89-23-02 BOEING: Amendment 39-6373. Docket No. 89-NM-100-AD. \n\n\tApplicability: Model 757 and 767 series airplanes, as listed in Boeing Alert Service Bulletins 757-29A0037, Revision 1, and 767-29A0035, Revision 1, both dated November 23, 1988, certificated in any category. \n\n\tCompliance: Required within the next 6,000 hours time-in-service after the effective date of this AD, unless previously accomplished. \n\n\tTo prevent the possible complete loss of hydraulic power, accomplish the following: \n\n\tA.\tRemove and rework or replace the Ram Air Turbine (RAT) Ground Checkout Module (GCM) in accordance with Boeing Service Bulletin 757-29A0037, Revision 1, dated November 23, 1988, or Revision 2, dated August 3, 1989 (for Model 757 airplanes); or Boeing Service Bulletin 767-29A0035, Revision 1, dated November 23, 1989, or Revision 2, dated August 3, 1989 (for Model 767 airplanes); as appropriate. Prior to returning the airplane to service: \n\n\t\t1.\tIf the RAT has been operated ortested since the airplane delivery, prior to returning the airplane to service, inspect the downstream filter screen of the removed GCM. \n\n\t\t2.\tIf the screen is damaged or missing, or if GCM has been removed previously without inspecting the screen, prior to further flight, either test the RAT hydraulic pump or replace it in accordance with the applicable service bulletins. \n\n\t\t3.\tIf the RAT hydraulic pump is tested and found to be damaged, prior to further flight, replace it with a serviceable pump in accordance with the applicable service bulletin. \n\n\tB.\tAn alternate means of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region. \n\n\tNOTE: The request should be forwarded through an FAA Principal Maintenance Inspector (PMI), who will either concur or comment, and then send it to the Manager, Seattle Aircraft Certification Office. \n\n\tC.\tSpecial flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD. \n\n\tAll persons affected by this directive who have not already received the appropriate service documents from the manufacturer may obtain copies upon request to Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124. These documents may be examined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 17900 Pacific Highway South, Seattle, Washington, or Seattle Aircraft Certification Office, 9010 East Marginal Way South, Seattle, Washington. \n\n\tThis amendment (39-6373, AD 89-23-02) becomes effective on December 1, 1989.