000, make turns via HDG, and I change speed. Sometimes it's quite good, altitude can slightly change by 100-200ft, but it goes back to correct one. But sometimes, and I think it happens mostly during changing speed (I try to change flaps according to speed), it can't keep the altitude at all. When I'm in turn, reducing the throttle for slowing down (from ex. 200kts to 160kts), it can start uncontrolled descent. Then, when I add throttle again to stop slowing down, AP starts to climb again (because of that it's still slowing, so even more throttle is needed), misses the set altitude and climbs a few hundreds above. It's hard to stabilize situation again...

I think, when I'm careful, and I don't make quite abrupt changes with throttle, it's quite good. But I'd be afraid to fly in higher traffic being vectored and expected to maintain speed and alt.

[Herman 1591]

Doesn't seem to be a universal problem. I ran over a dozen flights in the last couple of days, with cruise anywhere from FL210 to 370 depending on stage length and the altitude holding has been very steady. Includes level-offs during descent. I haven't tried 360s, so will give that a go in the next couple of days. I have the AS store version at 1.0.6.0, using a Honeycomb Alpha and Bravo. Aerosoft airports only in my Community folder at the moment, plus AxisAndOhs and the Bravo lights fix.

 

Here's the usual follow-up info needed to help run this down: Which version (In-game Marketplace or outside store)? Are you running the latest version (1.0.6.0 or if bought from the Marketplace, it may show as 1.0.9.0)? What controllers are you using? Reasonable turbulence level for whatever weather you're using? Hardware up to snuff? On the off-chance some other add-on may be causing this, have you tested with just the CRJ in your community folder if you bought this outside the Marketplace? Have you eliminated double bindings (something in your controls bound to the elevator axis)?

[Sven Telljohann 500]

I cannot confirm this with the AP. With me, as usual, everything is ok.  I fly at the moment only CRJ and DC-6. Best just times all MOD's out. The are lately with me again and again problem causer.  Especially the not SU6 compatible are

 

[Crabby 28]

Guys, when you are cruising in RVSM and on 29.92 or 1013, you will fly into areas where the pressure changes.  When a pressure change occurs, your altitude will change and the plane will climb or descend to lock into the selected altitude but with the standard altimeter.  This is not an autopilot issue.  This happens in real life, though normally not as abruptly as in a sim.  In the real world the local pressure is constantly varying by small amounts so the compensation is barely seen or felt.  In the sim, weather is read and injected in one fell swoop.  You can reach cruise where the local altimeter is 29.87 and then fly into another area where the weather is loaded and the local barometer is 30.32.  Your plane...ANY sim PLANE...will then have to compensate.   In MSFS, my experience shows this happens more with Rex Weather than the in sim weather as the injection is a bit more instantaneous.  That may be only a personal observation and not a fact.  Anyhow, there is, from what I can tell with almost 115 in this plane, a problem with maintaining altitude.  I have seen a lot of folks that think they can just walk away from the aircraft at cruise and hope it's still in the air when they get back.  Not a good idea in this class of aircraft.  It is not a 737 or an A320.

[pawel-d 11]

Hi again,

I tried to capture some some video to show what issues I have. Stutters are only in video, game is fluid.

What you can see:

- Clear sky WX theme, CRJ weight within limits. I use latest versions of sim and CRJ. Community folder contains just some sceneries and Just flight Piper Arrow. No WT mods, but Nxi from marketplace is installed.

- I fly at 4000ft, level flight, stable 180kt at the beginning. Simple AP modes - HDG, ALT (ALTS displayed on PFD), flaps 20 all the time.

- I turn with HDG selector, and I also change power input to slow down or speed up.

- In the beginning you can see that with decreasing speed, CRJ also starts to loose altitude (around 500ft), AP mode changes to ALTS CAP. Later it starts to gain altitude when I try to speed up to 200kts.

 

It's not easy to reasonably manage speed and altitude when for ex. being vectored, and you have to keep focus on whole approach.

And during normal cruise on some higher FLs and in NAV mode, aircraft performs correct.

So, maybe it's just me, maybe there's some issue on my side? Any ideas? Any hardware problem? For controls I use Saitek X52 pro, and it doesn't cause any trouble with other aircraft...

 

Video is private, so you need link below to see it (i hope you can see it, it's my first clip on YT ever ).

 

 

 

Best regards,

Paweł

[Doug Johnson 0]

On 11/8/2021 at 8:19 AM, Herman said:

Doesn't seem to be a universal problem. I ran over a dozen flights in the last couple of days, with cruise anywhere from FL210 to 370 depending on stage length and the altitude holding has been very steady. Includes level-offs during descent. I haven't tried 360s, so will give that a go in the next couple of days. I have the AS store version at 1.0.6.0, using a Honeycomb Alpha and Bravo. Aerosoft airports only in my Community folder at the moment, plus AxisAndOhs and the Bravo lights fix.

 

Here's the usual follow-up info needed to help run this down: Which version (In-game Marketplace or outside store)? Are you running the latest version (1.0.6.0 or if bought from the Marketplace, it may show as 1.0.9.0)? What controllers are you using? Reasonable turbulence level for whatever weather you're using? Hardware up to snuff? On the off-chance some other add-on may be causing this, have you tested with just the CRJ in your community folder if you bought this outside the Marketplace? Have you eliminated double bindings (something in your controls bound to the elevator axis)?

Herman, thank you for the reply.  I am running the latest version of the CRJ (1.0.6.0) purchased through the Aerosoft store and managed with the AS One updater.  I have the latest version of MSFS installed.  I have the Honeycomb Alpha/Bravo setup.  I have gone as fas as unbinding the autopilot controls to confirm this is not the problem. The situation occurs in smooth air also.  The Autopilot is always a few hundred feet high but does manage to maintain altitude most of the time.  I cannot get the IAS (speed) hold to work no matter how much i try.  It did work in the past, before the latest MSFS patch.  Also, i "reset" the aircraft according to the instructions in the FAQ section of the support forum.  Please let me know if you have any other ides.  I often fly "missions" while working from home and the speed hold is a big inconvenience as I have to control it with the VS control and cannot leave it alone for too long.

 

[Herman 1591]

The video was really helpful. With flaps 20, that bank angle and slow speed, there simply isn't enough energy to hold altitude and airspeed. You'd find the same thing if you tried hand flying it trying to hold altitude in that configuration. There's a lot of drag there and the speed decay along with the pitch attitude is telling you all about it. You have to add energy = thrust to overcome it. You can see how much better that worked when you did so. Clean and at 250 KIAS or so, it copes more smoothly with the thrust changes. When you had the speed up towards 200-ish and then made thrust changes, the wandering altitude was still due I think to the drag from flaps 20 making it hard for the autopilot to hold. No not really a fault or problem that's likely to get much if any work to improve.

 

If you haven't already done so, please fly the complete tutorial flight from Volume 3 of the manuals. If you can get through it successfully, I think you'll find the jet does quite well enough to handle a real-world scenario, which is the developer's goal.

[pawel-d 11]

Thank you for your feedback.

As for tutorial flight - yes I did it, I also was successful with quite some flights for now (I own it since release). In most cases CRJ performs nicely, no major issues.

I noticed this behaviour I describe in one of my last flights - I descended a bit early, so I was in level flight and I wanted to slow down to 160 before capturing localizer - it was difficult to manage speed and level flight.

And I think such flying is real-world scenario - it can be for ex. after missed approach - climb to those 4000ft, being vectored for another try and asked for maintaining particular speed.

 

I'll try to make more training, maybe I'll learn to handle it better.

 

[CRJay 427]

The behavior still is not really correct. It should pitch up more to keep the altitude instead of losing altitude.

If it is unable to keep the altitude it means it should be pretty much stalling, which in turn means you'd have to be seeing low speed warning on the speed tape, stall warning and stick pusher activation. Not just slowly losing altitude.

And unable to keep altitude with flaps 20 at 160kts means the performance of the addon is not very accurate. At 30.000kg and flaps 20 your V_appr should be around 147kts and the margin to 160kts is enough for a fair bit of bank angle as well.

Just saying, it is not only user error here. The altitude also does seem to wander 100ft up or down in regular, 210-220kts turns on AP in clean configuration in my experience.

[Herman 1591]

I haven't flown the CRJ 700 in real life, but the Gulfstream II I have. It's a little lighter and a bit less thrust, and also has no autothrust. No FADEC either, but does have those lovely Speys (Man, I loved that sound at spoolup), so overall, I think the characteristics could be similar. This approach regime maneuvering flight scenario was a typical exercise day one every six months in the sim . In the G-II, that same configuration would pretty much result in the same autopilot behavior. It would give up altitude nearing V_appr by some margin so as to not get any slower. In the G-II, the autopilot was a somewhat cranky Sperry unit, so that could explain it too. Anyway, that scenario was a great way to ensure you were well reacquainted with your thrust management to keep the desired speed within 5 knots, either on autopilot or hand flying. I'll have to play with that in the CRJ to see if I can still manage it, notwithstanding that the behavior may or may not be close to accurate.

[oisk 51]

I have always had many many problems with the CRJ AP.....lately however, I always empty my community folder before setting out with the CRJ. I leave in airports/sceneries, but I remove all other aircraft and mods. Since I do this, have had far fewer problems. Could it be that something was screwing with the autopilot? Does this explain why some have huge problems and some do not?

Nonetheless, sometimes when I engage AP in ALT mode, it pitches up to the point that it will stall the aircraft, I only engage AP in a climb or in a descent....Also, the FD refuses to work sometimes, it just shows incorrect info. There are a few other issues too, but by and large it's mostly useable.

 

I find that the Aerosoft CRJ is a lovely aircraft....absolutely lovely, but it's such a pity that Aerosoft has not taken the time to fix the last remaining issues. I feel that their lack of attention to these fixes has really hurt their reputation. The CRJ is almost a fantastic addon, almost....come on Aerosoft.