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Obstacle Data

Please refer to the published 18-01 DOF Data Check Elimination (PDF) informing users the Federal Aviation Administration has made this change to improve efficiencies, consolidate processes and eliminate redundancies. The compressed dataset with these codes and associated programs chckall and dai_datchk are obsolete. The codes and programs have never been included in the Daily DOF (DDOF) Product.

Please update any programs to reflect the shorter record length and refer to the June 19, 2018 DOF ReadMe (PDF) file for the revised format. If you have any questions, please select the Email General Comments link on the right side of this page.
NOTE: Energy Information Administration Documents
If you are looking for DOF file numbers to use in Energy Information Administration documents, please contact EIA Team Lead Glenn McGrath.


The Obstacles Team investigates and evaluates existing obstacles that may be hazardous to safe flight navigation. We receive obstacle data from a variety of sources both inside and outside the FAA. After determining proof of a completed structure by receiving supporting documentation and performing all necessary verification checks, the team assigns an accuracy code to the obstacle and enters it into the Obstacle Authoritative Source (OAS) as verified.


1/30/18 New Daily Digital FIle CSV Format available.

6/19/18 DOF Data check elimination.


  • Daily Digital Obstacle File (DDOF): This zipped .dat file provides the latest obstacle information in our database (same as the DOF below), and is updated daily.
  • Daily Change File: This .dat file provides all DDOF changes. Internet Explorer users: When you right-click and the "Save As" window appears, IE changes the file extension to .htm for some reason. The workaround is to manually change the .htm to .dat before clicking on "Save."
  • The Digital Obstacle File (DOF): This database contains all known man-made obstructions that penetrate Title 14 of the Code of Federal Regulations (CFR) Part 77 within the U.S. and its territories. It also contains known obstacles within the Caribbean, Mexico, Canada and the Pacific. It is prepared and posted on this website every 56 days and it includes the latitude and longitude, structure type, height above ground, height above sea level, lighting, marking, accuracy code, and other associated information.
  • Weekly Construction Notices: These publications include obstacles that were added, modified, or dismantled during the prior week. They are NO LONGER in the National Flight Data Digest (NFDD).

The Obstacles Team is dedicated to providing our customers with accurate and timely obstacle data that is critical for a safe and efficient National Airspace System. We are actively evaluating and investing in new technologies to make our data more accurate and accessible.

If you have any questions or comments, please contact Obstacle Data.

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