88-01-02 BOEING: Amendment 39-5809. Applies to Model 727 series airplanes through Line Number 1607, certificated in any category. Compliance required as indicated, unless previously accomplished. \n\n\tTo prevent main landing gear (MLG) failure to extend properly as a result of structural failure in the lock system, accomplish the following: \n\n\tA.\tFor airplanes listed in Boeing Service Bulletin 727-32-251, dated March 11, 1977: Within the next 3,000 landings after the effective date of this AD, inspect the MLG manual extension support yoke attach bolts (2 on each gear) for size and condition, and replace with larger bolts, if necessary, prior to further flight, in accordance with Boeing Service Bulletin 727-32-251, dated March 11, 1977, or later FAA-approved revision. \n\n\tB.\tFor airplanes listed in Boeing Service Bulletin 727-32-237, Revision 3, dated September 19, 1980, that have not been modified in accordance with Boeing Service Bulletin 727-32-275, dated March 28, 1980, orlater FAA-approved revisions: Prior to the accumulation of 25,000 landings or within one year after the effective date of this AD, whichever occurs later, replace the aluminum MLG downlock cranks with new steel cranks in accordance with Boeing Service Bulletin 727-32-237, Revision 3, dated September 19, 1980, or later FAA-approved revision. \n\n\tC.\tFor airplanes listed in Boeing Service Bulletin 727-32-286, Revision 1, dated December 12, 1980, that have not been modified in accordance with Boeing Service Bulletin 727-32-275, dated March 28, 1980, or later FAA-approved revisions: Prior to the accumulation of 25,000 landings or within one year after the effective date of this AD, whichever occurs later, replace the aluminum MLG downlock cranks with new steel cranks in accordance with Boeing Service Bulletin 727-32-286, Revision 1, dated December 12, 1980, or later FAA-approved revision. \n\n\tD.\tAn alternate means of compliance or adjustment of the compliance time, which provides an acceptable level of safety and which has the concurrence of an FAA Principal Maintenance Inspector, may be used when approved by the Manager, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region. \n\n\tE.\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 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 the Boeing Commercial Airplane Company, 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 the Seattle Aircraft Certification Office, 9010 East Marginal Way South, Seattle, Washington. \n\n\tThis Amendment becomes effective February 2, 1988.