Obstruction Evaluation/Airport Airspace Analysis

Northwest Mountain Regional Airports Division


Each construction season, airport sponsors and their tenants gear up to build or expand facilities on airports. Among these are such sponsor- or tenant-financed improvements as automobile parking lots, T-hangars, and other miscellaneous buildings not funded through FAA grants.

Federal Aviation Regulation (FAR) Part 77 and airport grant Assurances require that all such construction on an airport be coordinated with FAA prior to commencement, using FAA Form 7460-1, "Notice of Proposed Construction or Alteration" — even if the proposed improvement is depicted on the approved Airport Layout Plan (ALP). This is because the FAA must determine that the height, layout and composition of the structure are consistent with the ALP, and that it will not obstruct the navigable airspace or adversely affect such FAA facilities as navigational aids or buried cables.

The typical processing time for FAA to conduct an aeronautical study on proposed construction is at least 60 days. As hundreds of airspace proposals are received from seven states, they are normally studied in the order received. Expedited evaluation can be expected only for emergencies or other extraordinary circumstances. Tenants and other proponents should be advised well in advance to expect a turn- around time of at least 2 months from the time the notice is received by FAA, and to factor this into their plans. In order to advise prospective builders of this consideration, we suggest that the airport sponsor notify them through periodic tenants meetings or through newsletters distributed to the airport's users. The important thing is for all potential proponents to be aware well ahead of their planned time of notice submittal.

The Form 7460-1 includes instructions and is fairly self-explanatory. However, a point of emphasis regarding geographical coordinates: latitude and longitude of the proposed improvement must be provided in order for FAA to evaluate the proposal. Also, the proponent must indicate whether the coordinates' source was based on the 1927 or the 1983 North American Datum. This information is typically found on a USGS 7 1/2' quad map. The source datum of NAD 27 or NAD 83 may be checked in one of the boxes provided on the Form 7460-1 below the coordinates.

For on-airport construction, all tenant or third-party proposals must be submitted through the airport sponsor to the appropriate Airports District Office. FAA will not process proposals for on-airport construction without evidence of airport sponsor concurrence. Upon completion of the aeronautical study, the ADO will respond with the FAA study determination to the proponent and a copy to the airport sponsor.

Sponsors should also be alert to construction off-airport but in its immediate vicinity, especially in the runway approach areas. Construction cranes and tall structures are of particular concern. Off-airport structures which might affect the navigable airspace are also covered under FAR Part 77. A Form 7460-1 should be provided to those proponents as well, but should be submitted instead to the FAA Northwest Mountain Region address on the form's attached instructions. The same processing time can be expected.

We are ready to help airports and their tenant/users by evaluating proposed improvements. For more information, contact your Airports District Office.


National Policy and Guidance

Last updated: Tuesday, August 2, 2022