Airworthiness Directives; Airbus Canada Limited Partnership (Type Certificate Previously Held by C Series Aircraft Limited Partnership (CSALP); Bombardier, Inc.) Airplanes

SUPPLEMENTARY INFORMATION:

Background

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain Airbus Canada Limited Partnership Model BD-500-1A10 and BD-500-1A11 airplanes. The NPRM published in the Federal Register on May 6, 2024 (89 FR 37144). The NPRM was prompted by AD CF-2023-67, dated October 4, 2023, issued by Transport Canada, which is the aviation authority for Canada (Transport Canada AD CF 2023-67) (also referred to as the MCAI). The MCAI states that at lavatory and galley locations within the airplane, incorrect terminal lugs have been installed which are not compatible with the associated wire gauge.

In the NPRM, the FAA proposed to require removing and replacing existing lug terminals at various lavatory and galley locations, as specified in Transport Canada AD CF-2023-67. The FAA is issuing this AD to address incorrect terminal lugs that may become loose causing a loss of electromagnetic interference protection, which could result in false alarms of the lavatory smoke detectors, false alarms of low crew oxygen pressure, loss of automatic control of automatic cabin temperature control, and loss of lavatory flush. The unsafe condition, if not corrected, could result in an increase in crew workload, including diversions and descent to below 10,000 feet or the lowest safe altitude.

You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2024-1289.

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 an additional comment from an individual, who requested to be informed as to how the FAA will continue coordination between the FAA and Transport Canada to ensure the effectiveness of the AD, and to address any emerging issues related to the replacement of terminal lugs.

The FAA continuously evaluates operator and manufacturer reports and other data to promote safe type certification and production. Since this commenter did not ask for a change to the final rule, no change has been made to this AD in response to this request.

Conclusion

This product has been approved by the aviation authority of another country and is approved for operation in the United States. Pursuant to the FAA's bilateral agreement with this State of Design Authority, it has notified the FAA of the unsafe condition described in the MCAI referenced above. The FAA reviewed the relevant data, considered the 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 this product. 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

Transport Canada AD CF-2023-67 specifies procedures for removing existing terminal lugs and installing new terminal lugs at lavatories A, C1, C2, C3, D2, D4, and E, and galleys G2A, G2G, and G4, including replacing the ground wires for new terminal lugs if the ground wire length is not sufficient; and installing the service bulletin incorporation placards.

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 that this AD affects 66 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD: