flyinheight not working for low altitude?

[kocrachon 2]

Currently trying to make some Fast Roping missions using ACE.

 

I place the ghosthawk on the map, give the helicopter and each unit the following init

 

this flyInHeight 20; 

 

However, it will still only fly at 50. However, If I set this

 

this flyInHeight 200; 

 

He helicopter will fly up to 200. So is there some reason I can't get the helicopter to fly to 30 or less? ACE3 requires the helo to hover at 30 meters. 

[driftingnitro 38]

All vehicles refuse to fly lower than 50m even if you want them too. It's part of the engine in the AI