WASHINGTON – The U.S. Department of Energy’s National Nuclear Security Administration (DOE/NNSA) will continue to conduct low-altitude helicopter flights over downtown Washington, D.C., primarily over the weekend of Oct. 31-Nov. 1, including over the restricted airspace that includes the National Mall. The flights are expected to conclude by Nov. 6.

The flights are part of a mission to measure background radiation in and around the Nation’s capital in preparation for the Presidential Inauguration, which is scheduled to take place Jan. 20, 2021.

NNSA’s Nuclear Emergency Support Team (NEST) aircraft are collecting data to prepare a “map” of naturally occurring background radiation over Washington, D.C. These flights are part of standard preparations to protect public health and safety on the day of the event and are regularly conducted prior to major public events, including previous presidential inaugurations and Super Bowls.

Local residents may see a twin-engine Bell 412 helicopter, which is equipped with sensitive, state-of-the-art passive radiation sensing technology. The helicopter will fly in a grid pattern over the areas at 150 feet (or higher) above the ground at a speed of approximately 80 mph. Flyovers will occur only during daylight hours and are estimated to take approximately two hours to complete per area. The aircraft measurements will be purely scientific in nature, and no surveillance or other form of monitoring will occur during these flights.

The aerial surveys are a regular part of security and emergency preparedness activities for major U.S. cities.  By calculating the “normal” amount of radiation occurring in an area, the NEST team is able to quickly recognize unusual levels before, during, or after an event. NNSA is making the public aware of the upcoming flights so citizens who see the low-flying aircraft are not alarmed.

The NEST survey aircraft is an element of the Aerial Measuring System (AMS), based at Joint Base Andrews in Maryland. For more information and video footage of NNSA’s AMS aircraft, see https://www.energy.gov/nnsa/aerial-measuring-system-ams.

NEST is part of NNSA’s Counterterrorism and Counterproliferation Program and provides the Nation’s nuclear or radiological emergency response capability. NEST provides domestic and international reach through regional programs, offices, and personnel.