I assume it is so this fellow can practice halo-diving without having to continually restart the mission. Alternatively, it might be a mission wherein the helo continually hovers at a high altitude and you can keep haloing from it when you respawn (but cosjacket says "then once on the ground go back to the barrel", which implies that it is not including a respawn). Schuler was assuming that you wanted to force AI to continually jump (he might be right, but I'll persevere), which would be a bit more complex.
If you just want to make a map so you can practice jumping, then this should cover it. It will just teleport the player whenever they are standing on the ground (at start of mission or when they land from a jump again). Saves you walking back to a barrel if you mess up the halo-jump:
Activation: NONE, REPEATEDLY
Delay: TIMEOUT, 2, 2, 2 (wait a few seconds on the ground before teleporting)
((getPos player) select 2) <= 0.5
player moveInCargo myHelo
If that isn't what you wanted, then explain exactly what you want and we can work with you.