Airworthiness Directives; General Electric Company CF34-8E Series Turbofan Engines

The FAA is adopting a new airworthiness directive (AD) for General Electric Company (GE) CF34-8E series turbofan engines, with certain serial number (SN) master variable geometry (VG) actuators installed. This AD requires initial and repetitive reviews of the airplane computer systems for master VG actuator fault messages. This AD also requires replacement of actuators reported faulty by the Full Authority Digital Engine Control (FADEC). This AD results from nine reports of CF34-8C master VG actuator electrical signal faults, one report of which was a dual-channel fault, resulting in the FADEC commanding the engine power to idle. We are issuing this AD to prevent VG master actuator dual-channel electrical signal faults which will cause an uncommanded reduction of thrust to idle with a subsequent loss of the ability to advance thrust above idle; and which could result in a multi-engine loss of thrust if dual-channel faults occur on more than one engine simultaneously.