Strange FDM Issue

[xcvb85]

Steps to reproduce: Start the do328 in Flightgear 2016.3.1 on Linux (not tested on other os), select "stormy monday" weather and wait for about 1min. Then the aircraft jumps around and in bad cases it flips on its roof. This only happenes once and it never happenes if you start in the air. This issue does not occur in Flightgear 3.4 and I'm pretty sure that this is a bug in Flightgear itself and somehow related to this:
FGMEMBERS/ATR72#1
But there is one difference: Unlike ATR72 you don't have this problem during take-off if the weather is fine.

[HHS81]

seems like a bug in 3.1.
I'm just testing it in 4.0, and the aircraft is resting calm with just very little and slow rocking on the ground.
Since 4.1 will bereleased the next days it will be probably a wontfix. Let's wait

[xcvb85]

Still the same in 2016.4.1. @D-ECHO: Can you verify this?

[HHS81]

I need more datas: default weather or Advanced weather? Turbulence settings? Airport and rwy? Framerate?

[HHS81]

And important: engines on?

[HHS81]

Tested more. I compared the Relase version of FlightGear with the dev-version (2016.4.1 versus 2016.4.0)

I see it now at the official FGFS-version 2016.4.1. I don't see it with the dev-version 2016.4.0 and 2017.1.0.

[xcvb85]

Basic weather, just "stormy monday" without any further adjustments, EDDH 23, 30 FPS, engines off. Do you also see the issue with the ATR72 at take-off?

[xcvb85]

The intesity of this effect is not reproducible. Sometimes the aircraft moves just a few meters (you can see that the plane is no longer aligned along the runway) and sometimes really bad things happen (one time I even ended in a black hole - black screen, everything was just black).

[HHS81]

I noticed the same - but only in the official, stable release version of FlightGear. I guess some compile issues....

[HHS81]

Or the turbulence settings... I noticed that the Cessna 182 S is not flyable in stormy monday with the official release, but with the dev-versions.....

[HHS81]

https://sourceforge.net/p/flightgear/codetickets/1916/

[xcvb85]

I'm not sure if we are talking about the same issue. I don't have problems while flying. I'm talking about a giant impulse which hits the plane once when it is on the ground and the engines are still switched off. I only have this problem with JSBsim turboprop planes like ATR72 or DO328 - not with yasim turboprops and not with the DO328 jet version (also JSBsim). If this only happens on Linux I could imagine that this is somehow related to "using not initialized variables" + "address space layout randomization" which is not used by default on Windows (extra compiler flags required).

[HHS81]

Maybe two different problems with similar output?
I can't reproduce the giant impulse here, but see different behavior with turbulence which ends very similar.