spotlight the wreckage on the AT near snake den ridge is a military F4 Phantom that crashed in 1984 near the summit of Inadu knob. I saw that in Jeff Wadley's book mayday mayday. He is a member of this sight and knows a lot about all the plane crashes in the smokies.
I don't remember anything in the book about the F-15 crash and I don't have my copy with me at the moment since I am out of town for Thanksgiving. The fisherman on the bradley fork trail who told me about the wreckage said it looked like a huge jet engine had fallen off a plane flying overhead and was laying right in the middle of the stream. He said it was way too big for anyone to ever remove it. He didn't mention any other wreckage nearby but maybe he didn't notice anything off the stream because it could have been overgrown and all.