AD 2018-10-12
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Boeing | Company | Airworthiness Directives; The Boeing Company Airplanes |
Unsafe Condition
Cracks in the left-side and right-side keel beam upper chords and both aft vertical stiffeners, which could result in the inability of the keel beam structure to sustain required flight loads, which could adversely affect the structural integrity of the airplane.
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Required Actions
Accomplish the actions identified as "RC" (required for compliance) in the Accomplishment Instructions of Boeing Alert Requirements Bulletin 737-57A1339 RB, dated April 16, 2018, which includes repetitive surface HFEC and detailed inspections for cracking of the aft vertical stiffeners; repetitive detailed inspections for cracking of time-limited repairs; a one-time surface HFEC inspection for cracking of the keel beam upper chord inboard flanges and a general visual inspection for cracking of the associated angle; and applicable on-condition actions.
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Compliance Time
Within 50 flight hours
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Affected Aircraft
All The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes.
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Source: Official FAA Source ↗
Retrieved: Apr 4, 2026
Rights: U.S. Government Public Domain
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