I don't know how this passed testing, but on the current patch, the L1011 wildly changes the EPR on TM/VNAV climb and the aircraft will literally go into a 1000ft or greater descent during VNAV climb to catch the speed it's trying to climb at. Not only that, once the aircraft is level in cruise, it descends AND climbs anywhere from 500 to 1000 feet as it tries to maintain speed (I guess??). It literally cannot maintain level flight. Guys, this is bad. The TM mode is completely unusable.

I decided to take another crack at it and see if I had messed something up, or if my moza AB9 was causing issues, but no it's not. Here's a screenshot of a 2000ft descent during the climb phase... My Moza software has all FFB trimming and autopilot following off, so it's not adding input to the aircraft while it's in autopilot.

To my eye, this actually appears to showcase two problems with the aircraft systems that I've previously noticed.

(1) Either the stabilizer trim is too slow to respond to necessary inputs commanded by the autopilot, the autopilot simply commands these inputs too gradually, or the autopilot starts commanding these inputs too late; it might be a combination of all three. This also results in, for example, the aircraft overshooting the 250-knots-below-10,000-ft limit by 10 knots or more in the acceleration phase of climbout, just after takeoff.

(2) When using the GPS for navigation, the GPS commands turns too late, and the autopilot usually doesn't seem to command enough bank angle at speeds of more than ~200 knots to make said turns. These issues combined result in the aircraft overshooting the turns, as seen in your screenshot above (note the right bank the aircraft is making in an attempt to get back on the GPS track). The sharper the turn and the higher the speed, the worse this problem appears to be.

The descent here is not something I've seen before, but it could be due to problems with the flight model, which I seem to recall the iniBuilds team is in the process of adjusting based on previous feedback from other forum users. Figuring out how to change the flight model in ways that make it realistic in all phases of flight is quite difficult though; I've previously made a flight model mod for another aircraft, so I know how tedious and time-consuming it can be to figure out what to change and by how much. In my case, it involved a lot of trial and error. So I hope iniBuilds will have those changes made and released soon, but I'm not counting on it.

Edited July 5Jul 5 by zbrainlezz

Exactly the same here. I'm just going to make sure I don't have any conflicting control bindings, but I'm about to uninstall.

Totally agree. In a climb there should be a gradual and steady decrease in the vertical speed. This one behaves like a yo-yo!

I've not heard/read anything from the developers that they're even looking at the flight model or VNAV as problematic, but I am near the point of wanting my money back. The thing literally doesn't work.

5 hours ago, FusionAC said:

I've not heard/read anything from the developers that they're even looking at the flight model or VNAV as problematic, but I am near the point of wanting my money back. The thing literally doesn't work.

Hi, we are still looking into reasons that could be occurring, additionally as I don't have a MOZA however, one of our other users who does have one managed to find a fix for this in the thread below:

Hopefully for MOZA users this can possibly alleviate any issues you've been seeing, let me know if this helps.
Thank you :)

I've turned off the autopilot following on my MOZA but I'll try turning off the trim following as well. That does defeat the purpose of FFB though, since having the stick change positions based off of trim is part of the experience. Is there any way to make the aircraft just ignore the stick when autopilot is engaged?

2 hours ago, FusionAC said:

I've turned off the autopilot following on my MOZA but I'll try turning off the trim following as well. That does defeat the purpose of FFB though, since having the stick change positions based off of trim is part of the experience. Is there any way to make the aircraft just ignore the stick when autopilot is engaged?

I'll ask the team about this

I did a flight with the following options off in the MOZA software and it was much better, thanks for the advice on that. The autopilot is still a little rough which may or may not be like the real aircraft, I wouldn't know lol The only glaring issues I saw were a tendency to go into a shallow descent to recapture speed during IAS climb, and there was a bug where the EFB didn't have the option to change to Navigraph charts until later in the flight; it was just stuck on LIDO charts for the climb phase and then the option appeared. Anyway, thanks again for the advice, much more flyable now.

I had to make an account to comment on the thread since it really has been bothering me the last couple of times I've flown it.

I have noticed a consistent +-20 knots of airspeed fluctuation on climb, and altitude select is +-300 feet when leveling out.

With that, you can't really fly the airplane on VATSIM since you'll easily accelerate to 280 knots before the autopilot trims and will blow through altitudes.

It is really frustrating because the Tristar is such an iconic airplane and the model is great, but the autopilot is borderline unusable.