Harley,
Yes, I lost one servo in the elevator which caused a crash. I know for sure that it was the elevator because when the plane crashed it was in a rather marshy are and it buried it self in the ground about 2 fee nose first. fortunately the tail section of the airplane was un damaged which resulted in being able to trace the problem. I was able to remove the elevator and rudder servos from the aircraft. The rudder servos are perfectly fine and so is one elevator servo, the other servo had it's gears stripped out. I had control over all the surfaces except pitch when it went in. After salvaging the servos from the wreckage I plugged them all into a receiver and found that one elevator servo was indeed stripped. So I had only one elevator servo working when it crashed. Also, in my case the surface had no resistance from the servo since it was stripped and was just flapping in the breeze and not locked in one position. That elevator was a bad design.