Making a Huey mission, help about conditions ?

[jef32]

Hi

 

I've done a little mission above Las Vegas with some IA Huey following their flightplans above Las Vegas. I've found how making a loop to force them to return to their first waypoint after passing the last but i would like to force them to land at KLAS only if the amount of kerosene is < 10%. I think that it's a lua predicate but i'm totally candid to do that. Thanks !