Airworthiness DirectiveEASA AD US-2018-10-12

Wings - Fuselage Keel Beam Upper Chords / Aft Vertical Stiffeners - Inspection

Published: Jun 7, 2018
Effective: Jun 7, 2018
Deadline: Jun 7, 2018

Boeing 737 100 200 200C 300 400

AI-generated summary of the official EASA document. Verify against the PDF before acting.

What to do

Operators of affected Boeing 737 models must perform the required repetitive high frequency eddy current and detailed inspections as specified in Boeing Alert Requirements Bulletin 737-57A1339 RB starting no later than the effective date of June 7, 2018. They must also conduct one-time inspections of the keel beam upper chord and associated angles and carry out any necessary on-condition repairs. Comments on this directive must be submitted by July 9, 2018.

Summary

Airworthiness Directive 2018-10-12 is a final rule issued by the Federal Aviation Administration addressing all Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. It mandates repetitive high frequency eddy current and detailed inspections for cracking in aft vertical stiffeners and keel beam upper chords, along with applicable on-condition corrective actions. This directive aims to ensure structural integrity by detecting and mitigating fatigue cracks in critical wing fuselage components.

What changed

This new airworthiness directive introduces mandatory repetitive inspections using high frequency eddy current and detailed visual methods for specific structural components prone to cracking. It also requires a one-time inspection of the keel beam upper chord inboard flanges and a general visual inspection of a related angle, with on-condition repairs as necessary. The directive supersedes previous inspection intervals and adds new inspection requirements to address increased stress and fatigue crack risks.

Why it matters

This directive is critical for aviation professionals because it addresses an unsafe condition that could compromise the structural integrity of the Boeing 737 fuselage keel beam and stiffeners. Operators and maintenance organizations must comply to prevent potential failure of the keel beam structure, which is essential for sustaining required flight loads. Timely detection and repair of cracks will help maintain airworthiness and avoid costly structural damage or grounding.

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