EASA AD US-2021-24-01
Fuselage - Strake Attachment Brackets / Fuselage Frame - Inspection
Summary
The Federal Aviation Administration's Airworthiness Directive 2021-24-01 addresses Pilatus Aircraft Ltd. Model PC-12/45, PC-12/47, and PC-12/47E airplanes equipped with Supplemental Type Certificate SA00634DE. This directive mandates inspections of the fuselage strake attachment brackets, surrounding structure, and bolts due to reported failures at the uppermost bracket attachment location. The goal is to detect and repair any damage or looseness to prevent airplane flutter and loss of control.
What Changed
This new airworthiness directive introduces mandatory inspections within 10 flight hours after its effective date and recurring inspections every 150 flight hours thereafter. It requires inspecting both the inside and outside of the fuselage strakes and attachment brackets for movement, loose or missing fasteners, discoloration, deformation, cracks, or other structural damage. Repairs must be performed using FAA-approved methods if any issues are found.
Why It Matters
This directive is critical for maintaining the structural integrity and aerodynamic stability of affected Pilatus PC-12 aircraft with the Spectre Lift Platform System installed. Failure to comply could result in buffeting, flutter, and reduced lateral stability, potentially leading to loss of airplane control. Operators, maintenance organizations, and compliance teams must ensure timely inspections and repairs to uphold flight safety and regulatory compliance.
What To Do
Operators of affected Pilatus PC-12/45, PC-12/47, and PC-12/47E airplanes with STC SA00634DE must perform an initial inspection of the fuselage strake assemblies within 10 hours time-in-service after January 13, 2022. Subsequent inspections must occur every 150 flight hours. Any detected damage or looseness must be repaired before further flight using FAA-approved procedures. Special flight permits may be issued with operational limitations to ferry aircraft for maintenance if necessary.
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