AD 86-05-11 R1

86-05-11 R1 BOEING: Amendment 39-5255 as amended by Amendment 39-5335. Applies to all Model 747 series airplanes, certificated in any category, listed in Boeing Alert Service Bulletin 747-57A2233, Revision 2, dated May 9, 1986.

To detect faulty self-locking nuts that could lead to separation of an engine, accomplish the following, unless already accomplished:

A. Within 100 landings after the effective date of this AD, perform a one-time inspection of the outboard attach fitting nuts of all nacelle struts for adequate self-locking torque of the nuts, part number BACN10HR162, in accordance with Boeing Alert Service Bulletin 747- 57A2233, Revision 2, dated May 9, 1986, or later FAA-approved revisions.

B. Within 600 landings after the effective date of this AD, perform a one-time inspection of the inboard attach fitting nuts of all nacelle struts for adequate self-locking torque of the nuts, part number BACN10HR162, in accordance with Boeing Alert Service Bulletin 747-57A2233, Revision 2, dated May 9, 1986, or later FAA-approved revisions.

C. Defective nuts must be replaced prior to further flight.

D. 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 time 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.

E. 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.

F. 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 receivedinformation on inspection procedures from the manufacturer may obtain copies upon request to the Boeing Commercial Airplane Company, P.O. Box 3707, Seattle, Washington 98124-2207. This information 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.

Amendment 39-5255 became effective March 31, 1986. This Amendment 39-5335 becomes effective July 7, 1986.