As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER ROTATE THE AIRCRAFT BEGAN TO SHAKE IN THE RUDDER PEDALS THEN ENTERED INTO A SUSTAINED DUTCH ROLL THAT CONTINUED TO WORSEN AS WE ACCELERATED. EMERGENCY DECLARED. AMM: 22-00-02-2 AMM: 27-23-00-5 AMM: 22-21-00-5 PERFORMED MCDP TEST 30/40. RUDDER PCU MONITORING TEST, YAW DAMP OPERATIONAL TEST. CYCLED RUDDER PEDALS FULL LEFT AND FULL RIGHT SEVERAL TIMES. NO DEFECTS NOTED. REF WRI 22-23/2748 FOR R YAW DAMPER DISCREPANCY.