89-07-05 BOEING: Amendment 39-6163.\n\tApplicability: All Model 727 series airplanes, certificated in any category. \n\n\tCompliance: Required as indicated, unless previously accomplished. \n\tTo prevent binding of the aileron control wheel caused by internal damage in the aileron power control unit (PCU), accomplish the following: \n\n\tA.\tPrior to the accumulation of 18,000 hours time in service on the PCU since new or overhauled with new seals, or within the next 3,000 hours time in service on the PCU after the effective date of this AD, whichever occurs later, accomplish either of the following, in accordance with Boeing Alert Service Bulletin 727-27A0220, Revision 1, dated July 28, 1988: \n\n\t\t1.\tReplace any aileron power control unit with a PCU which has been overhauled including new piston seals or one which has accumulated less than 18,000 hours time in service. Continue to replace any PCU prior to the accumulation of 18,000 hours time in service on the PCU. \n\n\t\t2.\tPerforma hydraulic bench internal leakage test on the aileron power control unit. Before further flight, replace any PCU which fails the test. Repeat the hydraulic bench internal leakage test at intervals not to exceed 2,500 flight cycles. \n\n\tB.\tInspection of the aileron power control unit, and modification of the aileron power control unit including replacement of piston seals, in accordance with National Waterlift Service Bulletin 27-21-1/200, dated April 8, 1988, or National Waterlift Service Bulletin 27-10- 1/200, Revision 1, dated November 4, 1988, constitutes terminating action for the repetitive replacement or internal leakage test required by paragraph A., above. \n\n\tC.\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 may add any comments and then send it 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 accomplishment of the rework 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 98124-2207. These documents may be examined at the FAA, Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington, or the Seattle Aircraft Certification Office, 9010 East Marginal Way South, Seattle, Washington. \n\n\tThis amendment (39-6163, AD 89-07-05) becomes effective April 26, 1989.