We've probably all seen dramatic footage of a plane swooping over a wildfire to dump its payload of flame retardant and water on the blaze. What we may not have known about, though, are the high-tech, behind-the-scenes efforts that ensure there's water to drop when the time comes.
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.
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.
"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).
This image shows a neutron radiograph of an outlet tube from one of the retardant tanks. Pits of corrosion that have reduced the thickness of the metal are marked.
A second radiograph showing the outlet tube. The radiographs are analyzed with software similar to that used for X-rays, and the files can be e-mailed to relevant parties.
Once any repairs have been made and the tanks have been OK'd for service, they make their way back to the airstrip, where they're loaded onto a MAFF and into a C-130...
...and refilled with the concoction of retardant and water. Here we see the retardant cocktail being mixed (top) and pumped into a tank.
Then it's off to fight fires. With the landscape visible beyond the tail of the plane, a MAFF operator gets prepared (left--note the reverse angle on the pipes shown earlier). On the right, a U.S. Forest Service lead plane directs the C-130 to the drop site...
...and it's bombs away--in part thanks to the techies at U.C. Davis and their army of neutrons.