EASA AD US-2021-07-17
Electrical Power - Main Landing Gear Wheel Well Electrical Connectors - Inspection
Summary
Federal Aviation Administration Airworthiness Directive 2021-07-17 is a final rule addressing all Boeing 737-900ER series airplanes. It mandates repetitive records checks and inspections for corrosion of electrical connectors in the main landing gear wheel well, prompted by reports of significant corrosion that could lead to electrical shorting and unsafe flight conditions.
What Changed
This new airworthiness directive introduces mandatory repetitive inspections and records checks for corrosion on main landing gear wheel well electrical connectors on Boeing 737-900ER airplanes. It updates the referenced service bulletin to Boeing Alert Service Bulletin 737-24A1148, Revision 2, which revises maximum allowable electrical resistance values and corrects previous discrepancies in inspection instructions.
Why It Matters
This AD is critical for aviation professionals because corrosion in these electrical connectors can cause electrical shorting and malfunction of systems essential for safe flight and landing. Operators and maintenance teams must ensure compliance to prevent potential safety hazards and maintain airworthiness of affected aircraft.
What To Do
Operators of Boeing 737-900ER airplanes must perform repetitive records checks and inspections for corrosion of the main landing gear wheel well electrical connectors, following Boeing Alert Service Bulletin 737-24A1148, Revision 2. Corrective actions must be taken if corrosion or excessive electrical resistance is found. The AD becomes effective on May 25, 2021, and initial inspections must be completed within 24 months of the original airworthiness certificate or within 12 months after the AD's effective date, whichever is later.
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