4 ms·

I'm sure many people who don't fly aircraft are not aware of the pre-flight check procedure part of which is to check the fuel. There is a small graduated cyli

I'm sure many people who don't fly aircraft are not aware of the pre-flight check procedure part of which is to check the fuel. There is a small graduated cylinder with a spike at the top it is pushed into a valve under the wing to get some fuel from that tank. You look to see if there is any water floating in the gas. After you check it you toss the leaded gas on the tarmac. Then you do the same for the other wing tank. Airports especially small airports with piston powdered light aircraft using leaded avgas must be soaked in 70 years lead.

mmaunder 5y ago
I’m a pilot and use a GATS jar that lets me separate out water and toss the fuel back in the tank. Tossing fuel on the ramp is frowned upon at some FBOs.
- ericpauley 5y ago
  Same, it amazes me how many people around my airport don't use these. In my mind they enhance safety too because I can sump more gas and sump all the tanks at once, so if one tank is all water I'd know.
  - stevehawk 5y ago
    On the other hand the FBO could accidentally put in jet fuel and not realize it.. and it could be done in such a proportion that your eyes won't notice it in a gats jar.. the best way to test it is either to dip a paper towel or toss it on the ground
    - sokoloff 5y ago
      The screen on the GATS jar is for testing for Jet-A contamination. Gas evaporates cleanly off the screen. Jet leaves a film in a random pattern as it evaporates. https://www.pooleys.com/shop/pooleys/the-gats-jar-fuel-tester/ https://www.pooleys.com/shop/pooleys/the-gats-jar-fuel-teste...
- GekkePrutser 5y ago
  We have a bucket of sand to throw it in. Local policy is not to throw it back in the tank for the risk of introducing contamination from the jar.
praveen9920 5y ago
Im curious to know what happens if they find some water floating.
- RNCTX 5y ago
  Keep draining until you don't. Pretty common when there's a fog and you get condensate. The tank on a small airplane isn't gonna be sealed air-tight, it's vented to the outside air so a little condensate is pretty normal. Water is heavier than the gas, so it sinks to the bottom where the drain fitting is.
- tobinfricke 5y ago
  You continue to sump the fuel until all the water is gone.
535188B17C93743 5y ago
>After you check it you toss the leaded gas on the tarmac. Good god, I think I'd be chewed out if I did this at my field. Always back in the tank. Avgas is too expensive to dump it all over the ramp.
- hugh-avherald 5y ago
  It'd be less than a $0.01 worth of fuel. You should still put it back in the tank but for environmental reasons not for the cost.
  - sokoloff 5y ago
    $0.01 of fuel is about 7mL. If you’re only sumping 7mL of fluid in total, you might as well just skip the theater and not do it at all.
    - GekkePrutser 5y ago
      If it's all fuel it should be enough, right? The goal is to figure out if there's water at the bottom. We take about 20-30ml in general (about half a shotglass)
      - sokoloff 5y ago
        It very much depends on the airplane. Mine has 7 sump locations. A C172S has 13. If it overall adds up to 7mL, I think you’re not sampling enough. 7mL per sump location might be barely enough.
        GekkePrutser 5y ago
        Ah we were taught only to use the bottom two on the wing tanks. This is probably why. Of course they do this for every student flight where it's really only necessary before the first flight of the day. So I think this plays into it (not wanting to waste too much fuel). Also the 7ml is not my figure. The "shotglass" is usally more than half full. I agree 7ml is not a lot.

mmaunder 5y ago

I’m a pilot and use a GATS jar that lets me separate out water and toss the fuel back in the tank. Tossing fuel on the ramp is frowned upon at some FBOs.

ericpauley 5y ago
Same, it amazes me how many people around my airport don't use these. In my mind they enhance safety too because I can sump more gas and sump all the tanks at once, so if one tank is all water I'd know.
- stevehawk 5y ago
  On the other hand the FBO could accidentally put in jet fuel and not realize it.. and it could be done in such a proportion that your eyes won't notice it in a gats jar.. the best way to test it is either to dip a paper towel or toss it on the ground
  - sokoloff 5y ago
    The screen on the GATS jar is for testing for Jet-A contamination. Gas evaporates cleanly off the screen. Jet leaves a film in a random pattern as it evaporates. https://www.pooleys.com/shop/pooleys/the-gats-jar-fuel-tester/ https://www.pooleys.com/shop/pooleys/the-gats-jar-fuel-teste...
GekkePrutser 5y ago
We have a bucket of sand to throw it in. Local policy is not to throw it back in the tank for the risk of introducing contamination from the jar.

praveen9920 5y ago

Im curious to know what happens if they find some water floating.

RNCTX 5y ago
Keep draining until you don't. Pretty common when there's a fog and you get condensate. The tank on a small airplane isn't gonna be sealed air-tight, it's vented to the outside air so a little condensate is pretty normal. Water is heavier than the gas, so it sinks to the bottom where the drain fitting is.
tobinfricke 5y ago
You continue to sump the fuel until all the water is gone.

535188B17C93743 5y ago

>After you check it you toss the leaded gas on the tarmac. Good god, I think I'd be chewed out if I did this at my field. Always back in the tank. Avgas is too expensive to dump it all over the ramp.

hugh-avherald 5y ago
It'd be less than a $0.01 worth of fuel. You should still put it back in the tank but for environmental reasons not for the cost.
- sokoloff 5y ago
  $0.01 of fuel is about 7mL. If you’re only sumping 7mL of fluid in total, you might as well just skip the theater and not do it at all.
  - GekkePrutser 5y ago
    If it's all fuel it should be enough, right? The goal is to figure out if there's water at the bottom. We take about 20-30ml in general (about half a shotglass)
    - sokoloff 5y ago
      It very much depends on the airplane. Mine has 7 sump locations. A C172S has 13. If it overall adds up to 7mL, I think you’re not sampling enough. 7mL per sump location might be barely enough.
      - GekkePrutser 5y ago
        Ah we were taught only to use the bottom two on the wing tanks. This is probably why. Of course they do this for every student flight where it's really only necessary before the first flight of the day. So I think this plays into it (not wanting to waste too much fuel). Also the 7ml is not my figure. The "shotglass" is usally more than half full. I agree 7ml is not a lot.