"Tanks on both" checklist item

Koopas Ly wrote:

With regards to fuel tanks in a C172, why does the takeoff and landing
checklists both call for the fuel selector handle to be in the "both
tanks" position?

It's basically to ensure that you will have fuel through the entire takeoff. The
reason it's done for landing is in case you need to go around. The idea is that,
even if one tank goes empty or has some other problem, you will have a steady
supply of fuel.

The only time that fuel is set to one particular tank is on the
ground.

Then you don't have to worry too much about it, do you?

I've never used fuel from only one tank in flight. Why would
someone do that?

I do it in my Maule to equalize fuel burn. It will draw down the left tank more
rapidly than the right if I don't. I believe most Cessnas are worse in this
regard than my aircraft; my 150 certainly was.

Also, why is the fuel selector set to one tank during refueling? Is
it to minimize crossfeeding?

Yep. In my Maule, the lower tank will overflow through the vents if this is not
done. My 150 (which didn't have the option of selecting tanks) would do the
same if the vented tank was the lower one. Note that my Maule will do this even
if the selector is set to "off". Dunno if that's the case with a Cessna.

George Patterson
Some people think they hear a call to the priesthood when what they really
hear is a tiny voice whispering "It's indoor work with no heavy lifting".