Tearing off control surface at low speed?

[pixelshader]

I did a few barrel rolls pretty viciously but at less than 400km/h. I was feeling more and more comfortable in the plane so I really pulled into them. Afterwards I went into a turn and noticed the plane was very weird, I thought it must have been bad luck with wind gusts or something.. then I look and my aileron is gone! 

 

I'm no pilot, so I ask Is this normal? Lucky I didn't learn about this in the middle of a fight.