EASA AD US-2021-03-09
Wings - Structural Significant Items - Inspection
Summary
The Federal Aviation Administration's Airworthiness Directive 2021-03-09 addresses all Boeing 727 series airplanes. This directive focuses on the inspection of internal wing Structural Significant Items (SSIs) due to concerns that excessive sealant coating may hide cracks during inspections. It mandates revisions to maintenance programs and repetitive inspections to ensure structural integrity of the wings.
What Changed
This new airworthiness directive introduces requirements to revise existing maintenance or inspection programs to include inspections that meet the required damage tolerance rating for certain wing SSIs. It also mandates repetitive inspections for cracks and necessary repairs to address the issue of excessive sealant coating potentially masking structural cracks.
Why It Matters
This directive is critical for aviation professionals because undetected cracks in wing SSIs could propagate and compromise the wing's ability to sustain limit loads, potentially leading to loss of airplane control. Operators, maintenance, and compliance teams must ensure inspections are thorough and meet updated standards to maintain airworthiness and safety.
What To Do
Operators of Boeing 727 series airplanes must revise their maintenance or inspection programs to incorporate the specified inspections before reaching certain flight cycle thresholds. Initial inspections must be completed by March 31, 2022, or before accumulating 46,000 or 55,000 total flight cycles depending on the model. Repetitive inspections must continue at intervals defined in the Boeing 727 Supplemental Structural Inspection Documents, and any cracks found must be repaired before further flight using FAA-approved methods.
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