AD 86-18-06

86-18-06 BOEING: Amendment 39-5386. Applies to all Model 747 series airplanes listed in Boeing Alert Service Bulletin 747-57A2234, dated February 21, 1986, certificated in any category. To detect loose or broken bolts used for the forward attachment of the Numbers 1, 2, 3, 6, 7, and 8 trailing edge flap tracks to the wing lower surface, accomplish the following, unless already accomplished:

A. Prior to the accumulation of 5,000 flight cycles or within the next 300 flight cycles after the effective date of this AD, whichever occurs later, conduct a one-time inspection for loose or broken bolts in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747- 57A2234, dated February 21, 1986, or later FAA-approved revisions. NOTE: "Proof Torque" inspections previously accomplished in accordance with Boeing Service Letters Numbers 747-SL-57-44, dated December 18, 1985, or 747-SL-57-44A, dated December 20, 1985, constitute an equivalent means of compliance with the above requirement.

B. If one bolt is found loose or broken, replace all eight bolts used for the forward attachment of the trailing edge flap track to the wing lower surface within the next 600 flight cycles in accordance with Boeing Alert Service Bulletin 747-57A2234, dated February 21, 1986, or later FAA- approved revision.

C. If two bolts are found loose or broken, replace all eight bolts used for the forward attachment of the trailing edge flap track to the wing lower surface within the next 300 flight cycles in accordance with Boeing Alert Service Bulletin 747-57A2234, dated February 21, 1986, or later FAA- approved revision.

D. If three or more bolts are found loose or broken, replace all eight bolts used for the forward attachment of the trailing edge flap track to the wing lower surface prior to further flight in accordance with Boeing Alert Service Bulletin 747-57A2234, dated February 21, 1986, or later FAA- approved revision.

E. Alternate meansof compliance for paragraphs B., or C., above, is:

1. If broken bolts are found, their replacement may be deferred for 1,200 flight cycles, provided the remaining non-broken bolts are retorqued to installation requirements in accordance with Boeing Alert Service Bulletin 747-57A2234, dated February 21, 1986, or later FAA-approved revisions.

2. If loose bolts are found, retorque all bolts to installation requirements in accordance with the Boeing Alert Service Bulletin 747-57A2234, dated February 21, 1986, or later FAA- approved revisions.

3. Perform a visual inspection of the H-11 bolts for broken bolts (evidenced by missing heads) within 15 months after the inspections of paragraph A., of this AD, and repeat the inspections thereafter at intervals not to exceed 15 months.

4. Replacement of the bolts with new bolts in accordance with Boeing Alert Service Bulletin 747-57A2234, dated February 21, 1986, or later FAA-approved revisions is terminating action for therepetitive inspections required by paragraph E.3.

F. 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.

G. 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 directive who have not already received this service information 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 September 11, 1986.