A friend of mine went to fly his A2S on one of the local mountaintop parks a while back. It is approximately 500ft elevation. He said he got airborn but was unable to fly higher than about 50ft before he got the max altitude reached. He asked me about the problem so I went through the obvious things like checking the max altitude setting, rebooting everything, etc. Said he did all that and found nothing unusual and still got the warning. Anybody have any ideas what would cause this problem?