The Federal Aviation Administration issued a notice of proposed rulemaking on January 7, 2026, to adopt a new airworthiness directive for specific De Havilland Aircraft of Canada Limited Model DHC-8-401 and -402 airplanes. This proposal responds to multiple in-service reports of cracks in elevator power control unit brackets and the elevator front spar, which could lead to elevator jams and, in severe cases, loss of pitch control if both elevators are affected. Published in the Federal Register Volume 91, Number 4, the action stems from investigations identifying force-fight loads as a key factor, potentially caused by mis-rigging, improper clamping, or assembly misalignments. Comments are due by February 23, 2026, highlighting the urgency of addressing this safety concern for the affected fleet, estimated at 54 U.S.-registered airplanes.
Background and Key Players
Reports of cracking emerged from in-service data, with Transport Canada, the state of design authority for these aircraft, issuing AD CF-2025-19 on March 24, 2025. This Canadian directive, incorporated by reference in the FAA's proposal, details instances where cracks progressed to detachment of a PCU bracket. The FAA, under its bilateral agreement with Transport Canada, reviewed these findings and determined the unsafe condition likely exists across similar type designs approved for U.S. operation.
De Havilland Aircraft of Canada Limited, holding the type certificate previously owned by Bombardier Inc., plays a central role as the manufacturer. The company has provided service information referenced in the Canadian AD, including procedures for inspections and modifications. Aviation safety engineer Yaser Osman from the FAA's New York Aircraft Certification Office oversees the technical aspects, emphasizing the collaborative effort between U.S. and Canadian regulators to ensure airworthiness.
This issue connects to prior regulatory actions. The proposal notes that completing certain requirements would terminate inspections mandated by Transport Canada AD CF-2024-10, which corresponds to FAA AD 2025-19-05, published in the Federal Register on September 26, 2025 (90 FR 46340). That earlier AD addressed related elevator concerns, illustrating a pattern of iterative safety enhancements for the DHC-8 series, a regional turboprop widely used in commercial aviation.
Proposed Actions and Requirements
The proposed AD requires several mandatory actions to mitigate the cracking risks. Operators must replace bushings and install new washers on the elevator PCU arm fitting assembly, including inspections for corrosion, scoring, or structural degradation in bushing holes. If any such damage is found, repairs must be approved by the FAA, Transport Canada, or De Havilland's Design Approval Organization.
Additionally, the rule calls for installing doublers at the front spar of the elevator structure between specific ribs. This involves detailed visual inspections of spar caps and upper skin panels for cracking or corrosion, eddy current inspections for cracks at fastener holes and rib lightening holes, and checks for missing or torn pressure-sensitive tape on lightening holes. On-condition actions include replacing damaged tape and contacting technical support for approved repairs.
The proposal also mandates replacing horizontal stabilizer rear spar elevator PCU fittings, with eddy current inspections for cracking at mating holes if fittings are removed. Any detected cracks require FAA-approved repairs. These steps, drawn directly from Transport Canada AD CF-2025-19, aim to reinforce structural integrity and prevent force-fight induced failures.
The FAA estimates compliance costs at up to $21,118 per airplane, totaling $1,140,372 for the U.S. fleet, though warranty coverage may offset some expenses. No definitive data exists for on-condition repair costs, underscoring the variable financial impact on operators.
Legal and Political Context
Airworthiness directives fall under 14 CFR Part 39, authorized by 49 U.S.C. 44701, which empowers the FAA to prescribe regulations for aviation safety. This proposal aligns with Executive Order 12866, deemed not a significant regulatory action, and avoids federalism implications under Executive Order 13132. It reflects broader U.S.-Canada aviation cooperation, as outlined in bilateral agreements.
Precedents include similar ADs for other aircraft models addressing control surface fatigue, such as those for Boeing 737s involving rudder PCU issues. Political forces include ongoing emphasis on aviation safety post-high-profile incidents, with stakeholders like airlines pushing for cost-effective solutions. Regulators prioritize risk mitigation, while manufacturers advocate for design improvements. Operators may view the AD as burdensome yet necessary, potentially debating compliance timelines during the comment period.
Implications and Perspectives
Short-term implications involve fleet inspections and modifications, possibly grounding aircraft during implementation and increasing operational costs. Long-term, enhanced durability could reduce maintenance needs and improve safety records, benefiting the DHC-8's reputation in regional transport.
Different perspectives emerge: Safety advocates, including pilot unions, support swift adoption to prevent accidents. Airline operators, facing economic pressures, may seek extensions or alternative compliance methods, as allowed under the AD's provisions for AMOCs. Regulators balance urgency with feasibility, while academics might analyze this as a case study in fatigue failure mechanics. The proposal's forward path includes public comments, potentially leading to amendments before finalization.
