Airworthiness Directives; Bell Helicopter Textron Canada Helicopters

We are superseding Airworthiness Directive (AD) 2010-19-51 for Bell Helicopter Textron Canada (Bell) Model 222, 222B, 222U, 230, and 430 helicopters. AD 2010-19-51 required inspecting parts of the main rotor hydraulic servo actuator (servo actuator) for certain conditions and replacing any unairworthy parts before further flight. This new AD requires installing a servo actuator with a new stainless steel piston rod. This AD was prompted by a collective servo actuator malfunction. We are issuing this AD to detect corrosion on a piston rod, which could result in failure of the servo actuator and consequent loss of helicopter control.