Thks Paul, Mine took in the vicinity of 8hrs but ithink I could reduce that to about 4hrs now I have the experience. I took it out not so much as to replace the filter but to address the issue of the hot air flap bushes coming adrift from the fibreglass housing resulting in continuous hot air ingestion. the reason for the question was that I thought I may have been missing the obvious, but no it seems. i needed to remove most of the fuel hoses ,the little "black boxes' to provide clearance, but that faded into to insignificance compared to getting the flexible air intake ducts and actuation cable back into place. I can see it would be a piece of cake with the engine out and at one stage contemplated that. Not sure about the fly in at this stage. David