# AD 2022-11-07: Main Rotor System - Type: Airworthiness directive - Status: Current - Products: Airbus Helicopters Deutschland MBB-BK 117 A-1, MBB-BK 117 A-3, MBB-BK 117 A-4, MBB-BK 117 B-1, MBB-BK 117 B-2, MBB-BK 117 C-1, MBB-BK 117 C-2 and MBB-BK 117 D-2 - Effective: July 8, 2022 - Published: June 3, 2022, 87 FR 33630–33632 - Issued: May 17, 2022 - Issued as: Final rule - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Rotorcraft - Amendment: 39-22057 - Docket: FAA-2022-0294 (https://www.regulations.gov/docket/FAA-2022-0294) - Project: MCAI-2021-00550-R - Registered aircraft: 192 may be affected, by airframe or engine model (OpenAirDocs) - Official PDF: https://openairdocs.org/files/sha256/66/95/6695510519394001909a9056396c8dd6f9f9c9d53174bb10b86a7b4853703731 (from https://www.govinfo.gov/content/pkg/FR-2022-06-03/pdf/2022-11936.pdf) - Federal Register: https://www.federalregister.gov/documents/2022/06/03/2022-11936/airworthiness-directives-airbus-helicopters-deutschland-gmbh-ahd-helicopters - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/FR-ADFRAWD-2022-11936-0000000000.0001 - DRS record last changed: November 21, 2025 - Page: https://openairdocs.org/ad/2022-11-07 ## Summary The FAA is adopting a new airworthiness directive (AD) for all Airbus Helicopters Deutschland GmbH (AHD) Model MBB-BK117 A-1, MBB-BK117 A-3, MBB-BK117 A-4, MBB-BK117 B-1, MBB-BK117 B-2, MBB-BK117 C-1, MBB-BK117 C-2, and MBB-BK117 D-2 helicopters. This AD was prompted by the FAA's determination that aging of the elastomeric material of certain tension torsion straps (TT-Straps), during the period since manufacturing date up to first flight on a helicopter, may affect its structural characteristics. This AD requires the replacement of certain TT-Straps, implementation of storage life limits for TT-Straps, a prohibition on installing certain TT-Straps, and conditions for installation of certain other TT-Straps, as specified in a European Union Aviation Safety Agency (EASA) AD, which is incorporated by reference. The FAA is issuing this AD to address the unsafe condition on these products. ## The airworthiness directive 1. The authority citation for part 39 continues to read as follows: 2. The FAA amends § 39.13 by adding the following new airworthiness directive: 2022-11-07 Airbus Helicopters Deutschland GmbH (AHD): Amendment 39-22057; Docket No. FAA-2022-0294; Project Identifier MCAI-2021-00550-R. ### (a) Effective Date This airworthiness directive (AD) is effective July 8, 2022. ### (b) Affected ADs None. ### (c) Applicability This AD applies to all Airbus Helicopters Deutschland GmbH (AHD) Model MBB-BK117 A-1, MBB-BK117 A-3, MBB-BK117 A-4, MBB-BK117 B-1, MBB-BK117 B-2, MBB-BK117 C-1, MBB-BK117 C-2, and MBB-BK117 D-2 helicopters, certificated in any category. ### (d) Subject Joint Aircraft Service Component (JASC) Code: 6200, Main Rotor System. ### (e) Unsafe Condition This AD was prompted by the FAA's determination that aging of the elastomeric material of certain tension torsion straps (TT-Straps), during the period since manufacturing date up to first flight on a helicopter, may affect its structural characteristics. The FAA is issuing this AD to address aging of the elastomeric material of certain TT-Straps. The unsafe condition, if not addressed, could result in premature failure of a TT-Strap, possibly resulting in loss of control of the helicopter. ### (f) Compliance Comply with this AD within the compliance times specified, unless already done. ### (g) Requirements Except as specified in paragraph (h) of this AD: Comply with all required actions and compliance times specified in, and in accordance with, European Union Aviation Safety Agency (EASA) AD 2021-0122, dated May 6, 2021 (EASA AD 2021-0122). ### (h) Exceptions to EASA AD 2021-0122 (1) Where EASA AD 2021-0122 refers to its effective date, this AD requires using the effective date of this AD. (2) Where EASA AD 2021-0122 specifies the “cure date” of a TT-Strap, the cure date can be determined using the information provided in the service information specified in EASA AD 2021-0122, or by contacting Airbus Helicopters Deutschland GmbH for applicable instructions. If the option of contacting Airbus Helicopters Deutschland GmbH for instructions is chosen, those instructions must be approved by the Manager, General Aviation & Rotorcraft Section, International Validation Branch, FAA; or EASA; or Airbus Helicopters' EASA Design Organization Approval (DOA). If approved by the DOA, the approval must include the DOA-authorized signature. (3) This AD does not mandate compliance with the “Remarks” section of EASA AD 2021-0122. (4) Where the service information referenced in EASA AD 2021-0122 specifies scrapping a part, this AD requires removing that part from service. (5) Where paragraph (1) of EASA AD 2021-0122 specifies to replace each Lord TT-Strap and Bendix TT-Strap “in accordance with the instructions of the applicable ASB,” for this AD, the replacement must be done using FAA-approved procedures. (6) Where EASA AD 2021-0122 refers to the airworthiness limitations items of the airworthiness limitations section of the aircraft maintenance manual (AMM) for the definition of service life limit (SLL), this AD requires using the life limits specified in paragraphs (h)(6)(i) through (iii) of this AD, as applicable. (i) For Bendix TT-Strap P/N 2604067 and P/N 117-14110: Before 10 years or 25,000 flight cycles on the part, whichever occurs first. (ii) For Lord TT-Strap P/N J17322-1 and P/N 117-14111: Before 12 years or 40,000 flight cycles on the part, whichever occurs first. (iii) For Lord TT-Strap P/N B622M10T1001: Before 12 years or 30,000 flight cycles on the part, whichever occurs first. (7) Where table 1 of EASA AD 2021-0122 specifies a compliance time of “During the next helicopter periodical inspection or within 2 months, whichever occurs later after the effective date of this AD, but not exceeding the SLL,” for this AD, the compliance time is “Within 2 months after the effective date of this AD but not exceeding the applicable SLL specified in paragraphs (h)(6)(i) through (iii) of this AD.” ### (i) Special Flight Permit Special flight permits, as described in 14 CFR 21.197 and 21.199, are not allowed. ### (j) 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 (k) 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. ### (k) Related Information For more information about this AD, contact Kristi Bradley, Program Manager, COS Program Management Section, Operational Safety Branch, Compliance & Airworthiness Division, FAA, 10101 Hillwood Pkwy., Fort Worth, TX 76177; phone: (817) 222-5110; email: kristin.bradley@faa.gov. ### (l) Material Incorporated by Reference (1) The Director of the Federal Register approved the incorporation by reference of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51. (2) You must use this service information as applicable to do the actions required by this AD, unless this AD specifies otherwise. (i) European Union Aviation Safety Agency (EASA) AD 2021-0122, dated May 6, 2021. (ii) [Reserved] (3) For EASA AD 2021-0122, contact EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; telephone +49 221 8999 000; email ADs@easa.europa.eu; internet www.easa.europa.eu. You may find the EASA material on the EASA website at https://ad.easa.europa.eu. (4) 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. This material may be found in the AD docket at https://www.regulations.gov by searching for and locating Docket No. FAA-2022-0294. (5) You may view this material that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, email fr.inspection@nara.gov, or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html. ## Rule preamble ### Dates This AD is effective July 8, 2022. The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of July 8, 2022. ### Addresses For EASA material incorporated by reference (IBR) in this final rule, contact EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; telephone +49 221 8999 000; email ADs@easa.europa.eu; internet www.easa.europa.eu. You may find the EASA material on the EASA website at https://ad.easa.europa.eu. You may view this material 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. It is also available in the AD docket at https://www.regulations.gov by searching for and locating Docket No. FAA-2022-0294. ### For further information contact Kristi Bradley, Program Manager, COS Program Management Section, Operational Safety Branch, Compliance & Airworthiness Division, FAA, 10101 Hillwood Pkwy., Fort Worth, TX 76177; phone: (817) 222-5110; email: kristin.bradley@faa.gov. ### Background EASA, which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2021-0122, dated May 6, 2021 (EASA AD 2021-0122), to correct an unsafe condition for all Airbus Helicopters Deutschland GmbH (AHD) (formerly Eurocopter Deutschland GmbH, Eurocopter Hubschrauber GmbH, Messerschmitt-Bölkow-Blohm GmbH; Airbus Helicopters Inc., formerly American Eurocopter LLC) Model MBB-BK117 A-1, MBB-BK117 A-3, MBB-BK117 A-4, MBB-BK117 B-1, MBB-BK117 B-2, MBB-BK117 C-1, MBB-BK117 C-2, and MBB-BK117 D-2 helicopters. The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to all Airbus Helicopters Deutschland GmbH (AHD) Model MBB-BK117 A-1, MBB-BK117 A-3, MBB-BK117 A-4, MBB-BK117 B-1, MBB-BK117 B-2, MBB-BK117 C-1, MBB-BK117 C-2, and MBB-BK117 D-2 helicopters. The NPRM published in the Federal Register on March 28, 2022 (87 FR 17201). The NPRM was prompted by the FAA's determination that aging of the elastomeric material of certain TT-Straps, during the period since manufacturing date up to first flight on a helicopter, may affect its structural characteristics. The NPRM proposed to require the replacement of certain TT-Straps, implementation of storage life limits for TT-Straps, a prohibition on installing certain TT-Straps, and conditions for installation of certain other TT-Straps, as specified in EASA AD 2021-0122. The FAA is issuing this AD to address aging of the elastomeric material of certain TT-Straps. The unsafe condition, if not addressed, could result in premature failure of a TT-Strap, possibly resulting in loss of control of the helicopter. See EASA AD 2021-0122 for additional background information. ### Comments The FAA received no comments on the NPRM or on the determination of the costs. ### Conclusion 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 reviewed the relevant data and determined that air safety requires adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on these helicopters. Except for minor editorial changes, this AD is adopted as proposed in the NPRM. ### Related Service Information Under 1 CFR Part 51 EASA AD 2021-0122 requires the replacement of certain TT-straps, implementation of storage life limits for TT-Straps since cure date, a prohibition on installing certain TT-Straps, and provides conditions for installation of certain other TT-Straps. 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 213 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 AD. *Estimated Costs* | Action | Labor cost | Parts cost | Cost per product | Cost on U.S. operators | | --- | --- | --- | --- | --- | | Replace the TT-Strap | 5 work-hours × $85 per hour = $425 | $4,800 | $5,225 | $1,112,925 | ### 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, (2) Will not affect intrastate aviation in Alaska, and (3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. ### The Amendment Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS H13EU](https://openairdocs.org/tcds/H13EU): Airbus Helicopters Deutschland GmbH (AHD); names 8 of 9 models: MBB-BK 117 C-2, MBB-BK 117 B-2, MBB-BK 117 A-3, MBB-BK 117 B-1, MBB-BK 117 A-4, MBB-BK 117 A-1, MBB-BK 117 C-1, MBB-BK 117 D-2 ## Registered aircraft it may apply to (OpenAirDocs) Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment. - Aircraft: 192 (192 by airframe model, 0 by engine model) - Makers: Eurocopter Deutschland 121, Airbus Helicopters 35, Airbus Helicopters Deutschland 34, American Eurocopter 1, Messerschmitt-Bolkow-Blohm 1 Models with the most aircraft: - [Eurocopter Deutschland MBB-BK 117 C-2](https://openairdocs.org/model/eurocopter-deutschland-mbb-bk-117-c-2): 109 aircraft (airframe model) - [Airbus Helicopters MBB-BK 117 C-2](https://openairdocs.org/model/airbus-helicopters-mbb-bk-117-c-2): 35 aircraft (airframe model) - [Airbus Helicopters Deutschland MBB-BK 117 D-2](https://openairdocs.org/model/airbus-helicopters-deutschland-mbb-bk-117-d-2): 21 aircraft (airframe model) - [Airbus Helicopters Deutschland MBB-BK 117 C-2](https://openairdocs.org/model/airbus-helicopters-deutschland-mbb-bk-117-c-2): 13 aircraft (airframe model) - [Eurocopter Deutschland MBB-BK 117 C-1](https://openairdocs.org/model/eurocopter-deutschland-mbb-bk-117-c-1): 9 aircraft (airframe model) - [Eurocopter Deutschland MBB-BK 117-B2](https://openairdocs.org/model/eurocopter-deutschland-mbb-bk-117-b2): 3 aircraft (airframe model) - [American Eurocopter MBB-BK 117 C-2](https://openairdocs.org/model/american-eurocopter-mbb-bk-117-c-2): 1 aircraft (airframe model) - [Messerschmitt-Bolkow-Blohm MBB-BK 117 B-2](https://openairdocs.org/model/messerschmitt-bolkow-blohm-mbb-bk-117-b-2): 1 aircraft (airframe model) All 8 models: https://openairdocs.org/ad/2022-11-07/models.md Every aircraft: https://openairdocs.org/ad/2022-11-07/aircraft.md ## Related documents - [Proposed rule FAA-2022-0294](https://openairdocs.org/proposed/FAA-2022-0294): Notice of proposed rulemaking (NPRM), published Mar 28, 2022 Its text cites no advisory circulars or STCs. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.