Sniffing Out Water

Thats the lowly fuel samplers job. With some states levying fines for dumping gas on the ramp, we think the GATS jar is worth the higher cost.

There are lots of excuses for not sumping the tanks before every flight, none of them good. A snowy or wet ramp makes it a miserable job for the pilot of a low-wing airplane, but the usual reason for not sampling fuel is the X$#@^% tester is missing again. So buy several. Or buy one good one and keep track of it.

Admittedly, fuel samplers are about as exciting as socks for Christmas but if you don’t have one and you don’t use it religiously, we would bet even money that you’ll be treated to a dirt sandwich off the end of the runway some day. And thats if everything goes your way. Worst case, an engine stoppage on takeoff can be fatal.

We recently gathered up all of the fuel testers we could find and ramp-tested them on our Mooney. The last time we sampled the samplers, we were most impressed with Jeppesens well-made tester and the GATS Jar, which, such that something as simple as a fuel sampler can be sophisticated, is just that. Our conclusions are the same this time around, but the GATS jar looks more attractive for the simple reason that some state governments have decided to fine the hell out of their citizens for open dumping of gas.

A tester should do four things: pull a clean sample, even in the wind, clearly show water, be durable enough not to break after a couple of uses and be easy to use. All of the testers we tried meet this design brief but some are clearly better than others. The true acid test-or gas test, if you will-is to fish around under the wing of a low-wing and poke at the sump with the probe.

Right off, three of the testers don’t do that very well. The economy model from Sportys ($5.95) has a too-flexible probe that bends with the slightest side loading, just what you exert at arms length when reaching under a wing.Ditto the ASA model ($5.95), although it has a better designed, more robust probe, in our view.

The cup-type tester ($5.50 from Sportys, $4.95 from ASA) with its metal probe is more effective but its also smaller and more difficult to grip.These testers are fine for high-wing airplanes, where you can easily position them under the sump without getting an armload of gas. But for low wings, you need a better mousetrap.

The Winners
And that leads to the two winners. Jeppesens Deluxe Aircraft Fuel Checker ($12.30 from Spruce, $12.95 from Jeppesen) is similar in design to the conventional test-tube screwdriver type sold by Sportys, but its improved in three regards. Its made of beefier plastic, has a removable splash guard that keeps gas off your hands and arms and the probe is a beefy metal pin that extends to the bottom of the tester. Its built right and works well, in our view. Its worth more than twice the price, since the probe will last forever.

The GATS jar ($19.95 from Sportys, $18.65 from Spruce) is only a few bucks more and although larger than the other designs, it can draw a more voluminous sample if you need to clear a slug of water from a tank. The large clear jar makes it easy to see any water in the sample and a filter in the cap makes it practical to pour good gas back into the tank. While the GATS is not as easy to store as the others and is somewhat tedious to use, the pour-back option is worth the hassle, in our view, since some localities are fining for gas dumping on ramps. Last, the GATS filter can distinguish between Jet-A and avgas by examining how the sample evaporates on the filter, a handy capability to have.

Also With This Article
“Rain Protection for Recessed Caps”

ASA, 800-272-2359,
Aircraft Spruce and Specialty, 877-477-7823,
Jeppesen, 303-799-9090,
Sportys Pilot Shop, 800-776-7897,