AD 2014-21-04
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Boeing | Company | Airworthiness Directives; the Boeing Company Airplanes |
Unsafe Condition
Cracks emanating from the aft-most barrel nut holes of the left and right upper rear spar caps of the horizontal stabilizer, which could propagate until an upper rear spar cap severs, and result in failure of the horizontal stabilizer upper center or aft skin panel and adversely affect the structural integrity of the airplane.
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Required Actions
Perform repetitive high frequency eddy current (ETHF) inspections for cracks in the areas around the two aft-most barrel nut holes of the upper rear spar caps, and take corrective actions if necessary. Repeat ETHF inspections for cracks in the areas around the two aft-most barrel nut holes of any repaired or replaced upper rear spar cap, and take corrective actions if necessary.
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Compliance Time
Within the compliance times specified in Boeing Alert Service Bulletin MD80-55A070, Revision 1, dated December 17, 2013.
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Affected Aircraft
All The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 airplanes, certificated in any category.
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Source: Official FAA Source ↗
Retrieved: Apr 6, 2026
Rights: U.S. Government Public Domain
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