EASA AD US-2021-09-08
Flight Deck Metallic Support Panel Assemblies - Modifications
Summary
The Federal Aviation Administration's Airworthiness Directive 2021-09-08 addresses certain Boeing 737-8 and 737-9 airplanes. It mandates modifications to the electrical bonding of metallic support panel assemblies in the flight deck to ensure proper electrical grounding of installed equipment. This directive responds to design changes that caused insufficient electrical bonding and grounding, posing safety risks.
What Changed
This new airworthiness directive requires modifying the electrical bonding of specific flight deck metallic support panel assemblies, including the P6 panel assembly and the main instrument panel assembly. It introduces mandatory corrective actions to restore adequate electrical grounding paths that were compromised by recent design changes. The FAA will approve forthcoming manufacturer service information as compliance methods once available.
Why It Matters
The directive is critical because inadequate electrical bonding can degrade or disrupt grounding essential for flight deck equipment operation, potentially affecting systems like engine ice protection. This condition could lead to loss of critical functions or multiple simultaneous flight deck failures, threatening safe flight and landing. Operators and maintenance teams must address this to maintain airworthiness and safety compliance.
What To Do
Operators of affected Boeing 737-8 and 737-9 airplanes must modify the electrical bonding of the specified flight deck panel assemblies as required by the AD. All affected airplanes have been removed from service pending corrective action development. Compliance with the AD is effective immediately as of April 30, 2021, and comments on the directive are accepted until June 14, 2021.
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