EASA AD US-2020-21-17
SUPERSEDED BY FAA AD 2022-08-12
Summary
Airworthiness Directive 2020-21-17 is a final rule issued by the Federal Aviation Administration (FAA) that supersedes AD 2018-16-05 and applies to certain Boeing 757-200, -200PF, -200CB, and -300 series airplanes. It addresses repetitive inspections for skin cracking, shim migration, diagonal brace cracking, and fastener looseness at the upper link drag fittings and adds new inspection requirements for additional fastener hole locations. The directive aims to maintain structural integrity of the engine strut by preventing unsafe conditions caused by cracks and bolt rotation.
What Changed
This AD retains the inspection and on-condition actions required by AD 2018-16-05 but reduces compliance times for certain inspections and adds repetitive inspections at additional fastener hole locations. It also clarifies compliance dates, provides credit for previously accomplished inspections, and confirms that installation of winglets under STC ST01518SE does not affect compliance. The AD incorporates Boeing Alert Requirements Bulletin 757-57A0073 RB, Revision 1, dated August 1, 2019.
Why It Matters
The directive is critical for operators and maintenance personnel to detect and address cracks and fastener issues that could compromise the upper link drag fittings and engine strut structural integrity. Compliance ensures continued airworthiness and safety of affected Boeing 757 airplanes, preventing potential structural failures. It also aligns inspection intervals with updated damage tolerance analyses, balancing safety with operational maintenance planning.
What To Do
Operators must perform repetitive inspections for skin cracking, shim migration, diagonal brace cracking, and fastener looseness as specified, including new inspections at additional fastener hole locations. Compliance with the AD is mandatory by January 14, 2021, the effective date of the directive. Previously completed inspections per earlier service bulletins may be credited, but new inspections for additional fastener locations must still be completed as required.
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