FAA AC 70/7460-1M Obstruction Marking and Lighting Requirements

The FAA’s obstruction marking and lighting requirements live in Advisory Circular 70/7460-1M and 14 CFR Part 77. If your structure will stand more than 200 feet above the ground, or sits close enough to an airport to penetrate the FAA’s imaginary approach slopes, you must file Notice of Proposed Construction or Alteration on FAA Form 7460-1, wait for a determination, and then paint and light the structure to the specifications that determination sets. Daily inspections and prompt outage reports to the NOTAM system keep the structure in compliance for as long as it stands.

When You Have to Notify the FAA

Two independent triggers in 14 CFR 77.9 create the filing obligation. Any proposed construction or alteration taller than 200 feet above ground level requires notice regardless of location. Shorter structures still require notice if they penetrate an imaginary slope extending outward from a nearby runway: 100-to-1 out to 20,000 feet for airports with runways longer than 3,200 feet, 50-to-1 out to 10,000 feet for shorter runways, and 25-to-1 out to 5,000 feet for heliports.¹

These triggers reach any public-use airport in U.S. Government flight information publications, any military airport, any federally operated airport, and any airport or heliport with an FAA-approved instrument approach. A structure completely shielded by existing buildings or terrain of equal or greater height in a congested area is exempt, as are certain FAA-approved navigational aids whose location is fixed by function.

Adding an antenna, lightning rod, or other attachment to something already built can push total height past a threshold and create a new filing obligation. If the modification pushes the structure past the 200-foot mark or any obstruction standard, notify both the FAA and the FCC before making changes; a new aeronautical study may be required.²

How to File Form 7460-1

Filing is done on FAA Form 7460-1 through the Obstruction Evaluation / Airport Airspace Analysis (OE/AAA) online portal.³ The form asks for precise latitude and longitude (NAD 83 preferred), height both above ground level and above mean sea level, a site description, the purpose of the construction, and the structure type. Height must include every attachment at the highest point, including antennas, lightning rods, and the obstruction lights themselves.

The notice must be filed at least 45 days before construction begins or before a construction permit application is filed, whichever comes first. The aeronautical study itself takes at least 60 days to run, so build that time into the project schedule.⁴

What the FAA Sends Back

The study ends in one of two outcomes. A Determination of No Hazard lets the project proceed, usually with specific marking and lighting conditions attached. A Determination of Hazard, sometimes issued first as a Notice of Presumed Hazard, means the structure as proposed would interfere with air navigation.

A Determination of No Hazard expires 18 months after its effective date unless the FAA extends, revises, or terminates it earlier. If construction has not begun by then, the determination lapses and you file again.⁵

To challenge a determination, file a written petition for discretionary review within 30 days of issuance. If the 30th day falls on a weekend or federal holiday, the deadline moves to the next business day. The petition must present new aeronautical information or facts not considered during the original study; disagreement alone is not enough.⁶

Daytime Marking

The default daytime treatment is paint in alternating bands of Aviation Orange and white. The specific shade of orange corresponds to color number 12197 under the federal color standard (AMS-STD-595, formerly FED-STD-595).

Vertical structures use an odd number of equal-width horizontal bands so both the top and the bottom band are orange. Structures up to 700 feet tall get bands roughly one-seventh of total height each. Taller structures add one orange and one white band per additional 200 feet, keeping each band between 1.5 and 100 feet wide.⁷ Water tanks, buildings, and other structures with large flat surfaces use a checkerboard of orange and white instead. Smaller objects get solid Aviation Orange. Paint needs regular maintenance because UV, weather, and dirt degrade visibility.

Overhead wires crossing rivers, canyons, valleys, or other low-altitude flight corridors get marker spheres strung along the highest wire. Spheres on extensive crossings are at least 36 inches in diameter, though 20-inch spheres are acceptable on shorter spans or on lines below 50 feet within 1,500 feet of a runway end. Spacing runs about 200 feet, alternating solid Aviation Orange, white, and yellow, with orange at each end of the line. When fewer than four spheres are needed, all are Aviation Orange.⁷

Construction cranes and other temporary obstructions use flags rather than paint. Flags are 36 inches square in an orange-and-white checkerboard pattern, mounted at the highest point.⁷

Nighttime and Low-Visibility Lighting

The FAA classifies obstruction lighting by type and intensity, and the determination will tell you which system your structure needs.

Red Systems

Red lighting is the default nighttime system and works well in residential areas. Steady-burning L-810 lamps mark lower levels, and L-864 flashing red beacons sit at the top and at intermediate heights.⁷ A photocell runs the system from dusk to dawn.

White Flashing Systems

Medium-intensity white flashing lights (L-865) suit structures between 200 and 500 feet tall. High-intensity systems (L-856) are for taller structures or places where daytime conspicuity matters.⁷ White systems step automatically through three intensity settings as daylight changes. The top daytime setting reaches 200,000 candelas, visible from several statute miles in reduced daytime visibility.

Dual Systems

A dual system combines white and red fixtures. White runs during day and twilight; the system switches to red at night, giving strong daytime visibility while cutting nighttime light pollution. Enough fixtures must sit at each tier to give 360-degree coverage.

Synchronized Flashing

When multiple obstructions cluster, their flashing lights must synchronize within ±1/20 of a second so a pilot reads the group as a single hazard rather than as scattered points of light.²

Wind Turbines

Wind turbines have their own chapter because their height, spinning blades, and clustering create distinct problems. Each lit turbine carries L-864 red flashing beacons on the nacelle, mounted for visibility from every direction.² Not every turbine in a farm gets a light. Perimeter turbines are lit so no unlit gap along the boundary exceeds half a statute mile. Interior turbines get lights only when the cluster is more than one statute mile across.

When the rotor tip at top dead center exceeds 499 feet, a second L-864 fixture goes on the opposite side of the nacelle, flashing simultaneously with the first. At or above 699 feet, an additional light level is required midway between the nacelle and the ground.²

Aircraft Detection Lighting Systems

Aircraft Detection Lighting Systems (ADLS) use radar to keep obstruction lights off until an aircraft actually approaches, then activate them automatically. The FAA approves ADLS case by case and may deny or restrict it near airports, military training areas, or low-altitude routes. In some wind farms, turbines closest to heavy traffic must stay lit continuously while the rest of the array runs on sensor control.²

The sensor array must cover the airspace out to at least 3 nautical miles horizontally from the obstruction perimeter and vertically from 200 feet above ground to 1,000 feet above the highest point of the structure. It must detect any aircraft with a cross-sectional area of one square meter or more within that volume and activate the lights in time for them to reach full brightness and synchronized flash before the aircraft enters the protected zone. If the ADLS cannot continuously track an aircraft, a fallback timer keeps lights on: 30 minutes when tracking is lost mid-flight, seven minutes for a single obstruction when the system does not track at all, or a calculated duration based on the width of a group. Any component failure must trigger automatic reversion to full-time lighting.²

Every ADLS radar frequency must be individually licensed through the FCC. Each installation keeps an activity log for at least 15 days recording activation times, aircraft tracks, maintenance issues, system errors, and lighting outages.²

Keeping the System Compliant

Most compliance failures happen after installation. Systems without automatic monitoring must be visually inspected at least once every 24 hours across all operating intensities. Systems with remote monitoring, including ADLS, need their communication and operational status confirmed on the same daily schedule. Keep a log recording the lighting system’s status each day. Lens condition also matters: a visual lens inspection is required at least every 24 months, or whenever a light fails, because UV, cracking, and dirt eventually reduce output below the fixture’s certified rating.²

Reporting Outages

Any failure lasting more than 30 minutes that affects a top light, any flashing obstruction light, or a wind turbine lighting or synchronization system must be reported immediately by calling the FAA’s NOTAM line at 877-487-6867 (or 800-478-3576 in Alaska).⁷ The report must include the name and contact information of the reporter, the type and location of the structure with latitude and longitude, its height, the expected return-to-service date, and the FCC Antenna Structure Registration number if applicable. Notify the same NOTAM office when the lights are working again.

Two situations do not require a NOTAM report: when a primary lamp in a double obstruction light fails but the secondary lamp activates automatically, and when the failure affects lights installed voluntarily rather than required by an FAA determination.

Penalties and the Parallel FCC Filing

Violating FAA obstruction requirements can trigger civil penalties under 49 U.S.C. § 46301, with a base statutory maximum of $75,000 per violation for companies and $1,100 per violation for individuals and small businesses.⁸ The FAA adjusts these amounts for inflation. As of the adjustment effective December 30, 2024, the individual and small-business maximum is $1,875 per violation, and certain individual violations under specific aviation safety chapters carry a maximum of $17,062.⁹ Each day of noncompliance may count as a separate violation.

Antenna structures that require FAA notification must also be registered with the FCC through its Antenna Structure Registration program. The structure owner obtains the FAA’s painting and lighting specifications and includes them in the FCC registration before construction begins.¹⁰ Missing the FCC filing is a separate violation from the FAA side, so antenna owners carry dual compliance obligations.

1
eCFR. 14 CFR 77.9 – Construction or Alteration Requiring Notice
2
Federal Aviation Administration. Obstruction Marking and Lighting AC 70/7460-1M, Change 1
3
Federal Aviation Administration. FAA Form 7460-1 – Notice of Proposed Construction or Alteration
4
Federal Aviation Administration. Obstruction Evaluation/Airport Airspace Analysis
5
eCFR. 14 CFR Part 77 Subpart D – Aeronautical Studies and Determinations
6
eCFR. 14 CFR Part 77 – Safe, Efficient Use, and Preservation of the Navigable Airspace
7
Federal Aviation Administration. Advisory Circular 70/7460-1M
8
Office of the Law Revision Counsel. 49 USC 46301 – Civil Penalties
9
eCFR. 14 CFR Part 13 Subpart H – Civil Monetary Penalty Inflation Adjustment
10
Federal Communications Commission. Antenna Structure Registration (ASR) – Overview