I had that happen to me once, blade was kinda messed up, took off about 10-15 seconds after it starts shaking horribly. I try to land it softly and try to find out what happened, took the blades off thinking maybe a chuck came out or something. One felt alot lighter then the other. Inspect the other one to find a weight the other is missing. I hadn't used blades that are to messed up, and i'm using plastiblades now.