ENVIRONMENTAL ASSESSMENT ENNIS BIG SKY MADISON COUNTY, MT

1. BACKGROUND

AND PROPOSED

ACTION

ROBERT PECCIA & ASSOCIATES

1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT

BACKGROUND AND PROPOSED ACTION

This chapter describes Ennis Big Sky Airport and presents the planning background for the proposed projects. Madison County owns and operates the airport and is the Sponsor for the proposed improvements at the facility. This chapter also describes the Proposed Action the Sponsor is seeking to implement to safely accommodate a change in the “critical aircraft” (the most demanding aircraft type or grouping of aircraft) that make regular use of the Ennis Big Sky Airport. The Proposed Action includes acquiring additional property for the airport, extending and widening the existing , and making other facility improvements to better and more safely accommodate the aircraft using the facility. Further, this chapter discusses a timeline for implementation of the proposed improvements.

This Environmental Assessment (EA) was prepared to identify the potential environmental impacts associated with the Proposed Action, as well as how any identified impacts can be avoided, minimized, or mitigated. The EA was prepared pursuant to Section 102(2)(c) of the National Environmental Policy Act (NEPA) and the President’s Council on Environmental Quality (CEQ) Regulations Title 40 CFR §§ 1500-1508, the implementing regulations for NEPA, and in accordance with FAA Order 1050.1F Environmental Impacts: Policies and Procedures and FAA Order 5050.4B National Environmental Policy Act (NEPA) Implementing Instructions for Airport Actions. 1.1 Background 1.1.1 Airport Location

The Ennis Big Sky Airport (also referred to as “Airport” or by its Airport “EKS” in this document) is located approximately seven miles south-southeast of the Town of Ennis in the Madison River Valley of southwestern . The airport property lies 1.5 miles east of Highway 287, which is the major north-south arterial through Ennis and the Madison Valley. The airport is accessed by an east-west oriented gravel access road (Airport Road/County Road 212) maintained by Madison County. A secondary north-south oriented, pulverized asphalt surfaced access road (Runway Road) provides direct access to a small gravel parking area next to the central apron and Fixed-Base Operator (FBO).

The Airport lies in Sections 19, 30, and 31 of Township 6 South, Range 1 East and Section 06 of Township 7 South, Range 1 East. Figure 1‐1 shows the Airport’s location. 1.1.2 Airport History

The Ennis Big Sky Airport is owned and operated by Madison County and has existed at its present location for more than 40 years. The Airport was originally established in the mid-1970s as the Big Sky Air Park, a private airport within the Shining Mountains land development. The Air Park was a planned development designed and constructed to provide residents with convenient access to an airport from adjoining residential areas.

After a planning process that lasted from 1986 to 1989, the FAA accepted the Ennis Big Sky Airport (formerly known as the Big Sky Air Park) into the National Plan of Integrated Airport Systems

1-1

1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT

Figure 1-1: Location of Ennis Big Sky Airport (EKS)

ENNIS

BEAVERHEAD-DEERLODGE NATIONAL FOREST

MOONLIGHT BASIN

BIG SKY RESORT

ENNIS BIG SKY AIRPORT

YELLOWSTONE CLUB

1-2

1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT

(NPIAS). Entrance into the NPIAS made the facility eligible to receive federal funding. The County subsequently received an Airport Improvement Program (AIP) grant in 1990 to design and construct improvements at the existing Ennis Big Sky Airport in order to meet FAA design standards and recommendations. The Airport has conducted numerous projects since 1992 to maintain and improve the airport.

Since 2015, Madison County used local funds to acquire lands adjacent to the Ennis Big Sky Airport as they became available to ensure land use compatibility with the airport environs and to protect design and airspace surfaces for aviation purposes. The County used local funds to acquire a parcel from the Longhorn Ranch, Tract 29-A-1, and portions of Tracts 20-A, 20-B, 13-A, and 13-B (See Figure 1‐2). The FAA had no involvement or approvals associated with the acquisitions made with local funds and therefore, there was no federal action triggering NEPA. The FAA has a federal action at the time that the FAA would approve reimbursement of land acquisition costs through the federal grant program and/or for an update to the ALP requiring FAA approval. The Sponsor is now requesting reimbursement for the land acquisitions associated with master plan improvements that require FAA ALP approval, so this prior land acquisition is being evaluated as part of the proposed action in this EA. 1.1.3 Existing Facilities at EKS

The general layout of the existing airport is shown in Figure 1‐3. The primary facilities at EKS include Runway 16/34 (a 6,601-foot long x 75-foot wide asphalt runway), and a 35-foot wide partial parallel taxiway beginning at the Runway 34 end (the northern portion of the parallel taxiway is currently closed) with two connecting taxiways. A turnaround and aircraft holding area (with no parallel taxiway connection) exists at the Runway 16 threshold.

Runway 16/34 is lighted with a radio-controlled, medium-intensity runway lighting (MIRL) system. The connecting taxiways have dual medium-intensity taxiway lights defining the entrance to the taxiways from the runway and retroreflective markers along the remaining taxiways and aprons.

The airfield has three asphalt apron areas (South, Central, and North) encompassing about 5 acres, taxilanes for hangar access, a segmented circle with lighted wind cone, Sponsor-owned AWOS III/P weather system, a rotating beacon, Sponsor-owned Precision Approach Path Indicators (PAPI’s) at both runway ends, several guidance signs, and numerous hangars and other airport buildings. Figure 1‐4 provides a detail of the terminal area at the Ennis Big Sky Airport.

Several smaller hangars front the taxilane, while two large private hangars are located along the west edge of the central apron. The FBO has been in operation at EKS since September 2012 and operates out of both large hangars. There are several buildings and structures located within the area between the central and south apron including: fuel tanks (located within a concrete containment structure), the 100LL self-serve dispensing unit, a pilot shack, an outhouse, two hangars and some smaller storage buildings, a flagpole, and the airport beacon. 24-hour self-serve 100LL fuel is provided on the taxiway, while Jet A and 100LL are available via fuel trucks during normal business hours or by previous arrangement with the FBO.

1-3

1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT

Figure 1-2: Ennis Big Sky Airport Lands

1-4

1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT

Figure 1-3: Ennis Big Sky Airport Layout Runway 16 End Runway Turnaround and Aircraft Holding Area

Currently CLOSED Section of Taxiway A

Connecting Taxiway A3 Segmented Circle, Wind Cone, and AWOS III/P Partial Parallel Taxiway A

See Figure 1-4 for Detail of Connecting Taxiway A4 Terminal Area

Runway 34 End

1-5

1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT

Figure 1-4: EKS Terminal Area

North Apron

Taxilanes

Above Ground Storage Tanks FBO (Fuel Farm) Self-Service Fuel Hangars Dispensing Unit

SRE Building (Existing) Beacon Central Apron

New SRE/AARF Building (Under Construction 2019)

South Apron

Connecting Taxiway A4

1-6

1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT

There is a Snow Removal Equipment (SRE) storage building located west of the central apron and construction of a new Snow Removal Equipment and Aircraft Rescue and Firefighting (SRE/AARF) building began in 2019.

The Ennis Big Sky Airport has several designated Residential-Through-The-Fence (RTTF) access locations dating to the facility’s initial development as a residential air park. Madison County has an FAA-approved RTTF Access Agreement, which establishes the terms and conditions of use of RTTF access points for users. 1.1.4 Airport Classification and Use

The FAA’s National Plan of Integrated Airport Systems 2017‐2021 (NPIAS) identifies that are significant for national air transportation. The NPIAS identifies Ennis Big Sky Airport as a nonprimary General Aviation (GA) airport. Nonprimary airports are further categorized based on existing activity, geographic factors, and public interest functions such as national, regional, local, basic, and unclassified airports. The NPIAS lists EKS as a Local airport, one of 25 similarly classified GA airports in Montana. The airport primarily serves the Madison Valley and Ennis areas, but also provides nearby access into the Big Sky and Moonlight Basin resort areas.

Airports are typically designed in accordance with the Runway Design Code (RDC) designations from the FAA’s Advisory Circular (AC) 150/5300-13 Airport Design. The RDC provides information needed to determine applicable design standards. Other factors, such as aircraft haul length and Maximum Takeoff Weight (MTOW), are also considerations in the development of design standards. The RDC has three components. The first component, designated by a letter (A through E), is the Aircraft Approach Category (AAC) and relates to aircraft approach speed. The second component, designated by Roman numerals (I through VI), is the Aircraft Design Group (ADG) and relates to aircraft wingspan and tail height, whichever is most restrictive. The third component relates to the visibility minimums (distance in feet) expressed by Runway Visual Range (RVR).

EKS currently meets design standards for an RDC designation of B-II-5000. 1.1.5 14 CFR Part 77 Airspace at EKS 14 Code of Federal Regulations Part 77.19 Civil Airport Imaginary Surfaces (14 CFR Part 77) establishes a complex structure of imaginary surfaces in relation to runways at public use airports. Imaginary surfaces either slope out and up from all sides and ends of runways or are a horizontal plane or a sloping plane above the airport. The size of each imaginary surface is based on the category of each runway according to the type of instrument approach available or planned for that runway and the MTOW of the critical aircraft.

Imaginary surfaces exist primarily to prevent existing or proposed manmade objects, objects of natural growth, or terrain from extending upward into navigable airspace. According to the provisions in 14 CFR Part 77, an object is an Obstruction to Air Navigation if it is of greater height than any imaginary surface established under the regulation. There are five imaginary surfaces applied to public use airports for determining obstructions to air navigation—the primary surface, the horizontal surface, the conical surface, the transitional surface, and the approach surface. Figure 1‐5 illustrates the14 CFR Part 77 surfaces.

1-7

1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT

The terrain east and north of the runway at EKS currently penetrates the primary, horizontal, conical, transitional, and approach surfaces. Buildings, fencing, and other airport features (the wind cone and segmented circle, AWOS equipment, and a flagpole) also penetrate one or more of the imaginary surfaces at the facility (see Figure 1‐9 at the end of this chapter). Information about airspace obstructions can also be found in the 2018 Ennis Big Sky Airport Master Plan Update (see Appendix E) and on Sheet 3 of the ALP set (see Appendix B).

Figure 1-5: 14 CFR Part 77 Surfaces

1.1.6 Airport Planning FAA guidance recommends that a Master Plan be completed or updated approximately every five years or when an airport experiences unexpected, rapid growth in activity. The most recent planning effort for the Ennis Big Sky Airport was undertaken in response to notable changes in the type of aviation activity occurring at EKS.

2018 Master Plan Update/Alternative Development and Evaluation Study The 2018 Master Plan Update and Alternative Development & Evaluation Study was initiated in 2015 and concluded in May 2018.

The airport planning effort was conducted to determine the type of airport facilities appropriate for EKS based on current and forecasted aircraft activity. The 2018 Master Plan Update (found in Appendix E of this EA) included a detailed examination of past and current aviation activity to identify trends for local versus itinerant use, annual operations, based aircraft, and the types of aircraft using the airport. The trend analysis, along with relevant socio-economic information and other published aviation forecasts, were used to establish growth rates to help forecast future aviation activity at EKS. The updated aviation forecasts for the Airport can be found in Chapter 5 of

1-8

1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT the 2018 Master Plan Update. The FAA’s approval of the forecast can be found in Appendix I of the 2018 Master Plan Update (see Appendix E).

Notably, the 2018 Master Plan Update documented a rapid increase in the number of Aircraft Approach Category “C” operations in recent years and forecasted an 11.78% increase in the number of annual aircraft operations at EKS in the short term. This resulted in a forecast in which Category “C” aircraft would exceed the FAA’s regular use threshold of 500 annual operations in 2018. This is significant since the critical aircraft category dictates many of the airport’s essential design standards and airspace requirements. Additionally, the critical aircraft has been forecasted to change from less than 12,500-lbs MTOW, to greater than 12,500-lbs but less than 60,000-lbs MTOW and occasional use of aircraft with up to 114,850 MTOW.

Considering the forecasted change in critical aircraft category at EKS, the 2018 Master Plan Update examined existing aviation facilities and identified design changes or improvements required to accommodate the change in critical aircraft category. Numerous development alternatives to meet the new facility requirements were evaluated and a preferred development alternative for EKS was ultimately recommended in the 2018 Master Plan Update. Other activities associated with the 2018 Master Plan Update included revising the ALP to reflect the preferred future development at EKS, public involvement opportunities, and development of an implementation plan for the recommended airport improvements. 1.2 Current and Forecasted Aviation Activity at EKS 1.2.1 Types of Aircraft Using EKS

Ennis Big Sky Airport is used for business, governmental, recreational, emergency, medical, and personal uses. The Airport is most frequently used for local and itinerant operations by small GA aircraft. However, EKS also experiences air taxi and itinerant operations by larger twin-engine aircraft and business jets.

The aircraft currently using Ennis Big Sky Airport primarily fall within Aircraft Approach Categories A, B, and C and Airplane Design Groups I and II (A-I, A-II, B-I, B-II, C-I, and C-II categories). Many of these aircraft also have MTOWs greater than 30,000 pounds but less than 100,000 pounds. Aircraft associated with the C-III category occasionally use EKS. Examples of aircraft from each major approach category are shown in Figure 1‐6.

The critical aircraft (or design aircraft) designation is important for purposes of airport geometric design and represents the most demanding aircraft type (or grouping of aircraft with similar characteristics) that makes regular use of the airport. Regular use is defined as 500 operations, including both itinerant and local operations, but excluding touch-and-go operations. Critical aircraft are designated based on their Aircraft Approach, Category (AAC), Airplane Design Group (ADG), and Taxiway Design Group (TGD). Critical aircraft can be further defined by their MTOW.

1-9

1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT

Figure 1-6: Aircraft Using EKS By Airport Reference Code

1-10

1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT

1.2.2 Current Aviation Activity at EKS

EKS has seen steady increases in the total number of annual operations over the past twenty years, growing from about 10,500 operations in 1997 to 12,200 operations in 2015. Although some minor year-to-year fluctuations occurred, the number of total annual aircraft operations grew at an average annual rate of 0.83% between 1997 and 2015. Over the same period, local aircraft operations and itinerant operations grew at average annual rates of 0.60% and 0.38%, respectively.

An analysis of operational data shows a notable trend of increased use by higher performance aircraft at the airport, particularly by air taxis, over the past decade. Air taxi operations at EKS have increased at a rate of more than 11% annually since 2009. This trend can be attributed to changes in facilities and services offered at EKS including: increasing the runway’s length to 6,600 feet in 2008, the addition of FBO-provided services in 2012, and the development of an instrument approach procedure in 2014. However, a healthy economy driven by recreation-based development and the associated demand for more seasonal, recreational, or occasional use housing in the area is the underlying factor contributing to the changes in the type aircraft seen at EKS.

The 2018 Master Plan Update forecasts continued growth in the number of annual operations at EKS and continued significant increases in air taxi operations over a planning period ending in 2030. The current aviation activity (operational baseline) and forecasted aviation activity at the airport are discussed in the following sections.

Current Operational Baseline

Like most non-towered airports, EKS does not have full-time equipment or personnel assigned to record the number and type of operations occurring at the facility. For this reason, the FAA’s Terminal Area Forecasts represent a consistent source of aircraft operational data at non-towered airports. The Terminal Area Forecast operational data comes from the FAA’s 5010 Airport Master Record forms, which reflect estimates from airport managers about the number of operations seen annually at each facility.

The 5010 Airport Master Record data for 2015 at the Ennis Big Sky Airport is shown in Table 1.1. This information served as the operational baseline for aviation forecasts established in the 2018 Master Plan Update.

In 2015, EKS had 12,200 total operations. Local GA operations accounted for 53% (6,500) of the operations and itinerant GA operations accounted for about 41% (5,000) of the operations. Operations by air taxis (which include B-II, C-II, and C-III aircraft) represented about 5% of all operations at the airport.

The FAA’s 5010 Airport Master Record lists 600 annual operations by air taxi in 2015. This estimate correlates well with FlightAware operational data, which showed a total of 528 operations over the 12-month period from June 2015 to June 2016. FlightAware is a privately held company that provides aviation flight tracking in over 50 countries. Air taxis are commonly operated under Instrument Flight Rules (IFR) for all flights, and are therefore, usually tracked in the data compiled by FlightAware.

1-11

1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT

There are currently 21 aircraft based at the Ennis Big Sky Airport, which comprise the entirety of the local operations. Each based aircraft averaged approximately 310 operations (6,500 operations/21 local aircraft) or 155 flights in 2015.

Table 1.1. Operational Baseline (2015) for EKS*

ANNUAL OPERATIONS BASED AIRCRAFT

Air Carrier 0 Single Engine 20 Air Taxi/Commuter 600 Multi-Engine 1

General Aviation - Itinerant 5,000 Jet 0 General Aviation - Local 6,500

Military 100 TOTAL OPERATIONS 12,200

* Annual operations and based aircraft as established in the current FAA 5010 Airport Master Record. Available at: https://www.gcr1.com/5010WEB/ by entering airport location identifier “EKS”. 1.2.3 Forecasted Annual Operations

The number of annual operations presently occurring and projected to occur at EKS through the year 2030 were established in the 2018 Master Plan Update and a forecast was approved by the FAA on February 24, 2016. As discussed in the 2018 Master Plan Update, a variety of data and forecasting methods were considered to develop appropriate annual growth rates for local and itinerant operations, air taxi operations, and military operations to arrive at reasonable projections of future operations at the airport.

The forecasting effort in the 2018 Master Plan Update resulted in selection of annual growth rates of 0.60% for local operations, 0.38% for itinerant operations, and 3.0% for military operations at EKS.

Forecasting efforts relied on FlightAware data to help identify trends in air taxi operations at the Airport. The FlightAware data showed a 29.44% average annual growth rate for all AAC-C IFR operations over the June 2012 to June 2016 period and a 6.04% average annual growth rate for all AAC-B IFR operations over a 3-year period between June 2012 and June 2015. The AAC-C aircraft operating at EKS are most commonly air taxis. Considering this data, the 2018 Master Plan Update forecasts air taxi operations to continue increasing at an annual growth rate of 11.78% through 2020. Air taxi operations are then projected to grow at an annual rate of 2.4% through 2030, consistent with FAA’s current forecast for the turbine-powered fleet. Table 1.2 shows the number of forecasted annual operations at the airport over the 2015 to 2030 period as summarized in the 2018 Master Plan Update.

1-12

1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT

Table 1.2: Forecasted Itinerant and Local Operations at EKS

FORECAST YEARS ESTIMATED NUMBER OF ANNUAL OPERATIONS Operational Base Year +1 Base Year Base Year Base Year Base Year Year +5 Years +10 Years +15 Years 2015* (2016) (2020) (2025) (2030) Itinerant Operations 5,000 5,019 5,096 5,193 5,293 Air Taxi/Commuter 600 671 1,047 1,179 1,327 Military 100 103 116 134 156 Local Operations 6,500 6,539 6,697 6,901 7,110 TOTAL OPERATIONS 12,200 12,332 12,956 13,407 13,886 BASED AIRCRAFT 21 22 22 23 24 * Base Total Operations as established in the 2015 FAA 5010 Airport Master Record

The analysis done for the 2018 Master Plan Update suggests the total number of annual aircraft operations may increase by nearly 14% by 2030. The forecast for EKS also indicates:  Total annual local operations are projected to increase by 9.4% by 2030;  Total annual itinerant operations are projected to increase by 5.9% by 2030; and  Total annual air taxi/commuter operations are projected to increase by 121% by 2030. 1.2.4 Critical Aircraft Determination Based on Forecasting

The types of aircraft currently using and expected to use EKS during the forecast period were also analyzed in the 2018 Master Plan Update to identify changes in the critical aircraft category for the facility. Operations by aircraft exceeding the existing critical aircraft category of B-II, TDG-2, with a MTOW of less than 12,500 lbs at EKS were of interest.

As discussed previously in this section, FlightAware data showed a 29.44% average annual increase in IFR operations by AAC-C aircraft over the 2012-2016 period. The 2018 Master Plan Update indicates 373 operations by AAC-C aircraft at EKS in 2016. Forecasting methodologies predict the 500-annual operations threshold by AAC-C aircraft would be exceeded in 2018. This suggests AAC- C is now the appropriate Aircraft Approach Category for EKS.

The 2018 Master Plan Update examined FlightAware data to determine if changes were necessary to the Airplane Design Group (ADG) and Taxiway Design Group (TDG) at EKS. The data showed operations by aircraft in ADG-III or TDG-3 would not approach the 500-annual operations threshold during the forecast period. ADG-II and TDG-2 remain valid designations for the critical aircraft category at EKS.

Due to the increased use of the airport by heavier aircraft, the MTOW of the aircraft using EKS was also forecasted in the 2018 Master Plan Update. The analysis of FlightAware data for the 2014-2016 period indicated significant increases in the use by aircraft exceeding 60,000-lbs MTOW. However, the number of operations by aircraft in the >60,000 pounds MTOW fleet is currently low and

1-13

1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT forecasts show operations will not reach the regular use threshold during the forecast period. The analysis of FlightAware data revealed most of the AAC-C aircraft operating at EKS were in the “>12,500 lbs but < 60,000 lbs MTOW” fleet. With the application of anticipated annual growth rates, the number of operations by aircraft in this MTOW category is forecasted to exceed the 500 operations regular use threshold by 2019.

The 2018 Master Plan Update showed the appropriate critical design aircraft category for EKS is now C‐II‐2, >12,500 lbs but <60,000 lbs MTOW. As stated above, EKS also experiences aircraft that exceed 60,000 lbs, but that do not exceed the regular use threshold. Since the 2018 Master Plan Update, a new aircraft with a MTOW of 114,850 pounds dual wheel has been developed. These aircraft will be utilized as air taxis by operators that currently frequent EKS. Therefore, it is recommended that all pavements be designed to accommodate occasional use of aircraft up to 114,850-lbs MTOW (see Section 2.2.2.4 for a discussion of pavement strength). This change in critical design aircraft category relates directly to the recent and anticipated increase in aviation activity at the Airport. This increase is forecast to occur regardless of any improvements being made to the Airport.

The 2018 Master Plan Update also considered the need for changes to the Runway Visual Range (RVR) visibility minimums at EKS. Although an RVR designation of 5,000 feet or 4,000 feet would be applicable given the usage of the airport and the surrounding terrain, it was ultimately determined that a lower RVR was not justified or necessary. Therefore, the RVR designation of 5,000 feet for EKS remains unchanged and the forecasted ARC for the airport changes from B-II- 5000 to C‐II ‐5000.

The change in critical design aircraft category and its implications are discussed in Chapter 2. 1.3 Proposed Action The Proposed Action evaluated in this EA includes a variety of improvements at EKS that will satisfy the Purpose and Need described in Chapter 2. The Proposed Action would modify the existing airport configuration to provide a 100-foot-wide by 7,600-foot-long paved runway constructed to C-II-5000 standards and a 35-foot-wide full-length parallel taxiway (TDG-2 standards). The following elements are required to complete the Proposed Action, and the major components are shown on Figure 1‐7:

 Land Acquisition (see Figure 1‐8 for proposed acquisitions)  Acquire 3.17 acres of private land from two parcels adjoining the airport: . Tract 4-A (Fee acquisition of 1.96 acres of 6.42-acre parcel); and . Tract 4-B (Fee acquisition of 1.21 acres of 6.43-acre parcel).  Acquire a Perpetual Easement on 17.82 acres of State of Montana land (Tract 6).  Consideration of Airport Improvement Program (AIP) funding to reimburse Madison County for the use of local funds to acquire a parcel from the Longhorn Ranch, Tract 29-A-1, and portions of Tracts 20-A, 20-B, 13-A, and 13-B.  Reconstruct, Extend, and Widen Runway 16/34  Reconstruct approximately 2,600 feet of Runway 16/34 to a 1.5% maximum slope and meeting vertical curve criteria.

1-14

1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT

Figure 1-7: Proposed Action at EKS

1-15

1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT

Figure 1-8: Proposed Land Acquisitions at EKS

1-16

1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT

 Place a 2-inch thick Hot Mix Asphalt (HMA) structural overlay on the portion of the existing runway which is not reconstructed.  Construct a 999-foot-long northerly extension to Runway 16 to provide 7,600-foot-long runway with a 1.5% maximum slope.  Widen Runway 16/34 to 100 feet.  Grade Runway Safety Areas (RSA) to meet C-II-5000 standards and move or extend existing drainage ditches and culverts.  Relocate or replace the Medium Intensity Runway Lighting (MIRL) system for Runway 16/34.  Relocate the Precision Approach Path Indicators (PAPI) for Runway 16 and expand it to a four-box unit.  Expand the PAPI for Runway 34 to a four-box unit.  Relocate and Construct an Extension to the Partial Parallel Taxiway to a Full Length Parallel Taxiway  Provide the required runway to parallel taxiway separation distance to meet C-II-5000 standards (300 feet minimum).  Reconstruct the closed segment of the parallel taxiway between Taxiways A-2 and A-3 and the parallel taxiway segment connecting Taxiway A-4 and the southern edge of the central apron to restore the partial parallel taxiway to its previous length of 4,700 feet.  Extend the existing partial parallel taxiway to a full-length parallel taxiway.  Reconstruct Taxiways A-2 and A-4, which connect the runway to the parallel taxiway.  Install Taxiway Edge Reflectors, Medium Intensity Taxiway Lighting (MITL), and guidance signs.  Remove Airport Buildings  Demolish two hangars located between the Central and South Aprons.  Demolish or relocate Pilot’s Shack/Public Room, adjacent vault toilet, and a shed.  Reconstruct the South Apron  Shift apron westward to accommodate the increased width of the Runway 16/34 Object Free Area (OFA).  Increase the strength of the apron pavement.  Extend Taxilane C, Construct a Portion of Taxilane D, and Construct Hangars  Relocate NAVAIDs, AWOS III/P, and Relocate/Rehabilitate Electrical Vault  Relocate wind cone, segmented circle, and Automated Weather Observing Equipment (AWOS III/P) beyond the Runway 16/34 OFA.  Relocate beacon and install beacon on a tip-down pole.  Relocate vault and rehabilitate/install vault equipment. e Relocat Self‐Service Fuel Dispensing Unit  Remove Obstructions to 14 CFR Part 77 Airspace (Terrain, buildings, fencing, wind cone, segmented circle, AWOS equipment, and flagpole – See Figure 1‐9)  Amend Instrument Approach and Departure Procedures  Install wildlife fencing around the new perimeter of the airport property

1-17

1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT

Figure 1-9: Proposed 14 CFR Part 77 Airspace Obstruction Removal at EKS

1-18

1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT

1.4 Implementation of the Proposed Action The primary components of the Proposed Action are projected to be completed between 2019 and 2021 pending completion of the environmental review process. Construction would be implemented in stages and under multiple FAA grants. Acquisition of east side properties and granting of the northerly perpetual easement from the State of Montana, necessary for the proposed improvements at EKS are anticipated to be completed in 2019.

Construction activities would likely begin in FY 2020 with work on the South Apron and the adjacent southern portion of the parallel Taxiway A and Runway 34 connecting Taxiway A-4. Widening and extension work would continue in FY 2020 along with other associated and miscellaneous improvements (taxilanes, runway lighting, navigational aids, full-length parallel taxiway construction). The exact timing of the individual improvements will vary based on many factors, but primarily, it will depend upon the availability of FAA funding.

Reconstruction, widening, and extension work for Runway 16/34 would result in temporary closures of the runway. Efforts would be made to keep the runway in service to the extent practicable during reconstruction work at the airport. Overall, the runway may be closed for about 90 days; however, necessary final construction closure(s) would not be determined until final design is completed.

1-19

1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT

THIS PAGE INTENTIONALLY LEFT BLANK

1-20