[alexanderstears]

During the D maintenance, every part should be inspected. Things like fuel lines should be inspected much more regularly, ideally more often than it would take to rub through a fuel line.

But a visual inspection on a fuel line can be really difficult. I had a motorcycle with a leaky fuel line once, luckily it sprung a leak while warming up in my driveway and I turned off the bike before anything bad happened but it was almost impossible to tell where the leak was without pressurized fuel, the hose looked pristine without positive pressure to highlight the crack.

In race cars, they sometimes 'overpressure' the fuel line (above operating pressure but below max pressure) to check for leaks, I wonder if they ever do that routinely for aircraft.

[foldr]

If the 6 million parts figure is correct, it's obvious that it is not possible to inspect every part of a 747. Suppose we allow 1 minute per part inspection. Then that's still about 11 years of inspection time (without taking any breaks!)

[dozzie]

> that's still about 11 years of inspection time

11 person-years. You don't need the same person to conduct all the inspection.

[foldr]

Sure, but you'd need thousands of people to get it down to anything reasonable, even with the highly optimistic 1 minute per part inspection estimate.

I'm open to being corrected on this, but no-one has yet posted any evidence that there is any extant procedure for inspecting every part of a 747.