Obstruction Evaluation /Airport Airspace Analysis for Construction/Alteration

FAA Construction & Airspace Determination - 7460 One-Pager

The Obstruction Evaluation/Airport Airspace Analysis (OE/AAA) process exists to protect the safety and efficiency of the National Airspace System (NAS). It evaluates whether proposed construction or alterations such as buildings, communication towers, wind turbines, cranes, or other tall structures could penetrate or negatively affect navigable airspace or airport operations. To notice the FAA of an airport airspace analysis, an airspace determination application must be filed at least 45 days prior to construction/alteration for the following types of projects:

  • Any structure 200 feet or more in height above the ground. Any structure on airport property.
  • Any construction or alteration that exceeds an imaginary surface extending outward and upward at any of the following slopes:
    • Penetrating a 100:1 slope within 20,000 feet of an airport with a runway 3,200 feet or greater.
    • Penetrating a 50:1 slope within 10,000 feet of an airport with a runway less than 3,200 feet.
    • Penetrating a 25:1 slope for a horizontal distance of 5,000 feet from the nearest landing and takeoff area of a heliport.
    • Any highway, railroad, or other traverse way for mobile objects
      • Clearance requirements for aircraft over-crossings must be:
        • ≥ 17 feet for Interstates; ≥ 15 feet for other public roadways; ≥ 10 feet for private roadways; ≥ 23 feet for railroads; ≥ height of highest mobile object for waterways and any other traverse way not mentioned.

Use the Pre-Screening Tool for your structure to determine if the proposed construction or alteration project requires notice to the FAA.

Use the following link to the Code of Federal Regulations for better understanding on the construction or alteration requirements to provide notice to the FAA.

The application collects data to enable a through aeronautical study. Typical required information includes:

  • Project details and description — Type of structure or alteration proposed (tower, building, crane, etc.). 
  • Precise location — Latitude & longitude coordinates of the site. 
    • Coordinates must be in a clear datum (e.g., NAD 83) to avoid errors.
  • Structure height — Both height above ground level (AGL) and total height above mean sea level (AMSL).
  • Site elevation, which supports accurate airspace surface calculations.
  • Contact information for the entity responsible for the project.
To access the application's website, go to: https://oeaaa.faa.gov/oeaaa/external/portal.jsp. Detailed user sign-up instructions are included in E-Filer User Manual created by the Obstruction Evaluation/Airport Airspace Analysis (OE/AAA).

Other Tools

You do not need to file notice for construction/alteration of: 

  1. Objects hidden behind permanent buildings or natural terrain of equal or greater height, located in a crowded city area, as long as they don’t affect air‑navigation safety.
  2. Air‑navigation equipment, landing aids, arresting devices, or weather instruments whose height and location are fixed by FAA or military siting rules.
  3. Any construction or change that must be reported under another FAA rule.
  4. Antennas 20 feet tall or shorter, unless they increase the height of an existing antenna.

Note: Notice is required by 14 Code of Federal Regulations, part 77 pursuant to 49 U.S.C., Section 44718. Persons who knowingly and willingly violate the notice requirements of part 77 are subject to a civil penalty of $1,000 per day until the notice is received, pursuant to 49 U.S.C., Section 46301(a). These penalties are administered by the FAA, not TDOT Aeronautics.