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Tall structure proposals and airspace determinations
Tall structures, such as buildings, towers, wind turbines, etc., can be detrimental to the safety and welfare of people in an aircraft and those on the ground.

The construction of structures meeting certain criteria require Federal Aviation Administration (FAA) notification and an airspace determination. An airspace determination usually takes 30-60 days for the FAA to complete. An airspace determination is required prior to the beginning of construction for:

• Any structure 200 feet or more in height above the ground.
• Any structure on airport property.
• Any structure penetrating a Part 77 approach surface.
• Any structure penetrating a 100:1 slope within 20,000 feet of an airport with a runway 3,200 feet or greater.
• Any structure penetrating a 50:1 slope within 10,000 feet of an airport with a runway less than 3,200 feet.

Specialized FAA website
The FAA’s Obstruction Evaluation/Airport Airspace Analysis website provides information on proposed construction of tall structures and airspace determinations. Airport representatives and other users can sign up to receive notices of determinations via E-mail.

At this time, the FAA does not provide E-mail notification of proposed construction; however, plans are to offer that service in the future. As a result, those who are interested in seeing information regarding proposed construction in the vicinity of an airport should plan on conducting searches every 1-2 weeks on the Obstruction Evaluation/Airport Airspace Analysis website.

To access the website, go to: https://oeaaa.faa.gov/oeaaa/external/portal.jsp. Review the following overview of some of the useful features of the website. Detailed user and sign-up instructions are included in the tutorial prepared by the Iowa Department of Transportation’s Office of Aviation.

Useful tools available without the registration or sign-in requirements

Use the website to review proposed cases and FAA determinations for up to 50 miles around an airport. Proposed cases for the state can also be viewed.

• View proposed cases: Proposed cases for a state can be viewed and sorted by case number or city.
• Circle search for cases: Cases within a specified number of miles of an airport can be viewed. Type in the airport identifier, mile radius and status type of cases to view.
• You can sort by date, city or any of the data categories by clicking on the column heading.
• Notice criteria tool: Check to see if a proposed structure
  requires review.
• Wind turbine build-out: Type in latitude and longitude for an airport (the information is listed in the Airport Directory) and select submit. Wind turbine determined cases within 48 nautical miles of the location entered will be displayed, with an indication of whether the FAA determined them as a hazard.

Tools requiring user registration or sign in