What was found
(CAN) AFTER PASSING TURBULENT CONDITIONS OVER MOUNTAINS AND APPROACHING DESTINATION, DURING CRUISE AT FL30, THE PILOT ENGAGED THE ALT AND HDG UPPER MODES AND APPROXIMATELY 2 MIN. LATER IN CALM CONDITIONS, THE HELO ABRUPTLY ROLLED RT AT 90 FOLLOWED BY A DIVE WHICH JERKED THE CYCLIC SEVERELY TOWARDS THE REAR RT SIDE. THE PILOT DISENGAGED THE UPPER MODES AND MANAGED TO RECOVER CONTROL AFTER A DIVE OF 1500 FT TO 2000 FT. HE LANDED THE HELO SHORTLY AFTERWARDS. SOME MINOR DAMAGE OCCURRED ON THE HELO AND SOME FAULTS WERE RECORDED INCLUDING ENGINE 1 & 2 EXCEED. TROUBLESHOOTING IS ON-GOING.