AD 2013-21397
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Boeing | Company | Airworthiness Directives; The Boeing Company Airplanes |
Unsafe Condition
Cracks up to 18.5 inches were found at stringer (S)-6L and S-6R on several airplanes, and analysis indicated that the protruding head fastener modification and related post-modification inspections required by AD 90-23-14 are not adequate to prevent cracking at the upper row of fasteners in the S-6 lap joint before the cracks reach a critical length.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect the fuselage skin lap splice between body station (BS) 340 and BS 400 at stringers (S)-6L and S-6R for cracking. Perform new repetitive inspections for cracking in the S-6 skin lap splice. Eventually modify the lap splice. Conduct post-modification inspections. Take corrective actions if necessary.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within the compliance times specified in the AD, unless already done.
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Affected Aircraft
The Boeing Company Model 747-100, 747-100B, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP series airplanes, certificated in any category, as identified in Boeing Special Attention Service Bulletin 747-53-2253, Revision 4, dated September 9, 2010.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 4, 2026
Rights: U.S. Government Public Domain
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