What was found
UNCOMMANDED RUDDER FLUCTUATION DURING FLIGHT WITH BOTH AUTOPILOT AND YAW DAMP ON OR OFF. WHEN ON THE GROUND CREW NOTICED THE PEDALS WERE PULSATING EVERY COUPLE SECONDS WITH NO HYDRAULIC PRESSURE ON THE SYS. DECLARED AN EMERGENCY AND RETURNED TO THE FIELD. R & R NR 1 AND NR 2 FCC CARDS. PN ON 822-1308-320 1M64B, PN ON 822-1308-320, SN ON TUS1A4; PN OFF 811-1308-320, SN OFF 18V3R; PN OFF 822-1308-320, SN OFF 2959.