EASA AD US-2018-23-09
Stabilizers - Horizontal Stabilizers - Inspection
Summary
Airworthiness Directive 2018-23-09 is a final rule issued by the Federal Aviation Administration addressing The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. It mandates inspections of horizontal stabilizers to detect cracks in the rear spar upper chord caused by galvanic corrosion due to a manufacturing oversight involving missing protective finishes on certain bushings.
What Changed
This directive supersedes AD 2016-13-16 by retaining its requirements but revises service information to clarify inspection areas and serial number details of the horizontal stabilizer. It continues to require inspections or records checks to identify affected stabilizers, repetitive crack inspections, and corrective actions as necessary.
Why It Matters
This AD is critical for aviation professionals because it addresses a safety risk that could lead to failure of the horizontal stabilizer's rear spar upper chord, potentially causing loss of control of the airplane. Operators and maintenance teams must ensure compliance to prevent structural failure and maintain airworthiness of affected Boeing 737 models.
What To Do
Operators must perform inspections or records checks to identify affected horizontal stabilizers and conduct repetitive high frequency eddy current inspections for cracks on those with affected serial numbers. Corrective actions must be taken if cracks are found. Compliance with this AD is mandatory by December 19, 2018.
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