EASA AD US-2019-14-12
Flight Controls - Main Slat Track Assemblies - Inspection
Summary
Federal Aviation Administration Airworthiness Directive 2019-14-12 is a final rule addressing certain Boeing 737-8 and 737-9 airplanes. It mandates inspection and maintenance record checks of main slat track assemblies due to concerns about hydrogen embrittlement affecting their structural integrity. This directive aims to prevent potential slat failure that could jeopardize flight safety.
What Changed
This new airworthiness directive requires operators to check maintenance records to identify if any main slat track assemblies have been removed, inspect these assemblies for suspect or indeterminate lot numbers, and perform on-condition actions such as replacement and reporting. It introduces mandatory compliance measures based on Boeing Alert Requirements Bulletin 737-27A1311 RB dated June 24, 2019.
Why It Matters
The directive addresses a critical safety issue where hydrogen embrittlement weakens main slat track assemblies, risking slat detachment during flight. For operators and maintenance organizations, timely identification and replacement of affected parts are essential to maintain aircraft airworthiness and prevent costly fleet-wide inspections. Compliance ensures continued safe flight and landing operations.
What To Do
Operators of Boeing 737-8 and 737-9 airplanes must perform a maintenance records check and inspect main slat track assemblies for suspect lot numbers by August 30, 2019. If affected parts are found, they must be replaced with serviceable assemblies, reported to Boeing, and shipped as required. Comments on the directive are accepted until September 30, 2019.
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