AD 86-07-06

86-07-06 BOEING: Amendment 39-5270. Applies to Model 747 series airplanes, listed in Boeing Service Bulletin 747-54-2111, Revision 1, dated November 22, 1985, certificated in any category. To prevent failure of the forward lug of an inboard pylon upper link, accomplish the following, unless already accomplished:

A. Within the next 850 landings after the effective date of this AD or prior to the accumulation of 8,000 landings, whichever occurs later, perform a close visual or ultrasonic inspection of the forward lug of the inboard pylon upper link for cracks in accordance with Boeing Service Bulletin 747-54-2111, Revision 1, dated November 22, 1985, or later FAA- approved revision.

NOTE: Definition of close visual (detailed) inspection method: Close intensive visual inspections of highly defined structural details or locations searching for evidence of structural irregularity. Using adequate lighting and where necessary, inspection aids such as mirrors, etc., surfacecleaning and access procedures may be required to gain proximity.

B. Cracked parts must be replaced or modified prior to further flight. The part may be modified, if cracking is within rework limits, by the installation of bushings of a new design in accordance with Boeing Service Bulletin 747-54-2111, Revision 1, dated November 22, 1985, or later FAA-approved revision.

C. If no cracks are found, perform repetitive inspections, as described in paragraph A., above, at the following intervals:

1. If the immediately prior inspection was a close visual inspection, reinspect within the next 850 landings.

2. If the immediately prior inspection was an ultrasonic inspection, reinspect within the next 1,700 landings.

D. Installation of inboard pylon upper links that have been modified in accordance with Boeing Service Bulletin 747-54-2111, Revision 1, dated November 22, 1985, or later FAA- approved revision, is considered to be terminating action for the requirementsof this AD.

E. Compliance with this AD does not terminate the inspection requirements of the Supplemental Structural Inspection Document (SSID) Airworthiness Directive AD 84-21-02 (Amdt. 39-4936; 49 FR 44890), if applicable.

F. Upon the request of an operator, an FAA Principal Maintenance Inspector, subject to prior approval of the Manager, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region, may adjust the inspection times specified in this AD to permit compliance at an established inspection period of that operator, if the request contains substantiating data to justify the change for that operator.

G. Alternate 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.

H. Special 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.

All persons affected by this proposal 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 98124-2207. 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.

This amendment becomes effective May 8, 1986.