As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING APPROACH TO IAD CREW REPORTED THE AUTOPILOT SYSTEM PITCHING UP AND DOWN WHILE AIRCRAFT WAS UNDER CAPTAINS CONTROL. NO EMERGENCY WAS DECLARED AND FLIGHT LANDED UNEVENTFUL AND PASSENGER DEPLANED NORMALLY. THE FCC WAS FOUND TO BE FAULTY AND WAS REPLACED. A SATISAFACTORY OPERATIONAL CHECK WAS PERFORMED AND AIRCRAFT WAS RELEASED FOR CONTINUED SERVICE.