EASA AD US-2023-07-09
Fuel - Horizontal Stabilizer Fuel Tank Motor Impeller Inlet Check Valves and Transfer Pump Inlet Adapters - Inspection
Summary
Airworthiness Directive 2023-07-09 is a final rule issued by the Federal Aviation Administration (FAA) addressing certain Boeing Model 747-400 and 747-8 series airplanes. It mandates inspections of the transfer pump housing inlet check valves and transfer pump motor impeller inlet adapters in the horizontal stabilizer fuel tank for wear, with corrective actions as necessary. The directive also refines the applicability criteria and limits installation of affected parts to enhance safety.
What Changed
This directive supersedes AD 2022-27-07 by removing certain airplanes from applicability, clarifying component descriptions, and limiting the affected parts to those from Crane Aerospace Hydro-Aire. It redefines the term 'activated' horizontal stabilizer fuel tank to exclude provisioned but non-functional tanks and excludes airplanes without the specified pump assemblies from the AD's scope.
Why It Matters
This AD addresses a critical safety concern involving wear that could create an ignition source within the horizontal stabilizer fuel tank, potentially leading to a fuel tank explosion. Operators and maintenance personnel must ensure compliance to prevent catastrophic failure and maintain airworthiness. The clarified applicability reduces unnecessary inspections on unaffected aircraft, optimizing maintenance resources.
What To Do
Operators of affected Boeing 747-400 and 747-8 airplanes must inspect the transfer pump housing inlet check valves and transfer pump motor impeller inlet adapters for wear and perform corrective actions if needed. Compliance with this AD is required by May 1, 2023. Comments on the AD must be submitted by May 30, 2023.
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