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###### Department of Transportation

###### Federal Aviation Administration

          - 14 CFR Part 39
          - [Docket No. FAA-2021-0727; Project Identifier AD-2021-00835-R; Amendment 39-21726; AD 2021-19-08]
          - 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 certain Robinson Helicopter Company Model R44 and R44 II helicopters. This AD was prompted by reports of cracked tail rotor blades (blades). This AD requires checking each blade for any crack and removing any cracked blade from service. This AD also requires removing all affected blades from service and prohibits installing any affected blade on any helicopter. The FAA is issuing this AD to address the unsafe condition on these products.

# DATES:

This AD is effective September 22, 2021.

The FAA must receive comments on this AD by October 22, 2021.

# 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                          https://www.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.                    

                        For service information identified in this final rule, contact Robinson Helicopter Company, Pete Riedl, 2901 Airport Drive, Torrance, CA 90505, United States; phone: (310) 539-0508; email:                         *eng1@robinsonheli.com;*                         website:                         *https://robinsonheli.com/​.*                         You may view this service information at the FAA, Office of the Regional Counsel, Southwest Region, 10101 Hillwood Pkwy., Room 6N-321, Fort Worth, TX 76177. For information on the availability of this material at the FAA, call (817) 222-5110.                    

## Examining the AD Docket

                    You may examine the AD docket at                     *https://www.regulations.gov*                     by searching for and locating Docket No. FAA-2021-0727; 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 the Docket Operations is listed above.                

# FOR FURTHER INFORMATION CONTACT:

                        James Guo, Aerospace Engineer, Airframe Section, Los Angeles ACO Branch, Compliance & Airworthiness Division, FAA, 3960 Paramount Blvd., Lakewood, CA 90712; telephone (562) 627-5357; email                         *james.guo@faa.gov.*

# SUPPLEMENTARY INFORMATION:

## Background

The FAA received reports of spanwise cracks found along the leading edge of part number (P/N) C029-3 blades, serial numbers (S/N) 9410 through 9909. These affected blades were factory-installed or shipped as spares between March and December 2019. The cracks were found at different inspection intervals ranging from preflight inspections to 100-hour inspections. In one instance, a cracked blade was suspected when the pilot felt abnormal vibrations during flight; subsequent investigation determined that the blade was cracked. The cause of the cracks is a manufacturing defect in the properties of the blade skin that makes the blades prone to stress corrosion cracking. This condition, if not addressed, could result in reduced controllability and subsequent loss of control of the helicopter. The FAA is issuing this AD to address the unsafe condition on these products.

## FAA's Determination

The FAA is issuing this AD because the agency has determined the unsafe condition described previously is likely to exist or develop in other products of the same type design.

## Related Service Information

The FAA reviewed Robinson Helicopter Company R44 Service Bulletin

SB-108, dated June 30, 2021. This service bulletin specifies removing P/N C029-3 blades with S/N 9410 through 9909 from service. For continued operation until the affected blades are replaced, the service bulletin specifies a preflight inspection to be performed by the pilot.

## AD Requirements

This AD requires, before further flight and thereafter before each flight, checking blade P/N C029-3 with S/N 9410 through 9909 inclusive, for any crack along the leading edge of the blade. An owner/operator (pilot) may perform this required check but must enter compliance with the applicable paragraph of this AD in the helicopter maintenance records in accordance with 14 CFR 43.9(a)(1) through (4) and 91.417(a)(2)(v). A pilot may perform this check because it involves visually checking each blade for a crack. This action can be performed equally well by a pilot or a mechanic. This check is an exception to the FAA's standard maintenance regulations. This AD also requires, before further flight, removing from service any cracked blade and prohibits installing the affected blades on any helicopter. Additionally, this AD requires, within three months after the effective date of this AD, removing all affected blades from service.

## 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                           ( print page 49916)                        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 foregoing notice and comment prior to adoption of this rule because an urgent unsafe condition exist and corrective actions must accomplished before further flight and then within three months. Accordingly, notice and opportunity for prior public comment are impracticable and contrary to the public interest pursuant to 5 U.S.C. 553(b)(3)(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 forego notice and comment.

## 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                     **ADDRESSES**                    . Include “Docket No. 2021-0727 and Project Identifier AD-2021-00835-R” 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                     *https://www.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 James Guo, Aerospace Engineer, Airframe Section, Los Angeles ACO Branch, Compliance & Airworthiness Division, FAA, 3960 Paramount Blvd., Lakewood, CA 90712; telephone (562) 627-5357; email                     *james.guo@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.                

## 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 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

The FAA estimates that this AD affects 164 helicopters of U.S. registry. The FAA estimates the following costs to comply with this AD. Labor costs are estimated at $85 per work-hour. Checking the tail rotor blade for any crack takes about 0.25 work-hour for an estimated cost of $22 per inspection. Replacing the tail rotor blade takes about 3.5 work-hours and parts cost about $3,320 for an estimated cost of $3,618 per helicopter.

The FAA has included all known costs in its cost estimate. According to the manufacturer, however, some 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, 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: 

**2021-19-08 Robinson Helicopter Company:**                             Amendment 39-21726; Docket No. FAA-2021-0727; Project Identifier AD-2021-00835-R.                        

## (a) Effective Date

This airworthiness directive (AD) is effective September 22, 2021.

## (b) Affected ADs

None.

## (c) Applicability

Robinson Helicopter Company Model R44 and R44 II helicopters, certificated in any category, with a tail rotor blade (blade) part number (P/N) C029-3 with serial number (S/N) 9410 through 9909 inclusive, installed.

## (d) Subject

                            Joint Aircraft System Component (JASC) Code: 6410, Tail Rotor Blades.                                  ( print page 49917)    

## (e) Unsafe Condition

This AD was prompted by reports of cracked blades. The FAA is issuing this AD to detect and prevent cracks in the affected blades. The unsafe condition, if not addressed, could result in reduced controllability and subsequent loss of control of the helicopter.

## (f) Compliance

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

## (g) Required Actions

(1) Before further flight and thereafter before each flight, check each blade at the leading edge for a crack. This action may be performed by the owner/operator (pilot) holding at least a private pilot certificate and must be entered into the aircraft records showing compliance with this AD in accordance with 14 CFR 43.9(a)(1) through (4) and 14 CFR 91.417(a)(2)(v). The record must be maintained as required by 14 CFR 91.417, 121.380, or 135.439.

(2) If there is any crack, before further flight, remove the blade from service.

(3) As of the effective date of this AD, do not install a blade identified in paragraph (c) of this AD on any helicopter.

(4) Within three months after the effective date of this AD, remove from service any blade identified in paragraph (c) of this AD.

## (h) Alternative Methods of Compliance (AMOCs)

                            (1) The Manager, Los Angeles ACO 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 certification office, send it to the attention of the person identified in paragraph (i) of this AD. Information may be emailed to:                             *9-ANM-LAACO-AMOC-REQUESTS@faa.gov.*

(2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office.

## (i) Related Information

                            For more information about this AD, contact James Guo, Aerospace Engineer, Airframe Section, Los Angeles ACO Branch, Compliance & Airworthiness Division, FAA, 3960 Paramount Blvd., Lakewood, CA 90712; telephone (562) 627-5357; email                             *james.guo@faa.gov.*

## (j) Material Incorporated by Reference

None.

Issued on September 1, 2021.

Gaetano A. Sciortino,

Deputy Director for Strategic Initiatives, Compliance & Airworthiness Division, Aircraft Certification Service.

[FR Doc. 2021-19300 Filed 9-2-21; 11:15 am]

BILLING CODE 4910-13-P