[Federal Register Volume 90, Number 243 (Monday, December 22, 2025)]
[Proposed Rules]
[Pages 59764-59767]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-23613]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2025-5394; Project Identifier AD-2025-01194-R]
RIN 2120-AA64
Airworthiness Directives; Restricted Category Model CH-47D
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 all restricted category Model CH-47D helicopters. This proposed AD
was prompted by reports of fatigue cracking of the right-hand (RH)
forward transmission support beam fitting. This proposed AD would
require repetitively inspecting the RH forward transmission support
beam fitting for cracking and, depending on the results, repairing any
crack(s). This proposed AD would also require submitting data on any
previous repairs and replaced fittings. 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 February 5,
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-2025-5394; or in person at
[[Page 59765]]
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.
FOR FURTHER INFORMATION CONTACT: Sarah Illg, Aviation Safety Engineer,
FAA, 3960 Paramount Boulevard, Lakewood, CA 90712; phone: (206) 231-
3517; 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-2025-5394; Project Identifier
AD-2025-01194-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 Sarah
Illg, Aviation Safety Engineer, FAA, 3960 Paramount Boulevard,
Lakewood, CA 90712. 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 reports of fatigue cracking of the RH forward
transmission support beam fitting having part number 145S1838-1 on CH-
47D helicopters. CH-47D type certificate holders and operators have
reported experiencing at least one cracking event around the fastener
on the RH forward transmission support beam fitting at the right butt
line (RBL) 18 from station (STA) 76 to STA 120. This condition, if not
addressed, could result in crack propagation and lead to failure of the
RH forward transmission support beam fitting, excessive vibration, and
consequent loss of control of the helicopter.
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 repetitively inspecting the RH
forward transmission support beam fitting for cracking and, depending
on the results, repairing any crack(s) or replacing parts. This
proposed AD would also require submitting data on any previous repairs
and replaced fittings to the FAA.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 42 helicopters of U.S. registry.
The FAA estimates the following costs to comply with this proposed
AD:
Estimated Costs
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Parts Cost per Cost on U.S.
Action Labor cost cost product operators
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Inspect RH forward transmission support 2 work-hours x $85 per hour = $0 $170 $7,140
beam fitting. $170.
Report previous repairs and replaced 1 work-hour x $85 per hour = 0 85 3,570
fittings. $85.
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The FAA has received no definitive data on which to base the cost
estimates for the on-condition repairs specified in this proposed AD.
Paperwork Reduction Act
A federal agency may not conduct or sponsor, and a person is not
required to respond to, nor shall a person be subject to a penalty for
failure to comply with a collection of information subject to the
requirements of the Paperwork Reduction Act unless that collection of
information displays a currently valid OMB Control Number. The OMB
Control Number for this information collection is 2120-0056. Public
reporting for this collection of information is estimated to be
approximately 1 hour per response, including the time for reviewing
instructions, searching existing data sources, gathering and
maintaining the data needed, and completing and reviewing the
collection of information. All responses to this collection of
information are mandatory. Send comments regarding this burden estimate
or any other aspect of this collection of information, including
suggestions for reducing this burden, to: Information Collection
Clearance Officer, Federal Aviation Administration, 10101 Hillwood
Parkway, Fort Worth, TX 76177-1524.
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.
[[Page 59766]]
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:
Restricted Category Model CH-47D Helicopters: Docket No. FAA-2025-
5394; Project Identifier AD-2025-01194-R.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive
(AD) by February 5, 2026.
(b) Affected ADs
None.
(c) Applicability
This AD applies to restricted category Model CH-47D helicopters;
current type certificate holders include but are not limited to
Billings Flying Service, Inc.; Columbia Helicopters, Inc.; Tandem
Rotor, LLC; and Unical Air Inc.
(d) Subject
Joint Aircraft System Component (JASC) Code 6330, Main Rotor
Transmission Mount.
(e) Unsafe Condition
This AD was prompted by reports of fatigue cracking of the
right-hand (RH) forward transmission support beam fitting. The FAA
is issuing this AD to detect and address fatigue cracking of the RH
forward transmission support beam fittings. The unsafe condition, if
not addressed, could result in crack propagation and lead to failure
of the RH forward transmission support beam fitting, excessive
vibration, and consequent loss of control of the helicopter.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Required Actions
(1) Within 30 hours time in service (TIS) after the effective
date of this AD and thereafter at intervals not to exceed 100 hours
TIS, using a 7X or higher power magnification and light source,
visually inspect the RH forward transmission support beam fitting
having part number 145S1838-1 at right butt line (RBL) 18 from
station (STA) 76 to STA 120 for cracks. Fastener holes in the area
circled in figure 1 to paragraph (g)(1) of this AD are most
susceptible to cracking. If any crack is detected, before further
flight, repair or replace parts using a method approved by the
Manager, West Certification Branch, FAA, in accordance with the
procedures specified in paragraph (i) of this AD.
BILLING CODE 4910-13-P
Figure 1 to Paragraph (g)(1)--Transmission Support Beam Inspection
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[GRAPHIC] [TIFF OMITTED] TP22DE25.005
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(2) For repairs accomplished before the effective date of this
AD, within 30 days after the effective date of this AD, submit the
information specified in paragraphs (g)(2)(i) through (v) of this AD
to the person identified in paragraph (j) of this AD.
(i) Aircraft serial number, registration number, and TIS when
fitting was repaired.
(ii) Design data used to accomplish repair (drawings,
engineering orders, etc.).
(iii) Substantiation data used to approve repair.
(iv) Copy of FAA Form 337 ``Major Repair or Alteration'' or
other approval of return to service. If repair was performed by the
U.S. military, provide a copy of Form 2408-15 (or equivalent)
documenting major repair.
(v) Alternative methods of compliance for previously approved
repairs.
(3) For fittings that have been replaced before the effective
date of this AD, within 30 days after the effective date of this AD,
submit the information specified in paragraphs (g)(3)(i) and (ii) of
this AD to the person identified in paragraph (j) of this AD.
(i) If the replacement fitting was new production (under 14 CFR
21.9 or exemption): where the part was sourced from, when the part
was produced, and the manufacturer of the part.
(ii) If the replacement fitting was used: where the part was
sourced from (aircraft registration and serial number or
manufacturer), TIS of the used part prior to installation, and TIS
after installation.
(h) Special Flight Permits
Special flight permits are prohibited.
(i) Alternative Methods of Compliance (AMOCs)
(1) The Manager, West 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 West Certification Branch, send it to
the attention of the person identified in paragraph (j) 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.
(j) Additional Information
For more information about this AD, contact Sarah Illg, Aviation
Safety Engineer, FAA, 3960 Paramount Boulevard, Lakewood, CA 90712;
phone: (206) 231-3517; email: [email protected].
(k) Material Incorporated by Reference
None.
Issued on December 17, 2025.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2025-23613 Filed 12-19-25; 8:45 am]
BILLING CODE 4910-13-P