[Federal Register Volume 90, Number 139 (Wednesday, July 23, 2025)]
[Rules and Regulations]
[Pages 34593-34596]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-13863]
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Rules and Regulations
Federal Register
________________________________________________________________________
This section of the FEDERAL REGISTER contains regulatory documents
having general applicability and legal effect, most of which are keyed
to and codified in the Code of Federal Regulations, which is published
under 50 titles pursuant to 44 U.S.C. 1510.
The Code of Federal Regulations is sold by the Superintendent of Documents.
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Federal Register / Vol. 90, No. 139 / Wednesday, July 23, 2025 /
Rules and Regulations
[[Page 34593]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 73
[Docket No. FAA-2023-2371; Airspace Docket No. 22-ANM-42]
RIN 2120-AA66
Establishment of Restricted Area R-4601 in the Vicinity of
Townsend, MT
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
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SUMMARY: This action establishes restricted area R-4601 in the vicinity
of Townsend, MT. The new restricted area will provide the Montana Army
National Guard (MTARNG) and the 40th Helicopter Squadron with the
ability to conduct aerial gunnery training in the Limestone Hills
Training Area (LHTA).
DATES: Effective date 0901 UTC, October 2, 2025.
ADDRESSES: A copy of the Notice of Proposed Rulemaking (NPRM), all
comments received, this final rule, and all background material may be
viewed online at www.regulations.gov using the FAA Docket number.
Electronic retrieval help and guidelines are available on the website.
It is available 24 hours each day, 365 days each year.
FOR FURTHER INFORMATION CONTACT: Steven Roff, Rules and Regulations
Group, Policy Directorate, Federal Aviation Administration, 600
Independence Avenue SW, Washington, DC 20597; telephone: (202) 267-
8783.
SUPPLEMENTARY INFORMATION:
Authority for This Rulemaking
The FAA's authority to issue rules regarding aviation safety is
found in Title 49 of the United States Code. 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. This rulemaking is promulgated under the authority described
in Subtitle VII, Part A, Subpart I, Section 40103. Under that section,
the FAA is charged with prescribing regulations to assign the use of
the airspace necessary to ensure the safety of aircraft and the
efficient use of airspace. This regulation is within the scope of that
authority as it increases the safety of aircraft by segregating non-
participants from hazardous activities.
History
The FAA published a NPRM for Docket No. FAA 2023-2371 in the
Federal Register (88 FR 88288; December 21, 2023), proposing to
establish special use airspace (SUA) near Townsend, MT. The FAA
received 18 comments that addressed several areas of concern. Multiple
commenters expressed concern that the restricted area would impose a
significant adverse impact on local flying especially during periods of
inclement weather. Additionally, they contend that there is other
airspace within the state of Montana that can be used in lieu of
establishing new restricted airspace. They specifically mentioned the
Powder and Hays Military Operations Areas (MOA) in the state of
Montana.
As reported by a local pilot and airport manager, the majority of
the visual flight rules (VFR) traffic moving through the Townsend area
fly down the middle of the valley (over the river and/or over U.S.
Route 287 and the railroad tracks). The proposed R-4601 does not
overlie the river, highway, or railroad tracks. The Limestone Hills
Training Area is easily identifiable west of U.S. Route 287, leaving
adequate space to navigate through the valley.
The use of R-4601 during inclement weather would be highly unlikely
as the type of training to be conducted requires visual meteorological
conditions (VMC). Flight crews will not risk flying and training during
marginal weather. Also, flight crews are precluded from conducting
training in instrument meteorological conditions (IMC).
The location of the proposed R-4601 is adjacent to the very
southern tip of Canyon Ferry Lake. At the narrowest point, there is
approximately 1.5 nautical miles (NM) between the restricted area and
the lake, leaving adequate airspace for aircraft that want to avoid
flying over any portion of the lake. If an aircraft elected to fly
further east around Broadwater County Airport (8U8), it would fly over
a small portion of what is a large but very narrow lake. Very High
Frequency Omnidirectional Range (VOR) Federal airways V-365, V-536, V-
2, and United States Area Navigation (RNAV) Route T-268 all exist over
the top of Canyon Ferry Lake.
Traffic counts at the Canyon Ferry Airport (8U9) are extremely low,
and VFR traffic can easily circumnavigate both the 8U9 traffic pattern
and the proposed R-4601. VFR transient aircraft should utilize the
common traffic advisory frequencies (CTAF) of both 8U9 and 8U8 when in
the vicinity.
The best practice for VFR traffic transiting the Townsend, MT area
would be to fly above the 8U8 and 8U9 traffic patterns. The standard
pattern altitude at a non-towered airport is 1,000 feet above ground
level (AGL). The airport elevation at both 8U8 and 8U9 is just under
4,000 feet, mean sea level (MSL). Therefore, the standard pattern
altitude at both airports would be approximately 5,000 feet MSL. It is
reasonable to believe that most VFR aircraft transiting the area would
commonly be operating at 5,500 feet or higher. If an aircraft plans to
fly at lower altitudes through either traffic pattern (for weather or
otherwise), operators are required to broadcast on the CTAF and
determine if there is any traffic in the pattern. Also, most aircraft
could circumnavigate R-4601 to the west.
The establishment of R-4601 will require pilots to be more aware of
potential surrounding air traffic as they avoid the restricted area
when active. While several of the Helena Regional Airport (HLN) Runway
(RWY) 27 instrument approach procedures (IAP) are in the vicinity of R-
4601, none of the IAPs begin over R-4601.
The HLN RNAV Global Positioning System (GPS) X RWY 27 initial
approach fix is at SWEDD, MT, Fix with a crossing restriction of 10,000
feet MSL; the procedure path then proceeds north along the shore of
Canyon Ferry Lake to GASBE, MT, Waypoint (WP), before turning west to
HLN.
The HLN RNAV Required Navigation Performance (RNP) Y RWY 27 and
RNAV RNP Z RWY 27 both have a crossing restriction of 10,000 feet MSL
at SWEDD, MT, Fix before proceeding north along the shore of Canyon
Ferry Lake to BOSCA, MT, WP, then turning west to HLN.
SWEDD, MT, Fix is 6.9 NM north of the farthest-most point of the
proposed
[[Page 34594]]
R-4601. This gives VFR pilots operating below 10,000 feet MSL
sufficient airspace to circumnavigate R-4601 and then fly west to avoid
IFR traffic utilizing these IAPs.
The southern arc of the HLN Instrument Landing System (ILS) Z or
Localizer (LOC) Z RWY 27 comes closest to R-4601 and has an altitude
of, at or above 11,000 feet MSL until KEDEC, MT, Fix (approximately the
same location as SWEDD, MT, Fix) and, therefore, has less of an impact
than the aforementioned IAPs.
The flight track of the HLN ILS Y or LOC Y is more than 12 NM north
of the proposed R-4601 and is not considered a factor.
The HLN STAKK FIVE departure procedure (DP) includes a Bozeman
transition that proceeds east over SWEDD, MT, Fix before turning to
Bozeman. The required climb rates for both HLN runways place departing
aircraft at or above 11,000 feet MSL before crossing SWEDD, MT, Fix,
meaning that other aircraft in this area will have sufficient airspace
to circumnavigate R-4601 and avoid aircraft on the DP. The remaining
HLN instrument procedures are even further away and did not require
additional evaluation.
Aircraft transiting from Bozeman to Helena should maintain
awareness of other air traffic in the Helena area, including traffic
utilizing any of the HLN instrument procedures. When R-4601 is active,
there will be less space to maneuver and pilots will need to monitor
their route of flight near R-4601, surrounding traffic, and the status
of R-4601.
There are 1.5 miles of airspace between Canyon Ferry Lake and R-
4601, which is considered adequate space to transit the area without
being forced to fly over the lake. As noted above, aircraft can also
circumnavigate R-4601 to the west.
The types of activities proposed for R-4601 are considered
hazardous activities and require restricted airspace to separate
nonparticipating aircraft from the hazardous activities. Although there
are several MOAs in Montana, they are not restricted airspace and are
inadequate/inappropriate for the proposed training activities. R-4601
will be the first restricted airspace in Montana.
The establishment of R-4601 at Limestone Hills Training Area
combines two training activities in an already established area and is
compatible with current land use. The establishment of a new restricted
area requires control of the ground/property beneath the airspace,
either by owning or agreement with the property owner. The DoD does not
own or control any other suitable land in Montana that would support
the establishment of restricted airspace. MTARNG has operated a firing
range in the Limestone Hills Training Area responsibly since the 1950s
and already manages the land in the area. Creating a new restricted
area in another location would require the acquisition of additional
Montana acreage/lands. The existing Limestone Hills Training Area was
partially selected to capitalize on already-held state land and
infrastructure assets and to avoid the need to acquire additional land
for DoD use.
The R-4601 using agency will not activate R-4601 for training
activities that do not require restricted airspace. If the training is
non-hazardous and can be accomplished in a MOA, then they will use an
existing MOA.
Multiple commenters believe that a transmitter should be installed
within the Limestone Hills Training Area prior to establishing a
restricted area to broadcast if the airspace is active or not. While a
transmitter could aid pilots in determining the status of R-4601, there
is no FAA requirement that such equipment be installed when
establishing SUA. The status of R-4601 will be published in a Notice to
Airmen (NOTAM), which is the current industry standard for publishing
the times of use for special use airspace. In addition, air traffic
control (ATC) frequencies are published on the VFR sectional charts,
which pilots can utilize as another way to ascertain the status of R-
4601. Pilots can also contact MTARNG Flight Operations at (406) 324-
5779 to find out the status of the range.
Several commenters asserted that the Air Force's environmental
analysis for this area was inadequate, and they disagreed with the
determination that there are no suitable alternative sites in Montana
to establish a restricted area. The Air Force prepared an environmental
assessment (EA), which was adopted by the FAA. Public involvement as
part of that process was conducted in accordance with the National
Environmental Policy Act of 1969 (NEPA) (42 U.S.C. 4321, et seq.)
implementing regulations issued by the President's Council on
Environmental Quality (CEQ), 40 CFR parts 1500 through 1508; \1\ and
agency regulations, policies, and procedures for implementing CEQ
Regulations and NEPA, including 32 CFR part 989, the Environmental
Impact Analysis Process of the Department of Air Force; 32 CFR part
651, Environmental Analysis of Army Actions, Final Rule and the 2011
Army National Guard NEPA Handbook; FAA Order 1050.1F, Environmental
Impacts: Policies and Procedures,\2\ and FAA Order JO 7400.2R,
Procedures for Handling Airspace Matters, which sets forth the FAA's
procedures for considering and changing the NAS.
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\1\ The CEQ NEPA-implementing regulations have since been
rescinded, effective April 11, 2025. 90 FR 10610 (Feb. 25, 2025).
However, at the time the EA was prepared, the regulations were
operative.
\2\ FAA Order 1050.1F has recently been cancelled and replace by
FAA Order 1050.1G. However, at the time the EA was prepared, Order
1050.1F was the operative version in effect.
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Several commenters believe that the data used for the analysis of
air traffic in the environmental analysis was out of date or
incomplete. They contend that there is considerably more traffic in the
area than the analysis reviewed. IFR traffic volumes, as well as
impacts on IFR procedures in the vicinity of the Limestone Hills
Training Area were discoverable/verifiable. The aeronautical study
identified two potential impacts to HLN IAPs, and mitigation measures
have been determined. One mitigation is to reduce the proposed altitude
of R-4601 from 10,000 feet MSL to 9,000 feet MSL, which is reflected in
the IAP, and the other is to amend one of the IAPs with a crossing
restriction. With these mitigations, no IFR traffic will be impacted by
R-4601.
VFR aviation traffic exists below 9,000 feet MSL in the Limestone
Hills Training Area, and R-4601 will impact this traffic. However, the
actual volume of VFR traffic is neither discoverable nor verifiable by
existing technology. As a commenter pointed out, some VFR aircraft
operate in the area without an operating transponder, etc., and many
are well below surveillance coverage. However, information received
indicates the route of flights for most VFR transient aircraft around
the Limestone Hills Training Area is to overfly U.S. Route 287 or the
railroad tracks; such a route is clear of R-4601.
The use of R-4601 is restricted to 140 days of the year due to
seasonal restrictions for wildfire and wildlife mitigations, leaving
air traffic unincumbered for 225 days of the year. Of the 140 days
available for activation of R-4601, the maximum estimated usage is up
to 50 events that may occur during the day or night. During each day or
night of usage, R-4601 would typically be used for a 2 to 3-hour block
for a maximum total of 150 hours per year. Assuming most air traffic
flies through the area between 0800 and 2000 (14 hours per day), the
airspace in the Limestone Hills Training Area is used
[[Page 34595]]
an average of 5,110 flying hours per year. Therefore, R-4601 could
potentially be a factor for approximately 3% of airspace availability
per year. Given that the majority of VFR aircraft follow the highway
and/or railroad tracks (which path is not impacted by R-4601), the
total percentage of airspace availability impacted by R-4601 is likely
less than 3% and estimated to be 2% or less per year.
One commenter questioned why the results of an electronically
distributed pilot survey seeking information on general aviation
operations that may be impacted by the restricted area was not
distributed to the public. Concerns raised by the Montana Department of
Transportation, Aeronautics Division, resulted in a pilot survey aimed
at gathering more information on the number of VFR flights in and
around the proposed restricted airspace since there is not adequate
radar information.\3\ The information gathered supported the
environmental analysis. Parties interested in the survey results should
contact Katie Rediske at [email protected].
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\3\ The Montana Department of Transportation, Aeronautics
Division submitted a comment on the NPRM criticizing the proposal
and claiming that inadequate coordination was conducted with the
agency as part of the EA process. Subsequent to submitting the
comment, further coordination occurred, including the pilot survey
mentioned here.
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Two commenters had concerns regarding the future expansion of the
size or utilization of R-4601 once it is established. Currently, the
DoD has no intent or ability to segment the LHTA into any broader
airspace utilization. This project was intended to make use of already
held assets, namely the LHTA, an artillery range for the MTARNG, and to
add restricted airspace to execute aerial gunnery for USAF and MTARNG
readiness training. It does not segment or connect to any other
project. The information analyzed for the number of training events in
the EA was the highest use case scenario for USAF training and based on
stated USAF training requirements. Table 2-2 in the EA lists the number
of proposed training events by USAF and MTARNG, which are all based on
range availability and other factors such as seasonal limitations,
weather, and supply of ammunition. Therefore, the potential to expand
the LHTA and/or R-4601 in the future is limited and would require
additional analysis and public input.
Differences From the NPRM
After publishing the NPRM, the name of the proposed restricted area
changed from ``R-4601 Townsend, MT'' to ``R-4601 Limestone Hills
Training Area, MT.'' Additionally, the FAA slightly modified the
dimensions of the airspace from what was published in the NPRM. The
shape of the airspace is relatively the same, however, portions have
been removed on the southwest corner and to the northeast because
[reason(s)]. Overall, the final size of the restricted area is smaller
than what was published in the NPRM. This action makes both changes.
The FAA has determined that good cause exists for not re-circulating
the proposal for public comment given that the changes are either
ministerial in nature or result in a reduction of the impacted
airspace.
The Rule
This action amends 14 CFR part 73 by establishing restricted area
R-4601 in the vicinity of Townsend, MT. This new restricted area will
provide a new training capability to the MTARNG in preparation for
combat deployments and the 40th Helicopter Squadron located at
Malmstrom Air Force Base (AFB) in support of security operations. The
new restricted area is described below.
R-4601: Restricted area R-4601 extends upward from the surface of
the ground to 9,000 feet MSL. The restricted area is located
approximately four miles west of Broadwater County Airport, MT (8U8)
and extends approximately eight miles to the southwest. The restricted
area will be activated by a NOTAM to inform nonparticipants when the
restricted area is active. During periods when the restricted area
airspace is not needed by the using agency for its designated purpose,
the airspace will be returned to the controlling agency for access by
other National Airspace System users. The controlling agency for this
proposed restricted area is the Salt Lake City Air Route Traffic
Control Center.
Regulatory Notices and Analyses
The FAA has determined that this regulation only involves an
established body of technical regulations for which frequent and
routine amendments are necessary to keep them operationally current.
It, therefore: (1) is not a ``significant regulatory action'' under
Executive Order 12866; (2) is not a ``significant rule'' under DOT
Regulatory Policies and Procedures (44 FR 11034; February 26, 1979);
and (3) does not warrant preparation of a regulatory evaluation as the
anticipated impact is so minimal. Since this is a routine matter that
only affects air traffic procedures and air navigation, it is certified
that this rule, when promulgated, does not have a significant economic
impact on a substantial number of small entities under the criteria of
the Regulatory Flexibility Act.
Environmental Review
The FAA's establishment of restricted area R-4601 in the vicinity
of Townsend, MT, for the MTARNG's and the 40th Helicopter Squadron's
conduct of aerial gunnery training, was evaluated and documented in
accordance with the National Environmental Policy Act (NEPA) (42 U.S.C.
4321, et seq.) in the United States Air Force's (USAF) Final
Environmental Assessment (FEA) for the Establishment and Operation of a
Helicopter Aerial Gunnery Range and Establishment of Special Use
Airspace Restricted Area R-4601 at the Limestone Hills Training Area,
in Broadwater County, MT, signed November 2024. The USAF's FEA analyzes
the FAA's modification of SUA, including the FAA's establishment of the
new restricted area, R-4601, at LHTA which will be used for military
flight training by the Air Force Global Strike Command (AFGSC) and the
National Guard Bureau (NGB) operator for the Montana Army National
Guard (MTARNG). The FAA, in fulfilling its mandated role as Cooperating
Agency for this USAF proposed action, has adopted the USAF's FEA in a
separate FAA NEPA adoption document and Record of Decision (ROD),
drafted in accordance with Section 107 of NEPA, NEPA's implementing
regulations concerning the roles and responsibilities of Cooperating
Agencies, and other applicable authorities, including FAA's NEPA
implementing guidance, FAA Order 1050.1F, Environmental Impacts:
Policies and Procedures, which sets forth the FAA's policies and
procedures for considering the environmental impacts of its actions
including the process for Adoption of Other Agencies' NEPA Documents;
and FAA Order JO 7400.2R, Procedures for Handling Airspace Matters,
which sets forth the FAA's procedures for evaluating and changing the
National Airspace System (NAS), including SUA.
Lists of Subjects in 14 CFR Part 73
Airspace, Prohibited areas, Restricted areas.
The Amendment
In consideration of the foregoing, the Federal Aviation
Administration amends 14 CFR part 73 as follows:
PART 73--SPECIAL USE AIRSPACE
0
1. The authority citation for part 73 continues to read as follows:
[[Page 34596]]
Authority: 49 U.S.C. 106(f), 106(g); 40103, 40113, 40120; E.O.
10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p.389.
Sec. 73.46 Montana (MT) [New]
0
2. Section 73.46 is amended as follows:
R-4601 Limestone Hills, MT [New]
Boundaries. Beginning at lat. 46[deg]19'22'' N, long.
111[deg]37'20'' W; to lat. 46[deg]20'08'' N, long. 111[deg]33'57''
W; to lat. 46[deg]19'18'' N, long. 111[deg]33'24'' W; to lat.
46[deg]18'43'' N, long. 111[deg]33'24'' W; to lat. 46[deg]18'43'' N,
long. 111[deg]33'43'' W; to lat. 46[deg]18'22'' N, long.
111[deg]34'02'' W; to lat. 46[deg]18'00'' N, long. 111[deg]34'02''
W; to lat. 46[deg]17'30'' N, long. 111[deg]33'10'' W; to lat.
46[deg]17'30'' N, long. 111[deg]32'11'' W; to lat. 46[deg]14'33'' N,
long. 111[deg]32'11'' W; to lat. 46[deg]13'30'' N, long.
111[deg]33'38'' W; to lat. 46[deg]13'31'' N, long. 111[deg]36'31''
W; to lat. 46[deg]14'19'' N, long. 111[deg]36'31'' W; to lat.
46[deg]14'33'' N, long. 111[deg]37'10'' W; to lat. 46[deg]14'33'' N,
long. 111[deg]38'00'' W; to lat. 46[deg]17'21'' N, long.
111[deg]38'00'' W; to lat. 46[deg]17'21'' N, long. 111[deg]37'47''
W; to lat. 46[deg]19'04'' N, long. 111[deg]37'46'' W; to the point
of beginning.
Designated altitudes: Surface to 9,000 feet MSL.
Time of designation: By NOTAM.
Controlling agency: FAA, Salt Lake City ARTCC.
Using agency: U.S. Army, Montana Army National Guard, Joint
Forces Headquarters, Fort Harrison, MT.
* * * * *
Issued in Washington, DC, July 21, 2025.
Brian Eric Konie,
Manager (A), Rules and Regulations Group.
[FR Doc. 2025-13863 Filed 7-22-25; 8:45 am]
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