to do this, i would use some jsbsim function and some nasal:
- a jsbsim switch , wich set a "negative-g" prop to 1 if
"accelerations/Nz gt 0"
- a nasal part listening to the "negative-g" prop (with a setlistener):
- if negative-g is 1, we use a settimer to change a "fuel-starvation" to "1" 15s later.
- if negative-g is 0 we use a setimer to immediately set to 0 "fuel-starvation", this way it close the previous setimer if the inverted flight is not long enough.
to close the loop, you can use nasal or a jsbsim function to listen to the "fuel-starvation" prop, and cut the feed when it's set to 1.