Over time I've gotten several questions about sumping fuel so I put this together because I just got another PM about crossfeed. I wasn't taught to sump crossfeed but we do now because I sumped it once and got lots of garbage. Now I will crossfeed while flying just to make sure this function is there when I want it. Studied before I tried it and was solo so I didn't disturb anyone if I had messed up.

 

I'm often asked why I hold the sump open when changing to sump another tank - it is because that is how fuel will flow while aloft. If I don't have two hands available, I just sump, change tanks and sump again.

N3322G FUEL HYGIENE

This is the process we use to sump fuel on our Twin Comanche. It has evolved from the methods we were taught. The results are that the fuel sump screens are remarkably clean at each 50 hour AD inspection – so much so that shops have commented upon their cleanliness. Sumped fuel has been entirely water and debris free for almost two years or more of flying. I should mention that all bladders were replaced in 2009/2010, fuel door seals are fresh and I do my best to keep the fuel caps in good condition. When home, the aircraft is hangared in Texas where the heat eats rubber for lunch.

1. Before the first flight, place 30 gallon sterlite bin bottom under sump drain lines (or something that will catch fuel)
2. Start with selectors on main tanks
3. Sump right main by holding up rear sump drain
4. While holding sump open, change to right aux (notice movement of mechanism in sump area)
5. While holding sump open, change right selector to crossfeed
6. Release sump drain
7. Return selector to right main
8. Sump left main by holding up forward sump drain
9. While holding sump open, change to left aux (notice movement of mechanism in sump area)
10. While holding sump open, change left selector to crossfeed
11. Release sump drain
12. Return selector to left main

a. If fuel in tips - with selector on right aux, turn on master and switch to right tip
b. Sump right tip by holding up rear sump drain
c. Return switch to aux
d. Return selector to right main
e. If fuel in tips - with selector on left aux, turn on master and switch to left tip
f. Sump left tip by holding up forward sump drain
g. Return switch to aux, master off
h. Return selector to left main

13. Check fuel in bin. If debris, individually sump tanks until sumped fuel is clean

a. If fuel in tips, sump right tip external sump on tip
b. If fuel in tips, sump left tip external sump on tip
c. If nacelle tanks have fuel sump at external sump valves both sides
d. If Miller wet wings have fuel, sump at external sump valve on both sides

14. Fly
15. Fuel main and aux tanks (and any other desired tanks)
16. After last flight of day, sump main and aux tanks again.

Hope this helps. There is a SB on this and the bottom side of the sump access panel has directions printed on it - not that you'll be able to easily read it but saw it a couple of annuals ago when I was cleaning.

It would be nice if others would share their sumping regimen.

Thanks for sharing, I have not done the cross feed part but will start. george

Like I said, I wasn't trained to drain it either but I do now.

A comment on the "no catch" procedure when away from home base. Some airports go ballistic when they see gas being dumped on the ramp, especially in Florida. It seems some one from the state EPA saw pilots dumping fuel sample and got it declared a violation of the clean air statutes and offered to penalize airports and operators that allowed it to happen. They are required to set up collection stations for the fuel samples. This is not too widespread, but it can get an interesting conversation with airport officialdom.

Jim, right you are.

 

Another change is I will carry a WalMart plastic 2-cup measuring cup with handle - just for this reason. If I'm solo I find a willing helper to catch as I drain.

Pat, this is an excellent post thank you. For the short while I've had my PA-30 I've been in the habit of sumping the crossfeeds and more or less following your procedure as written for main and aux (I have no tips ) except I hadn't thought of continuing the flow of fuel as I switch tanks. I'll start doing that - you're right - that's how it would be in flight.

 

Regarding the method of catching the fuel and particularly for away from home airports, I'd posted this before when I built it but here's a pic of the sump fuel catcher I made up...

Its just a little home-made plywood box with two compartments designed to hold two "GATS" jars that you can get from almost any FBO or on-line supply. I like the GATS Jars because they have a screen that allows the fuel to be poured back into the tanks while keeing any contaminants in the jar (including water which will not pass through the screen).

All I did is build a box to hold two jars just so they can be under the plane and even in a wind - not be knocked over. Then I used clear plumbers tubing from Home Depot stuck into the "in" port of the GATS Jar and the other end sleves over the similar but smaller diameter tube coming out the belly of the fuel sumps. The reason for 2 GATS Jars is 2 fold.... 1) For capacity so I can give it a pretty good sump and 2) so if there is contamination I can know for sure if it came from the left or right tank.

Very easy to build though I did realize afterward that 100LL can strip the paint off the box so it may be better to leave as straight plywood or perhaps find a better paint.

- Charles

I just finished mine today just like yours Charles except I used a clear wax over the red oak, great idea!!

 

I use a clear plastic kitchen tray that is approximately 12" x 18" x 3" deep that has a plastic push on top to carry a quart of oil, funnel to pour oil in the PA30, a few tools, and paper towels. I dump out the contents and place the tray under the airplane to catch the drained fuel samples. I drain all tanks and crossfeeds into the dish and check it. Lower one corner of the dish and any particles or water will gravitate there and can be readily seen. I rarely have anything of concern, but if I do I go back and check tank by tank to find the source. If the fuel is clean, it can be poured back into a fuel tank from one corner of the plastic dish. Any water or minor particles settle in the low corner of the dish and can be seen. The clean fuel above can go back in the tank.

 

Al Powers

 

 

Pat, as usual you have provided a valuable lesson on the sump subject. Useful and accurate.
I use the same procedure, but not all tanks, and not often enough and I have paid the price.
Just had both selectors rebuilt in September due to corrosion.
"I now commit to proper sump before and after all flights", Ahh, that feels better!!
All is well with 8871Y and I am contemplating x-country to Seattle for the convention.
I've been out of the loop (Back at work) for a year and saddened by the Comanche news
that I've read. I need and thoroughly enjoy the CPPP, I've been twice Texas and Z-Hills and
I am ready again. So however, I'll be back!! KB

George - that looks awesome! Puts my painted plywood version to shame

 

- Charles

Hey Kevin - nice to see you here.

 

For those that haven't met Kevin - he wipes down his twin after every landing ... and you should see the cleanliness of his emergency gear extension area