Expectation

Plane does not suddenly go super sonic.

Actual behaviour

When exceeding around 100-200 m/s, an unknown force suddenly pushes the plane to super sonic speeds and beyond, even when TWR indicates 0.
After some debugging, I noticed the only way to get out of the bug was to explode the wings mid-air. Also, changing the wingspan changes the speed at which the bug begins. The more distance between the wingtips, the sooner the bug introduces itself.

Reprocude

Bug is in action in the sandbox.
For complete reproduction:
*Turn on activation 1 to enable elevator (pitch) and elevator trim (slider 1) .
*Activate engines.
*Take off and rotate at 90 m/s.
*Observe the bug after reaching 100-200 m/s