@FeatherWing

i know this, but in simpleplanes, it is all in the engine

@Madness
thanks bro

it works and now my plane cant go to space

@CarrotSlicingCompanyCat

if remaking tetris is possible in simpleplanes, then making a plane with a service ceiling is possible too

thanks guys for the code, ill try both of them

Throttle * clamp01(Altitude > altitude in meters)

@CarrotSlicingCompanyCat its easy, i can even kill my engine facing certain directions/pitch angle

Could possibly be wrong, but I don't think it's your engine that determines your service ceiling. Your engine would probably die at altitude when there isn't the air to keep your engines working, which is probably something like low earth orbit.
From what I know, service ceiling is determined by the altitude where the aircraft gets to a certain elevation and can no longer generate lift due to the air being too thin relative to the design, weight and other factors.

@CarrotSlicingCompanyCat If you don't know, don't answer, because he can do it. but maybe he just saw your comment first and now thinks its impossible.

@CarrotSlicingCompanyCat
It...
Is.
And it's pretty simple.
For example, if you want a service ceiling of 20.000m, you need to put exactly what @Madness said in the engine's input, which is:
Altitude>20.000 ? 0 : Throttle

Sorry but it’s not possible