SUPPLEMENTARY INFORMATION:

Background

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2024-04-06, Amendment 39-22685 (89 FR 19228, March 18, 2024) (AD 2024-04-06). AD 2024-04-06 applied to certain Airbus Canada Limited Partnership Model BD-500-1A10 and BD-500-1A11 airplanes. AD 2024-04-06 required repetitive operational checks of the gravity cross flow shut-off valve and, for certain airplanes, a one-time inspection of the motive flow fuel-feed tubes at the clamp blocks location and applicable corrective actions. The FAA issued AD 2024-04-06 to address mechanical wear damage on the motive flow fuel-feed tubes. Failure of the affected motive flow fuel-feed tubes and a subsequent failure of the gravity transfer system could lead to a fuel imbalance condition resulting in a reduction in airplane functional capabilities and increased crew workload.

The NPRM was published in the Federal Register on November 19, 2025 (90 FR 52005). The NPRM was prompted by Transport Canada AD CF-2025-24, dated April 29, 2025 (Transport Canada AD CF-2025-24) (also referred to as the MCAI), issued by Transport Canada, which is the aviation authority for Canada. Transport Canada AD CF-2025-24 superseded Transport Canada AD CF-2022-70, dated December 21, 2022 (Transport Canada AD CF-2022-70), which corresponds to AD 2024-04-06. The MCAI states that since Transport Canada AD CF-2022-70 was issued, the manufacturer issued new service information to require replacement of the saddle clamp of the motive flow tubes, along with an inspection and rectification of the flow fuel-feed tubes.

In the NPRM, the FAA proposed to continue to require the actions in AD ( printed page 31350) 2024-04-06 and require replacement of the saddle clamp, inspection of the motive flow fuel-feed tubes, and applicable corrective actions, as specified in Transport Canada AD CF-2025-24. The FAA is issuing this AD to address the unsafe condition on these products.

You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2025-5024.

Discussion of Final Airworthiness Directive

Comments

The FAA received comments from the Airline Pilots Association, International (ALPA) who supported the NPRM without change.

The FAA received additional comments from Delta Air Lines (Delta) and Citizens Rulemaking Alliance. The following presents the comments received on the NPRM and the FAA's response to each comment.

Request To Revise Exception for Tube Replacement

Delta requested that the FAA revise the exception in paragraph (h)(5) of the proposed AD by adding reference to Part III of Transport Canada AD CF-2025-24. Delta noted, as proposed, the exception would only apply to Part II of Transport Canada AD CF-2025-24. Delta stated that there is a clear coating on the area behind the saddle clamp, which makes it difficult to distinguish between actual damage and paint or coating damage. Delta concluded that revising the exception would allow operators to replace the motive flow fuel-feed tubes instead of doing rework if there is any confusion as to whether the damage is to the coating, paint, or tube.

The FAA agrees that the exception in paragraph (h)(5) of this AD applies to Parts II and III of Transport Canada AD CF-2025-24 and has revised that paragraph accordingly. The FAA infers that the area behind the saddle clamp as referred to by the commenter is the area of the motive flow fuel-feed tube that mates with the saddle clamp. The FAA notes that the rework referenced in paragraph (h)(5) of this AD is related to different tasks required by Parts II and III of Transport Canada AD CF-2025-24. The rework under Part II is provided in Step 2.6 of Section 2 (Procedure) of Spirit Service Bulletin 500SHW-28-2109, Issue 005, dated October 2, 2023, as documented in the preamble of AD 2024-04-06, and it requires checking the motive flow fuel-feed tube for pre-load condition if the tube is found with no damage or paint damage only. The rework under Part III is provided in Step 2.7 of Section 2 (Procedure) of Spirit AeroSystems Belfast Service Bulletin 500SHW-28-2112, Issue 001, dated July 24, 2024, and it requires application of finish to the motive flow fuel-feed tube if the tube is found with paint damage only.

Request To Use Alternative Service Information for Tube Installation

Delta requested that the FAA add an exception to paragraph (h) of the proposed AD to allow the installation of new motive flow fuel-feed tubes specified in Part III of Transport Canada AD CF-2025-24 to be done using the service information referenced in Part II of Transport Canada AD CF-2025-24, if the tube installations in Parts II and III are done concurrently. Delta noted that the service information referenced in Part III of Transport Canada AD CF-2025-24 specifies doing the tube installation per an airplane maintenance manual (AMM) task. Delta stated that if the actions in Parts II and III of Transport Canada AD CF-2025-24 are done concurrently and damage is found behind the saddle clamp and clamp block, then operators would need to follow two different instruction methods to address the damage.

The FAA disagrees with the request because an exception is not needed to address Delta's concern. The service information referenced in Part III of Transport Canada AD CF-2025-24 does not prescribe a specific method for installing new motive flow fuel-feed tubes. Instead that service information refers to a maintenance manual as an acceptable procedure for doing the installation. Therefore, if the actions in Parts II and Part III of Transport Canada AD CF-2025-24 are done concurrently and new motive flow fuel-feed tubes must be installed per Parts II and III, then operators may comply with the tube installation specified in Part III by using the tube installation method prescribed in the service information referenced in Part II. The FAA did not change this AD as a result of this comment.

Request To Issue an NPRM or Delay Effective Date for Non-Immediate Tasks

The Citizens Rulemaking Alliance requested that the FAA either provide its justification for finding good cause to bypass notice and comment procedures, or convert this action to an NPRM and stay enforcement for non-immediate requirements. The commenter asserted the FAA's use of the good cause exemption appears insufficiently supported.

The FAA notes the comment was submitted in response to an NPRM for which the FAA provided a 45-day comment period. This final rule is effective 35 days after its publication in the Federal Register . Therefore, no change to this AD is necessary.

Request To Make Incorporation by Reference (IBR) Materials Reasonably Available

The Citizens Rulemaking Alliance stated that the FAA's current practices for IBR frequently fail to meet the legal and regulatory standards for reasonable availability. The commenter called on the FAA to guarantee that all IBR materials are easily and freely accessible to the public and affected parties for both commenting and compliance purposes. The commenter also requested that this access be documented in the rulemaking record.

The FAA notes that this AD incorporates by reference Transport Canada AD CF-2025-24, not the manufacturer service information referenced in that Transport Canada AD. The FAA posted Transport Canada AD CF-2025-24 to the AD docket when the NPRM was published in the Federal Register . The material referenced in Transport Canada AD CF-2025-24 may only be posted before the final rule's publication if it is already publicly available or if there is written consent from the owner of that material. Additionally, the FAA provided notice in the NPRM that the material referenced in Transport Canada AD CF-2025-24 will be available in the AD docket after this AD is published. Therefore, the FAA did not change this AD as a result of this comment.

Request To Comply With the Paperwork Reduction Act (PRA)

The Citizens Rulemaking Alliance requested that the FAA revise the AD to comply with the PRA if reporting is required or remove any reporting provisions until PRA requirements are satisfied. If reporting is not required, the commenter requested the FAA clarify that in the AD.

The FAA notes paragraph (i) of this AD specifies that this AD does not require reporting. If an AD were to require reporting, the preamble of the AD would include a paragraph titled “Paperwork Reduction Act” that would provide the applicable OMB control number, required PRA statements, and the estimated time to collect the required information (burden). Any costs associated with the reporting requirement would be included in the Costs of Compliance section in the preamble of the AD. Therefore, the FAA did not change this AD as a result of this comment. ( printed page 31351)

Request To Consider Impact on Small Entities

The commenter requested that the FAA certify under the Regulatory Flexibility Act (RFA) that the AD will not have a significant economic impact on a substantial number of small entities, or prepare an initial regulatory flexibility analysis if it cannot be certified.

The FAA provides the following clarification. The RFA of 1980 (5 U.S.C. 601-612), as amended by the Small Business Regulatory Enforcement Fairness Act of 1996 (Pub. L. 104-121) and the Small Business Jobs Act of 2010 (Pub. L. 111-240), requires Federal agencies to consider the effects of the regulatory action on small business and other small entities and to minimize any significant economic impact. The term “small entities” comprises small businesses and not-for-profit organizations that are independently owned and operated and are not dominant in their fields, and governmental jurisdictions with populations of less than 50,000.

The FAA identified three air carriers that will be affected by this AD. Based on the Small Business Administration (SBA) size standard, all three entities are large businesses:

If an agency determines that a rulemaking will not result in a significant economic impact on a substantial number of small entities, the head of the agency may certify under section 605(b) of the RFA. Therefore, as provided in section 605(b) and based on the foregoing, the head of the FAA certifies that this AD will not result in a significant economic impact on a substantial number of small entities. The FAA did not change this AD as a result of this comment.

Request To Revise the Cost Estimate

The Citizens Rulemaking Alliance requested that the FAA augment the rulemaking docket with the cost methodology and assumptions, including the labor rate, parts availability, and expected downtime.

In the Costs of Compliance section of the proposed AD, the FAA disclosed the number of affected airplanes on the U.S. registry, estimated number of work hours and parts cost provided by the manufacturer, and the aggregate costs. Additionally, the FAA considered the impact that this AD will have on affected operators and determined this AD will not trigger any downtime costs because the requirements of this AD can be performed during regularly scheduled maintenance. Since the FAA has assessed and disclosed the total known costs of the AD requirements in the Costs of Compliance section of the proposed AD, and the commenter did not provide additional cost data for the FAA to consider in its cost analysis, it is not necessary to reopen the comment period or provide additional information in the AD docket. The FAA did not change this AD as a result of this comment.

Conclusion

These products have been approved by the civil aviation authority of another country and are approved for operation in the United States. Pursuant to the FAA's bilateral agreement with this State of Design Authority, that authority has notified the FAA of the unsafe condition described in the MCAI referenced above. The FAA reviewed the relevant data, considered any comments received, and determined that air safety requires adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on these products. Except for minor editorial changes, this AD is adopted as proposed in the NPRM. None of the changes will increase the economic burden on any operator.

Material Incorporated by Reference Under 1 CFR Part 51

The FAA reviewed Transport Canada AD CF-2025-24, which specifies procedures for performing a repetitive operational check of the gravity cross flow shut-off valve and, for certain airplanes, inspecting the motive flow fuel-feed tubes for mechanical wear damage (damage includes, but is not limited to, cracks, scores, scratches, nicks, and gouges) and pre-load condition, and, based on findings, replacing the motive flow fuel-feed tube. This material also specifies procedures for replacing the saddle clamp of the motive flow fuel-feed tubes on both left and right sides, inspecting the motive flow fuel-feed tubes for damage (damage includes, but is not limited to, cracks, scores, scratches, nicks, and gouges) and, based on findings, repairing or replacing the motive flow fuel-feed tube. This material is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.

Interim Action

The preamble to AD 2024-04-06 explained that the FAA considers that AD an “interim action” and the FAA might consider further rulemaking if a final action is identified. The manufacturer has since developed additional corrective actions to address the unsafe condition. The FAA has determined that the additional corrective actions should be required.

Costs of Compliance

The FAA estimates that this AD affects 96 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD:

( printed page 31352)

The FAA estimates the following costs to do any necessary on-condition action that would be required based on the results of any required actions. The FAA has no way of determining the number of aircraft that might need this on-condition action:

According to the manufacturer, some or all of the costs of this AD may be covered under warranty, thereby reducing the cost impact on affected operators. The FAA does not control warranty coverage for affected operators. As a result, the FAA has included all known costs in the cost estimate.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII: Aviation Programs, describes in more detail the scope of the Agency's authority.

The FAA is issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701: General requirements. Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

This AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify that this AD:

(1) Is not a “significant regulatory action” under Executive Order 12866,

(2) Will not affect intrastate aviation in Alaska, and

(3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

The Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

91 FR 31349