The National Nuclear Security Administration said it's part of normal protocol.

A low-flying NNSA helicopter is flying over the San Francisco Bay Area to measure background radiation levels ahead of Super ...

A mysterious helicopter spotted flying super low around the Bay Area turns out to be Super Bowl related. Consumer Investigator Chris Chmura spotted the helicopter flying back and forth over downtown ...

The low-altitude flights are happening through Wednesday, and they are being done to measure expected background radiation ...

Helicopters with the the U.S. Department of Energy’s National Nuclear Security Administration will fly at low altitudes around the Bay Area between Feb. 2 and Feb. 4 in preparation of Super Bowl LX at ...

Low-altitude helicopter flights by the National Nuclear Security Administration will be conducted over the Bay Area in advance of Super Bowl LX.