Proposed Rule2026-04966
Airworthiness Directives; Various Helicopters
Primary source
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Published
March 13, 2026
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
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.
Full Text
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<title>Federal Register, Volume 91 Issue 49 (Friday, March 13, 2026)</title>
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[Federal Register Volume 91, Number 49 (Friday, March 13, 2026)]
[Proposed Rules]
[Pages 12314-12318]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-04966]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2026-2297; Project Identifier AD-2025-00184-R]
RIN 2120-AA64
Airworthiness Directives; Various Helicopters
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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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:
<bullet> Federal eRulemaking Portal: Go to <a href="http://regulations.gov">regulations.gov</a>. Follow
the instructions for submitting comments.
<bullet> Fax: (202) 493-2251.
<bullet> 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.
<bullet> 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 <a href="http://regulations.gov">regulations.gov</a> 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:
<bullet> 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: <a href="/cdn-cgi/l/email-protection#790e1a0a261a0c0a0d260a1c0b0f101a1c261c171e571e0b540a10123915141a16571a1614"><span class="__cf_email__" data-cfemail="1d6a7e6e427e686e69426e786f6b747e784278737a337a6f306e74765d71707e72337e7270">[email protected]</span></a>; website:
<a href="http://sikorsky360.com">sikorsky360.com</a>.
[[Page 12315]]
<bullet> 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: <a href="/cdn-cgi/l/email-protection#367375741b7579657650575718515940"><span class="__cf_email__" data-cfemail="befbfdfc93fdf1edfed8dfdf90d9d1c8">[email protected]</span></a>.
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
<a href="http://regulations.gov">regulations.gov</a>, 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:
Estimated Costs
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Cost per
Action Labor cost Parts cost product Cost on U.S. operators
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Visually inspect auxiliary servo 1 work-hour x $85 per $0 $85 $6,460 per inspection
assembly. hour = $85. cycle.
Determine remaining life of yaw pedal 3 work-hours x $85 per 0 255 $19,380.
damper check valve housing. hour = $255.
Inspect yaw pedal damper check valve 15 work-hours x $85 per 0 1,275 $96,900.
housing and attachment bolts. hour = $1,275.
Revise RFM........................... 1 work-hour x $85 per 0 85 $6,460.
hour = $85.
Revise ALS........................... 1 work-hour x $85 per 0 85 $6,460.
hour = $85.
[[Page 12316]]
Record life limit in existing 1 work-hour x $85 per 0 85 $6,460.
helicopter log card. hour = $85.
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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:
On-Condition Costs
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Action Labor cost Parts cost Cost per product
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Blend repair and remeasure housing 4 work-hours x $85 per $0.................... $340.
edge break radius. hour = $340.
Replace yaw pedal damper check valve 1 work-hour x $85 per $1,200................ $1,285.
housing. hour = $85.
Replace attachment bolts............. 1 work-hour x $85 per $1 (per bolt)......... $86.
hour = $85.
FPI of yaw pedal damper check valve 2 work-hours x $85 per $0.................... $170 per inspection
housing and attachment bolts. hour = $170. cycle.
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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
0
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
0
2. The FAA amends Sec. 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
[[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
[GRAPHIC] [TIFF OMITTED] TP13MR26.002
(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: <a href="/cdn-cgi/l/email-protection#7f3e32303c3f191e1e51181009"><span class="__cf_email__" data-cfemail="91d0dcded2d1f7f0f0bff6fee7">[email protected]</span></a>.
(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: <a href="/cdn-cgi/l/email-protection#703533325d333f23301611115e171f06"><span class="__cf_email__" data-cfemail="367375741b7579657650575718515940">[email protected]</span></a>.
(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: <a href="/cdn-cgi/l/email-protection#7c0b1f0f231f090f08230f190e0a151f192319121b521b0e510f15173c10111f13521f1311"><span class="__cf_email__" data-cfemail="532430200c302620270c203621253a30360c363d347d34217e203a38133f3e303c7d303c3e">[email protected]</span></a>; website:
<a href="http://sikorsky360.com">sikorsky360.com</a>.
(4) You may view this material at the FAA, Office of the
Regional Counsel, Southwest
[[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 <a href="http://www.archives.gov/federal-register/cfr/ibr-locations">www.archives.gov/federal-register/cfr/ibr-locations</a> or email <a href="/cdn-cgi/l/email-protection#4b2d39652225383b2e283f2224250b252a392a652c243d"><span class="__cf_email__" data-cfemail="6a0c18440304191a0f091e0305042a040b180b440d051c">[email protected]</span></a>.
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
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