RNC Milwaukee: 'Background radiation' flyovers conducted downtown

A helicopter was flown low over downtown Milwaukee on Tuesday, July 9. Now, officials have confirmed it has to do with security and safety for the Republican National Convention. 

The U.S. Department of Energy's National Nuclear Security Administration said Tuesday was the last of its flyovers. Some aircraft went as low as 150 feet to measure "background radiation."

"We are flying very low through an urban area, so we need to work very closely with the pilots to make sure we are not running into any buildings, wires, towers," said Jacqueline Brandon, aerial measuring system manager. 

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While helicopters can detect radiation from the sky, there was also a team with detection systems on the ground. The pilots communicated anything that was radiologically out of the ordinary, so those ground crews could get a closer look at what caused it. 

"(Brandon) happens to see something that is not supposed to be there, then I have a team of vehicles with some very large radioactive detectability that we can go in and take a closer look," said Chuck Mansfield, Radiological Assistance Program Region 5 manager. 


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The state of Wisconsin provides a list of radioactive material that is supposed to be located downtown. That way, detection teams knew the difference. 

Flyovers are now over, but officials said crews in the sky will return if something happens. Their No. 1 priority is safety.