89-02-02 BOEING: Amendment 39-6100. Applicability: Model 757 series airplanes, Group 1 and Group 2, as listed in Boeing Alert Service Bulletin 757-32A0081, dated June 24, 1988, certificated in any category. \n\n\tCompliance: Required within the next 120 days after the effective date of this AD, unless previously accomplished. \n\n\tTo prevent the loss of airplane braking due to a single hydraulic failure, accomplish the following: \n\n\tA.\tInspect Group 1 and 2 airplanes left and right alternate antiskid valve module return ports for proper check valve configuration, and correct, if necessary, in accordance with Boeing Alert Service Bulletin 757-32A0081, dated June 24, 1988. \n\n\tB.\tOn Group 1 airplanes, remove the reducer unions installed in the left and right alternate brake metering valve module return ports and install check valves, in accordance with Boeing Alert Service Bulletin 757-32A0081, dated June 24, 1988. \n\n\tC.\tAn alternate means of compliance or adjustment ofthe 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\t\tNOTE: The request should be forwarded through an FAA Principal Maintenance Inspector (PMI), who may add any comments and then send to the Manager, Seattle Aircraft Certification Office. \n\n\tD.\tSpecial flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base for the accomplishment of the inspections and/or modifications required by 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, 17900 Pacific Highway South, Seattle, Washington, or Seattle Aircraft Certification Office, FAA, Northwest Mountain Region, 9010 East Marginal Way South, Seattle, Washington. \n\n\tThis amendment (39-6100, AD 89-02-02) becomes effective February 8, 1989.