Source: www.pilotworkshop.com, featuring Bob Nardiello
A conversation with Bob Nardiello regarding "pre" preflighting your airplane
"Bob, if we're planning to make a long cross country flight, what steps can we take in advance to make sure that we're completely prepared?"
"It is a good idea a day or two before the flight that you "pre-preflight" the airplane. And what I mean by this is get out to your airplane and take a look at the tires; be sure the tires are inflated. Check the battery; be sure the battery is up to snuff. If you live in a climate where it snows as it does up here in Connecticut, it might be a good idea to dig out your airplane at this point if there is any snow around it.
What you want to do is minimize the difficulty or the hassle you will have on the day of the flight. On the day of the flight you want to be doing your tactical planning and you want to be able to preflight your airplane smoothly without any difficulties. So, if you haven't looked at your airplane in a couple weeks, it might be a good idea to get out there and check the status of things like tires, battery, ice on the airplane, snow, could even check your avionics out to be sure everything is functioning. Good idea to do this a day or two before the flight when you have an opportunity to correct it if need be without influencing your actual preflight and tactical flight planning on the day of the flight.
Your "pre-preflight" is also a good time to inventory your chart materials, both for your planned route and alternate routes, both to your destination and for your return flight. If during the "pre-preflight" you find you are missing something essential, you still have time to round it up. That might be difficult on the day of the flight. Additionally, this is a good time to check your GPS equipment for a current database."