SUPPLEMENTARY INFORMATION:

Background

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2025-06-01, Amendment 39-22989 (90 FR 12457, March 18, 2025) (AD 2025-06-01). AD 2025-06-01 applied to all Airbus Canada Limited Partnership Model BD-500-1A10 and BD-500-1A11 airplanes. AD 2025-06-01 required revising the existing AFM to incorporate the procedures for the flightcrew to manually isolate the opposite functional engine in the event of an engine bleed duct large leak condition. The FAA issued AD 2025-06-01 to address partially impaired software protection logic for potential large leaks from the engine bleed duct inside the engine core compartments, which could result in dual engine failure.

The NPRM was published in the Federal Register on February 23, 2026 (91 FR 8390). The NPRM was prompted by Transport Canada AD CF-2025-12, dated March 4, 2025 (Transport Canada AD CF-2025-12) (also referred to as the MCAI), issued by Transport Canada, which is the aviation authority for Canada. The MCAI states that Pratt & Whitney developed an EEC software update (version 2.12.1, part number 5324158-15) to address the detection and protection for potential large leaks. Installation of EEC software version 2.12.1 on both engines is a terminating action to the AFM revision specified in the MCAI. The MCAI also removes production airplanes from the applicability that will have an equivalent modification incorporated before delivery.

In the NPRM, the FAA proposed to continue to require the actions in AD 2025-06-01 and require installing a certain EEC software update on both engines, as specified in Transport Canada AD CF-2025-12. 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-2026-1336.

Discussion of Final Airworthiness Directive

Comments

The FAA received a comment from Air Line Pilots Association, International (ALPA) who supported the NPRM without change.

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

Request To Allow Replacement of the EEC

Delta requested that the FAA revise paragraph (h)(4) of the proposed AD to allow either replacement or modification of the EEC to a software version eligible for installation, for added operator flexibility. Delta stated that Transport Canada AD CF-2025-12 mandates installation of EEC software version V2.12.1 either through replacement or modification of the EEC as terminating action of the Transport Canada AD. Delta suggested that the ability to either modify or replace the EEC would allow operators additional flexibility in AD implementation.

Replacement of an EEC is an optional method of compliance. The FAA has revised paragraph (h)(4) of this AD to specify replacement of an EEC with an EEC that has EEC software version 2.12.1 or later approved version as an optional method of compliance for this AD.

Request To Allow Later Software Versions

Delta requested that the FAA revise the proposed AD to allow later EEC software versions. Delta recommended that the FAA add a new paragraph to the proposed AD titled “Definitions” and define “EEC Software Version Eligible for Installation” as “EEC Software Version V2.12.1 or later” to accommodate future EEC software ( printed page 47952) version releases. Delta noted that other FAA ADs for these aircraft that have mandated installation of a specific EEC software version have allowed for future EEC software versions to be considered as AD-compliant. Delta suggested that defining an EEC software version eligible for installation as V2.12.1 or later would accommodate future EEC software versions released by the manufacturer for continued fleet reliability improvements and would align with previous ADs with EEC software version mandates.

The FAA agrees to allow later EEC software versions. The FAA coordinated with Transport Canada regarding the acceptability of specifying later versions of EEC software for this aircraft. While the FAA has not revised this AD to add a definitions paragraph, the FAA has revised paragraph (h)(4) of this AD to allow later versions of the EEC software.

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, and any other changes described previously, 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

Transport Canada AD CF-2025-12 specifies procedures for revising the “Non-Normal Procedure” of the AFM to incorporate the procedures for the flightcrew to manually isolate the opposite functional engine in the event of an engine bleed duct large leak condition, and the installation of a certain EEC software update on both engines, which terminates the AFM revision. The installation consists of updating the EEC software to version 2.12.1 by either replacing or modifying the EEC to include software version 2.12.1. 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.

Costs of Compliance

The FAA estimates this AD affects 152 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD:

The FAA has determined that it is not likely that operators would need to replace the EEC in order to complete the software upgrade; therefore, the rule is not significant.

The FAA has included all known costs in its cost estimate. According to the manufacturer, however, some or all of the costs of this AD may be covered under warranty, thereby reducing the cost impact on affected operators.

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: