As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 350 AT AUS DURING PRE-FLIGHT CHECK THE FLIGHT CREW REPORTED A LATERAL VIBRATION WHEN RUDDER PEDALS WERE BUMPED. CREW SELECTED RUDDER STAND-BY AND FLUTERING OF RUDDER STOPPED. REMOVED AND REPLACED THE RUDDER PCU I.A.W. BMM 27-21-91 OPS AND LEAK CHECKS GOOD.