EASA AD US-2021-05-14
Flight Controls - Trailing Edge Flap Control System - Inspection / Replacement
Summary
Federal Aviation Administration Airworthiness Directive 2021-05-14 is a final rule addressing cracks in the flap torque tube actuator attachment brackets on all Air Tractor, Inc. Models AT-250 through AT-802A airplanes. The directive mandates repetitive visual and dye penetrant inspections of the flap actuator attachment bracket welds and requires replacement of any cracked torque tubes to prevent flap actuator detachment. This AD aims to ensure continued safe operation of affected Air Tractor aircraft by mitigating the risk of sudden flap retraction and potential loss of control.
What Changed
This new airworthiness directive introduces mandatory repetitive inspections using visual and dye penetrant methods for the flap torque tube actuator attachment brackets on specified Air Tractor models. It requires replacement of any torque tube found with cracks, allowing replacement parts with more than zero hours time-in-service if they have passed inspection. The AD also adjusts inspection intervals and clarifies compliance requirements based on aircraft time rather than component time.
Why It Matters
This AD is critical for aviation professionals because cracks in flap actuator brackets can lead to sudden flap retraction and loss of aircraft control, posing a significant safety hazard. Operators and maintenance organizations must implement these inspections and replacements to maintain airworthiness and comply with FAA regulations. Compliance ensures the structural integrity of the flap control system, reducing the risk of in-flight incidents and potential accidents.
What To Do
Operators of affected Air Tractor models must perform an initial dye penetrant inspection within 300 hours time-in-service after April 29, 2021, followed by repetitive visual and dye penetrant inspections at intervals specified in the AD. Any cracked flap torque tube must be replaced with an inspected and airworthy torque tube. Maintenance records must document inspection results in accordance with 14 CFR part 43. Voluntary reporting of cracks to Air Tractor or the FAA is recommended to support fleet safety analysis.
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