You love the idea of a home or land near Ennis Big Sky Airport, with easy access to trails, rivers, and town. But airport overlay rules can surprise buyers and affect future plans. Here’s a clear, buyer-friendly guide to what the Airport Affected Area means for height, trees, land use, permits, and timelines so you can move forward with confidence. Let’s dive in.
Airport overlay basics in Madison County
Madison County uses an Airport Affected Area overlay for Ennis Big Sky Airport to keep airspace safe and projects predictable. The county adopted these rules in 2014 and grounded them in Montana’s Airport Compatibility Act and FAA standards. You can review the full rules in the county’s Airport Affected Area Regulations and see the state legal basis in the Airport Compatibility Act.
What the overlay covers
The overlay maps the FAA’s “imaginary surfaces” and labels zones as Primary, Approach, Transitional, Horizontal, and Conical around the runway. The county’s regulations include Appendix B drawings for Ennis Big Sky, and the Planning Office posts forms and maps online. Start with the Planning Office Publications page to download current materials.
Do you need an airport permit?
You need an Airport Affected Area Permit before you:
- Build any structure that exceeds 40 feet in height or penetrates FAA imaginary surfaces.
- Plant new or replacement trees expected to reach 40 feet at maturity.
- Change the use of land or structures, such as shifting from residential to commercial.
There are common exemptions. In the Conical and Horizontal zones, structures up to 40 feet are allowed without a permit. In the Transitional zone, uninhabited structures up to 15 feet are allowed without a permit if you maintain a 25-foot setback from the property line. Many standard single-family homes under these thresholds do not need an AAAP, but always verify height and location against the maps in the county regulations.
FAA notice and special cases
Some projects trigger federal notice and possibly county hearings. If your plan may affect navigable airspace, you may need to file FAA Form 7460-1, and FAA review typically takes about 45 days. The county can also direct you to a Special Exception hearing or consider a variance in specific situations. Find the application procedures and fees on the county’s permit and variance forms and review FAA requirements on the Part 77 guidance page.
What uses are limited or conditioned
The rules prohibit uses that regularly attract birds, such as landfills and sewage lagoons. For approved projects, the county can require mitigation like lighting or markers on taller structures or trees, limits on lighting or electromagnetic emissions, and wildlife attractant controls. These conditions are detailed in the county’s AAA Regulations.
Buying checklist near EKS
Use this quick plan to protect your timeline and budget.
Confirm your zone
- Review the Ennis Big Sky AAA maps in Appendix B of the AAA Regulations.
- Ask the Planning Office to verify your parcel’s zone and any prior permits on file. Start at the Planning Office Publications page.
Match your plans to the rules
- Note the 40-foot structure and tree thresholds and the 15-foot allowance in Transitional zones.
- If you plan a use change, expect a permit review and possible conditions.
Prepare a complete application if needed
- Assemble site plan, survey, topographic info, exact peak heights, lighting details, and tree species at maturity.
- If FAA notice is required, file Form 7460-1 early and allow 45 or more days for review. See the county forms for submittal details.
Request documents from the seller
- Ask for prior AAAPs, variances, Special Exceptions, FAA determinations, and any recorded conditions.
- Nonconforming uses that predate the rules may remain, but reconstruction after substantial damage can be limited under state law. See the statute on prior uses in the Montana Code.
Watch for red flags
- Prohibited bird-attracting uses on or near the site.
- Required marking or lighting that could affect design.
- Pending FAA determinations that could delay your start.
Timeline and cost planning
Administrative AAAP reviews are processed by the county and have no charge listed on the forms. Special Exception and variance applications carry fees, with examples shown on county forms. FAA aeronautical studies usually take about 45 days, and any required mitigation like lighting or markers is an additional cost. Plan early using the county’s permit and variance forms.
Selling property in the AAA
If you are listing a home or land near Ennis Big Sky Airport, prepare buyers with clear documentation. Gather prior permits, variances, FAA determinations, and any recorded conditions. Position the AAA overlay as a standard safety measure that manages heights and uses near the runway, and highlight how your property fits within those rules. Transparency helps buyers move from interest to offer with confidence.
Local contacts and maps
- County regulations, maps, and appendices. Start with the AAA Regulations PDF and the Planning Office Publications page.
- Airport information and contacts. See the county’s Airports page for Ennis Big Sky details.
- Planning Office contact. Visit the Planning Board page for current contact information.
Ready to explore property near Ennis Big Sky Airport with a clear plan for permits and timelines so you can focus on mountain days and river time? Reach out to Callie Pecunies for local guidance and a smooth, well-managed process.
FAQs
What is the Airport Affected Area overlay around Ennis Big Sky Airport?
- It is a Madison County zoning overlay that applies FAA Part 77 airspace surfaces to land around the runway and sets rules for building heights, tree planting, and land uses, as outlined in the county’s AAA Regulations.
When does a homeowner need an Airport Affected Area Permit in Madison County?
- You need a permit before building structures over 40 feet, planting trees expected to exceed 40 feet at maturity, or changing the use of land or structures, according to the AAA Regulations.
How tall can I build near EKS without a permit?
- In the Conical and Horizontal zones, structures up to 40 feet are allowed without a permit, and in the Transitional zone, uninhabited structures up to 15 feet are allowed if you keep a 25-foot setback, per the AAA Regulations.
Do I need FAA approval to build near EKS?
- If your project may affect navigable airspace, you may need to file FAA Form 7460-1 and wait for an FAA determination, which typically takes about 45 days, as described on the FAA’s Part 77 page.
Are certain land uses prohibited in the Ennis Big Sky AAA?
- Yes. Uses that attract birds on a regular basis, such as landfills and sewage lagoons, are prohibited, and mitigation can be required for allowed uses, per the AAA Regulations.
How long does the permit process take in Madison County’s AAA?
- County administrative reviews vary, but FAA aeronautical studies typically require about 45 days, and Special Exception or variance hearings add time and fees, as outlined in the county’s permit and variance forms.
