MP:
You're right, that the O-ring shouldn't be there. And I'm sure that you have read the 3rd prelim report at
http://www.hcl.dk/graphics/Synkron-L...K_03112007.pdf.
IMO you're a bit to quick to write off Bombardiers responsability. Apparently there is a history of the filterelement with the particular O-ring attached, which can
collapse and migrate into the landing gear hydraulic system.
We probably agree, that thats not supposed to happen in the first place. I'm not so convinced, that Bombardier can't be blamed for anything, at this point. So I'm saying: it's too early to say, that is probably due to "poor maintenance procedures" (unless we talk about about "maintenance procedures" in its broadest way, including the manufacturer and their actions)
But the investigation will shed more light on this, I'm sure.