X plane 10 SITL disarms after a few seconds of arming

hello, I am new to ardupilot and using it research where I need to hold a helicopter at an altitude constant while I give inputs, I have connected x plane 10 and mission planner but once I arm the helicopter it arms successfully for a couple of seconds and then im

mediately disarms.
also when i change fight mode it just gives me an error saying unable to change flight mode.
can someone help me with this problem?
Thanks in advance.

After arming, simply give some throttle like: rc 3 1500 from mavproxy.py CLI.
This should work :slight_smile: