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###### Department of Transportation

###### Federal Aviation Administration

          - 14 CFR Part 39
          - [Docket No. FAA-2021-0797; Project Identifier MCAI-2021-00218-R]
          - RIN 2120-AA64

# AGENCY:

Federal Aviation Administration (FAA), DOT.

# ACTION:

Notice of proposed rulemaking (NPRM).

# SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for certain Airbus Helicopters Deutschland GmbH Model EC135P1, EC135P2, EC135P2+, EC135P3, EC135T1, EC135T2, EC135T2+, and EC135T3 helicopters. This proposed AD was prompted by reduced life limits being established for certain part-numbered tail rotor (TR) blades. This proposed AD would require determining the total hours time-in-service (TIS) of certain part-numbered TR blades, establishing a life limit for certain part-numbered TR blades, removing from service any TR blade that has reached or exceeded its life limit, creating a component history card, re-identifying certain part-numbered TR blades, and removing any TR blade from service before reaching its retirement life. This proposed AD would also prohibit installing certain TR blades on certain model helicopters. The FAA is proposing this AD to address the unsafe condition on these products.

# DATES:

The FAA must receive comments on this proposed AD by November 8, 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 between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.                    

                        For service information identified in this NPRM, contact Airbus Helicopters, 2701 North Forum Drive, Grand Prairie, TX 75052; telephone (972) 641-0000 or (800) 232-0323; fax (972) 641-3775; or at                         *https://www.airbus.com/​helicopters/​services/​technical-support.html.*                         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-2021-0797 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 NPRM, the European Union Aviation Safety Agency (EASA) AD, any comments received, and other information. The street address for Docket Operations is listed above.                

# FOR FURTHER INFORMATION CONTACT:

                        Andrea Jimenez, Aerospace Engineer, COS Program Management Section, Operational Safety Branch, Compliance & Airworthiness Division, FAA, 1600 Stewart Ave., Suite 410, Westbury, NY 11590; telephone (516) 228-7330; email                         *andrea.jimenez@faa.gov.*

# SUPPLEMENTARY INFORMATION:

## Comments Invited

                    The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under                     **ADDRESSES**                    . Include “Docket No. FAA-2021-0797; Project Identifier MCAI-2021-00218-R” at the beginning of your comments. The most helpful comments reference a specific portion of the proposal, 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 proposal because of those comments.                          ( print page 52857)    

                    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 NPRM.                

## 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 NPRM 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 NPRM, 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 NPRM. Submissions containing CBI should be sent to Andrea Jimenez, Aerospace Engineer, COS Program Management Section, Operational Safety Branch, Compliance & Airworthiness Division, FAA, 1600 Stewart Ave., Suite 410, Westbury, NY 11590; telephone (516) 228-7330; email                     *andrea.jimenez@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

EASA, which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2021-0050, dated February 23, 2021 (EASA AD 2021-0050), to correct an unsafe condition for Airbus Helicopters Deutschland GmbH (AHD), formerly Eurocopter Deutschland GmbH, Eurocopter España S.A., Model EC135 P1, EC135 P2, EC135 P2+, EC135 P3, EC135 T1, EC135 T2, EC135 T2+, EC135 T3, EC635 P2+, EC635 P3, EC635 T1, EC635 T2+, and EC635 T3 helicopters, all variants, and all serial numbers. EASA advises that a reduced life limit has been established for certain part-numbered TR blades due to higher loads experienced in service. This condition, if not addressed, could result in fatigue and failure of a TR blade and loss of control of the helicopter.

Accordingly, EASA AD 2021-0050 requires determining the total hours TIS for certain part-numbered TR blades, recalculating the TIS for affected parts, and implementing a reduced life limit. EASA AD 2021-0050 also prohibits installing certain part-numbered TR blades and TR head assemblies and provides conditions for re-installation of certain TR blades.

## FAA's Determination

These helicopters have been approved by EASA and are approved for operation in the United States. Pursuant to the FAA's bilateral agreement with the European Union, EASA has notified the FAA about the unsafe condition described in its AD. The FAA is proposing this AD after evaluating all known relevant information and determining that the unsafe condition described previously is likely to exist or develop on other helicopters of these same type designs.

## Related Service Information Under 1 CFR Part 51

The FAA reviewed Airbus Helicopters Alert Service Bulletin ASB EC135H-04A-002 and Airbus Helicopters Alert Service Bulletin ASB EC135-04A-014, both Revision 1, and both dated December 21, 2020. This service information specifies procedures to determine the total hours TIS of certain TR blades and provides instructions to re-identify certain part-numbered TR blades.

                    This service information 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.                

## Proposed AD Requirements in This NPRM

This proposed AD would require within 350 hours time-in-service (TIS), determining the total hours TIS of certain part-numbered TR blades and removing from service certain part-numbered TR blades that have accumulated or exceeded 6,800 total hours TIS. This proposed AD would also require for certain part-numbered TR blades with less than 6,800 total hours TIS, creating a component history card or equivalent record to establish a life limit of 6,800 total hours TIS, and removing these TR blades from service before accumulating 6,800 total hours TIS. This proposed AD would require for certain model helicopters re-identifying certain part-numbered TR blades with new part numbers and removing those newly re-identified TR blades from service before exceeding 6,800 total hours TIS.

This proposed AD would also require for certain model helicopters with certain part-numbered TR blades installed that have been previously installed on certain model helicopters determining the total hours TIS of the TR blade in accordance with a method approved by the FAA or EASA. Finally, for certain model helicopters this proposed AD would prohibit installing certain part-numbered TR blades and for certain model helicopters this proposed AD would prohibit installing certain part-numbered TR blades that have exceeded or accumulated 500 total hours TIS while previously installed on certain model helicopters.

## Differences Between This Proposed AD and EASA AD 2021-0050

EASA AD 2021-0050 requires compliance using calendar time, whereas this proposed AD would require compliance using hours TIS instead. EASA AD 2021-0050 applies to Model EC635 P2+, EC635 P3, EC635 T1, EC635 T2+, and EC635 T3 helicopters, which are not certificated by the FAA and are not included on the U.S. type certificate data sheet, except where the U.S. type certificate data sheet explains that the model EC635 T2+ helicopter having serial number 0858 was converted from Model EC635 T2+ to Model EC135 T2+. This proposed AD, therefore, does not include Model EC635 P2+, EC635 P3, EC635 T1, EC635 T2+, and EC635 T3 helicopters in the applicability. EASA AD 2021-0050 specifies contacting Airbus Helicopters Deutschland GmbH to determine the total hours TIS accumulated by certain TR blades whereas this proposed AD would require determining the total hours TIS accumulated by the TR blade in accordance with a method approved by the FAA or EASA. EASA AD 2021-0050 prohibits installing certain part-numbered TR head assemblies as defined in its AD, whereas this AD would not contain this prohibition.

## Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 341 helicopters of U.S. Registry. Labor rates are estimated at $85 per work-hour. Based on these numbers, the FAA estimates the following costs to comply with this proposed AD.

Determining the total hours TIS of each TR blade, updating the helicopter records and re-identifying each TR blade would take about 10 work-hours for each TR blade, for an estimated cost of $850 per TR blade.

                    Replacing each TR blade would take about 10 work-hours and parts would                           ( print page 52858)                        cost about $4,400 for an estimated cost of $5,250 per TR blade replacement.                

## 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

The FAA determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would 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, I certify this proposed regulation:

(1) Is not a “significant regulatory action” under Executive Order 12866,

(2) Would not affect intrastate aviation in Alaska, and

(3) Would not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

# List of Subjects in 14 CFR Part 39

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

## The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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: 

**Airbus Helicopters Deutschland GmbH:**                         Docket No. FAA-2021-0797; Project Identifier MCAI-2021-00218-R.                    

## (a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by November 8, 2021.

## (b) Affected ADs

None.

## (c) Applicability

This AD applies to Airbus Helicopters Deutschland GmbH Model EC135P1, EC135P2, EC135P2+, EC135P3, EC135T1, EC135T2, EC135T2+, and EC135T3 helicopters, certificated in any category, with tail rotor (TR) blade part number (P/N) L642A2002101, L642A2002103, L642A2002104, L642A2002111, or L642A2002112 installed.

## (d) Subject

Joint Aircraft Service Component (JASC) Code: 6410, Tail rotor blades.

## (e) Unsafe Condition

This AD was prompted by a notification of certain parts needing a reduced life limit when installed on certain model helicopters. The FAA is issuing this AD to prevent certain part-numbered TR blades from remaining in service beyond their fatigue life. The unsafe condition, if not addressed, could result in fatigue and failure of a TR blade and loss of helicopter control.

## (f) Compliance

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

## (g) Required Actions

(1) For all model helicopters identified in paragraph (c) of this AD, within 350 hours time-in-service (TIS) after the effective date of this AD, determine the total hours TIS of each TR blade P/N L642A2002101 or P/N L642A2002111 in accordance with paragraph 3.B.2 of the Accomplishment Instructions of Airbus Helicopters Alert Service Bulletin ASB EC135H-04A-002, Revision 1, dated December 21, 2020 (ASB EC135H-04A-002) or paragraph 3.B.2 (version A) or 3.B.4 (version B) of the Accomplishment Instructions of Airbus Helicopters Alert Service Bulletin ASB EC135-04A-014, Revision 1, dated December 21, 2020 (ASB EC135-04A-014) as applicable to your model helicopter. Remove from service any TR blade that has accumulated or exceeded 6,800 total hours TIS. For each TR blade that has accumulated less than 6,800 total hours TIS do the following:

(i) Create a component history card or equivalent record to establish a life limit of 6,800 total hours TIS.

(ii) Re-identify each TR blade P/N L642A2002101 as P/N L642A2002104 and re-identify each T/R blade P/N L642A2002111 as P/N L642A2002112 by following paragraph 3.B.5 of the Accomplishment Instructions of ASB EC135H-04A-002, or paragraph 3.B.7 of the Accomplishment Instructions of ASB EC135-04A-014 as applicable to your model helicopter.

(iii) Thereafter, remove from service any TR blade P/N L642A2002104 or P/N L642A2002112 before it accumulates 6,800 total hours TIS.

(2) For Model EC135P1, EC135P2, EC135P2+, EC135T1, EC135T2, and EC135T2+ helicopters with TR blade P/N L642A2002103 that has previously been installed on Model EC135P3 or EC135T3 helicopters, within 350 hours TIS after the effective date of this AD, determine the total hours TIS of the TR blade in accordance with a method approved by the Manager, General Aviation and Rotorcraft Section, International Validation Branch, FAA; or European Union Aviation Safety Agency (EASA); or Airbus Helicopters' EASA Design Organization Approval (DOA). If approved by the DOA, the approval must include the DOA-authorized signature.

(3) For Model EC135P3 and EC135T3 helicopters within 350 hours TIS after the effective date of this AD, remove from service any TR blade P/N L642A2002103 before exceeding 6,800 total hours TIS.

(4) For Model EC135P3 and EC135T3 helicopters, as of the effective date of this AD, do not install any TR blade P/N L642A2002101, P/N L642A2002103, or P/N L642A2002111 on any helicopter.

(5) For Model EC135P1, EC135P2, EC135P2+, EC135T1, EC135T2, EC135T2+, and EC635T2+ helicopters, as of the effective date of this AD, do not install any TR blade P/N L642A2002101 or L642A2002111 that has accumulated or exceeded 500 total hours TIS while installed on a Model EC135P3 or EC135T3 helicopter.

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

                        (1) 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, send it to the attention of the person identified in paragraph (i)(1) of this AD. Information may be emailed to:                         *9-AVS-AIR-730-AMOC@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

                        (1) For more information about this AD, contact Andrea Jimenez, Aerospace Engineer, COS Program Management Section, Operational Safety Branch, Compliance & Airworthiness Division, FAA, 1600 Stewart Ave., Suite 410, Westbury, NY 11590; telephone (516) 228-7330; email                         *andrea.jimenez@faa.gov.*

                        (2) For service information identified in this AD, contact Airbus Helicopters, 2701                               ( print page 52859)                            North Forum Drive, Grand Prairie, TX 75052; telephone (972) 641-0000 or (800) 232-0323; fax (972) 641-3775; or at                         *https://www.airbus.com/​helicopters/​services/​technical-support.html.*                         You may view this referenced 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.                    

                        (3) The subject of this AD is addressed in EASA AD 2021-0050, dated February 23, 2021. You may view the EASA AD on the internet at                         *https://www.regulations.gov*                         in Docket No. FAA-2021-0797.                    

Issued on September 15, 2021.

Gaetano A. Sciortino,

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

[FR Doc. 2021-20409 Filed 9-22-21; 8:45 am]

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