Digital Obstacle File
While no national database of low level towers has been constructed just yet per federal legislation NAAA was instrumental in urging Congress to enact, there are some resources ag aviators can utilize. The FAA’s Digital Obstacle File (DOF) can provide you information about potential obstacles in your flight path before you even take off.
The FAA produces the DOF product that includes existing obstacles that may be hazardous to safe flight navigation. The FAA receives obstacle information from a variety of sources both inside and outside the FAA. The FAA then evaluates the obstacle data based on their analysis of supporting documentation and assigns an accuracy code.
These include many obstacles of interest to aviation users above 200 feet or lower obstructions mainly near airports. Thanks in part to a new automated process, low-level obstacles can be added to this database more quickly making it a valuable resource for agricultural aviators. As a result of this automated process, a backlog of 75,000 obstructions below 200 feet spread throughout the country were added in January (even if they are not in the vicinity of an airport).
Both the Daily Digital Obstacle File (published every business day) and the Digital Obstacle File (published every 8 weeks) can provide you information about potential obstacles in your flight path before you even take off. To access the Daily Digital Obstacle File, click here to download in a text or comma delimited (csv) format for ease in importing into Geographic Information Systems (GIS) applications, i.e. ESRI ArcGIS and agricultural aviation applications. To access the Digital Obstacle File, which contains the last 8 weeks of obstacle data, click here and then click the latest “DOF” (Digital Obstacle File) under “Product.” That will download a folder containing all the obstacle data. That folder contains abbreviations for all 50 states.
You can scroll down the list to find the city or cities that you’ll be flying near, and then find the exact latitude and longitude for each potential obstacle (towers, stacks, poles, fences, etc.). The FAA verifies the location of each structure using satellite or other aerial imaging. The FAA also verifies a structure no longer exists when the owner files a notice of dismantlement or abandonment or when the FAA is notified by aviators.
However, all structures below 200 feet not near airports are only submitted to this database voluntarily. The marking requirements for towers between 50 and 200 feet and 10 feet in diameter or less in rural areas that was supposed to be promulgated by July of 2017 would make this database and towers in general far more robust and less of a safety hazard and NAAA is urging the FAA to develop this requirement quickly. The FAA’s Obstacle Team is working on new techniques to improve the accuracy of obstacle data accessible to the public. The FAA is interested in learning about obstacles (include the coordinates and height if known) not in the DOF, of interest for flight safety. If an obstacle is listed as existing in the database when that is not the case, please notify their office.
For more information, email 9-AJV-532-OBSTData-REQ@faa.gov.