The fly-by-cable system on the MD
-11 rarely gives problems ( in almost two years working on this plane every day I never had one).
Problem areas are sloppily routed wiring and piping, e.g. causing hydraulic leaks through cracked pipes.
On point is e.g. the fuel quantity system, where there are often problems with the wiring inside the tanks (no danger of an explosion, these are only digital data lines with about 3 volts on them), causing delays for dipsticking.
The wiring/plumbing issues are adressed by various EOs, as I said most of them derive from sloppy work at the factory.
Another thing (but I´ve seen this problem on many modern "electronic" planes) is that the computers occasionaly get hung up (just like your PC
at home). The typical fix is rebooting the computer by cycling power or the respective C/B.
Then the remote controlled circuit breakers for the fuel pumps are a PITA. They are essentially big relays in the AC
bus cabinets in the center accessory compartment, which control the power to the boost and transfer pumps, so that the power wiring doesn´t have to be routed up to the cockpit. They occasionally tend to get stuck in the open position. I understand that this problem derives from the unit being the old DC-10 analog relays having been converted by adding some logic (flip flop etc) into a digital relay. They are just not very reliable, but on the other hand, the plane has a lot of redundacy.
Having a bit of experience on the MD
-11, I´ve got to say that by now I can fix most problems on a turnaround without too much trouble and usually get the plane out on time.
I would like to have some input from other MD
-11 maintenance/engineering people.