85-24-02 BOEING: Amendment 39-5170. Applies to all Model 727-200 series airplanes, certificated in any category. Compliance is required as indicated, unless previously accomplished. \n\n\tTo detect corrosion of the wing lower skin that could result in fuel entering the ram air plenum chamber accomplish the following: \n\n\tA.\tOn airplanes with more than 10,000 hours time-in-service or 4 years since date of manufacture, accomplish the following within the next 3,000 hours time-in-service or 1 year, whichever occurs first after the effective date of this AD: \n\n\t\t1.\tVisually inspect the upper wall of the air conditioning ram air plenum chamber for corrosion in accordance with Part II of Boeing Service Bulletin 727-51-17, dated April 26, 1974, or later FAA approved revision. \n\n\t\t2.\tIf corrosion is detected, repair and refinish in accordance with Figure 3 of the Boeing Service Bulletin 727-51-17 dated April 26, 1974, or later FAA-approved revision, or in a manner approved by the Manager, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region. \n\n\tB.\tRepeat the procedures required in paragraph A., above, at intervals not to exceed either 8,000 hours time-in-service or 4 years, whichever occurs first. \n\n\tC.\tInspections accomplished in accordance with Part II of Boeing Service Bulletin 727-51-17 prior to the effective date of this AD satisfy the initial inspection requirements of this AD. \n\n\tD.\tAlternate means of compliance which provide an acceptable level of safety 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 proposal who have not already received these documents from the manufacturer may obtain copies upon request to the Boeing Commercial Airplane Company, 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 becomes effective December 23, 1985.