I believe the pinnacle of investigation has to be within the AAIB, in any if the roles. Second best is working as an investigator for an airline. But don't be deluded into thinking that you kick over a bit of bent metal to find the broken rivet that caused the prang. Most of your time will be reading very boring manuals, writing, re-writing, editing bits of text to make them readable. The rest of your time will be spent waiting for every bugger on the earth to get back to you with the information you need to move your investigation on.
So if you are into administration and you have an organised mind, this is a job for you.