Federal Register #FAA-2026-7215

FAA Proposed Rule: Repetitive Inspections and Replacement of Transfer Pump Components on Boeing 747-400 and 747-8 Aircraft

The Federal Aviation Administration (FAA), under the Department of Transportation, is proposing a new Airworthiness Directive (AD) for Boeing 747-400 and 747-8 series airplanes to address safety concerns in the horizontal stabilizer fuel tank transfer pump components. - Government Buyer: - Federal Aviation Administration (FAA), Aircraft Certification Service - OEMs and Vendors: - The Boeing Company (primary aircraft OEM) - Crane Aerospace Hydro-Aire (OEM for transfer pump components) - Products/Services Requested: - Repetitive detailed inspections of transfer pump housing inlet check valves (2 per airplane) - Repetitive detailed inspections of transfer pump motor impeller inlet adapters (2 per airplane) - On-condition replacement of damaged transfer pump motor impellers - On-condition replacement of damaged transfer pump housing inlet check valves (Option 1) - On-condition replacement of transfer pump housing (Option 2) - Notable Requirements: - Compliance with Boeing Alert Requirements Bulletin 747-28A2373 RB - Accelerated initial inspection intervals (within 1 year or 5,000 flight hours) - Repetitive inspections not to exceed 20,000 flight hours - Removal of previous wear allowances for affected parts - Strict limitation on installation of affected parts unless inspected and deemed serviceable - Estimated to affect 31 U.S.-registered airplanes - Cost estimates: $1,530 per inspection cycle per airplane; replacement parts may cost up to $20,000 each - Aimed at preventing unsafe conditions that could result in fuel tank explosions and loss of aircraft

Description

The FAA proposes to supersede Airworthiness Directive (AD) 2023-07-09, which applies to certain Boeing Model 747-400 and -8 series airplanes. The current AD requires inspecting for wear of the transfer pump housing inlet check valves and transfer pump motor impeller inlet adapters for the horizontal stabilizer fuel tank, performing corrective actions if necessary, and limiting the installation of affected parts. The proposed AD would require repetitive inspections for damage of the transfer pump components and applicable on-condition actions, and would limit the installation of affected parts under certain conditions. This action addresses an unsafe condition that could result in a fuel tank explosion and consequent loss of the airplane.

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