AICUZ, Explained: What Can Be Built Near a Military Runway

Aerial view of a military airfield with AICUZ clear zones and accident potential zones overlaid — the compatible land use map around the runway.

 

Field notes

I'm Nathaniel Pyron, a military urban planner specializing in military master planning with an airport and airfield focus. Every airfield I've worked on — most recently as a community planner with the United States Marine Corps at Camp Blaz and in Darwin, Australia — has something a civilian airport usually doesn't: a second map laid over the first. The first map shows runways, taxiways, and hangars. The second one shows where you can and can't build — and it starts the moment you leave the pavement.

That second map comes from the Air Installations Compatible Use Zone program, AICUZ. If you live or plan near a military airfield, it's the most important planning document you've never read. Here's what it says, and why it works.

A program built to keep neighbors and missions safe

The Department of Defense started AICUZ in the early 1970s with a straightforward dual purpose: protect the health, safety, and welfare of people living and working near military installations, and sustain the flying mission. The studies aren't one-and-done — they get updated as missions change. Recent examples include the 2025 studies for Keesler and Barksdale Air Force Bases, the 2021 study for Tinker, and a 2026 study for Maxwell.

Each study draws two kinds of lines around an airfield: accident potential zones, based on where crashes have historically happened, and noise contours, based on how loud operations get. Then it tells planners which land uses are compatible inside each one. Off the installation, the guidelines are advisory — local governments are encouraged to fold them into their own land-use planning. On the installation itself, they're the law of the land-use map.

The accident zones: 15,000 feet of math

In the late 1960s and early 1970s, the Air Force studied 369 accidents that occurred within 10 nautical miles of airfields. The pattern was stark: 75 percent happened on or immediately beside the runway — within 1,000 feet of the centerline on either side — or in a corridor just 3,000 feet wide, extending 15,000 feet past the runway threshold along the flight path.

From that pattern came three zones, and every military airfield planner learns their dimensions by heart:

The Clear Zone. A 3,000-by-3,000-foot square at each runway end, centered on the extended centerline. The risk here is so high that DoD policy is to own or control the land outright — through purchase or easement — and keep it undeveloped.

APZ I. Beyond the clear zone: 3,000 feet wide, 5,000 feet long. Significant accident potential, but not so high that acquisition is warranted. Instead, planning and land-use controls are strongly encouraged.

APZ II. Beyond APZ I: 3,000 feet wide, 7,000 feet long. Lesser, but still significant, potential.

Add them up — 3,000 + 5,000 + 7,000 — and you get the 15,000-foot corridor from the original study. One honest caveat the studies make themselves: these zones describe relative potential, not prediction. They are not forecasts of where an accident will happen.

What goes where

This is where AICUZ gets practical, and where I've spent a lot of my planning hours. The guidelines aim to keep certain things out of the APZs: high-density housing, labor-intensive uses, anything involving explosives or hazardous materials, uses that concentrate people who couldn't respond quickly in an emergency — schools, churches, theaters, hospitals — and anything that could itself become a hazard to flight.

What does fit? In APZ I: industrial and manufacturing, transportation, communications and utilities, wholesale trade, open space, recreation, agriculture — productive uses that don't pack people in. APZ II loosens further: the APZ I uses plus low-density single-family residential, ideally no more than one home per acre, and low-intensity commercial and personal services. Multistory buildings and places of assembly stay out. For nonresidential buildings, the guidance is simple: keep them to one story, and lot coverage under 20 percent.

The real-world stakes show up in the studies. At Tinker Air Force Base in Oklahoma, the clear zone and APZs extend past the fence line into Midwest City, Oklahoma City, and Del City — the airfield's safety footprint is literally part of the metro area's zoning map. At Maxwell, analysts flagged hundreds of acres of residential land sitting inside APZ I as incompatible. At Keesler, planners had to wrestle with casino proposals in APZ II — tall buildings, crowds, light pollution — exactly the combination the guidelines discourage.

The noise side of the map

The second layer is sound, measured in DNL — the day-night average sound level. DNL averages every aircraft event over 24 hours, with a 10-decibel penalty added to anything between 10 p.m. and 7 a.m., because nighttime noise hits harder. Connect the points of equal value and you get contours, drawn at 65, 70, 75, and 80 decibels for planning purposes.

The compatibility rules are blunt:

• Below 65 dB DNL: every land use is compatible. Build what you want.
• 65 to 75: residential and school uses are incompatible unless buildings incorporate real noise attenuation — thicker envelopes, sealed windows, the works.
• Above 75: residential is considered unacceptable, even with attenuation. Commercial, industrial, open space, and manufacturing can still work there.

That 65-decibel line matters more than most people realize. Federal guidance treats anything above it as a noise-impacted area, and both military and civilian airport planning revolve around it — the FAA's own Part 150 airport noise program uses the same 65 dB threshold.

Why this is a planner's job, not just an engineer's

AICUZ is often treated as an engineering product — contours and rectangles drawn by analysts. But its success or failure is a land-use planning problem, and it lives or dies off the installation. The military doesn't control zoning beyond the fence. When a city approves apartments inside an APZ or a school under a 70-decibel contour, the conflict doesn't stay local. That's the entire point of the program: incompatible development near runways threatens the very mission AICUZ exists to sustain. Compatible land use around airfields is mission protection wearing a planner's clothes.

Nathaniel Pyron's rule of thumb: the runway doesn't negotiate. You can redesign the district, rezone the corridor, or move the proposed school — but the clear zone's dimensions were written by accident data, and accident data doesn't compromise.

The principle

Most land-use fights are about preferences: density, character, traffic. Around a military airfield, they're about physics and probabilities. AICUZ takes the hardest constraint a community can face — things come down here, more often than anywhere else — and turns it into a buildable map: what goes where, at what density, and what never goes there at all. It's the least glamorous and most consequential planning I know.

About the author

Nathaniel Pyron is a military urban planner specializing in military master planning with an airport and airfield focus, based in Honolulu, Hawaii. He has served with the United States Marine Corps for the last 3 years as a community planner, based at Camp Blaz and Darwin, Australia, and studied urban planning at Arizona State University, School of Urban Planning. His LinkedIn title is "Urban Planner (Land Use & Airspace)".