Questions about pitch/roll/yaw gyro stability parameter

I am confused by the documentation of the gyro stability terms, which are
separate from the gyroscopic precession terms. One part of the description
makes it appear that these terms relate the overall stability of these
airplane axes to the world frame of reference, and in that way are overall
stability parameters not dependent on gyroscopic precession of moving parts.
Another part relates this stability to “turning parts” as if it is related to
gyroscopic precession. The description goes on to say that it makes the
airplane less sensitive to turbulent air by making the airplane more stable
relative to the world. The default value is 0. What is the allowable or
“normal” range of values that are either possible or would make sense, and
what is the sensitivity of this parameter? For example, is the normal range
from 0 to 1, 0 to 20, 0 to 500, or what?

Hello @donstim The original precession parameters are inherited from FSX and
allowed you to adjust aerodynamic stability. The issue when you had just those
is that it only accounts for stability relative to local airflow, and has no
influence on instability caused by microturbulences and vortices that were
added to MSFS. We therefore exposed a set of parameters to independently
adjust stability relative to world so that the influence of local air flow can
be diminished. You can see this as a way to parameter the influence of
rotating parts on stability with 2 separate components: aerodynamic and
global. As for the range of values, these are used as scalar so you can use
pretty much what you want although I think you’ll often be in the [0;2] range.
Does that make sense? Regards, Sylvain

So, both precession parameters only affect the influence of rotating parts on
stability? That is, they would normally have no effect on a turbojet airplane?
This question stems from an attempt to find a way to make the airplane less
affected by big jumps in atmospheric pressure or winds that seem to be caused
by environment injections in the sim or maybe overly large updrafts/downdrafts
in mountainous areas.

That’s right, precession scalar are applied when computing engine torque in
the case of piston engine and turboprops, not jet engines. To adjust the
stability of your aircraft in the case you are mentioning,
pitch/roll/yaw_gyro_stability is the way to go.