Curv Aero FAA Filing for Wind Turbines and Met Towers: The 2026 Rules
Modern turbines stand 400 to 700 ft tall at blade tip, so every one of them needs FAA notice. In October 2026 the rules for wind projects changed: notice is now due 90 days ahead instead of 45, meteorological towers as short as 50 ft must be filed, and marking and lighting conditions in new determinations are mandatory. This guide covers what changed, how wind filings work, and the lighting standards in the FAA's new advisory circular.
Updated November 7, 2026 · Based on 14 CFR Part 77 as amended effective October 28, 2026, and AC 70/7460-1N
Do wind turbines need a 7460-1?
Almost always. Any structure more than 200 ft above ground needs notice under 14 CFR 77.9(a), and utility-scale turbines exceed that at tip height. Smaller distributed turbines under 200 ft still need notice if they're near a qualifying airport and exceed the 100:1, 50:1 or 25:1 notice surface.
Height is the blade tip at top dead center: tower plus nacelle plus rotor radius, plus any lighting or lightning protection above that. Measure it the same way on every case.
How wind farm filings work
One case per turbine
Each turbine and each met tower is filed as its own case. OE/AAA has dedicated wind turbine and met tower filing paths and a bulk import feature for large projects.
Surveyed coordinates
Surveyed or high-quality coordinates for every position. A shift of a few hundred feet can move a turbine into a different procedure area or radar sector.
File early
With the 90-day minimum and studies that often run longer, file once layouts are stable enough, then refile positions that move.
Treat the layout as a set
Wind farm determinations often note that lighting is designed for the whole project, so any change in height, location or number of turbines can require new notice for the affected cases.
What the FAA studies
Beyond the Part 77 obstruction standards, wind projects are commonly evaluated for:
Instrument procedures
Turbines inside approach, departure, circling or en route obstacle clearance areas can raise minimums, which is one of the most common reasons for a hazard finding.
Radar effects
Moving blades can create clutter for air traffic, weather and military radars. Projects near air defense or long-range radar may also draw Department of Defense review.
VFR routes and low-level flight
Such as agricultural aviation and military training routes.
Cumulative effects
New turbines are studied alongside existing and proposed ones in the area.
A Notice of Presumed Hazard (Notice of Preliminary Findings) on some positions is common in large projects. Developers usually resolve it by shifting or dropping individual turbines, or lowering tip height.
Met towers: the new requirement
Meteorological evaluation towers are tall, thin and guyed, and they often go up quickly in farmland where agricultural aircraft fly at very low altitude. That's the safety problem behind the new rule. As of October 28, 2026:
- A met tower whose highest point is at least 50 ft and up to 200 ft AGL needs a 7460-1.
- New or altered met towers associated with a permanent wind energy system follow the 90-day deadline.
- Met towers that already exist in that range must be filed within 90 days of October 28, 2026.
- Met towers over 200 ft were already covered by 77.9(a) and still are.
AC 70/7460-1N adds marking standards for met towers: alternating aviation orange and white bands, high-visibility sleeves on the outer guy wires, and orange spherical markers on the guys. It also recommends voluntarily marking met towers under 50 ft in rural areas.
- Met tower notice range
- 50–200 ft AGL
- Filing deadline
- 90 days
- Existing towers
- ~ Jan 26, 2027
Wind turbine marking and lighting (AC 70/7460-1N, Chapter 13)
Day marking
- Turbines are marked white or light grey: pure white RAL 9010 is preferred, and light grey RAL 7035 is the darkest acceptable.
- No camouflage colors on blades or tips.
- In areas with long periods of snow cover, the mast may carry orange-and-white bands; nacelle and blades stay white.
- Daytime lighting of turbines is not required.
Night lighting
- Red L-864 flashing lights on top of the nacelle, all synchronized to flash within 1/20 of a second of each other.
- Not every turbine is lit (for tip heights of 499 ft or less). Light the ends of lines and the perimeter so there's no unlit gap over ½ statute mile, and the interior of clusters and grids so there's no unlit gap over 1 statute mile. Outlying turbines and interior turbines 100 ft or more taller than their neighbors get lights too.
- Over 499 ft tip height: every turbine is lit, with a second L-864 on the opposite side of the nacelle.
- 699 ft and above: every turbine is lit, plus a mid-mast level of at least three L-810 F flashing red lights (four if the mast is over 20 ft in diameter), flashing with the nacelle lights.
During construction
Turbines under construction should carry temporary lighting once they reach 50 ft, moved up as the structure rises, using a steady red L-810 (solar-powered if needed) until the permanent lights are on. Relying on a NOTAM instead of lighting turbines is prohibited. Remember that the cranes used to erect turbines are their own temporary structures.
Outages
Report any outage lasting more than 30 minutes that affects a turbine light or the farm's synchronization to the FAA's outage line so a NOTAM can be issued, and report again when it's restored. For turbines over 499 ft, the failure of one of the two nacelle lights doesn't need a report, but it should be fixed promptly.
Aircraft Detection Lighting Systems (ADLS)
ADLS keeps obstruction lights off until radar or other sensors detect an aircraft approaching, which addresses one of the most common community complaints about wind farms. Under Chapter 10 of AC 70/7460-1N, a system must:
Detect aircraft and have lights on and synchronized before they enter a volume 3 nautical miles around the farm, from 200 ft above ground to 1,000 ft above the tallest turbine.
Detect targets with a cross-section of one square meter or more.
Keep lights on while a tracked aircraft is in the volume, or for set times if it can't track: 7 minutes for a single obstacle, longer for groups.
Fail safe: any system or component failure turns the affected lights on.
Use individually FCC-licensed frequencies; unlicensed devices can't be used.
Log activity for at least 15 days and check status at least every 24 hours.
Approval is case by case. Your filing should show sensor locations and coverage maps, including any terrain masking, and the FAA may require some turbines near airports or low-level routes to stay lit regardless.
A filing checklist for wind developers
- 01
Screen the full layout early for 77.9 notice, obstruction standards and nearby instrument procedures.
- 02
Identify all met towers, existing and planned, and file any 50–200 ft towers that haven't been.
- 03
Set the filing date at least 90 days before construction or the permit application, and build in time for the study.
- 04
File one case per turbine with surveyed coordinates and tip height.
- 05
Decide on standard lighting or ADLS before filing, and request it in Item 7 and the description.
- 06
Track each determination's 18-month expiration across the whole project.
- 07
File Form 7460-2 as each determination requires: Part 1 typically at least ten days before construction, Part 2 within five days of reaching full height.
Screen a turbine layout before you file
The CurvAero Part 77 Report checks each position against the notice criteria and obstruction surfaces, so you can see which turbines sit closest to airports and procedures before committing a layout. When you're ready, we can prepare and track the filings across the project.
Frequently asked questions
How long is a wind turbine determination valid?
A Determination of No Hazard expires 18 months after its effective date unless extended, revised or terminated. Request extensions at least 15 days before expiry.
Do small farm or residential turbines need notice?
Only if they meet a 77.9 criterion: over 200 ft, near a qualifying airport and above the notice surface, or on an airport. Their met towers may now need notice if 50 ft or taller.
Does the FAA approve the turbine?
No. The FAA determines whether it's a hazard to air navigation. State siting, local zoning and other federal reviews are separate.
We have existing met towers. What do we do?
If any are 50–200 ft AGL and haven't been studied, file a 7460-1 for each before the 90-day window closes.