I have a friend who is a C-130 pilot for the USAF and is often on tour for most of the year and back for a short while. Looking at this picture makes me want to ask him what the heck is up with all that black soot or hydraulic fluid or even fuel staining on the bottom of that aircraft. We just found out today that a few of the C-130s in the EAF are as old as 40+ years and were built in 1978. At first I thought this might be just the tire soot from them smoking out on landing impacts, but then you can see that much of it comes from that round fitting in the center of the fuselage's bottom further forward of the rear landing gear. So it's more likely some type of normal fluid leaking but looks a bit excessive. I'll post what he tells me when I get in touch with him.