Airworthiness Directive · Amendment 39-14033 · General Electric Company CF34-8E Series Turbofan Engines
General Electric Company CF34-8E Series Turbofan Engines
This AD applies to General Electric Company (GE) CF34-8E series turbofan engines with the master variable geometry (VG) actuators, GE part number (P/N) 4120T02P02, serial number (SN) APM238AE, and SNs APM242AE and up; and Arkwin Industries, Inc. Parts Manufacturer Approval (PMA) P/N 1211508-002, SN 238AE, and SNs 242AE and up installed. The Arkwin PMA parts are also marked with P/N 4120T02P02. These engines are installed on, but not limited to, Embraer 170 series airplanes.
The FAA is superseding an existing airworthiness directive (AD) for General Electric Company (GE) CF34-8E series turbofan engines with certain serial number (SN) master variable geometry (VG) actuators installed. That AD currently requires initial and repetitive reviews of the airplane computer systems for master VG actuator fault messages. That AD also requires replacement of actuators reported faulty by the Full Authority Digital Engine Control (FADEC). This AD requires the same reviews. This AD also prohibits installation of affected master VG actuators onto any CF34-8E series turbofan engine after the effective date of the AD. This AD results from the need to add to the list of affected parts, master VG actuators made by a parts manufacturing approval (PMA) holder. We are issuing this AD to prevent dual-channel electrical signal faults in the master VG actuator which will cause an uncommanded reduction of thrust to idle with a subsequent loss of the ability to advance thrust above idle, and will result in a multiengine loss of thrust if dual-channel faults occur on more than one engine simultaneously.
You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done.
(f) After the effective date of this AD, do not install master VG actuators specified in this AD onto any engine.
Within 10 days after the effective date of this AD, initially review the airplane computer systems for fault messages, and replace actuators with faults reported by the full-authority digital electronic control (FADEC). Follow the review and replacement requirements of paragraph 3 of the Accomplishment Instructions of GE Alert Service Bulletin (ASB) No. CF34-8E-AL S/B 75-A0001, Revision 3, dated February 14, 2005. The specific review instructions depend on the version of FADEC software installed at the time of the review, as detailed in the ASB.
At intervals not to exceed 10 days, repetitively review the computer systems for fault messages, and replace actuators with faults reported by the FADEC. Follow the review and replacement requirements of paragraph 3 of the Accomplishment Instructions of GE ASB No. CF34-8E-AL S/B 75-A0001, Revision 3, dated February 14, 2005. The specific review instructions depend on the version of FADEC software installed at the time of the review, as detailed in the ASB.
(i) As an optional terminating action to the repetitive reviews specified in this AD, replace the master VG actuator with a master VG actuator not specified in this AD.
Previous credit is allowed for reviews and replacements of master VG actuators performed before the effective date of this AD, using paragraph 3 of GE ASB No. CF34-8E-AL S/B 75-A0001 Revision 1, dated February 10, 2004, or Revision 2, dated December 15, 2004, or Revision 3, dated February 14, 2005.
