Reading into the msg-3 methodology, I would conclude that since the cable is a critical flight system, it must be subjected to either some rigorous NDT at defined intervals, or perhaps even replacement at defined intervals. I am just making a guess here at how msg-3 could possibly cover this issue making it immune to the AD.
I guess my point is, SCC is a highly increased susceptibility to corrosion relating to material properties and sustained stress levels, like you would see in a swaged connection. Being an uncoated, unprotected (passivated?) surface, I just don't see how you maintain it other than looking at it. SCC can be visually undetectable at certain stages, and typically detected after the larger crack is found. Then material, environmental, and stress analysis usually aid to conclude the root cause SCC.
Either way, I am going to visually inspect my cables ends to the best of my ability, since they are at least 19 years old. I tend to agree with you that if a cable is progressively destroyed by corrosion and cracking, that you would expect some visual indicator. I have never heard of a cable failure on an old RV. Mine has lived in a dry environment its entire life, maybe that is a good thing.
