I assume that the heli did fly well before this. With that in mind all I can think of is that the gyro gave up ,it has happend before so it's not unheard of. Do you know anyone with a gyro you can try ? My buddy has been going thrue this same thing but he has extra gyro's to play with and his 1 gyro did give up. But his would work once in a while this gave him greaf till he swapped them out. Just a thought. If you turn on your radio and while holding your heli turn it back and fourth, can you hear the tail rotor servo move ??? If it does not than the gyro is not sensitive enough or it is shot.. Hope this helps some... Alan