Hi all,

I had an interesting situation the other day. The receipt left in my airplane by the fuel company had written in the "product" box, this:

"Jet A"

Yup. Jet A. In my 152.

First, I call the fuel company -- I get a promise that it was a mistake in writing the receipt, not a mistake in the actual fueling. Now, I know the odds are near infinitesimal that Jet A was pumped into my plane, but I couldn't quite shake that super tiny off chance. It shouldn't be possible (different flared nozzle for Jet A, and other procedural precautions), but it still is.

So, of course, I sump it. Blue, smells like avgas. Great!

...

Well, until I do some googling. Google gave me conflicting results, regarding whether avgas & jet A can blend or if they separate out (water and oil style). Hmm. Sump it again. Looked at it sideways, very suspiciously.

Finally settled on a plan. It was time to science this s***. I had aprox. 8 gallons of avgas in each wing before it was filled. So four gallons of either avgas or jet a was pumped into each wing. Nice 2:1 ratio. I decided to try to simulate this mix, and see if they blend (doubtful) or separate (what I've always heard). If they do separate, then it's a very easy thing to check...just sump it and if it's blue, I'm good. So, I grab a jerry can of avgas I had sitting around and run home and grab a few empty glass jars. Next stop: gas station. I fill one glass jar with diesel and head home for some driveway science.

Fully expecting a beautiful water/oil style separation, just like I've been told many times before, I excitedly pour two cups of avgas into an empty glass jar. The moment of truth arrives, I pour one cup of diesel, and this is what I immediately see:



Well then. What a beautiful blend. The diesel from the gas pump was rather yellowish, so it did affect the color. However, I've heard that Jet A is almost clear...so it wouldn't have affected the color perceptibly. The smell..well, it smells a bit diesely, but not that much. Hmm.

In the end, I found that the only good indicator of diesel/jet-a presence was texture. The texture of my little blend was significantly oily, whereas the fuel I sumped out of my plane was not. So it was just an error in writing the receipt.

HOWEVER...I had always thought that I could detect an inadvertent Jet A fueling by sumping, since Jet A should settle to the bottom of Avgas. Not so.

Make sure you sump enough to get fuel from the tanks not just what is in the lines already. That might gine you a good indixator to keep the first bit sumped and after a quart or more.

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Did you do the paper towel test?

Gump

Nope - never heard of it. What's the paper towel test?

Put some of the liquid on a piece of paper.

AvGas will evaporate and dry quickly and leave a faint blue ring.

The Jet will stay wet, and leave an oily residue.

Gump

Mr Google had several articles. This one has pics!!!!

https://www.twincessna.org/pdf/Misfueli ... e-8-15.pdf

Gump

Seems like you missed an opportunity for a long taxi and runup and a new motor courtesy of the errant FBO.

They at least owe you a fuel system drain, cleaning, +/- IA inspection, a tank of (av)gas, a rental if you need to fly until that gets done, and an apology.

Slash fuel, used in drip torches for burning logging slash or "Burning out" on wild fires is 5 parts diesel and one part gasoline. 3 parts diesel and 2 parts gas if burning wet slash. I worked in that business and mixed it for for 45 years. Never had any indication that it didn't mix. Once in a while somebody would put some in a chainsaw by mistake. It'll run but pretty hard to get started and won't rev up and smokes like crazy.

"Trust no one". God bless you for not relying on a casual "It's OK". I have listened to that remark several times and nearly bought the farm.

Glad it's good for you! Stay vigilant.

Yet another reason to stand by and watch your airplane being refueled. If it's from the avgas truck, at least there's a fighting chance that it's avgas. But if you're not there, you don't know which truck was used.

Piston gas engines will not run very long on Jet A. They stop, after they've been trashed. There are numerous NTSB reports of exactly that happening, and often enough, there are fatalities. That's how the Hoover nozzle (the flared nozzle you mentioned) came into being. Some mixed up rampy filled the tanks of Bob Hoover's Shrike Commander with Jet A in San Diego in 1989, and he lost both engines at about 300' AGL and crashed. He and his passengers were unhurt. Over the next couple of years, the FAA required that all airplanes that take Jet A be refitted with an oval fuel port, and that oval nozzles be fitted to Jet A dispensing pumps/trucks. But it's a fact that many of the reported accidents occur because either the oval nozzle wasn't fitted, or an adapter was attached to it which allowed it to fuel a round avgas-size port--and that's because the majority of turbine helicopters don't have the oval fuel port! So you can see, it's not very hard for a misfueling to occur.

If I had the slightest doubts about what fuel had been put in my airplane, I'd demand that the tanks be emptied and flushed, all lines flushed, and a careful inspection of the airplane's engine be made by a good mechanic, especially if it had been run at all after the fueling. The danger of Jet A in an avgas engine is more than just significant--it's a killer. That's what I'd do--I recommend that you do the same.

Cary

Cary wrote:Yet another reason to stand by and watch your airplane being refueled. If it's from the avgas truck, at least there's a fighting chance that it's avgas. But if you're not there, you don't know which truck was used.

Piston gas engines will not run very long on Jet A. They stop, after they've been trashed. There are numerous NTSB reports of exactly that happening, and often enough, there are fatalities. That's how the Hoover nozzle (the flared nozzle you mentioned) came into being. Some mixed up rampy filled the tanks of Bob Hoover's Shrike Commander with Jet A in San Diego in 1989, and he lost both engines at about 300' AGL and crashed. He and his passengers were unhurt. Over the next couple of years, the FAA required that all airplanes that take Jet A be refitted with an oval fuel port, and that oval nozzles be fitted to Jet A dispensing pumps/trucks. But it's a fact that many of the reported accidents occur because either the oval nozzle wasn't fitted, or an adapter was attached to it which allowed it to fuel a round avgas-size port--and that's because the majority of turbine helicopters don't have the oval fuel port! So you can see, it's not very hard for a misfueling to occur.

If I had the slightest doubts about what fuel had been put in my airplane, I'd demand that the tanks be emptied and flushed, all lines flushed, and a careful inspection of the airplane's engine be made by a good mechanic, especially if it had been run at all after the fueling. The danger of Jet A in an avgas engine is more than just significant--it's a killer. That's what I'd do--I recommend that you do the same.

Cary

The fuel filler on a Turbine/ jet is not oval. The point is the big "Hoover" nozzle is to prevent it from fitting in the smaller fuel filler ports/ tanks on AVGAS airplanes.

A Pratt Whitney PT6 can burn straight 100LL. The Pratt will let you run 100LL but the amount of hours you can run is limited before further action is required but it's around a 100 hours.

I have also been in a Jeep that was filled with diesel. We made it about 1/4 and it started to smoke something fierce and died.


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Opposite debacle:

Rainbow Beach, QLD, Australia:

Started to fill a Ford diesel truck with gasoline for about (15) liters. Then, realized it and shut off the nozzle in absolute horror!! Purchased a litre of 2-stroke motor oil, poured it into the tank and then topped with diesel. Engine ran great. I also accidentally drove on the wrong side of the road once or twice.

PAMR MX wrote:

Cary wrote:Yet another reason to stand by and watch your airplane being refueled. If it's from the avgas truck, at least there's a fighting chance that it's avgas. But if you're not there, you don't know which truck was used.

Piston gas engines will not run very long on Jet A. They stop, after they've been trashed. There are numerous NTSB reports of exactly that happening, and often enough, there are fatalities. That's how the Hoover nozzle (the flared nozzle you mentioned) came into being. Some mixed up rampy filled the tanks of Bob Hoover's Shrike Commander with Jet A in San Diego in 1989, and he lost both engines at about 300' AGL and crashed. He and his passengers were unhurt. Over the next couple of years, the FAA required that all airplanes that take Jet A be refitted with an oval fuel port, and that oval nozzles be fitted to Jet A dispensing pumps/trucks. But it's a fact that many of the reported accidents occur because either the oval nozzle wasn't fitted, or an adapter was attached to it which allowed it to fuel a round avgas-size port--and that's because the majority of turbine helicopters don't have the oval fuel port! So you can see, it's not very hard for a misfueling to occur.

If I had the slightest doubts about what fuel had been put in my airplane, I'd demand that the tanks be emptied and flushed, all lines flushed, and a careful inspection of the airplane's engine be made by a good mechanic, especially if it had been run at all after the fueling. The danger of Jet A in an avgas engine is more than just significant--it's a killer. That's what I'd do--I recommend that you do the same.

Cary

The fuel filler on a Turbine/ jet is not oval. The point is the big "Hoover" nozzle is to prevent it from fitting in the smaller fuel filler ports/ tanks on AVGAS airplanes.

A Pratt Whitney PT6 can burn straight 100LL. The Pratt will let you run 100LL but the amount of hours you can run is limited before further action is required but it's around a 100 hours.

I have also been in a Jeep that was filled with diesel. We made it about 1/4 and it started to smoke something fierce and died.


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Mostly true, the allowed run time on a Pratt is 10 hours, it's not that it'll hurt the engine, it's that the high pressure fuel pump will cavitate and pit the pump vanes and eventually erode them beyond service limits.
At least that's how it is for King Airs.

Hafast wrote:

PAMR MX wrote:

Cary wrote:Yet another reason to stand by and watch your airplane being refueled. If it's from the avgas truck, at least there's a fighting chance that it's avgas. But if you're not there, you don't know which truck was used.

Piston gas engines will not run very long on Jet A. They stop, after they've been trashed. There are numerous NTSB reports of exactly that happening, and often enough, there are fatalities. That's how the Hoover nozzle (the flared nozzle you mentioned) came into being. Some mixed up rampy filled the tanks of Bob Hoover's Shrike Commander with Jet A in San Diego in 1989, and he lost both engines at about 300' AGL and crashed. He and his passengers were unhurt. Over the next couple of years, the FAA required that all airplanes that take Jet A be refitted with an oval fuel port, and that oval nozzles be fitted to Jet A dispensing pumps/trucks. But it's a fact that many of the reported accidents occur because either the oval nozzle wasn't fitted, or an adapter was attached to it which allowed it to fuel a round avgas-size port--and that's because the majority of turbine helicopters don't have the oval fuel port! So you can see, it's not very hard for a misfueling to occur.

If I had the slightest doubts about what fuel had been put in my airplane, I'd demand that the tanks be emptied and flushed, all lines flushed, and a careful inspection of the airplane's engine be made by a good mechanic, especially if it had been run at all after the fueling. The danger of Jet A in an avgas engine is more than just significant--it's a killer. That's what I'd do--I recommend that you do the same.

Cary

The fuel filler on a Turbine/ jet is not oval. The point is the big "Hoover" nozzle is to prevent it from fitting in the smaller fuel filler ports/ tanks on AVGAS airplanes.

A Pratt Whitney PT6 can burn straight 100LL. The Pratt will let you run 100LL but the amount of hours you can run is limited before further action is required but it's around a 100 hours.

I have also been in a Jeep that was filled with diesel. We made it about 1/4 and it started to smoke something fierce and died.


Sent from my iPhone using Tapatalk

Mostly true, the allowed run time on a Pratt is 10 hours, it's not that it'll hurt the engine, it's that the high pressure fuel pump will cavitate and pit the pump vanes and eventually erode them beyond service limits.
At least that's how it is for King Airs.

I appreciate the correction--not ever having been a rampy or refueled turbine aircraft, I was under the erroneous impression that the Hoover nozzle and the refueling port was the same shape.

The important thing, though, is that an engine designed to run on avgas will be ruined if it's run on jet fuel. Conversely, at least for a short time, a turbine engine designed to be run on jet fuel can be run on avgas.

Cary

I'm with Cary: it's imperative to wait at the plane until the fueler arrives with the right truck. And afterwards, to check the caps and sump the tanks.

PAMR MX wrote:The fuel filler on a Turbine/ jet is not oval. The point is the big "Hoover" nozzle is to prevent it from fitting in the smaller fuel filler ports/ tanks on AVGAS airplanes.

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I only wish the "Hoover" nozzle was a required item on all Jet-A trucks. Three years ago a Malibu got 54 gallons of Jet-A because an untrained lineman mistook the normally aspirated piston powered aircraft for a Rocket Engineering turbine conversion. The truck had an adaptor on it to fuel aircraft with the conversion... which didn't always include the larger openings. I've seen about one to two misfueling accidents a year in the NTSB reports since then. As GumpAir suggests, the paper test (and the smell test) are important.

gumpair wrote:Mr Google had several articles. This one has pics!!!!

https://www.twincessna.org/pdf/Misfueli%20...%20e-8-15.pdf

Gump

Great article. It's very similar to one written by Mike Busch a few years ago after his twin Cessna got a tank full of Jet-A. Regardless of whether we see the "100 LL" sticker on the fuel truck or self serve pumps I think it's a REALLY good idea to check that it's gas in the tanks. After I've confirmed the stuff in the truck (or self serve) is ok for some airport I might be a bit relaxed about my next fueling. But stuff happens, and the pilot always arrives at the accident first...

I had a station manager at a flying outfit I worked for proudly show me when I got back from my ten days off, how he had used our old 3,000 gal Jet-A tank and turned it into our new 3,000 gal 100LL tank. Complete with 1,000 gallons of shiny blue 100LL in it.

Being the curious sort that I am, I asked him about the approximate 100 gallons or so of Jet-A that had been left in the tank.

He just looked at me funny and said, "Nothing. It'll dilute out." "But I did put a new filter on the pump."

Needless to say, Anchorage did not like my phone call.

Gump

GumpAir wrote:I had a station manager at a flying outfit I worked for proudly show me when I got back from my ten days off, how he had used our old 3,000 gal Jet-A tank and turned it into our new 3,000 gal 100LL tank. Complete with 1,000 gallons of shiny blue 100LL in it.

Being the curious sort that I am, I asked him about the approximate 100 gallons or so of Jet-A that had been left in the tank.

He just looked at me funny and said, "Nothing. It'll dilute out." "But I did put a new filter on the pump."

Needless to say, Anchorage did not like my phone call.

Gump

Great story. Spookier than the ghosts that howled in the dark outside the light of my first campfire (6+ decades ago).