EASA AD US-2019-11-03
Flight Controls - Main Slat Track Assemblies - Identification / Replacement
Summary
Federal Aviation Administration Airworthiness Directive 2019-11-03 is a final rule addressing certain Boeing 737-700C, -800, and -900ER series airplanes. It mandates inspection and maintenance record checks of main slat track assemblies to identify those affected by hydrogen embrittlement due to incorrect manufacturing. The directive aims to prevent potential failure of the main slat track assemblies that could lead to slat departure and compromise flight safety.
What Changed
This new airworthiness directive introduces requirements for operators to check maintenance records for removed main slat track assemblies, inspect assemblies for suspect or indeterminate lot numbers, and perform on-condition actions such as replacement and reporting. It also establishes procedures for shipping affected parts to Boeing and reporting findings. The directive applies immediately with an effective date of June 10, 2019.
Why It Matters
This directive is critical for aviation professionals because hydrogen embrittlement in main slat track assemblies reduces structural strength, posing a risk of slat failure and potential injury or loss of safe flight. Operators and maintenance organizations must comply promptly to ensure continued airworthiness and regulatory compliance. Failure to address this unsafe condition could result in serious safety incidents and regulatory penalties.
What To Do
Operators of affected Boeing 737-700C, -800, and -900ER airplanes must perform a maintenance records check and inspect main slat track assemblies for suspect lot numbers or unknown lot numbers as specified in Boeing Alert Requirements Bulletin 737-27A1312 RB dated June 4, 2019. Any affected assemblies must be replaced and reported to Boeing. Compliance with these actions is required by June 10, 2019, the effective date of the directive.
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