Height check in a trigger?

[Maldovix]

I am used to using a trigger condition such as:

speed object > value

But when I tried to do the same trigger condition for altitude I ran into a problem: the game will not recognize the word 'height.'

What I want to do is "height heli < 10" for my condition.  Can anyone help me here?

[CrashnBurn]

getpos heli select 2 < 10