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Proposed Rule

Airworthiness Directives; Various Helicopters

A Proposed Rule by the Federal Aviation Administration on 03/13/2026

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3. Document Details Published Content - Document Details Agencies Department of Transportation Federal Aviation Administration Agency/Docket Numbers Docket No. FAA-2026-2297 Project Identifier AD-2025-00184-R CFR 14 CFR 39 Document Citation 91 FR 12314 Document Number 2026-04966 Document Type Proposed Rule Pages 12314-12318 (5 pages) Publication Date 03/13/2026 RIN 2120-AA64 Published Content - Document Details

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• Document Details Published Content - Document Details Agencies Department of Transportation Federal Aviation Administration Agency/Docket Numbers Docket No. FAA-2026-2297 Project Identifier AD-2025-00184-R CFR 14 CFR 39 Document Citation 91 FR 12314 Document Number 2026-04966 Document Type Proposed Rule Pages 12314-12318 (5 pages) Publication Date 03/13/2026 RIN 2120-AA64 Published Content - Document Details
• Document Dates Published Content - Document Dates Comments Close 04/27/2026 Dates Text The FAA must receive comments on this proposed AD by April 27, 2026. Published Content - Document Dates

• Table of Contents Enhanced Content - Table of Contents This table of contents is a navigational tool, processed from the
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  • AGENCY:
  • ACTION:
  • SUMMARY:
  • DATES:
  • ADDRESSES:
  • FOR FURTHER INFORMATION CONTACT:
  • SUPPLEMENTARY INFORMATION:
  • Comments Invited
  • Confidential Business Information
  • Background
  • Material Incorporated by Reference Under 1 CFR Part 51
  • FAA's Determination
  • Proposed AD Requirements in This NPRM
  • Costs of Compliance
  • Authority for This Rulemaking
  • Regulatory Findings
  • List of Subjects in 14 CFR Part 39
  • The Proposed Amendment
  • PART 39—AIRWORTHINESS DIRECTIVES
  • (a) Comments Due Date
  • (b) Affected ADs
  • (c) Applicability
  • (d) Subject
  • (e) Unsafe Condition
  • (f) Compliance
  • (g) Repetitive Visual Inspection and Corrective Actions
  • (h) Determining Life and Parts Replacement
  • (i) Fluorescent Penetrant Inspection (FPI) and Corrective Action
  • (j) Update Maintenance Records
  • (k) Provisions for Alternative Actions and Intervals
  • (l) Revision of Existing Rotorcraft Flight Manual (RFM)
  • Figure 1 to Paragraph (l)—New RFM Caution
  • (m) No Reporting or Returning Parts Requirements
  • (n) Special Flight Permits
  • (o) Alternative Methods of Compliance (AMOCs)
  • (p) Additional Information
  • (q) Material Incorporated by Reference Enhanced Content - Table of Contents

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AD-2025-00184-R; Sikorsky Aircraft Corporation S-61A, S-61D, S-61E, S-61L, S-61N, S-61NM, S-61R, S-61V

Siller Helicopters CH-3E, SH-3A
Carson Helicopters, Inc. S-61L, SH-3H
Croman Corporation SH-3H
Glacier Helicopter, Inc. CH-3E
Reynolds Aviation HH-3E, HH-3C, CH-3E

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Department of Transportation

Federal Aviation Administration

1. 14 CFR Part 39
2. [Docket No. FAA-2026-2297; Project Identifier AD-2025-00184-R]
3. 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 various helicopters. This proposed AD was prompted by a report of a loss of tail rotor authority due to auxiliary system fluid loss caused by a yaw pedal damper housing fatigue fracture and attachment bolt fatigue fracture. This proposed AD would require performing repetitive visual inspections of the auxiliary servo assembly, a fluorescent penetrant inspection (FPI) of the yaw pedal damper housing and, if necessary, corrective actions.

This proposed AD would also require determining and recording the remaining life of a certain part and revising the existing rotorcraft flight manual (RFM) to provide the flight crew with procedures to follow under certain conditions. This proposed AD would also require revising the airworthiness limitations section (ALS) of the existing maintenance manual (MM) or instructions for continued airworthiness (ICAs) and the existing approved maintenance or inspection program, as applicable by incorporating a new service life limit for a certain part. This proposed AD would also require re-identifying the serial number of a certain part. 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 April 27, 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-2026-2297; 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, any comments received, and other information. The street address for Docket Operations is listed above.

Material Incorporated by Reference:

• For Sikorsky Aircraft Corporation material identified in this proposed AD, contact Sikorsky Field Representative or Sikorsky's Service Engineering Group at Sikorsky Aircraft Corporation, Mailstop K100, 124 Quarry Road, Trumbull, CT 06611; phone: 1-800-946-4337 (1-800-Winged-S); email: wcscustservice_eng.gr-sik@lmco.com; website: sikorsky360.com. ( printed page 12315)
• 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:

Fatin Saumik, Aviation Safety Engineer, FAA, 1701 Columbia Avenue, College Park, GA 30337; phone: (516) 228-7350; email: ECB-COS@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 using a method listed under ADDRESSES. Include “Docket No. FAA-2026-2297; Project Identifier AD-2025-00184-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 revise 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 Fatin Saumik, Aviation Safety Engineer, FAA, 1701 Columbia Avenue, College Park, GA 30337. Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking.

Background

The FAA received a report of an accident involving a Sikorsky Aircraft Model S-61N helicopter due to the loss of tail rotor authority resulting from auxiliary system fluid loss. An investigation revealed that the auxiliary system fluid loss was caused by a yaw pedal damper housing fatigue fracture and attachment bolt fatigue fracture. During the investigation, it was identified that a non-conforming yaw pedal damper housing lug radius, improper maintenance (failure to properly torque and safety wire bolts), and improper operation (failure to heed the caution in the RFM regarding full activation of rudder pedals in less than five seconds) were contributing factors to the unsafe condition. This condition, if not addressed, could result in auxiliary system fluid loss, loss of tail rotor authority, and consequent reduced controllability of the helicopter or loss of control of the helicopter.

Material Incorporated by Reference Under 1 CFR Part 51

The FAA reviewed Sikorsky Aircraft Corporation S-61 Helicopter Alert Service Bulletin ASB 61B65-25, Basic Issue, dated October 17, 2022, as corrected by Sikorsky Aircraft Corporation S-61 Helicopter Alert Service Bulletin Errata, effective February 3, 2026 (ASB 61B65-25, dated October 17, 2022). This material specifies procedures for repetitive visual inspections of the auxiliary servo assembly, an FPI of the yaw pedal damper housing and, if necessary, corrective actions to include removing from service the yaw pedal damper check valve housing and attachment bolts and replacement with airworthy parts. This material also includes procedures for determining and recording the remaining life of a certain part.

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

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 the material already described. This proposed AD would also require revising the existing RFM for your helicopter by revising the normal procedures section by inserting a preflight inspection of the flight control servo system, which provides the flight crew with a caution to follow under certain conditions.

This proposed AD would also require revising the ALS of the existing MM or ICAs and the existing approved maintenance or inspection program, as applicable, by incorporating a new service life limit for the yaw pedal damper check valve housing and re-identifying the part with a new serial number.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 76 helicopters of U.S. registry.

The FAA estimates the following costs to comply with this proposed AD:

| Action | Labor cost | Parts cost | Cost per
product | Cost on U.S. operators |
| --- | --- | --- | --- | --- |
| Visually inspect auxiliary servo assembly | 1 work-hour × $85 per hour = $85 | $0 | $85 | $6,460 per inspection cycle. |
| Determine remaining life of yaw pedal damper check valve housing | 3 work-hours × $85 per hour = $255 | 0 | 255 | $19,380. |
| Inspect yaw pedal damper check valve housing and attachment bolts | 15 work-hours × $85 per hour = $1,275 | 0 | 1,275 | $96,900. |
| Revise RFM | 1 work-hour × $85 per hour = $85 | 0 | 85 | $6,460. |
| Revise ALS | 1 work-hour × $85 per hour = $85 | 0 | 85 | $6,460. |
| ( printed page 12316) | | | | |
| Record life limit in existing helicopter log card | 1 work-hour × $85 per hour = $85 | 0 | 85 | $6,460. |
The FAA estimates the following costs to do any repairs or replacements that would be required based on the results of the proposed inspection. The agency has no way of determining the number of helicopters that might need these repairs or replacements:

| Action | Labor cost | Parts cost | Cost per
product |
| --- | --- | --- | --- |
| Blend repair and remeasure housing edge break radius | 4 work-hours × $85 per hour = $340 | $0 | $340. |
| Replace yaw pedal damper check valve housing | 1 work-hour × $85 per hour = $85 | $1,200 | $1,285. |
| Replace attachment bolts | 1 work-hour × $85 per hour = $85 | $1 (per bolt) | $86. |
| FPI of yaw pedal damper check valve housing and attachment bolts | 2 work-hours × $85 per hour = $170 | $0 | $170 per inspection cycle. |

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

Various Helicopters: Docket No. FAA-2026-2297; Project Identifier AD-2025-00184-R.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by April 27, 2026.

(b) Affected ADs

None.

(c) Applicability

This AD applies to the helicopters identified in paragraphs (c)(1) through (7) of this AD, certificated in any category.

(1) Carson Helicopters, Inc. Model S-61L and SH-3H helicopters.

(2) Croman Corporation Model SH-3H helicopters.

(3) Glacier Helicopter, Inc. Model CH-3E helicopters.

(4) Reynolds Aviation Model USAF CH-3C, CH-3E, HH-3C, and HH-3E helicopters.

(5) Sikorsky Aircraft Corporation Model S-61A, S-61D, S-61E, and S-61V helicopters.

(6) Sikorsky Aircraft Model S-61L, S-61N, S-61NM, and S-61R helicopters.

(7) Siller Helicopters Model CH-3E and SH-3A helicopters.

(d) Subject

Joint Aircraft System Component (JASC) Code 6700, Rotorcraft Flight Control; 6730, Rotorcraft Servo System.

(e) Unsafe Condition

This AD was prompted by a report of a loss of tail rotor authority due to auxiliary system fluid loss caused by a yaw pedal damper housing fatigue fracture and attachment bolt fatigue fracture. The FAA is issuing this AD to detect and address cracking of the yaw pedal damper housing and attachment bolts and a non-conforming lug radius on the yaw pedal damper housing. The unsafe condition, if not addressed, could result in auxiliary system fluid loss, loss of tail rotor authority, and consequent reduced controllability of the helicopter or loss of control of the helicopter.

(f) Compliance

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

(g) Repetitive Visual Inspection and Corrective Actions

As of the effective date of this AD, before the first flight of each day, inspect the lockwire to determine if attachment hardware does not rotate under finger pressure, and use a high-powered light source and mirror to perform a visual inspection of the auxiliary servo assembly located in the controls compartment (also known as the broom closet) for hydraulic fluid leakage, cracks, missing or loose lockwire, and compromised bolt security ( printed page 12317) (loose, missing, cracked, fractured, or stretched bolts) in accordance with the Accomplishment Instructions Section 3.C.(3)(a) and (b) of Sikorsky Aircraft Corporation S-61 Helicopter Alert Service Bulletin ASB 61B65-25, Basic Issue, dated October 17, 2022, as corrected by Sikorsky Aircraft Corporation S-61 Helicopter Alert Service Bulletin Errata, effective February 3, 2026 (Sikorsky ASB 61B65-25).

(1) If there is any hydraulic fluid leakage, compromised bolt security (loose, missing, cracked, fractured, or stretched bolts), or if there are any cracks on the yaw pedal damper check valve housing, before further flight, replace the yaw pedal damper check valve housing and the associated attachment bolts with serviceable parts.

(2) If there is any loose or missing lockwire, before further flight, inspect that each bolt has a torque value of 45-50 in./lbs. and perform the applicable corrective actions as follows.

(i) If the torque value is correct replace the lockwire.

(ii) If the torque value is below 45 in./lbs. or above 50 in./lbs., or if evidence of compromised bolt security (loose, missing, cracked, fractured, or stretched bolts) is found, replace the yaw pedal damper check valve housing, the associated attachment bolts, and lockwire with serviceable parts.

(h) Determining Life and Parts Replacement

Within 10 hours time-in-service (TIS) from the effective date of the AD:

(1) Determine the remaining life of the yaw pedal damper check valve housing having part number S6165-61517 in accordance with the Accomplishment Instructions, paragraph 3.B., of Sikorsky ASB 61B65-25 and record it in the existing helicopter log card or equivalent record.

(2) Before the yaw pedal damper check valve housing has accumulated 30,000 total hours TIS or within 60 days after the effective date of this AD, whichever occurs later, remove the yaw pedal damper check valve housing from service and replace with a serviceable part.

(i) Fluorescent Penetrant Inspection (FPI) and Corrective Action

(1) Within 150 hours TIS or 4 months, whichever occurs first after the effective date of this AD, perform a fluorescent penetrant inspection (FPI) of the yaw pedal damper check valve housing in accordance with the Accomplishment Instructions, paragraphs 3.C.(3) through (9), of Sikorsky ASB 61B65-25. If there are any cracks in the yaw pedal damper check valve housing, before further flight, remove the yaw pedal damper check valve housing and the associated attachment bolts from service and replace the affected parts with serviceable parts. This FPI terminates the daily checks required by (g)(1) of this AD.

(2) After accomplishing the actions as required by paragraph (i)(1) of this AD, thereafter at every 15 hours TIS, perform the repetitive visual inspection required by paragraph (g)(1) of this AD.

Note 1 to paragraph (i)(2): The 15-hour repetitive inspection is established to coincide with any existing 15-hour TIS safety inspections of the auxiliary servo assembly. For example, Sikorsky Aircraft Model S-61N helicopters have this inspection as specified in Sikorsky Aircraft S-61 Equalized Inspection and Maintenance Program, SA 4047-13, Revision No. 18, dated January 15, 2014.

(j) Update Maintenance Records

Within 30 days after the effective date of this AD, incorporate into existing maintenance records required by 14 CFR 91.417(a)(2) or 135.439(a)(2), as applicable for your helicopter, a new service life limit of 30,000 hours TIS for the yaw pedal damper check valve housing.

(k) Provisions for Alternative Actions and Intervals

After the action required by paragraph (j) of this AD has been accomplished, no alternative actions and associated thresholds and intervals, including life limits, are allowed.

(l) Revision of Existing Rotorcraft Flight Manual (RFM)

Within 30 days after the effective date of this AD, revise the normal procedures section, specifically the preflight inspection of the flight control servo system procedure, of the existing RFM for the helicopter by inserting the information specified in figure 1 to paragraph (l) of this AD or by inserting a copy of this AD.

Figure 1 to Paragraph (l)—New RFM Caution

(m) No Reporting or Returning Parts Requirements

Although Sikorsky ASB 61B65-25 specifies submitting certain information or returning an affected part to the manufacturer, this AD does not include those requirements.

(n) Special Flight Permits

Special flight permits are prohibited.

(o) Alternative Methods of Compliance (AMOCs)

(1) The Manager, East Certification 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 East Certification Branch, send it to the attention of the person identified in paragraph (p) of this AD and email to: 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.

(p) Additional Information

(1) For more information about this AD, contact Fatin Saumik, Aviation Safety Engineer, FAA, 1701 Columbia Avenue, College Park, GA 30337; phone: (516) 228-7350; email: ECB-COS@faa.gov.

(2) Sikorsky Aircraft Corporation material identified in this AD that is not incorporated by reference is available at the address specified in paragraph (q)(3) of this AD.

(q) 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) Sikorsky Aircraft Corporation S-61 Helicopter Alert Service Bulletin ASB 61B65-25, Basic Issue, dated October 17, 2022, as corrected by Sikorsky Aircraft Corporation S-61 Helicopter Alert Service Bulletin Errata, effective February 3, 2026.

(ii) [Reserved]

(3) For Sikorsky Aircraft Corporation material identified in this AD, contact Sikorsky Field Representative or Sikorsky's Service Engineering Group at Sikorsky Aircraft Corporation, Mailstop K100, 124 Quarry Road, Trumbull, CT 06611; phone: 1-800-946-4337 (1-800-Winged-S); email: wcscustservice_eng.gr-sik@lmco.com; website: sikorsky360.com.

(4) You may view this material at the FAA, Office of the Regional Counsel, Southwest ( printed page 12318) 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 fr.inspection@nara.gov.

Issued on March 10, 2026.

Steven W. Thompson,

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

[FR Doc. 2026-04966 Filed 3-12-26; 8:45 am]

BILLING CODE 4910-13-P

Published Document: 2026-04966 (91 FR 12314)