Agent Fire, while it is ok to bump your question if it has been lost for a day or two, it is
not ok to bump it after a mere two hours.
Many questions lie essentially unanswered for a day or more, so please have some consideration for those people who have had no answer who you have pushed down the page by your inconsiderate post.
Those two hours, incidentally, would have been more than sufficient for you to discover the answer yourself by means of experiment. Having been given such an excellent answer, you should not make a post at all until you have tried the suggested answer and have something intelligent to report.
---------------------------------------------------------------------------------
I suspect that the whole map trigger would not be quite what you need in this situation ... the chopper would set off for the next waypoint and climb at its usual rate. By setting a move waypoint (with the embedded instruction) very close to the unload one, the chopper is compelled to stay in the area because it has to reach the specified height in order to complete the waypoint. Probably.