EASA AD US-2021-08-12
Wings - Lower Aft Wing Skin Aft Edge - Inspection
Summary
The FAA Airworthiness Directive 2021-08-12 is a final rule addressing all Boeing 737-100, -200, -200C, -300, -400, and -500 series airplanes. It mandates repetitive inspections of the lower aft wing skin aft edge at specific flap track locations due to crack indications found in bolt holes where flap tracks attach to the track support fitting. The directive aims to ensure structural integrity by detecting and repairing cracks that could compromise the wing's ability to carry limit loads.
What Changed
This new airworthiness directive introduces mandatory repetitive high frequency eddy current inspections for cracking in the lower aft wing skin at flap track attachment points. It also requires applicable on-condition actions, including repairs, with reduced compliance times for airplanes equipped with Aviation Partners Boeing blended winglets installed via STC ST01219SE. The directive incorporates Boeing and Aviation Partners Boeing service bulletins as the basis for required actions.
Why It Matters
This directive is critical for aviation professionals because undetected cracks in the lower aft wing skin could lead to structural failure, affecting flight safety. Operators and maintenance organizations must implement these inspections to prevent potential wing structural integrity issues. Compliance ensures continued airworthiness and avoids costly unplanned repairs or grounding due to structural damage.
What To Do
Operators of affected Boeing 737-100 through -500 series airplanes must perform repetitive inspections as specified in Boeing Alert Requirements Bulletin 737-57A1349 RB and Aviation Partners Boeing Alert Service Bulletin AP737C-57-003. Repairs must be completed before further flight if cracks are found. The directive is effective May 28, 2021, and for certain groups, corrective actions must be done within 120 days of this date.
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