TomH, Hi, I'm a AMC (formerly MAC) Flight Engineer, and your second line is exactly correct concerning the cord body. The wear indicators are usually interlayered fabric, and the cord body itself is metal. I haven't seen any exterior metal on the line in about 5 years, but I know exactly what your talking about. The heavies had a rash of incidents related to tire failure in the early 90's that led to a lot of changes, mostly in the area of wear limitations and retread capabilities, but I believe they also changed manufacturures to. I haven't seen any of the old "indians" or "internationals" on the line lately, mostly "BF Goodrich" and "Goodyear". Maybe this has something to do with it?
"Never trust a clean Crew Chief"