In stab mode, I acquired a gps lock and I entered the auto trim mode. lifted my iris+ with gimbal and GoPro aboard to about 2-3 ft. About 3-4 seconds into hover it became hard to maintain a steady hover. It went to the top of my shop and would no longer respond to throttle. I would get, what felt like, blips of elevator/aileron control. Tried the land switch and no response. Took a hit into a wall and busted a leg and props. I know metal bldgs are not Gps friendly but I thought I wouldn't need them for auto trim in stab or land? Trying to learn what not to do again. Thanks for reading. Any help is appreciated.