wrote in message oups.com...
I fly a 172 F.

The fuel selector says to select single tank operation at or above 5000
feet.

If you leave the selector in the "both" position, under 5000 for any
prolonged period of time (couple of hours) the right tank appears to go
down more quickly than the left. This is confirmed at fillup.

Here's my question, if the right tank runs out, but there is still fuel
in hte left tank, selector is on "both" what will happen.

As part of my pre-flight, I always check operation on each tank, then
switch to "both" before my run up.

Thanks,

Jamie A. Landers
PP-ASEL


Funny, the C-172A and the 1975 Skyhawk manuals I just looked at have no limitations on the 'both' position. They do
caution that right and left positions are for use in level flight only