What was found
(CAN) DURING CLIMBOUT OF A MOUNTAIN DEPARTURE POINT THE ROTOR SPEED DROPPED OFF. SUBSEQUENT TESTS CONFIRMED A SIGNIFICANT LOSS OF POWER. MX DISCOVERED THAT THE PISTON ROD WITH THE SPRING PACK WAS STUCK WITH ZERO AXIAL MOVEMENT. SIGNIFICANT HAND PRESSURE WAS REQUIRED TO BEGIN AXIAL MOVEMENT WITH SUBSEQUENT ACTIONS BECOMING EASIER. MOVEMENT WAS SMOOTH AND NON-RATCHETY, THE T1 SENSOR WAS REINSTALLED AND A TEST FLIGHT CARRIED OUT WITH EVERYTHING NOW PERFORMING NORMALLY. THE ACFT WAS RETURNED TO SERVICE.