assumes an average level of skill from the engineers maintaining the aircraft.
Or
building it on the production line.
The accident aircraft was too low time to have had any maintenance work done in this area. Which points to it being assembled incorrectly during production. Which in turn implies some ambiguity in how to correctly assemble the components. Which is a Human Factors issue.
I could bore you to death for hours talking about all the poor maintainability that every aircraft I have ever worked on had designed into it. A friend and former colleague of mine works for Airbus "ensuring that what the designers have designed can actually be manufactured" - his words.