What was found
AIRPLANE NOT SMOOTH (JERKY) IN ROLL WITH ANY A-P IN CMD & (HDG HOLD, HDG SEL, LNAV, LOC, B-CRS) MODE SELECTED. CREW COMMENTS: ALL AUTOPILOTS CAUSED A-C ROLLING BACK AND FORTH FL410 IN LT CHOP, LNAV AND HDG MODE. SAMC TEXT: PER CONVERSATION WITH INBD CREW, ACFT EXPERIENCED DUTCH ROLL IN LIGHT CHOP. DESCENDED TO FL370 AND ACFT FLEW NORMAL REST OF FLT. FLIGHT CREW FELT IT WAS MORE OF A YAW DAMP ISSUE. PLZ ACCOMPLISH YAW DAMP TEST PER MM. ACCOMPLISHED YAW DAMP BITE CHECK AND OPERATIONAL TEST PER MM. NO FAULTS INDICATED AND OPERATIONAL CHECK TEST GOOD.