86-08-02 BOEING: Amendment 39-5288. Applies to all Model 747 series airplanes through line number 625, certificated in any category. To prevent structural failure of the vertical fin in the event of failure of the aft pressure bulkhead, accomplish the following within 6 months after the effective date of this AD, unless already accomplished: \n\n\tA.\tInstall the vertical fin access cover in accordance with Boeing Service Bulletin 747-53A2264, dated November 25, 1985, or later FAA-approved revisions. \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\tC.\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 modifications required by this AD. \n\n\tAll persons affected by this proposal who have not already received the appropriate service document from the manufacturer may obtain copies upon request to the Boeing Commercial Airplane Company, P.O. Box 3707, Seattle, Washington 98124-2207. This document 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 May 19, 1986.