84-21-02 R1 BOEING: Amendment 39-4936 as revised by Amendment 39-6430. Docket No. 89-NM-159-AD.\n\n\tApplicability: Model 747 series airplanes, certificated in all categories, listed in Section 3.0 of Boeing Document No. D6-35022, "Supplemental Structural Inspection Document" (SSID), Revision C, dated April 1989.\n\n\tCompliance: Required as indicated in the body of the AD, unless previously accomplished.\n\n\tTo ensure the continuing structural integrity of the total Boeing Model 747 fleet, accomplish the following on the candidate fleet:\n\n\tA. Within 3 months after the effective date of this amendment, incorporate a revision into the FAA-approved maintenance inspection program which provides no less than the required Damage Tolerance Rating (DTR) for each Structural Significant Item (SSI) listed in Boeing Document D6-35022, Revision C, dated April 1989. (The required DTR value for each SSI is listed in the document.) The revision to the maintenance program shall include and beimplemented in accordance with the procedures in Sections 5.0 and 6.0 of the SSID.\n\n\tB. Cracked structure must be repaired before further flight, in accordance with an FAA-approved method.\n\n\tC. Aircraft may be ferried to a maintenance base for required repair, in accordance with FAR 21.197 and 21.199.\n\n\tD. An 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 will either concur or comment, and then send it to the Manager, Seattle Aircraft Certification Office.\n\n\tE. Operators who have acceptably incorporated Boeing Document No. D6-35022, Revision C, dated April 1989, into their approved maintenance program are exempt from the provisions of this AD.\n\n\tNOTE: Acceptable incorporation is considered to include the reporting requirements of Section 6.0 of the SSID.\n\n\tBoeing Supplemental Structure Inspection Document (SSID) D6-35022, Revision C, dated April 1989, identified and described in this directive, is incorporated by reference and made a part hereof pursuant to 5 U.S.C. 552(a) (1).\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, Transport Airplane Directorate, 17900 Pacific Highway South, Seattle, Washington, or Seattle Aircraft Certification Office, 9010 East Marginal Way South, Seattle, Washington.\n\n\tThis AD revises AD 84-21-02, Amendment 39-4936.\n\n\tThis amendment (39-6430, AD 84-21-02 R1) becomes effective on February 12, 1990.