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Ground crew hoses corrosive flame retardant off a planeThe University of California at Davis' McClellan Nuclear Radiation Center has been using neutron radiography to help make certain the tanks that hold the retardant and water are in good shape--no cracks, holes or weak spots that could end up distributing the mix of retardant and water everywhere but where it's needed.
Here, a member of the ground crew at the Channel Islands Air National Guard Station in California hoses spent retardant off the tail of a specially equipped C-130 aircraft, as the plane awaits more retardant and another trip to the blaze. (Look closely and you'll see the pipes that release the retardant-water mixture, as well as streaks of orange on the tail's underside.)
The retardant is corrosive, hence the need to hose off the plane--and test the tanks.
Tanks being unloaded from a C-130
Here we see the aforementioned tanks--and the overall MAFF (Modular Airborne Firefighting System) setup they're part of--being unloaded from a C-130.
The tanks are placed on a robotic platform
"You can't get inside the tanks to inspect them, and a camera only gives a surface view," says U.C. Davis Radiography Supervisor Hal Egbert, who conducts the safety tests. At the McClellan Nuclear Radiation Center, the tanks are placed on a robotic platform in a special scanning bay and turned through a neutron beam (which comes out of the block to the left).