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###### Department of Transportation

###### Federal Aviation Administration

          - 14 CFR Part 39
          - [Docket No. FAA-2023-1992; Project Identifier MCAI-2023-00414-T; Amendment 39-22568; AD 2023-20-09]
          - RIN 2120-AA64

# AGENCY:

Federal Aviation Administration (FAA), DOT.

# ACTION:

Final rule; request for comments.

# SUMMARY:

The FAA is adopting a new airworthiness directive (AD) for all MHI RJ Aviation ULC Model CL-600-2E25 (Regional Jet Series 1000) airplanes. This AD was prompted by a determination that a new airworthiness limitation is necessary. This AD requires revising the existing maintenance or inspection program, as applicable, to establish a new life limit for a certain main landing gear (MLG) retract actuator piston rod. The FAA is issuing this AD to address the unsafe condition on these products.

# DATES:

This AD is effective October 30, 2023.

The FAA must receive comments on this AD by November 27, 2023.

# 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-2023-1992; 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, any comments received, and other information. The street address for Docket Operations is listed above.                    

# FOR FURTHER INFORMATION CONTACT:

                        Gabriel D. Kim, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7343; email                         *9-avs-nyaco-cos@faa.gov.*

# SUPPLEMENTARY INFORMATION:

## Comments Invited

                    The FAA invites you to send any written relevant data, views, or arguments about this final rule. Send your comments to an address listed under                     **ADDRESSES**                    . Include “Docket No. FAA-2023-1992; Project Identifier MCAI-2023-00414-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 Gabriel D. Kim, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7343; 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

Transport Canada, which is the aviation authority for Canada, has issued Transport Canada AD CF-2022-56, dated September 26, 2022 (referred to after this as “the MCAI”), to correct an unsafe condition on all MHI RJ Aviation ULC (formerly Bombardier Inc.) Model CL-600-2E25 (Regional Jet Series 1000) airplanes. The MCAI states MLG fatigue testing that was accomplished at the time of aircraft certification was not performed in accordance with the Qualification Test Plan. According to the MCAI, the pressure impulse testing was repeated on the CL600-2E25 MLG retract actuator using the required load spectrum, and as a result, a “safe life limitation” of 9,300 flight cycles was established for piston rod part number (P/N) 55615-1.

The FAA is issuing this AD to establish a life limit for MLG retract actuator piston rod part number 55615-1. Exceeding this life limit could result in failure of the MLG retract actuator piston in flight, causing an undamped MLG free fall extension, which may result in MLG collapse on landing.

                    You may examine the MCAI in the AD docket at                     *regulations.gov*                     under Docket No. FAA-2023-1992.                

## 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 and service information referenced above. The FAA is issuing this AD after determining that the unsafe condition described previously is                           ( print page 70886)                        likely to exist or develop on other products of the same type design.                

## Requirements of the Final Rule

This AD requires revising the existing maintenance or inspection program, as applicable, to incorporate a new life limit of 9,300 flight cycles for MLG retract actuator piston rod P/N 55615-1.

## Justification for Immediate Adoption and Determination of the Effective Date

                    Section 553(b)(3)(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.                

The FAA has found that the risk to the flying public justifies foregoing notice and comment prior to adoption of this rule because there are no airplanes currently on the U.S. registry and thus, it is unlikely that the FAA will receive any adverse comments or useful information about this AD from U.S. operator. Accordingly, notice and opportunity for prior public comment are unnecessary, pursuant to 5 U.S.C. 553(b)(3)(B).

In addition, for the foregoing reasons, 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.

## Regulatory Flexibility Act

The requirements of the Regulatory Flexibility Act (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 prior notice and comment, RFA analysis is not required.

## Costs of Compliance

Currently, there are no airplanes with this type certificate on the U.S. registry. If an affected airplane is imported and placed on the U.S. Registry in the future, the FAA provides the following cost estimates to comply with this AD:

The FAA has determined that revising the maintenance or inspection program takes an average of 90 work-hours per operator, although the FAA recognizes that this number may vary from operator to operator. Since operators incorporate maintenance or inspection program changes for their affected fleet(s), the FAA has determined that a per-operator estimate is more accurate than a per-airplane estimate. Therefore, the FAA estimates the total cost per operator to be $7,650 (90 work-hours × $85 per work-hour).

## 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, and

(2) Will not affect intrastate aviation in Alaska.

# List of Subjects in 14 CFR Part 39

      - Air transportation
      - Aircraft
      - Aviation safety
      - Incorporation by reference
      - Safety

## The Amendment

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

# PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows: 

Authority:49 U.S.C. 106(g), 40113, 44701.

§ 39.13

2. The FAA amends § 39.13 by adding the following new airworthiness directive: 

**2023-20-09 MHI RJ Aviation ULC (Type Certificate Previously Held by Bombardier, Inc.):**                             Amendment 39-22568; Docket No. FAA-2023-1992; Project Identifier MCAI-2023-00414-T.                        

## (a) Effective Date

This airworthiness directive (AD) is effective October 30, 2023.

## (b) Affected ADs

None.

## (c) Applicability

This AD applies to all MHI RJ Aviation ULC (type certificate previously held by Bombardier Inc.) Model CL-600-2E25 (Regional Jet Series 1000) airplanes, certificated in any category.

## (d) Subject

Air Transport Association (ATA) of America Code 32, Landing Gear.

## (e) Reason

This AD was prompted by a determination that a new airworthiness limitation is necessary. The FAA is issuing this AD to establish a life limit for main landing gear (MLG) retract actuator piston rod part number 55615-1. Exceeding this life limit could result in failure of the MLG retract actuator piston in flight, causing an undamped MLG free fall extension. The unsafe condition, if not addressed, could result in MLG collapse on landing.

## (f) Compliance

Comply with this AD within the compliance times specified, unless already done.

## (g) Maintenance or Inspection Program Revision

Within 60 days after the effective date of this AD, revise the existing maintenance or inspection program, as applicable, to establish a life limit of 9,300 flight cycles for the MLG retract actuator piston rod (part of MLG retract actuator 55600), part number 55615-1. The initial compliance time for removing the part from service is at the applicable time specified in paragraphs (g)(1) through (3) of this AD.

**Note 1 to paragraph (g):**                             The life limit in paragraph (g) of this AD can be found in Airworthiness Limitation (ALI) Task Number 32-32-05-709 for Configuration B, “Piston Rod, MLG Retract Actuator (part of MLG Retract Actuator 55600)” of MHI RJ CRJ700/900/1000 Temporary Revision ALI-0763, dated April 14, 2022 (TR ALI-0763), which specifies an effective date of April 14, 2022.                        

(1) For a MLG retract actuator piston rod that has accumulated fewer than 4,300 total flight cycles as of April 14, 2022 (phase-in Effective Date of TR ALI-0763): Before accumulating 9,300 total flight cycles.

                            (2) For a MLG retract actuator piston rod that has accumulated 4,300 total flight cycles                                   ( print page 70887)                                or more and 18,000 total flight cycles or fewer as of April 14, 2022 (phase-in Effective Date of TR ALI-0763): Within 5,000 flight cycles from April 14, 2022, or before exceeding 20,000 total flight cycles, whichever occurs first.                        

(3) For a MLG retract actuator piston rod that has accumulated more than 18,000 total flight cycles as of April 14, 2022 (phase-in Effective Date of TR ALI-0763): Within 2,000 flight cycles from April 14, 2022.

## (h) No Alternative Actions or Intervals

                            After the existing maintenance or inspection program has been revised as required by paragraph (g) of this AD, no alternative actions (                            *e.g.,*                             inspections) or intervals may be used unless they are approved as an alternative method of compliance in accordance with paragraph (i)(1) of this AD.                        

## (i) Additional AD Provisions

The following provisions also apply to this AD:

                            (1)                             *Alternative Methods of Compliance (AMOCs):*                             The Manager, International Validation Branch, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the manager of the International Validation Branch, mail it to the address identified in paragraph (j)(3) of this AD or email to:                             *9-AVS-AIR-730-AMOC@faa.gov.*                             If mailing information, also submit information by email. Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the responsible Flight Standards Office.                        

                            (2)                             *Contacting the Manufacturer:*                             For any requirement in this AD to obtain instructions from a manufacturer, the instructions must be accomplished using a method approved by the Manager, International Validation Branch, FAA; or Transport Canada; or MHI RJ Aviation ULC Transport Canada Design Approval Organization (DAO). If approved by the DAO, the approval must include the DAO-authorized signature.                        

## (j) Additional Information

                            (1) Refer to Transport Canada AD CF-2022-56, dated September 26, 2022, for related information. This Transport Canada AD may be found in the AD docket at                             *regulations.gov*                             under Docket No. FAA-2023-1992.                        

                            (2) For more information about this AD, contact Gabriel D. Kim, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7343; email                             *9-avs-nyaco-cos@faa.gov.*

                            (3) For MHI RJ service information identified in this AD that is not incorporated by reference, contact MHI RJ Aviation Group, Customer Response Center, 3655 Ave. des Grandes-Tourelles, Suite 110, Boisbriand, Québec J7H 0E2 Canada; North America toll-free telephone 833-990-7272 or direct-dial telephone 450-990-7272; fax 514-855-8501; email                             *thd.crj@mhirj.com;*                             website                             *mhirj.com.*

## (k) Material Incorporated by Reference

None.

Issued on October 4, 2023.

Victor Wicklund,

Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service.

[FR Doc. 2023-22486 Filed 10-12-23; 8:45 am]

BILLING CODE 4910-13-P