Whatever happened to common sense I ask? Obviously if you've sunk 10 units 10 hours before report you're unlikely to be fit. If you've had 2 CAA standard pints the chances are you will be, although they have to use the term 'likely' to avoid any comeback. If you are ever stupid enough to get busted for drunk driving in the UK (and no, I haven't been), the alcohol abuse counsellors will tell you to work on 1 unit per hour. Everyones got a rough idea of how well they handle booze. I've seen crew refuse to have one beer twelve hours before report because "It's just not worth it". Such defiance of logic is perplexing given we work in an industry which is entirely based on statistics and calculated risk. Reasonable, responsible alcohol consumption within the rules is perfectly compatible with aviation.