Even there, a lot of redundantcy is built in.
Well, in most aircraft, yes. The DC-10 is another story, according to a senior aircraft mechanic I knew 'bout 20 years ago.
I don't know the current status, but back then TWA's Pilot Safety Review Board rejected the DC-10 because the primary and secondary control lines for the control surfaces run
in the same channel under the cabin. In any other plane, they separate them, for obvious reasons.
Another problem with the DC-10 is the engine mounting. Ever looked at one and thought the tail engine looks like an afterthought?
It was. THe plane was originally designed for 2 engines which GE had promised to develop for the plane. GE backed out, leaving Douglas with no available engine that had enough thrust to get the bird up with only two engines. a quick redesign and the tail engine was added.
Hey, it was cheaper than starting from scratch. Why, no, I
won't fly on a DC-10 if I can help it. Why do you ask?