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3470 Olney – Laytonsville Road, Suite 276, Olney, MD 20832

Obstruction Evaluation and Airspace Analysis

Part 77

Obstruction Evaluation and Airspace Analysis:
All builders regardless of the structure must contend with planning, zoning and permitting requirements before construction starts. Whether your project is a new high rise building, construction crane, wind turbine or broadcast tower, structures must meet local and state height zoning ordinances as well as Federal height standards under the Code of Federal Regulations. 

Obstruction Evaluation and Airspace Analysis

14 CFR Part 77 imaginary surfaces establish standards for determining obstructions in navigable airspace. These imaginary surfaces run out from the runway in a manner that reflects where aircraft are likely to fly while also accommodating unforeseen aircraft maneuvers. The height above the ground of the imaginary surface is lowest near the runway and increases at a distance from the runway. Away from airports, airspace begins at 200 feet above ground level.

Large structures, like communication towers and wind turbines, often exceed 200 feet in height and therefore are required to submit FAA Form 7460, Notice of Proposed Construction or Alteration. Structures shorter than 200 feet but located within 20,000 feet of a runway may also penetrate navigable airspace.

The FAA requires any proposed structure that meets certain criteria must be assessed against Part 77. Documents must be filed with the FAA for new structures so a determination can be made if the structure will be a hazard to air navigation. 

  • As a builder do you need to file?
  • Is the proposed structure going to be determined a hazard?
  • What steps must you take if the structure is determined a hazard?
  • Are you going to have to alter the construction plan?
  • Will your proposed project impact aviation communications, navigation aids or radar performance?

 JDA has been helping companies answer these questions for over 25 years. 

Savvy builders want to know if their structure will be acceptable to the FAA ahead of time and JDA’s Obstruction Evaluation (OE) and airspace experts will work closely with you to determine if your proposed structure will be acceptable to the FAA. JDA has successfully supported 100’s of clients build to their proposed structure height and location and obtaining an FAA determination of no hazard (DNH). 

With every OE and airspace project, JDA’s goal is to provide the best technical detail, advice and advocacy for builders, communities and airports to ensure that projects can be built while preserving the navigable airspace.

Our documented track record of success is based on a simple but very effective process:

  • Identify and assess the potential structure impact per 14 CFR Part 77 and Terminal Instrument Procedures (TERPS)
  • Provide information and reports that are easy to understand
  • Develop mitigation strategies
  • Involve key decision makers
  • Present viable solutions
  • Pursue approval and implementation through the FAA 7460 application process

Avoid unnecessary redesign costs and construction schedule delays by determining early in the planning phase the building height the FAA will approve. An FAA DNH will also be helpful in easing any concerns of local permitting and approval authorities. Not all municipalities make it clear that FAA review and approval is necessary until late in the permitting process. For most builders, finding out late that the FAA hazard review is required can have a costly impact on your project. 

JDA is ready to assist your team, delivering successful solutions for your project. Contact JDA today at or call 877-532-2378.