EASA AD US-2021-21-09
Fuselage - Aft Pressure Bulkhead - Repetitive Inspections
Summary
The Federal Register document titled 'Fuselage - Aft Pressure Bulkhead - Repetitive Inspections' is a final rule Airworthiness Directive (AD 2021-21-09) issued by the FAA affecting The Boeing Company Model 737-600, -700, -700C, -800, and -900 series airplanes. This directive mandates repetitive inspections for cracking in the webs of the aft pressure bulkhead and corrective actions if necessary. It also includes inspections for existing repairs on newly included airplanes to ensure continued airworthiness.
What Changed
This AD supersedes AD 2005-05-18 by expanding the applicability to include additional Boeing 737 models not previously covered. It retains the original repetitive inspection requirements and adds inspections for existing repairs on the newly included airplanes. The AD clarifies that installation of certain winglets does not affect compliance and updates service information references.
Why It Matters
This directive addresses the risk of fatigue cracks in the aft pressure bulkhead webs, which could lead to rapid decompression, posing a serious safety hazard. Operators, maintenance organizations, and compliance teams must ensure inspections and repairs are performed to prevent structural failure. The expanded applicability means more aircraft are subject to these safety requirements, increasing the scope of compliance.
What To Do
Affected operators must conduct repetitive detailed, high frequency eddy current, and low frequency eddy current inspections as specified in Boeing Alert Service Bulletin 737-53A1251 Revision 2. Any cracks found must be repaired according to the service instructions. Compliance with this AD is mandatory by December 13, 2021, the effective date of the directive.
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