Rule2026-18927
Airworthiness Directives; MD Helicopters, LLC Helicopters
Primary source
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Published
September 15, 2026
Effective
October 20, 2026
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA is superseding Airworthiness Directive (AD) 2024-23- 06, which applied to certain MD Helicopters, LLC Model 369, 369A, 369D, 369E, 369F, 369FF, 369H, 369HE, 369HM, 369HS, 500N, and 600N helicopters. AD 2024-23-06 required repetitively inspecting the torque tube assembly and roller bearings, and depending on the results, replacing parts or accomplishing additional inspections. Since the FAA issued AD 2024-23-06, the FAA has determined that additional torque tube assemblies are affected by this unsafe condition. This AD continues to require the actions of AD 2024-23-06 and expands the applicability. The FAA is issuing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 91 Issue 177 (Tuesday, September 15, 2026)</title>
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[Federal Register Volume 91, Number 177 (Tuesday, September 15, 2026)]
[Rules and Regulations]
[Pages 58365-58374]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-18927]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2025-3987; Project Identifier AD-2025-00017-R;
Amendment 39-23466; AD 2026-19-01]
RIN 2120-AA64
Airworthiness Directives; MD Helicopters, LLC Helicopters
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
-----------------------------------------------------------------------
SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2024-23-
[[Page 58366]]
06, which applied to certain MD Helicopters, LLC Model 369, 369A, 369D,
369E, 369F, 369FF, 369H, 369HE, 369HM, 369HS, 500N, and 600N
helicopters. AD 2024-23-06 required repetitively inspecting the torque
tube assembly and roller bearings, and depending on the results,
replacing parts or accomplishing additional inspections. Since the FAA
issued AD 2024-23-06, the FAA has determined that additional torque
tube assemblies are affected by this unsafe condition. This AD
continues to require the actions of AD 2024-23-06 and expands the
applicability. The FAA is issuing this AD to address the unsafe
condition on these products.
DATES: This AD is effective October 20, 2026.
ADDRESSES:
AD Docket: You may examine the AD docket at <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2025-3987; 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 final rule, any comments received, and other
information. The address for Docket Operations is U.S. Department of
Transportation, Docket Operations, M-30, West Building Ground Floor,
Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.
FOR FURTHER INFORMATION CONTACT: Eduardo Orozco-Duran, Aviation Safety
Engineer, FAA, 3960 Paramount Boulevard, Lakewood, CA 90712; phone:
(562) 627-5264; email: <a href="/cdn-cgi/l/email-protection#d6b3b2a3b7a4b2b9f8b9a4b9acb5b9fbb2a3a4b7b896b0b7b7f8b1b9a0"><span class="__cf_email__" data-cfemail="9ffafbeafeedfbf0b1f0edf0e5fcf0b2fbeaedfef1dff9fefeb1f8f0e9">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
Background
The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 to supersede AD 2024-23-06, Amendment 39-22885 (89 FR
91248, November 19, 2024) (AD 2024-23-06). AD 2024-23-06 applied to
certain MD Helicopters, LLC Model 369, 369A, 369D, 369E, 369F, 369FF,
369H, 369HE, 369HM, 369HS, 500N, and 600N helicopters. AD 2024-23-06
was prompted by a report of a seized and damaged roller bearing
assembly in the torque tube assembly of an MD Helicopters, LLC Model
369E helicopter. AD 2024-23-06 required repetitively inspecting the
torque tube assembly and roller bearings, and depending on the results,
replacing parts or accomplishing additional inspections.
The NPRM was published in the Federal Register on November 18, 2025
(90 FR 51596). The NPRM was prompted by a report that additional torque
tube assemblies are affected by the same unsafe condition addressed in
AD 2024-23-06 and should be included in the AD action. In the NPRM, the
FAA proposed to continue to require the actions of AD 2024-23-06, and
also proposed to expand the applicability to include all MD
Helicopters, LLC Model 369, 369A, 369D, 369E, 369F, 369FF, 369H, 369HE,
369HM, 369HS, 500N, and 600N helicopters, regardless of the torque tube
part number. The FAA is issuing this AD to prevent failure of the
torque tube assembly, which, if not addressed, could result in reduced
controllability and loss of control of the helicopter.
Discussion of Final Airworthiness Directive
Comments
The FAA received comments from the Citizens Rulemaking Alliance.
The following presents the comments received on the NPRM and the FAA's
response to each comment.
Request To Justify Forgoing Notice and Comment or Issue an NPRM
The Citizens Rulemaking Alliance requested that, absent
justification for finding good cause to bypass notice and comment
procedures, the FAA either convert this action to an NPRM with a 30-day
comment period or defer the effective date by 30 to 60 days while
maintaining a parallel safety alert or special airworthiness
information bulletin and highlighting voluntary compliance with the
service information. The commenter asserted the FAA has not adequately
justified use of the good cause exemption to bypass notice and comment
and the 30-day delayed effective date.
The FAA notes the comment was submitted in response to an NPRM for
which the FAA provided a 45-day comment period. This final rule is
effective 35 days after its publication in the Federal Register.
Therefore, the FAA did not change this AD as a result of this comment.
Request To Supplement the AD Docket With Supporting Data
The Citizens Rulemaking Alliance requested that the FAA add to the
AD docket the FAA's risk assessment, the background report data, the
dates of the triggering service information and any foreign authority
AD, and a summary of alternatives considered and rejected for safety
reasons. The commenter stated that this will allow commenters to
address safety tradeoffs while preserving urgent mitigation if
warranted.
The FAA has assessed and disclosed the background and basis for
this rulemaking in the preamble of the NPRM, including a discussion of
the previous AD, a description of the unsafe condition, and the FAA's
rationale for the required actions on additional torque tube
assemblies. This information was available to the public during the 45-
day comment period provided by the NPRM.
The FAA evaluated the alternative of not promulgating this AD but
ultimately determined that this alternative would create a significant
safety hazard. Relying on voluntary compliance or existing requirements
would leave the unsafe condition unaddressed and would not ensure an
acceptable level of safety. Accordingly, the FAA has determined that
promulgating this AD is necessary to ensure an acceptable level of
safety.
Since the FAA has assessed and disclosed the basis for this
rulemaking in the preamble of the NPRM, there is no service material or
foreign authority AD related to this rulemaking action, and the
commenter did not provide additional safety data for the FAA to
consider in its analysis, it is not necessary to provide additional
information in the AD docket.
Request To Comply With the Paperwork Reduction Act (PRA)
The Citizens Rulemaking Alliance requested that the FAA revise the
proposed AD to comply with the PRA if reporting is required, or remove
any reporting provisions and stay enforcement until PRA requirements
are satisfied. The commenter stated that the PRA requires providing the
applicable Office of Management and Budget (OMB) control number(s),
required PRA statements, and burden estimates in the AD and docket. If
reporting is not required, the commenter requested the FAA clarify that
in the AD.
The FAA notes that this AD does not require reporting. If an AD
were to require reporting, the preamble of the AD would include a
paragraph titled ``Paperwork Reduction Act'' that would provide the
applicable OMB control number, required PRA statements, and the
estimated time to collect the required information (burden). Any costs
associated with the reporting requirement would be included in the
Costs of Compliance section in the preamble of the AD. Therefore, the
FAA did not change this AD as a result of this comment.
[[Page 58367]]
Request To Make Incorporation by Reference (IBR) Materials Reasonably
Available
The Citizens Rulemaking Alliance stated that the FAA's current
practices for IBR frequently fail to meet the legal and regulatory
standards for reasonable availability. The commenter called on the FAA
to guarantee that all IBR materials are easily and freely accessible to
the public and affected parties for both commenting and compliance
purposes. They also requested that this access be documented in the
rulemaking record. Further, the commenter requested that, if reasonable
availability cannot be assured, enforcement of the incorporated by
reference requirements be deferred until it is assured.
The FAA notes that this AD does not incorporate by reference any
material. All required actions and compliance times are contained
within the regulatory text of this AD. Therefore, the FAA did not
change this AD as a result of this comment.
Request To Consider Impact on Small Entities
The Citizens Rulemaking Alliance requested that the FAA either
provide the factual basis for its Regulatory Flexibility Act (RFA)
certification that the AD will not have a significant economic impact
on a substantial number of small entities or prepare an initial
regulatory flexibility analysis and seek input from the Office of
Advocacy from the Small Business Administration (SBA).
The FAA has considered the AD's impact on small businesses and
provides the following analysis.
The Regulatory Flexibility Act of 1980, Public Law 96-354, 94 Stat.
1164 (5 U.S.C. 601-612), as amended by the Small Business Regulatory
Enforcement Fairness Act of 1996 (Public Law 104-121, 110 Stat. 857,
Mar. 29, 1996) and the Small Business Jobs Act of 2010 (Public Law 111-
240, 124 Stat. 2504, Sept. 27, 2010), requires Federal agencies to
consider the effects of the regulatory action on small business and
other small entities and to minimize any significant economic impact.
The term ``small entities'' comprises small businesses and not-for-
profit organizations that are independently owned and operated and are
not dominant in their fields, and governmental jurisdictions with
populations of less than 50,000.
Small Entities to Which This AD Applies
The FAA used the definition of small entities in the RFA for this
analysis. The RFA defines small entities as small businesses, small
governmental jurisdictions, or small organizations. In 5 U.S.C. 601(3),
the RFA defines ``small business'' to have the same meaning as ``small
business concern'' under section 3 of the Small Business Act. The Small
Business Act authorizes the SBA to define ``small business'' by issuing
regulations.
The SBA has established size standards for various types of
economic activities, or industries, under the North American Industry
Classification System (NAICS). These size standards generally define
small businesses based on the number of employees or annual receipts.
The following table provides the SBA size standards for all industries
with at least one entity \1\ impacted by this AD. Note that the SBA
definition of a small business applies to the parent company and all
affiliates as a single entity.
---------------------------------------------------------------------------
\1\ The FAA does not have entity data for, or the entity was
identified as a foreign business, 45 of the 680 affected
helicopters. Those helicopters are excluded from this analysis. The
number of affected helicopters has been updated in this final rule
to reflect the current fleet.
Small Business Size Standards
------------------------------------------------------------------------
NAICS NAICS description Size standard
------------------------------------------------------------------------
111199............. All Other Grain Farming......... $2,500,000.
111332............. Citrus, Except Orange, Groves... $4,000,000.
111998............. All Other Miscellaneous Crop $2,500,000.
Farming.
112519............. Other Aquaculture............... $3,750,000.
114111............. Finfish Fishing................. $25,000,000.
115112............. Soil Preparation, Planting, and $9,500,000.
Cultivating.
115116............. Farm Management Services........ $15,500,000.
115210............. Support Activities for Animal $11,000,000.
Production.
115310............. Support Activities for Forestry. $11,500,000.
212321............. Construction Sand and Gravel 500 Employees.
Mining.
213111............. Drilling Oil and Gas Wells...... 1,000 Employees.
213112............. Support Activities for Oil and $47,000,000.
Gas Operations.
221111............. Hydroelectric Power Generation.. 50,000 Employees.
221122............. Electric Power Distribution..... 1,100 Employees.
236115............. New Single-family Housing $45,000,000.
Construction.
236220............. Commercial and Institutional $45,000,000.
Building Construction.
237110............. Water and Sewer Line and Related $47,000,000.
Structures Construction.
237130............. Power and Communication Line and $45,000,000.
Related Structures Construction.
237210............. Land Subdivision................ $34,000,000.
237310............. Highway, Street, and Bridge $45,000,000.
Construction.
238210............. Electrical Contractors and Other $19,000,000.
Wiring Installation.
Contractors.....................
238220............. Plumbing, Heating, and Air $19,000,000.
Conditioning Contractors.
238910............. Site Preparation Contractors.... $19,000,000.
238990............. All Other Specialty Trade $19,000,000.
Contractors.
321113............. Sawmills........................ 550 Employees.
325920............. Explosives Manufacturing........ 750 Employees.
325998............. All Other Miscellaneous Chemical 650 Employees.
Product and.
Preparation Manufacturing.......
332912............. Fluid Power Valve and Hose 1,000 Employees.
Fitting Manufacturing.
334413............. Semiconductor and Related Device 1,250 Employees.
Manufacturing.
336212............. Truck Trailer Manufacturing..... 1,000 Employees.
336320............. Motor Vehicle Electrical and 1,000 Employees.
Electronic Equipment
Manufacturing.
[[Page 58368]]
336390............. Other Motor Vehicle Parts 1,000 Employees.
Manufacturing.
336411............. Aircraft Manufacturing.......... 1,500 Employees.
336413............. Other Aircraft Parts and 1,250 Employees.
Auxiliary Equipment
Manufacturing.
423430............. Computer and Computer Peripheral 250 Employees.
Equipment and Software Merchant
Wholesalers.
423820............. Farm and Garden Machinery and 175 Employees.
Equipment Merchant Wholesalers.
423860............. Transportation Equipment and 175 Employees.
Supplies (except Motor Vehicle)
Merchant Wholesalers.
423990............. Other Miscellaneous Durable 1,250 Employees.
Goods Merchant Wholesalers.
441110............. New Car Dealers................. 200 Employees.
481111............. Scheduled Passenger and Cargo 1,500 Employees.
Airlines Serving Western Alaska.
481112............. Scheduled Freight Air 1,500 Employees.
Transportation.
481211............. Nonscheduled Chartered Passenger 1,500 Employees.
Air Transportation.
481212............. Nonscheduled Chartered Freight 1,500 Employees.
Air Transportation.
481219............. Other Nonscheduled Air $25,000,000.
Transportation.
484110............. General Freight Trucking, Local. $34,000,000.
488119............. Other Airport Operations........ $40,000,000.
488190............. Other Support Activities for Air $40,000,000.
Transportation.
488210............. Support Activities for Rail $34,000,000.
Transportation.
488330............. Navigational Services to $47,000,000.
Shipping.
523910............. Miscellaneous Intermediation.... $47,000,000.
531110............. Lessors of Residential Buildings $34,000,000.
and Dwellings.
531120............. Lessors of Nonresidential $34,000,000.
Buildings.
531190............. Real Estate Holding and Specific $34,000,000.
Asset (Aircraft) Management.
531210............. Offices of Real Estate Agents $15,000,000.
and Brokers.
531311............. Residential Property Managers... $12,500,000.
531312............. Management of Nonresidential $30,000,000.
Real Estate.
531320............. Offices of Real Estate $9,500,000.
Appraisers.
531390............. Other Activities Related to Real $19,500,000.
Estate.
532112............. Passenger Car Leasing........... $34,000,000.
532411............. Commercial Air, Rail, and Water $45,500,000.
Transportation Equipment Rental
and Leasing.
532412............. Construction, Mining and $40,000,000.
Forestry Machinery and
Equipment Rental and Leasing.
532490............. Other Commercial and Industrial $40,000,000.
Machinery and Equipment Rental
and Leasing.
541110............. Offices of Lawyers.............. $15,500,000.
541211............. Offices of Certified Public $26,500,000.
Accountants.
541330............. Engineering Services............ $25,500,000.
541511............. Custom Computer Programming $34,000,000.
Services.
541611............. Administrative Management and $24,500,000.
General Management Consulting
Services.
541715............. Research and Development in the 1,000 Employees.
Physical, Engineering, and Life
Sciences.
541720............. Research and Development in the $28,500,000.
Social Sciences and Humanities.
541810............. Advertising Agencies............ $22,500,000.
541922............. Commercial Photography.......... $9,000,000.
551112............. Offices of Other Holding $45,500,000.
Companies.
561710............. Exterminating and Pest Control $17,500,000.
Services.
561730............. Landscaping Services............ $9,500,000.
562111............. Solid Waste Collection.......... $47,000,000.
611430............. Professional and Management $15,000,000.
Development Training.
611512............. Flight Training................. $34,000,000.
624230............. Emergency and Other Relief $41,500,000.
Services.
712110............. Museums......................... $34,000,000.
713990............. All Other Amusement and $9,000,000.
Recreation Industries.
811210............. Electronic and Precision $34,000,000.
Equipment Repair and
Maintenance.
813211............. Grantmaking Foundations......... $40,000,000.
813410............. Civic and Social Organizations.. $9,500,000.
921110............. Executive Offices............... 50,000 Employees.
921120............. Legislative Bodies.............. 50,000 Employees.
922110............. Law Enforcement................. 50,000 Employees.
922120............. Law Enforcement................. 50,000 Employees.
922160............. Fire & Rescue................... 50,000 Employees.
922190............. Other Justice, Public Order, and 50,000 Employees.
Safety Activities.
924110............. Government...................... 50,000 Employees.
924120............. Government...................... 50,000 Employees.
926140............. Government...................... 50,000 Employees.
928110............. Government...................... 50,000 Employees.
928120............. International Affairs........... 50,000 Employees.
------------------------------------------------------------------------
To identify small entities, the FAA first identified the primary
NAICS of the entity or parent company, and then used data from
different sources (e.g., company annual reports, Bureau of
Transportation Statistics) to determine whether the entity meets the
applicable size standard. The FAA provides the estimated number of
small entities affected by this AD:
[[Page 58369]]
Estimated Number of Small Entities
----------------------------------------------------------------------------------------------------------------
Number of
NAICS category Number affected Small business Percent small
entities aircraft entities entities
----------------------------------------------------------------------------------------------------------------
All Other Grain Farming......................... 1 1 1 100
Citrus, except Orange, Groves................... 1 1 1 100
All Other Miscellaneous Crop Farming............ 1 2 1 100
Other Aquaculture............................... 1 1 1 100
Finfish Fishing................................. 2 2 1 50
Soil Preparation, Planting, and Cultivating..... 9 12 9 100
Farm Management Services........................ 1 1 1 100
Support Activities for Animal Production........ 3 6 3 100
Support Activities for Forestry................. 3 4 3 100
Construction Sand and Gravel Mining............. 1 1 1 100
Drilling Oil and Gas Wells...................... 1 1 1 100
Support Activities for Oil and Gas Operations... 1 1 1 100
Hydroelectric Power Generation.................. 1 4 0 0
Electric Power Distribution..................... 1 1 1 100
New Single-family Housing Construction.......... 2 2 2 100
Commercial and Institutional Building 2 7 2 100
Construction...................................
Water and Sewer Line and Related Structures 1 1 1 100
Construction...................................
Power and Communication Line and Related 1 6 0 0
Structures Construction........................
Land Subdivision................................ 3 3 2 67
Highway, Street, and Bridge Construction........ 2 2 2 100
Electrical Contractors and Other Wiring 1 11 1 100
Installation Contractors.......................
Plumbing, Heating, and Air Conditioning 1 1 1 100
Contractors....................................
Site Preparation Contractors.................... 1 1 1 100
All Other Specialty Trade Contractors........... 1 1 0 0
Sawmills........................................ 1 1 1 100
Explosives Manufacturing........................ 1 1 1 100
All Other Miscellaneous Chemical Product and 1 1 0 0
Preparation Manufacturing......................
Fluid Power Valve and Hose Fitting Manufacturing 1 1 1 100
Semiconductor and Related Device Manufacturing.. 1 1 1 100
Truck Trailer Manufacturing..................... 1 1 0 0
Motor Vehicle Electrical and Electronic 1 1 1 100
Equipment Manufacturing........................
Other Motor Vehicle Parts Manufacturing......... 1 1 1 100
Aircraft Manufacturing.......................... 6 16 2 33
Other Aircraft Parts and Auxiliary Equipment 3 3 3 100
Manufacturing..................................
Computer and Computer Peripheral Equipment and 1 1 1 100
Software Merchant Wholesalers..................
Farm and Garden Machinery and Equipment Merchant 1 1 0 0
Wholesalers....................................
Transportation Equipment and Supplies (except 3 4 3 100
Motor Vehicle) Merchant Wholesalers............
Other Miscellaneous Durable Goods Merchant 1 1 0 0
Wholesalers....................................
New Car Dealer.................................. 1 1 1 100
Scheduled Passenger and Cargo Airline Serving 1 3 1 100
Western Alaska.................................
Scheduled Freight Air Transportation............ 2 2 2 100
Nonscheduled Chartered Passenger Air 79 165 75 95
Transportation.................................
Nonscheduled Chartered Freight Air 8 16 8 100
Transportation.................................
Other Nonscheduled Air Transportation........... 17 35 15 88
General Freight Trucking, Local................. 1 1 1 100
Other Airport Operations........................ 4 4 4 100
Other Support Activities for Air Transportation. 31 60 30 97
Support Activities for Rail Transportation...... 1 1 1 100
Navigational Services to Shipping............... 1 1 1 100
Miscellaneous Intermediation.................... 2 2 2 100
Lessors of Residential Buildings and Dwellings.. 3 3 2 67
Lessors of Nonresidential Buildings............. 2 2 2 100
Real Estate Holding and Specific Asset 1 1 1 100
(Aircraft) Management..........................
Offices of Real Estate Agents and Brokers....... 1 1 0 0
Residential Property Managers................... 1 2 1 100
Management of Nonresidential Real Estate........ 1 1 1 100
Offices of Real Estate Appraisers............... 1 1 1 100
Other Activities Related to Real Estate......... 3 3 3 100
Passenger Car Leasing........................... 1 1 1 100
Commercial Air, Rail, and Water Transportation 16 19 15 94
Equipment Rental and Leasing...................
Construction, Mining and Forestry Machinery and 1 5 1 100
Equipment Rental and Leasing...................
Other Commercial and Industrial Machinery and 2 2 2 100
Equipment Rental and Leasing...................
Offices of Lawyers.............................. 4 5 4 100
Offices of Certified Public Accountants......... 1 1 1 100
Engineering Services............................ 3 3 3 100
[[Page 58370]]
Custom Computer Programming Services............ 2 2 2 100
Administrative Management and General Management 6 6 6 100
Consulting Services............................
Research and Development in the Physical, 1 1 1 100
Engineering, and Life Sciences.................
Research and Development in the Social Sciences 1 1 1 100
and Humanities.................................
Advertising Agencies............................ 1 1 1 100
Commercial Photography.......................... 1 1 1 100
Offices of Other Holding Companies.............. 4 5 4 100
Exterminating and Pest Control Services......... 3 4 0 0
Landscaping Services............................ 2 12 1 50
Solid Waste Collection.......................... 1 1 0 0
Professional and Management Development Training 1 1 0 0
Flight Training................................. 7 8 7 100
Emergency and Other Relief Services............. 1 1 1 100
Museums......................................... 3 3 2 67
All Other Amusement and Recreation Industries... 1 1 1 100
Electronic and Precision Equipment Repair and 1 1 1 100
Maintenance....................................
Grantmaking Foundations......................... 1 1 1 100
Civic and Social Organizations.................. 1 1 0 0
Executive Offices............................... 4 10 0 0
Legislative Bodies.............................. 1 1 0 0
Law Enforcement................................. 18 40 1 6
Law Enforcement................................. 10 21 1 10
Fire & Rescue................................... 3 7 0 0
Other Justice, Public Order, and Safety 2 6 0 0
Activities.....................................
Government...................................... 1 1 0 0
Government...................................... 2 2 0 0
Government...................................... 1 1 0 0
Government...................................... 1 45 0 0
International Affairs........................... 1 2 0 0
---------------------------------------------------------------
Total....................................... 336 635 263 78
----------------------------------------------------------------------------------------------------------------
Projected Reporting, Recordkeeping, and Other Compliance Requirements
The FAA estimates affected entities will incur an inspection cost
of $149 per inspection cycle, with an average of 7 inspection cycles
per year. FAA analyzes the cost of inspection of $1,043 as the low-case
for each small entity. Based upon the results of the inspections,
operators could incur up to 3 on-condition costs of $6,024. If an
operator were to incur all inspection and on-condition costs, FAA
estimates each operator would incur $7,067 per helicopter annually. The
FAA has no way to determine if each helicopter will require these on-
condition costs. The high-case includes both inspection and on-
condition costs for each small entity. The following table presents the
small entity case burdens average percentage for compliance based on
the average annual revenue by each NAICS industry.
Number of Small Entities Affected by Industry and Cost Significance
----------------------------------------------------------------------------------------------------------------
Number of Low-Case High-Case
NAICS NAICS Number of Average annual aircraft burden average burden average
description operators revenue \1\ affected (%) (%)
----------------------------------------------------------------------------------------------------------------
111199........ All Other Grain 1 $315,780 1 0.33% 2.24%
Farming.
111332........ Citrus, except 1 286,790 2 0.73 4.93
Orange, Groves.
114111........ Finfish Fishing. 1 600,000 1 0.17 1.18
115112........ Soil 7 526,180 10 0.33 2.22
Preparation,
Planting, and
Cultivating.
115116........ Farm Management 1 158,020 1 0.66 4.47
Services.
115210........ Support 3 356,057 6 0.92 6.23
Activities for
Animal
Production.
115310........ Support 2 625,705 3 0.30 2.02
Activities for
Forestry \3\.
212321........ Construction 1 520,000 1 0.20 1.36
Sand and Gravel
Mining.
213111........ Drilling Oil and 1 1,680,000 1 0.06 0.42
Gas Wells.
213112........ Support 1 246,800 1 0.42 2.86
Activities for
Oil and Gas
Operations.
221122........ Electric Power 1 700,000 1 0.15 1.01
Distribution.
236115........ New Single- 1 104,160 1 1.00 6.78
family Housing
Construction.
236220........ Commercial and 2 575,330 7 0.54 3.66
Institutional
Building
Construction.
237110........ Water and Sewer 1 5,580,000 1 0.02 0.13
Line and
Related
Structures
Construction.
237210........ Land Subdivision 1 61,020 1 1.71 11.58
237310........ Highway, Street, 2 6,138,005 2 0.69 4.68
and Bridge
Construction.
238210........ Electrical 1 6,410,000 11 0.18 1.21
Contractors and
Other Wiring
Installation
Contractors.
238910........ Site Preparation 1 950,000 1 0.11 0.74
Contractors.
321113........ Sawmills........ 1 156,710 1 0.67 4.51
325920........ Explosives 1 1,210,000 1 0.09 0.58
Manufacturing.
334413........ Semiconductor 1 245,810 1 0.42 2.87
and Related
Device
Manufacturing.
336320........ Motor Vehicle 1 163,600 1 0.64 4.32
Electrical and
Electronic
Equipment
Manufacturing.
[[Page 58371]]
336411........ Aircraft 2 1,182,320 4 2.44 16.55
Manufacturing.
336413........ Other Aircraft 2 235,005 2 0.95 6.43
Parts and
Auxiliary
Equipment
Manufacturing.
423430........ Computer and 1 11,160,000 1 0.01 0.06
Computer
Peripheral
Equipment and
Software
Merchant
Wholesalers.
423860........ Transportation 3 3,202,923 4 0.42 2.84
Equipment and
Supplies
(except Motor
Vehicle)
Merchant
Wholesalers.
441110........ New Car Dealer.. 1 214,510 1 0.49 3.29
481111........ Scheduled 1 6,960,000 3 0.04 0.30
passenger and
cargo airline
serving Western
Alaska.
481112........ Scheduled 1 260,960 1 0.40 2.71
Freight Air
Transportation.
481211........ Nonscheduled 61 1,723,034 142 0.97 6.56
Chartered
Passenger Air
Transportation.
481212........ Nonscheduled 6 2,202,997 14 0.35 2.34
Chartered
Freight Air
Transportation.
481219........ Other 8 465,218 13 0.57 3.89
Nonscheduled
Air
Transportation.
484110........ General Freight 1 2,860,000 1 0.04 0.25
Trucking, Local.
488119........ Other Airport 2 396,330 2 0.90 6.12
Operations.
488190........ Other Support 23 955,989 52 0.58 3.90
Activities for
Air
Transportation.
488210........ Support 1 73,270 1 1.42 9.65
Activities for
Rail
Transportation.
488330........ Navigational 1 267,710 1 0.39 2.64
Services to
Shipping.
523910........ Miscellaneous 2 120,155 2 1.02 6.90
Intermediation.
531110........ Lessors of 1 114,980 1 0.91 6.15
Residential
Buildings and
Dwellings.
531120........ Lessors of 2 214,985 2 1.12 7.57
Nonresidential
Buildings.
531312........ Management of 1 329,080 1 0.32 2.15
Nonresidential
Real Estate.
531320........ Offices of Real 1 1,020,000 1 0.10 0.69
Estate
Appraisers.
531390........ Other Activities 2 120,580 2 1.13 7.63
Related to Real
Estate.
532112........ Passenger Car 1 65,270 1 1.60 10.83
Leasing.
532411........ Commercial Air, 11 434,369 14 0.37 2.51
Rail, and Water
Transportation
Equipment
Rental and
Leasing.
532412........ Construction, 1 234,180 5 2.23 15.09
Mining and
Forestry
Machinery and
Equipment
Rental and
Leasing.
532490........ Other Commercial 1 106,700 1 0.98 6.62
and Industrial
Machinery and
Equipment
Rental and
Leasing.
541110........ Offices of 1 33,720 2 6.19 41.92
Lawyers.
541330........ Engineering 3 206,827 3 0.61 4.13
Services.
541511........ Custom Computer 1 42,000 1 2.48 16.83
Programming.
541611........ Administrative 3 250,367 3 0.94 6.36
Management and
General
Management
Consulting
Services.
541922........ Commercial 1 326,530 1 0.32 2.16
Photography.
551112........ Offices of Other 2 318,350 3 0.49 3.31
Holding
Companies.
561730........ Landscaping 1 133,680 1 0.78 5.29
Services.
611512........ Flight Training. 7 565,947 8 0.51 3.47
712110........ History Museum & 2 65,315 2 1.64 11.14
Education
(501c3).
922110........ Law Enforcement. 1 116,229,610 3 0.00 0.02
922120........ Law Enforcement. 2 327,012,029 2 0.00 0.00
624230........ Emergency and 1 431,150 1 0.24 1.64
Other Relief
Services.
713990........ All Other 1 346,990 1 0.30 2.04
Amusement and
Recreation
Industries.
----------------------------------------------------------------------------------------------------------------
\1\ Source: Dun & Bradstreet, D&B Hoovers, retrieved April 28, 2024, <a href="http://app.hoovers.dnb.com">app.hoovers.dnb.com</a>; ZoomInfo, ZoomInfo
Technologie Inc., retrieved April 28, 2024, <a href="http://zoominfo.com">zoominfo.com</a>.
\2\ Note: NAICS codes with only one entity equals the number of aircraft.
\3\ Example: NAICS 115310 has two operators with a total of three aircraft affected. Operator 1 calculations:
Low Case Burden ($2,086/$980,000) = 0.21%. Operator 2 calculations: Low Case Burden ($1,043/$271,410) = 0.38%.
The average Low Case Burden is (0.21% + 0.38%)/2 = 0.30%. The same method was used to calculate the High Case
Burden. All NAICS with multiple operators use the same method of calculation.
Significant Alternatives Considered
The FAA evaluated the alternative of not promulgating this AD but
ultimately deemed that this alternative would create a significant
safety hazard. Since the issuance of AD 2024-23-06, which affected
certain MD Helicopters, LLC Model 369, 369A, 369D, 369E, 369F, 369FF,
369H, 369HE, 369HM, 369HS, 500N, and 600N helicopters, it has been
determined that the risk of failure of the torque tube assembly extends
to additional torque tube assemblies. Relying on the existing
requirements would leave these additional torque tube assemblies
unmonitored. By expanding the applicability, this AD addresses the
unsafe condition and prevents potential failure, ensuring a level of
safety that the alternative of no action could not provide.
Conclusion
The FAA reviewed the relevant data, considered any comments
received, 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 products. Except for minor editorial changes,
replacement of the RFA certification with a final regulatory
flexibility analysis, a change in the Costs of Compliance section (from
353 helicopters to 680 helicopters and corresponding cost changes), and
any other changes described previously, this AD is adopted as proposed
in the NPRM. None of the changes will increase the economic burden on
any operator.
Costs of Compliance
The FAA estimates that this AD affects 680 helicopters of U.S.
registry. The FAA estimates the following costs to comply with this AD:
[[Page 58372]]
Estimated Costs
----------------------------------------------------------------------------------------------------------------
Parts Cost on U.S.
Action Labor cost \1\ cost Cost per product operators
----------------------------------------------------------------------------------------------------------------
Visual inspection of torque tube 1 work-hour x $85 per $0 $85, per inspection $57,800, per
and roller bearings. hour = $85, per cycle. inspection cycle.
inspection cycle.
Inspection of torque tube for 0.75 work-hour x $85 0 $64, per inspection $43,520, per
freedom-of-movement. per hour = $64, per cycle. inspection cycle.
inspection cycle.
----------------------------------------------------------------------------------------------------------------
\1\ The FAA estimated operators will incur $85 in costs per labor hour, which is the weighted average fiscal
year (FY) 2026 fully loaded wage of an aircraft mechanic ($69.85) working 60 percent of the labor hours and a
general and operations manager ($108.15) working 40 percent of the labor hours. The FAA estimated these wages
by taking the average of the FY 2024 Bureau of Labor Statistics (BLS) air transportation industry average wage
for aircraft mechanics and general and operations managers (See: Occupational Employment and Wage Statistics
Query System, BLS (May 2024), <a href="http://data.bls.gov/oes/">data.bls.gov/oes/</a>); multiplying each wage by a fringe benefit factor of 1.42
(See: Employer Cost for Employee Compensation--December 2024, BLS (2024), <a href="http://bls.gov/news.release/archives/ecec_03142025.pdf">bls.gov/news.release/archives/ecec_03142025.pdf</a>); and adjusting these 2024 wages to 2026 dollars using an implicit Gross Domestic Product
(GDP) Price Deflator of 2.8 percent (See: Gross Domestic Product: Implicit Price Deflator, FRED (2026)
<a href="http://fred.stlouisfed.org/series/GDPDEF">fred.stlouisfed.org/series/GDPDEF</a>).
The FAA estimates the following costs to do any on-condition
actions that would be required based on the results of the inspections.
The agency has no way of determining the number of helicopters that
might need these on-condition actions:
On-Condition Costs
----------------------------------------------------------------------------------------------------------------
Cost per
Action Labor cost Parts cost product
----------------------------------------------------------------------------------------------------------------
Replacement of torque tube.................... 6 work-hours x $85 per hour = $4,773 $5,283
$510.
Visual inspection of roller bearings.......... 0.25 work-hour x $85 per hour = 0 21
$21.
Replacement of roller bearing................. 6 work-hours x $85 per hour = 210 720
$510.
----------------------------------------------------------------------------------------------------------------
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, and
(2) Will not affect intrastate aviation in Alaska.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
The Amendment
Accordingly, under the authority delegated to me by the
Administrator, the FAA amends 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:
0
a. Removing Airworthiness Directive 2024-23-06, Amendment 39-22885 (89
FR 91248, November 19, 2024); and
0
b. Adding the following new airworthiness directive:
MD Helicopters, LLC: Docket No. FAA-2025-3987; Project Identifier
AD-2025-00017-R.
(a) Effective Date
This airworthiness directive (AD) is effective October 20, 2026.
(b) Affected ADs
This AD replaces AD 2024-23-06, Amendment 39-22885 (89 FR 91248,
November 19, 2024) (AD 2024-23-06).
(c) Applicability
This AD applies to all MD Helicopters, LLC Model 369, 369A,
369D, 369E, 369F, 369FF, 369H, 369HE, 369HM, 369HS, 500N, and 600N
helicopters, certificated in any category.
(d) Subject
Joint Aircraft System Component (JASC) Code 6700, Rotorcraft
flight control.
(e) Unsafe Condition
This AD was prompted by a report of a seized and damaged roller
bearing assembly in the torque tube assembly. The FAA is issuing
this AD to prevent failure of the torque tube assembly. The unsafe
condition, if not addressed, could result in reduced controllability
and 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 100 hours time-in-service (TIS) or within 12 months
after the effective date of this AD, whichever occurs first, and
thereafter at intervals not to exceed 100 hours TIS, accomplish the
actions required by paragraphs (g)(1)(i) and (ii) of this AD.
(i) Using a flashlight and mirror, visually inspect the torque
tube for corrosion and cracks. If there is any corrosion or a crack,
before further flight, remove the torque tube
[[Page 58373]]
from service and install an airworthy torque tube.
(ii) Visually inspect each roller bearing (number 5) as depicted
in Figure 1 to paragraph (g)(1) of this AD for corrosion and
degradation. If a roller bearing has any corrosion or degradation,
before further flight, remove the roller bearing from service and
install an airworthy roller bearing.
BILLING CODE 4910-13-P
Figure 1 to Paragraph (g)(1)--Torque Tube Assembly
[GRAPHIC] [TIFF OMITTED] TR15SE26.013
BILLING CODE 4910-13-C
(2) Before the helicopter accumulates 3,000 total hours TIS or
within 100 hours TIS after the effective date of this AD, whichever
occurs later, and thereafter at intervals not to exceed 100 hours
TIS, perform a freedom-of-movement inspection on the torque tube
assembly by accomplishing the actions required by paragraphs
(g)(2)(i) through (v) of this AD.
(i) Disconnect the one-way lock (number 6) of the torque tube by
removing the cotter pin (number 7), nut (number 8), bolt (number 9),
washers (number 10), and slotted bushing (number 11) from the torque
tube assembly as depicted in Figure 1 to paragraph (g)(1) of this
AD.
(ii) Loosen the longitudinal cyclic friction knob (number 12 or
13) of the torque tube assembly as depicted in Figure 1 to paragraph
(g)(1) of this AD.
[[Page 58374]]
(iii) While moving the cyclic control forward and aft to allow
the torque tube assembly to rotate through its full range of motion,
inspect the torque tube assembly for binding and ratcheting.
(A) If there is any binding or ratcheting as a result of the
action required by paragraph (g)(2)(iii) of this AD, before further
flight, inspect each roller bearing (number 5) as depicted in Figure
1 to paragraph (g)(1) of this AD for damage. For the purposes of
this inspection, damage may be indicated by corrosion, lack of
lubrication (dry exterior surface), or material degradation.
(B) If any roller bearing (number 5) as depicted in Figure 1 to
paragraph (g)(1) of this AD has any damage, before further flight,
remove the roller bearing from service and install an airworthy
roller bearing.
(iv) If there is not any binding or ratcheting as a result of
the action required by paragraph (g)(2)(iii) of this AD or after
accomplishing the action required by paragraph (g)(2)(iii)(B) of
this AD, as applicable, tighten the cyclic friction knob (number 12
or 13) as depicted in Figure 1 to paragraph (g)(1) of this AD.
(v) Connect the one-way lock (number 6) as depicted in Figure 1
to paragraph (g)(1) of this AD by accomplishing the actions required
by paragraphs (g)(2)(v)(A) and (B).
(A) Install the slotted bushing (number 11), washers (number
10), bolt (number 9), nut (number 8), and new (zero total hours TIS)
cotter pin (number 7) as depicted in Figure 1 to paragraph (g)(1) of
this AD.
(B) Ensure the edge of the slotted bushing (number 11) protrudes
0.010 to 0.080 inch (0.25 to 2.03 millimeters) above the surface of
the cyclic torque tube after the nut is tightened.
(h) 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 responsible Flight
Standards 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 (i) of this AD and
email to: <a href="/cdn-cgi/l/email-protection#296864666a694f4848074e465f"><span class="__cf_email__" data-cfemail="2465696b67644245450a434b52">[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.
(i) Additional Information
For more information about this AD, contact Eduardo Orozco-
Duran, Aviation Safety Engineer, FAA, 3960 Paramount Boulevard,
Lakewood, CA 90712; phone: (562) 627-5264; email: <a href="/cdn-cgi/l/email-protection#482d2c3d293a2c2766273a27322b27652c3d3a2926082e2929662f273e"><span class="__cf_email__" data-cfemail="b8dddccdd9cadcd796d7cad7c2dbd795dccdcad9d6f8ded9d996dfd7ce">[email protected]</span></a>.
(j) Material Incorporated by Reference
None.
Issued on September 11, 2026.
Hollister B. Thorson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2026-18927 Filed 9-14-26; 8:45 am]
BILLING CODE 4910-13-P
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