# [Amended]
**AGENCY:**
Federal Aviation Administration (FAA), DOT.
**ACTION:**
Notice of proposed rulemaking (NPRM).
**SUMMARY:**
The FAA proposes to adopt a new airworthiness directive (AD) for all Airbus Helicopters Deutschland GmbH (AHD) Model MBB-BK 117 C-2 and MBB-BK 117 D-2 helicopters. This proposed AD was prompted by a determination that a certain part-numbered standard MS18027 type hook may be subject to localized yielding in the mating threads when assembled to higher assembly torques. This proposed AD would require modifying and re-identifying the affected part or replacing the affected part with a serviceable part. This proposed AD would also prohibit installing an affected part on any helicopter unless certain requirements are met. The FAA is proposing this AD to address the unsafe condition on these products.
**DATES:**
The FAA must receive comments on this NPRM by March 12, 2026.
**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-2026-0730; 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 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 European Union Aviation Safety Agency (EASA) material identified in this proposed AD, contact EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; phone: +49 221 8999 000; email: *[email protected];* website: *easa.europa.eu* . You may find the EASA material on the EASA website at *ad.easa.europa.eu* .
• You may view this material at the FAA, Office of the Regional Counsel, Southwest Region, 10101 Hillwood Parkway, Room 6N-321, Fort Worth, TX 76177. For information on the availability of this material at the FAA, call (817) 222-5110.
**FOR FURTHER INFORMATION CONTACT:**
Steven Warwick, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (817) 222-5225; email: *[email protected]* .
**SUPPLEMENTARY INFORMATION:**
**Comments Invited**
The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments using a method listed under *ADDRESSES* . Include “Docket No. FAA-2026-0730; Project Identifier MCAI-2025-01416-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.
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 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 Steven Warwick, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590. 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 2025-0188, dated September 1, 2025 (EASA AD 2025-0188) (also referred to as the MCAI), to correct an unsafe condition on AHD Model MBB-BK117 C-2 and MBB-BK117 D-2 helicopters. The MCAI states that the standard MS18027 hook part number (P/N) 42305-283 installed on the large hook damper assembly P/N 44307-480, may be subject to localized yielding in the mating threads when assembled to higher assembly torques.
This condition, if not addressed, could result in failure of the hook damper assembly, which could result in loss of the hoist load and injury to persons.
You may examine the MCAI in the AD docket at *regulations.gov* under Docket No. FAA-2026-0730.
**Material Incorporated by Reference Under 1 CFR Part 51**
The FAA reviewed EASA AD 2025-0188, which specifies procedures for modifying the large hook damper assembly having P/N 44307-480 by replacing the standard MS18027 hook P/N 42305-283 with D-Lok hook P/N 42315-488 and reidentifying the large hook damper assembly to P/N 44307-480-1.
EASA AD 2025-0188 also specifies procedures for replacing large hook damper assembly P/N 44307-480 with large hook damper assembly P/N 44307-480-1 (modification already accomplished) as an alternative to the initial modification requirement. EASA AD 2025-0188 also prohibits installing an affected large hook damper assembly having P/N 44307-480 on any helicopter unless certain requirements are met within 12 months of the effective date of this AD and prohibits installing the affected part on any helicopter.
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**
These products have been approved by the civil aviation authority (CAA) of another country and are approved for operation in the United States. Pursuant to the FAA's bilateral agreement with this State of Design Authority, that authority has notified the FAA of the unsafe condition described in the MCAI referenced above. The FAA is issuing this NPRM after determining that the unsafe condition described previously is likely to exist or develop on other products of the same type design.
**Proposed AD Requirements in This NPRM**
This proposed AD would require accomplishing the actions specified in EASA AD 2025-0188, described previously, as incorporated by reference, except for any differences identified as exceptions in the regulatory text of this AD.
**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 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, the FAA proposes to incorporate EASA AD 2025-0188 by reference in the FAA final rule. This proposed AD would, therefore, require compliance with EASA AD 2025-0188 in its entirety through that incorporation, except for any differences identified as exceptions in the regulatory text of this proposed AD. Using common terms that are the same as the heading of a particular section in EASA AD 2025-0188 does not mean that operators need comply only with that section. For example, where the AD requirement refers to “all required actions and compliance times,” compliance with this AD requirement is not limited to the section titled “Required Action(s) and Compliance Time(s)” in EASA AD 2025-0188. Material required by EASA AD 2025-0188 for compliance will be available at *regulations.gov* under Docket No. FAA-2026-0730 after the FAA final rule is published.
**Costs of Compliance**
The FAA estimates that this AD, if adopted as proposed, would affect 183 helicopters of U.S. registry.
The FAA estimates the following costs to comply with this proposed AD:
| Action | Labor cost | Parts cost | Cost per | Cost on U.S. |
| --- | --- | --- | --- | --- |
| Modify hook and reidentify large hook damper assembly | 1 work-hour × $85 per hour = $85 | $3,545 | $3,630 | $664,290 |
The FAA estimates the following cost to do any replacement that would be an alternative method of compliance. The agency has no way of determining the number of helicopters that might choose this replacement:
| Action | Labor cost | Parts cost | Cost per |
| --- | --- | --- | --- |
| Replace large hook damper assembly | 1 work-hours × $85 per hour = $85 | $23,867 | $23,952 |
**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 above, 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 (AHD):* Docket No. FAA-2026-0730; Project Identifier MCAI-2025-01416-R.
**(a) Comments Due Date**
The FAA must receive comments on this airworthiness directive (AD) by March 12, 2026.
**(b) Affected ADs**
None.
**(c) Applicability**
This AD applies to Airbus Helicopters Deutschland GmbH (AHD) Model MBB-BK 117 C-2 and MBB-BK 117 D-2 helicopters, certificated in any category.
**(d) Subject**
Joint Aircraft System Component (JASC) Code 2500, Cabin Equipment/Furnishings.
**(e) Unsafe Condition**
This AD was prompted by the determination that the standard MS18027 type hook may be subject to localized yielding in the mating threads when assembled to higher assembly torques. The FAA is issuing this AD to prevent failure of the hook. The unsafe condition, if not addressed, could result in failure of the large hook damper assembly, which could result in loss of the hoist load and injury to persons.
**(f) Compliance**
Comply with this AD within the compliance times specified, unless already done.
**(g) Required Actions**
Except as specified in paragraphs (h) and (i) of this AD: Comply with all required actions and compliance times specified in, and in accordance with, European Union Aviation Safety Agency AD 2025-0188, dated September 1, 2025 (EASA AD 2025-0188).
**(h) Exceptions to EASA AD 2025-0188**
(1) Where EASA AD 2025-0188 refers to its effective date, this AD requires using the effective date of this AD.
(2) Where the material referenced in EASA AD 2025-0188 specifies “discard”, this AD requires replacing that text with “remove from service”.
(3) Where the material referenced in EASA AD 2025-0188 specifies “check”, this AD requires replacing that text with “inspect”.
(4) Where the material referenced in EASA AD 2025-0188 specifies “if necessary clean the surface”, this AD requires replacing that text with “clean the surface”.
(5) This AD does not adopt the “Remarks” section of EASA AD 2025-0188.
**(i) No Reporting Requirement**
Although the material referenced in EASA AD 2025-0188 specifies to submit information to the manufacturer, this AD does not require those actions.
**(j) Special Flight Permits**
Special flight permits may be issued in accordance with 14 CFR 21.197 and 21.199 to operate the helicopter to a location where the actions of this AD can be accomplished provided that no external load is carried.
**(k) 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 (l) of this AD and email to: *[email protected].*
(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.
**(l) Additional Information**
For more information about this AD, contact Steven Warwick, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (817) 222-5225; email: *[email protected].*
**(m) Material Incorporated by Reference**
(1) The Director of the Federal Register approved the incorporation by reference of the material listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) You must use this material as applicable to do the actions required by this AD, unless the AD specifies otherwise.
(i) European Union Aviation Safety Agency (EASA) AD 2025-0188, dated September 1, 2025.
(ii) [Reserved]
(3) For EASA material identified in this AD, contact EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; phone: +49 221 8999 000; email: *[email protected];* website: *easa.europa.eu.* You may find the EASA material on the EASA website at *ad.easa.europa.eu.*
(4) You may view this material at the FAA, Office of the Regional Counsel, Southwest Region, 10101 Hillwood Parkway, Room 6N-321, Fort Worth, TX 76177. For information on the availability of this material at the FAA, call (817) 222-5110.
(5) You may view this material at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, visit *www.archives.gov/federal-register/cfr/ibr-locations* or email *[email protected].*
Issued on January 22, 2026.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service.