EASA AD US-2018-04-06
Fuselage - Forward Entry Door Cut-out Intercostals / Frame Inner Chord — Inspection / Repair
Summary
Federal Aviation Administration Airworthiness Directive 2018-04-06 is a final rule addressing The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. It mandates inspections and repairs related to cracking in the fuselage forward entry door cut-out intercostals and frame inner chord to ensure structural integrity and prevent potential loss of the forward entry door and rapid decompression.
What Changed
This AD supersedes AD 2012-12-05 by adding new repetitive inspections of certain areas of the frame inner chord and applicable on-condition actions. It continues to require repetitive inspections for cracking in various fuselage components and introduces inspections for additional cracking locations not previously covered. The AD also clarifies compliance for airplanes with Supplemental Type Certificate STC ST01219SE and incorporates previously approved alternative methods of compliance.
Why It Matters
This AD is critical for aviation professionals as it addresses fatigue cracking that could compromise the structural safety of Boeing 737 Classic series airplanes. Operators and maintenance teams must detect and repair cracks to prevent potential loss of the forward entry door and rapid decompression, which pose significant safety risks. Compliance ensures continued airworthiness and regulatory adherence, minimizing operational disruptions and safety hazards.
What To Do
Affected operators must perform repetitive inspections for cracking and missing fasteners as specified, including new inspections of the frame inner chord areas. Repairs or corrective actions must be taken if cracks or damage are found. The AD is effective March 30, 2018, and compliance with all inspection and repair requirements must be maintained according to the intervals and procedures outlined in Boeing Alert Service Bulletin 737-53A1240, Revision 2.
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