GATS Jar Fuel Tester Information


How to best use the GATS Jar

The purpose of any fuel sampler is to extract enough fuel to be assured that there is no water or debris present. CLICK HERE TO DOWNLOAD ORIGINAL INSTRUCTIONS For more detailed instructions, Click the button.

How to Clean a GATS Jar

From time to time your GATS Jar may need to be cleaned. If it gets too grimy or the screen collects debris on the back side, or if it seems like it isn't working as well as it used to, it's time clean it.

How to purchase GATS Jars

Single or a few GATS testers can be found at many FBO's or Pilot Shops and certainly online. Retail sellers or large quantity purchasers may contact a GATS distributor.

Theory of Operation

The GATS Jar Fuel Tester works on a molecular level and uses a physical screen to clean contaminated fuels to make it safe to put back into the aircraft tank after extracting and examining a sample.

Using the GATS Jar to Test for Jet Fuel Contamination

There is a procedure for using a certain type of material and the difference in the rate of evaporation between that of AVGAS and heavier fuels such as, Jet fuel, diesel fuel and other kerosene based fuels.

GATS OAQ's

Answers to Occasionally Asked Questions


Warranty Information

The GATS Jar Warranty is quite simple. Materials and workmanship are covered as long as you own the tester. This includes O-rings, cracked parts and melted parts. If you need to make a claim, Call 1 800 972 9670. You will likely get an answering machine. Leave a message describing your problem along with your name, Phone Number, and you need to leave your postal mailing address and we will forward the information. You will either be called to confirm the information provided or if it is clearly a warranty replacement issue the part(s) will be mailed to the address contained in the message. If you prefer using email, use our address: contact@aerosample.com


How to Use the GATS Jar

The first thing to do before using the GATS Jar to collect and test the fuel is to inspect the integrity of the screen material. If the screen is torn or has a hole larger than the normal mesh size the tester should be retired and one with an intact screen used. The proper end of the actuator part is then selected that mates with the style of sump valve to be operated. The actuator can be pulled out of the separator to select either the probe end or the castle end and then reinserted into the separator part. If the probe end is used the stainless steel rod should be located nearest the center of the tester to avoid any splashing of fuel outside the separator walls.

Draw, and examine the fuel samples from one or more spots. When the jar is as full as desired it should be inspected for debris in the samples and the color of the fuel. The white back of the sticker on the jar is used as a known white background to obviate the color of the fuel. The sample should be viewed with the most prominent light source (usually the sun) behind the observer to reflect off the back of the sticker and back through the sample. In the case of 100LL the color should be a clear blue. Before putting the fuel component of the samples back into the fuel tank, check the top of the screen material for any water sitting on the mesh. If there are large drops of water they should be directed to the by-pass holes to get them into the collection jar. Any remaining droplets should be dried off the screen with a tissue or cloth. All water must be eliminated from the screen material for the separation action to work properly.

After collecting the desired samples and after visually checking the level of the fuel in the tank, the fuel part of the samples of the GATS tester can be emptied back into the tank through the bottom segments of the screen material, taking care not to tip the tester too far as to pour the samples through the mesh too aggressively or over-pouring the screen altogether thereby, pouring sample fluids through the by-pass holes, which have no screen material covering them. Do not hold the tester in the pouring position too long if water is in the sample. After the fuel has flowed through the screen and the it has stopped there will be a skiff of fuel left on the surface of the water. This will not totally come out and eventually the AVGAS will evaporate out of the screen material and after about ten seconds after that the water will be allowed to start dribbling out through the mesh.

Immediately after pouring the fuel back into the tank test for the presence of Jet fuel contamination. For a detailed description of that process, please refer to the appropriate heading on this page. If only one tank has been fueled, pull samples from that tank alone and test for Jet fuel contamination before any other samples are collected and mixed with that tank's sample. After the fuel component of the samples has been returned to a tank and the jet fuel contamination test is complete, any water left in the collection jar as a result of the separating action of the tester, can be thrown on the ground with a clearer conscience. After the separation of fuel from commingled water there may be a skiff of fuel on top of the water. This cannot be avoided and even though the separation is not perfect, it is a vast improvement over just throwing fuel samples on the ground or up in the air.


Cleaning the GATS Jar Tester

If it is ever noticed that the GATS Jar fuel tester is allowing any water to pass through, or even dribble through the screen material when pouring fuel back into a tank and certainly if the collection jar or screen becomes fouled with particulate debris it is then time to clean the sampler.

The process is always the same. The first step is to take the tester apart. The lid, called the separator, can be difficult to unscrew, but careful and deliberate force will dislodge it so that it can be removed. The screen and O-ring should be inspected. If there are any holes larger than the normal mesh openings or if there is a tear in the screen material, the tester should not be used. The O-ring should be replaced if it is broken, or excessively chaffed or if it allows fuel to leak from under the separator. The O-ring is a number O36 if a replacement is needed.

The first washing should be done with clean water and mild soap or detergent. An acid brush, or sometimes called a chemical brush with relatively soft bristles can be used on both sides of the screen material in the separator. The parts are then rinsed thoroughly with fresh water and then allowed to air dry. Aggressive solvents should never be used. The final wash can be done with clean gasoline or commonly obtained charcoal lighter fluid. A soft brush can be used again on the filtration mesh.

To reassemble the tester the O-ring is placed in the underside of the separator in the crease formed by the skirt and the partition bisecting the cylindrically shaped separator. It will seal between the underside of the partition that holds the screen material and the skirt of the separator against the outer edge of the lip of the collection jar. This should provide a good seal against the leakage of fuel when the tester is tipped for pouring. Grasping the separator and the top shoulder of the collection jar, the separator and the jar can be screwed together until a positive seal is made.


How the GATS Jar works

The GATS Jar screen material creates a weak valence bond with petroleum distillate fuels. When the material is made into a mesh of a specific line count this property allows a film of fuel to cover the mesh forming a membrane of fuel across the surface of the mesh sections, which allows the passage of fuel through the membrane but not water. This action is the result of the difference in surface tensions between fuel and water. The separating action is therefore accomplished on a molecular level and as long as the film of fuel is not penetrated due to excess pressure driving the fuel and eventually any water contamination through the fuel membrane or water molecules initially occupying the screen openings thereby disrupting the continuity of the fuel film. When the GATS' operating instructions are followed all fuel samples are cleaned of any water and particles able to interfere with the operation of a plane's engine.


Testing for Jet fuel Contamination

The GATS Jar Fuel Tester uses the difference in the rate of evaporation between AVGAS and Heavier than AVGAS fuels to test for Jet fuel as a contaminant. The process is quick, simple, and once mastered is quite reliable. Immediately after the samples have been collected and examined and while the screen is still covered in fuel, blow gently and indirectly on the screen with your mouth from at least a foot away and observe the evaporation of the AVGAS from between the strands of the mesh. The AVGAS will evaporate quickly and continuously until it is gone from all but a few screen cells. If there is Jet fuel or another heavier than AVGAS fuel present a delay will be observed in the overall evaporation of the fuel clinging to the screen with a significant number of screen cells still containing fuel after the initial surge of evaporation. After a short interlude the remaining cells will begin to clear of fuel as the gentle air flow of breath over the mesh continues. This is the contaminating fuel evaporating from a slightly elevated temperature. The two different rates of evaporation is somewhat subtle and care must be taken not to overwhelm the process by blowing too hard on the screen. Once mastered, one should be able to detect Jet fuel contamination to as little as 5%.


Occasionally Asked Questions

If a plane I fly has more than a few sump points, do I have to test them all every time before I take off?

It’s always best to follow the aircraft manufacturers recommendations or requirements for sampling and testing the fuel. They put them there for good reasons and if there is ever a problem that gets investigated and all the test points were not checked, the findings will always include pilot error and depending on causes the FAA will have something to say to, or take some kind of action against, the pilot in command.

 

Does the GATS Jar have a certification document, MSDS sheet or STC approval? The United States FAR's classify fuel testers as a pilot accessory and is therefore, not required to comply with any specific regulations. Consequently, we do not supply any manufacturing data or any compliance documentation.

 

Does the lid come off the GATS Jar?

Yes. The Jar and lid have threads, so the Separator screws onto the Collection Jar. Over time, with use, the O-ring seal can become stuck between the Jar and the inside surface of the Separator making it difficult to unscrew them. It can be done however, just hold the jar close to the Separator and twist - hard.

 

With what fuels will the GATS Jar work?

The GATS Jar will work with any pure petroleum distillate fuel. These include: Auto Gas, AVGAS, Jet Fuel, and Diesel. However, the GATS Jar Fuel Tester is not designed nor intended to be used with Ethanol infused fuels.

 

Why did my collection jar collapse?

This is a rare occurrence and we have no simple answer. The Collection Jar is made of P.E.T. plastic and is usually unaffected by normally encountered conditions. We have no direct cause, but it could be a combination of contributing factors. It's best to keep the tester out of high temperature locations, or not stored where there is outside pressure on the jar like pinched between the seat back and the elastic top of the seat pouch, or stored with a small amount of fuel inside in a warm, tightly closed location. Another possibility could be some fuel additives included in the fuel by regional refineries for seasonal changes in their fuel formulation may be attacking the plastic's integrity. We do replace these jars as a materials defect.

 

What does it mean if some water globules dribble through the Separator screen?

Put simply, you either have not dried the screen before trying to use it to separate commingled fuel and water, you might be pouring the fuel through the screen with too much force, a combination of the two, the screen material may have been contaminated with some kind of organic substance or you are trying to separate a fuel containing ethanol. If the screen has been wiped clear, this can happen by trying to pour the fuel back too quickly and tipping the tester too far. The GATS jar, and every other separating fuel tester made, relies on the surface tension difference between fuel and water. This physical characteristic is reliable, but can be overwhelmed if the separating is not done slowly with as little head pressure as possible. If any of these conditions exist, a thorough cleaning is recommended.

 

Why did my lid crack?

If the tester has not been thrown violently down, run over, or stepped on, it can happen that internal stresses from the injection molding process may cause a Separator to split along an undetectable weakness path. We always cover this as a materials failure.

 

What do I do if I lost my instructions?

Instruction sheets can be downloaded under the "How to best use the GATS Jar" heading above.

 

Is the GATS Jar made in America?

Yes. We can't vouch for all the raw plastic or original source of the stainless steel, but as far as all the tester manufacturing, the GATS Jar is completely made in the U.S.A.