What was found
(CAN) A/C IN LOGGING OPS NEAR SAYWARD, BC. AS PILOT MADE HIS APPROACH TO LOG LDG& INITIATED FLARE TO SLOW DOWN HIS APPROACH, A/C'S NOSE ABRUPTLY PITCHED UP & CONTINUED TO DO SO EVEN WITH FULL FWD CYCLIC APPLIED. A/C FINALLY LEVELED OFF THEN BEGAN VIOLENTLY PITCHING UP & DOWN. CNTL OF A/C REGAINED BY SHUTTING OFF 1ST STAGE HYDRAULIC SYS. WITH SYS REMAINING TURNED OFF PILOT SET DOWN LOAD OF LOGS & THEN RETURNED TO SERVICE LANDING MAKING UNEVENTFUL LDG. AFTER LDG PILOT CARRIED OUT FULL HYDRAULIC SERVO CHECK & FOUND CYCLIC COULD NOT BE MOVED FWD WITH 1ST STAGE HYDRAULIC SYS ON. MAIN ROTOR TANDEM SERVO INST IN FOR & AFT POS WAS REPL & A/C RT-SRV.