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AGENCY:
Federal Aviation Administration (FAA), DOT.
ACTION:
Final rule; request for comments.
SUMMARY:
The FAA is superseding Airworthiness Directive (AD) 2024-04-11, which applied to certain Airbus Canada Limited Partnership Model BD-500-1A10 and BD-500-1A11 airplanes. AD 2024-04-11 required modifying the variable frequency generator (VFG) power-feeder harness routing. Since the FAA issued AD 2024-04-11, the FAA received a report of damage to a VFG power-feeder harness, resulting in the loss of the associated VFG and the posting of the L GEN FAIL (Caution) message. This AD continues to require modifying the VFG power-feeder harness routing, and also requires inspecting the VFG power-feeder harnesses for damage and clearance, repairing or replacing the VFG power-feeder harnesses if necessary, modifying and adjusting the VFG power-feeder harnesses if necessary, and prohibiting dispatch of certain airplanes under certain master minimum equipment list (MMEL) items; as specified in a Transport Canada emergency AD, which is incorporated by reference. The FAA is issuing this AD to address the unsafe condition on these products.
DATES:
This AD is effective November 14, 2024.
The Director of the Federal Register approved the incorporation by reference of certain publications listed in this AD as of November 14, 2024.
The FAA must receive comments on this AD by December 16, 2024.
ADDRESSES:
You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:
- Federal eRulemaking Portal: Go to regulations.gov. Follow the instructions for submitting comments.
- Fax: 202-493-2251.
- Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.
- Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.
AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA-2024-2415; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this final rule, the mandatory continuing airworthiness information (MCAI), any comments received, and other information. The street address for Docket Operations is listed above.
Material Incorporated by Reference:
- For Transport Canada material identified in this AD, contact Transport Canada, Transport Canada National Aircraft Certification, 159 Cleopatra Drive, Nepean, Ontario K1A 0N5, Canada; telephone 888-663-3639; emailTC.AirworthinessDirectives-Consignesdenavigabilite.TC@tc.gc.ca; website at tc.canada.ca/en/aviation.
- You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 2200 South 216th St., Des Moines, WA. For information on the availability of this material at the FAA, call 206-231-3195. It is also available atregulations.gov under Docket No. FAA-2024-2415.
FOR FURTHER INFORMATION CONTACT:
William Reisenauer, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7300; email 9-avs-nyaco-cos@faa.gov.
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA invites you to send any written data, views, or arguments about this final rule. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2024-2415; Project Identifier MCAI-2024-00545-T” at the beginning of your comments. The most helpful comments reference a specific portion of the final rule, explain the reason for any recommended change, and include supporting data. The FAA will consider all comments received by the closing date and may amend this final rule because of those comments.
Except for Confidential Business Information (CBI) as described in the following paragraph, and other information as described in 14 CFR 11.35, the FAA will post all comments received, without change, to regulations.gov, including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this final rule.
Confidential Business Information
CBI is commercial or financial information that is both customarily and actually treated as private by its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public disclosure. If your comments responsive to this AD contain commercial or financial information that is customarily treated as private, that you actually treat as private, and that is relevant or responsive to this AD, it is important that you clearly designate the submitted comments as CBI. Please mark each page of your submission containing CBI as “PROPIN.” The FAA will treat such marked submissions as confidential under the FOIA, and they will not be placed in the public docket of this AD. Submissions containing CBI should be sent to William Reisenauer, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7300; email 9-avs-nyaco-cos@faa.gov. Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking.
Background
The FAA issued AD 2024-04-11, Amendment 39-22690 (89 FR 21179, March 27, 2024) (AD 2024-04-11), for certain Airbus Canada Limited Partnership Model BD-500-1A10 and BD-500-1A11 airplanes. AD 2024-04-11 was prompted by an MCAI originated by Transport Canada, which is the aviation authority for Canada. Transport Canada issued AD CF-2023-24, dated April 6, 2023 (Transport Canada AD CF-2023-24), to correct an unsafe condition.
AD 2024-04-11 required modifying the VFG power-feeder harness routing. The FAA issued AD 2024-04-11 to prevent damage to VFG power-feeder harnesses from chafing due to vibration. The unsafe condition, if not addressed, could lead to a loss of generated power from both VFGs, or to a fire in the case of flammable fluid contact with arcing wires.
Actions Since AD 2024-04-11 Was Issued
Since the FAA issued AD 2024-04-11, Transport Canada superseded Transport Canada AD CF-2023-24 and issued Transport Canada Emergency AD CF-2024-34, dated September 19, 2024 (Transport Canada Emergency AD CF-2024-34) to correct an unsafe condition for certain Airbus Canada Limited Partnership (ACLP) Model BD-500-1A10 and BD-500-1A11 airplanes. The MCAI states damage to a VFG harness has been reported, which resulted in the loss of the associated VFG and the posting of the L GEN FAIL (Caution) message. An investigation determined that the in-service event occurred after the incorporation of Part C of ACLP Service Bulletin BD500-534101, Issue 007, dated October 2, 2020, which introduced a new bracket on both sides of the airplane to move the VFG power-feeder harness away from the wheel bins to prevent chafing. Transport Canada required the actions in that service bulletin in Transport Canada AD CF-2023-24 (which corresponds with FAA AD 2024-04-11) to mitigate the risks associated with VFG power-feeder harness/wheel bin chafing. It has been discovered that implementation of Part C of ACLP SB BD500-534101 (Issues 005 through 008) could potentially cause an unsupported VFG power-feeder harness length in a different location on both sides of the airplane. In addition, dispatching the airplane with certain items inoperative under the MMEL might exacerbate this risk. Transport Canada Emergency AD CF-2024-34 prohibits dispatch of airplanes under certain MMEL items to mitigate the exacerbated risk due to dispatching airplanes with certain items inoperative. Transport Canada subsequently superseded Transport Canada Emergency AD CF-2023-34 and issued Transport Canada Emergency AD CF-2024-34R1, dated October 15, 2024 (Transport Canada Emergency AD CF-2024-34R1) to clarify the requirements of Part II of Transport Canada Emergency AD CF-2024-34. Transport Canada Emergency AD CF-2024-34R1 does not change the requirements or applicability of Transport Canada Emergency AD CF-2024-34.
The FAA is issuing this AD to address damage to VFG power-feeder harnesses caused by unsupported VFG power-feeder harness length. The unsafe condition, if not addressed, could lead to a loss of generated power from both VFGs and loss of critical aircraft systems if alternate generators are also lost. You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2024-2415.
Explanation of Retained Requirements
Although this AD does not explicitly restate the requirements of AD 2024-04-11, this AD retains all of the requirements of AD 2024-04-11. Those requirements are referenced in Transport Canada Emergency AD CF-2024-34 and AD CF-2024-34R1, which, in turn, are referenced in paragraph (g) of this AD.
Material Incorporated by Reference Under 1 CFR Part 51
Transport Canada Emergency AD CF-2024-34 and AD CF-2024-34R1 specify procedures for modifying the VFG power-feeder harness routing, including a general visual inspection (GVI) for damage at the intersection of the VFG power-feeder harnesses and the surface of the wheel bins, and corrective actions including obtaining and following repair instructions; performing a GVI of the VFG power-feeder harnesses for damage (including chafing and kinks) and clearance between the VFG power-feeder harnesses and main landing gear in the retracted position; repairing or replacing the VFG power-feeder harnesses (includes repairing wiring or the sleeve); modifying and adjusting the VFG power-feeder harnesses; and prohibiting dispatch of certain airplanes under certain MMEL items. These documents are distinct because Transport Canada Emergency AD CF-2024-34R1 clarifies the requirements of Transport Canada Emergency AD CF-2024-34. 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.
FAA's Determination
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 is issuing this AD after determining that the unsafe condition described previously is likely to exist or develop on other products of the same type design.
Requirements of This AD
This AD requires accomplishing the actions specified in Transport Canada Emergency AD CF-2024-34 and AD CF-2024-34R1 described previously, except for any differences identified as exceptions in the regulatory text of this AD.
Clarification of Airplane Group Definition
Transport Canada defines Group B airplanes as Model BD-500-1A10 airplanes, having serial numbers 50001 through 50047, and Model BD-500-1A11 airplanes, having serial numbers 55001 through 55070. This AD clarifies Group B airplanes as only those airplanes on which Part C of the Accomplishment Instructions of ACLP SB BD500-534101, Issue 005, dated June 12, 2020, Issue 006, dated August 14, 2020, Issue 007, dated October 2, 2020, or Issue 008, dated March 13, 2024, has not been done.
Explanation of Required Compliance Information
In the FAA's ongoing efforts to improve the efficiency of the AD process, the FAA developed a process to use some civil aviation authority (CAA) ADs as the primary source of information for compliance with requirements for corresponding FAA ADs. The FAA has been coordinating this process with manufacturers and CAAs. As a result, AD 2024-04-11 is retained and Transport Canada Emergency AD CF-2024-34 and AD CF-2024-34R1 are incorporated by reference in this AD. This AD requires compliance with Transport Canada Emergency AD CF-2024-34 or AD CF-2024-34R1 in its entirety through that incorporation, except for any differences identified as exceptions in the regulatory text of this AD. Material required by Transport Canada Emergency AD CF-2024-34 and AD CF-2024-34R1 for compliance will be available at regulations.gov under Docket No. FAA-2024-2415 after this AD is published.
FAA's Justification and Determination of the Effective Date
Section 553(b) of the Administrative Procedure Act (APA) (5 U.S.C. 551 et seq.) authorizes agencies to dispense with notice and comment procedures for rules when the agency, for “good cause,” finds that those procedures are “impracticable, unnecessary, or contrary to the public interest.” Under this section, an agency, upon finding good cause, may issue a final rule without providing notice and seeking comment prior to issuance. Further, section 553(d) of the APA authorizes agencies to make rules effective in less than thirty days, upon a finding of good cause.
An unsafe condition exists that requires the immediate adoption of this AD without providing an opportunity for public comments prior to adoption. The FAA has found that the risk to the flying public justifies forgoing notice and comment prior to adoption of this rule because Transport Canada issued an emergency AD indicating that damage to a VFG harness resulted in the loss of the associated VFG and the posting of the L GEN FAIL (Caution) message. Implementation of Part C of ACLP SB BD500-534101 (Issues 005 through 008) could potentially cause an unsupported VFG power-feeder harness length in a different location on both sides of the airplane, which could lead to VFG power-feeder harness damage in these locations, which could lead to a loss of generated power from both VFGs and loss of critical aircraft systems if alternate generators are also lost. Additionally, the compliance time in this AD is shorter than the time necessary for the public to comment and for publication of the final rule. Accordingly, notice and opportunity for prior public comment are impracticable and contrary to the public interest pursuant to 5 U.S.C. 553(b).
In addition, the FAA finds that good cause exists pursuant to 5 U.S.C. 553(d) for making this amendment effective in less than 30 days, for the same reasons the FAA found good cause to forgo notice and comment.
Regulatory Flexibility Act (RFA)
The requirements of the RFA do not apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt a rule without prior notice and comment. Because the FAA has determined that it has good cause to adopt this rule without notice and comment, RFA analysis is not required.
Costs of Compliance
The FAA estimates that this AD affects 17 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD:
Estimated Costs for Required Actions
| Action | Labor cost | Parts cost | Cost per product | Cost on U.S. operators |
|---|---|---|---|---|
| Retained actions from AD 2024-04-11 | Up to 51 work-hours × $85 per hour = $4,335 | Up to $3,538 | Up to $7,873 | Up to $133,841. |
| New GVI | 1 work-hour × $85 per hour = $85 | $0 | $85 | $1,445. |
Estimated Costs of On-Condition Actions
| Labor cost | Parts cost | Cost per product |
|---|---|---|
| Up to 60 work-hours × $85 per hour = Up to $5,100 per side | $9,940 per harness | Up to $15,040 per side. |