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I realized I haven't really noticed where the fuel vent is for the 2016 Piper Archer TX that I've flown, but I assume the fuel is vented from the fuel cap. Is that correct?

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  • $\begingroup$ I dont know about the new ones but the older Archers had a small tube vent under the wing. It looks like a small straw sticking out near the tie down point. $\endgroup$ – Dave Mar 22 '17 at 20:25
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    $\begingroup$ They find interesting places to hide fuel vents. In my C-177, the vent is wedged between the aileron and the wingtip. Not a great design choice either as the vent used to get loose and jam the aileron, resulting in a clamp that has to be checked in preflight. $\endgroup$ – Ron Beyer Mar 22 '17 at 20:38
  • $\begingroup$ Refer to your​ POH or equivalent. $\endgroup$ – J Walters Mar 22 '17 at 21:47
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    $\begingroup$ I've looked through it and can't find anything about the vents. $\endgroup$ – nyorkr23 Mar 22 '17 at 21:47
  • $\begingroup$ Try looking on the checklist. Does it say to check the vents when looking under the wings, or does it say to check the fuel caps (vents). $\endgroup$ – JScarry Mar 22 '17 at 22:29
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There are four main tank vents on all PA28 (Cherokee/Warrior/Archer/Dakota/Arrow) aircraft, two in each tank.

The most visible vent is under the wing at the outboard aft side of the fuel tank (near the jack points):
Under-Wing Vent
This vent is a small tube that protrudes from the bottom of the wing and is cut at an angle facing forward to provide ram air pressure into the tank. It is the vent you typically check during preflight to ensure mud wasps or similar haven't built a nest in the conveniently bug-sized tube.

The second vent is located in the fuel cap: It is an orange rubber "umbrella" in the center of the fuel cap which covers breather holes.
Fuel cap vent
If pressure in the tank becomes negative (because the under-wing vent is obstructed) the umbrella will be forced open by air pressure and allow air into the tank through the fuel cap.
This vent is not normally "checked" during preflight except to ensure that the rubber umbrella is in fact there. A failure of the rubber "umbrella" is one common way that water finds its way into the fuel tank (the other being a failure of the O-ring around the perimeter of the cap).

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  • $\begingroup$ I thought that piece on the bottom of the wing is called a scupper drain. Am I mistaken? $\endgroup$ – nyorkr23 Mar 23 '17 at 2:10
  • $\begingroup$ @nyorkr23 I've never heard it called that - the Piper parts manual identifies it as element 75 in the fuel system diagram ("VENT ASSEMBLY - Fuel tank" left & right as appropriate). It does function as a scupper drain if the tank is overfilled though: If you look carefully at the filler neck inside the tank you'll see a hole where the vent tube connects, and if the tank is filled enough for fuel to reach that hole the excess fuel will be dumped overboard through the vent line. $\endgroup$ – voretaq7 Mar 23 '17 at 3:19

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