AD 91-21-04
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Airbus SAS | BAC 1-11 200 Series | Airworthiness Directives; British Aerospace Model BAC 1-11 200 and 400 Series Airplanes |
| aircraft | Airbus SAS | BAC 1-11 400 Series | Airworthiness Directives; British Aerospace Model BAC 1-11 200 and 400 Series Airplanes |
Unsafe Condition
Cracks in the left and right machined attachment angles (Part Number AB27-7761/2) and cracks in the top flange of the longitudinal boom of the left and right outboard auxiliary beam could degrade the structural capabilities of the pressure cabin.
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Required Actions
Perform dye penetrant inspections on attachment angles and visual inspections on auxiliary beams per specified service bulletin paragraphs. Replace or repair cracked structure before further flight. Replace attachment angles with new parts prior to 85,000 landings since new. Comply with service bulletin 53-A-PM5991 for all actions.
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Compliance Time
For airplanes operating at 7.5 psi: at or prior to 33,000 landings or within 4,000 landings after 11/19/1991, whichever is later, then every 8,000 landings. For those at 8.2 psi: at or prior to 22,000 landings or within 3,000 landings after 11/19/1991, whichever is later, then every 5,000 landings. Attachment angles must be replaced before 85,000 landings since new and every 85,000 landings thereafter.
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Affected Aircraft
British Aerospace Model BAC 1-11 200 and 400 series airplanes, certificated in any category.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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