1. Get in a helicopter (Easiest to damage tail rotor in MH-9).
2. Somehow damage the tail rotor (Eg. land slowly on the tail rotor), but only the tail rotor.
3. Type "vehicle player setDamage 0" (without the quotes) in the debug console and hit "Local Exec".
4. Attempt to take off with the newly repaired chopper and notice it rotates uncontrollably.