AD 87-24-02

87-24-02 BOEING: Amendment 39-5768. Applies to Model 747 series airplanes, as listed in Boeing Alert Service Bulletin 747-53A2280, dated April 16, 1987, certificated in any category. Compliance required as indicated, unless previously accomplished.

To detect cracking of the body station (BS) 2598 longeron skin splice fittings and breakage of the tension bolts common to the fittings, accomplish the following:

A. Prior to the accumulation of 10,000 landings, or within 500 landings after the effective date of this AD, whichever occurs later, perform a detailed visual inspection of BS 2598 longeron skin splice fittings for cracking, and tension bolts common to these fittings for breakage, in accordance with Boeing Alert Service Bulletin 747-53A2280, dated April 16, 1987, or later FAA-approved revision. Reinspect the splice fittings and tension bolts common to stringer 11 longeron at intervals not to exceed 2,000 landings; and reinspect the splice fitting and tension bolts common to stringer 23 longeron at intervals not to exceed 4,000 landings.

B. If any longeron skin splice fitting is cracked, prior to further flight replace the fitting and the tension bolt common to that fitting, in accordance with Boeing Alert Service Bulletin 747-53A2280, dated April 16, 1987, or later FAA-approved revision.

C. If a tension bolt is broken, but the fitting to which it is common is not cracked, prior to further flight, replace the bolt in accordance with Boeing Alert Service Bulletin 747- 53A2280, dated April 16, 1987, or later FAA-approved revision. This constitutes terminating action for the requirement to inspect the tension bolt.

D. Prior to the accumulation of 10,000 landings on new (replaced) BS 2598 longeron skin splice fittings, perform a detailed visual inspection of the splice fittings for cracking, in accordance with Boeing Alert Service Bulletin 747-53A2280, dated April 16, 1987, or later FAA-approved revision. Reinspect the splice fittingscommon to stringer 11 longeron at intervals not to exceed 3,000 landings; and reinspect the splice fittings common to stringer 23 longeron at intervals not to exceed 6,000 landings. Replace cracked fittings prior to further flight, in accordance with the service bulletin.

E. An alternate means of compliance or adjustment of the compliance time, which provide an acceptable level of safety and which has the concurrence of an FAA Principal Maintenance Inspector, 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 in order to comply with the requirements of this AD.

All persons affected by this directive 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. These documents may be examined at the FAA, Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington, or Seattle Aircraft Certification Office, FAA, Northwest Mountain Region, 9010 East Marginal Way South, Seattle, Washington.

This amendment becomes effective December 24, 1987.