Washington, DC, March 16 - The Federal Aviation Administration (FAA) has issued a proposed airworthiness directive targeting certain Boeing 787 Dreamliner models to address potential structural fatigue stemming from manufacturing discrepancies involving shim gaps. This action follows a Boeing investigation into manufacturing errors and excessive preload forces at the lower side-of-body splice plates, which connect to the lower outboard wing skins. The probe determined that shim gaps, thin spacers used to ensure proper fit between structural components, may have exceeded established engineering allowances in some aircraft. When these gaps are oversized, combined with high pull-up forces during assembly, they can induce undue stress around fastener holes, potentially leading to the initiation and propagation of fatigue cracks over time. The FAA's proposal aims to mitigate this risk through mandatory inspections, ensuring the continued airworthiness of the affected Boeing 787-8, 787-9, and 787-10 airplanes.
The proposed rule focuses on a limited subset of aircraft, specifically impacting approximately 17 U.S.-registered 787s based on their manufacturing dates and configurations, rather than the entire global fleet. It mandates repetitive ultrasonic inspections of critical areas, including splice plates, rear spar terminal fittings, lower chords, front spar terminal fittings, and jack pads, to detect any emerging cracks. Additionally, repetitive detailed inspections of certain splice plates would be required. If cracks are discovered during these checks, operators must perform applicable on-condition actions, such as repairs or replacements, in accordance with Boeing's approved procedures. The FAA emphasizes that existing routine structural inspection programs may not sufficiently identify these specific fatigue issues early enough, necessitating these enhanced, targeted measures to prevent progression to a more serious unsafe condition.
This development represents the latest regulatory response to longstanding concerns about shim-related nonconformances in Boeing 787 production. While shim gaps have been a recurring theme in prior quality reviews, this proposal stems directly from Boeing's recent analysis of preload and gap excesses at key structural interfaces. By requiring proactive detection of fatigue cracks, the FAA seeks to maintain the high safety standards associated with the Dreamliner, a composite-intensive widebody renowned for its efficiency on long-haul routes. Compliance would involve coordination between airlines, maintenance providers, and Boeing technical teams to execute the inspections without undue disruption to operations.
Industry stakeholders have the opportunity to submit comments on the proposed directive, published in the Federal Register, before it advances to a final rule. Once finalized, the requirements would become mandatory, reinforcing oversight of structural integrity in the Boeing 787 fleet. The FAA's action underscores its commitment to addressing manufacturing variances that could affect fatigue life, thereby safeguarding passengers and crews while supporting the aircraft's reliable performance in commercial service.