Fuel Contamination (New)

bob loblaw said:
These are just two of the 29 pages of accidents that were attributed to fuel contamination. I left out the ones that siad water in the fuel. We are flying aircraft that are sometimes 2 decades old or older. Some of the planes we fly had tanks that are currently rusting. This rust finds its way into the fuel and sometimes into the lines. Anyway, 29 pages of fuel contamination accidents and uncle Tom didn't help me run the search

http://ntsb.gov/ntsb/brief.asp?ev_id=20030813X01323&key=1
http://ntsb.gov/ntsb/brief.asp?ev_id=20030123X00098&key=1
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Nothing but red herrings. Those do not apply to our conversation. Please quit trying to change the subject.

We were talking about running a fuel tank *dry*. I contend that doing so does not cause sediment to get into the fuel system any more than normal operation, and you say otherwise. You post two links, one having to do with a rusted fuel line (leading to fuel contamination), the other having to do with improper preflight (leading to fuel contamination). Both of those, as well as your *rusting fuel tank* scenarios, have contamination getting into the fuel system whether or not the tank is run all the way down, and have nothing to do with what we are talking about.

How about we discuss the topics that I brought up above? Here is a diagram from the C172 fuel system:

7-24.jpg


Look at how the fuel pickup is located in the tank, and notice that during normal operation fuel would be drawn from all sides of the pickup, and not just from above. Some of the fuel entering the pickup is coming from below the pickup point, and is part of what you would consider *unusable* or, apparently, *unsafe* fuel. The fuel coming from below the pickup, even when the tanks are full, is the same as the fuel entering the pickup when the tank has been run all the way down to where air is entering the system and the engine begins to *miss*.





Oh, and don't forget to go back and read that I stipulated that a "proper preflight sumping of the system" is done. So don't bother going down that path.
 
Red Herrings? I am not saying that everytime the fuel in every airplane is run to the unusable fuel that sediment will clog the line, I am saying that it could. The one thing your diagram doesn't show is that normal operation of this system fuel is drawn from both tanks at once. Pipers and Beech systems are totally different. I showed you two instances where contamination lead to accidents. the hose line on one could have happened at any stage of the flight.
 
bob loblaw said:
Red Herrings? I am not saying that everytime the fuel in every airplane is run to the unusable fuel that sediment will clog the line, I am saying that it could.
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And I'm saying that it makes no difference whether the tank is full or down on empty. Do you have any reason to refute my stance?

The one thing your diagram doesn't show is that normal operation of this system fuel is drawn from both tanks at once. Pipers and Beech systems are totally different.
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If you're trying to make a point, I'm not following you.
I showed you two instances where contamination lead to accidents. the hose line on one could have happened at any stage of the flight.
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Neither of the two instances you brought up are related to our discussion of whether or not running a tank to empty can cause fuel contamination. Other than the fact that both were fuel contamination accidents. :whatever:

All that you have done so far is prove that fuel contamination accidents and incidents happen. We knew that.

Do you have any basis for saying that running a tank to empty has a higher chance of causing sediment to enter the fuel system when compared to operation with a full tank?
 
SteveC said:
And I'm saying that it makes no difference whether the tank is full or down on empty. Do you have any reason to refute my stance?

If you're trying to make a point, I'm not following you.
Neither of the two instances you brought up are related to our discussion of whether or not running a tank to empty can cause fuel contamination. Other than the fact that both were fuel contamination accidents. :whatever:

All that you have done so far is prove that fuel contamination accidents and incidents happen. We knew that.

Do you have any basis for saying that running a tank to empty has a higher chance of causing sediment to enter the fuel system when compared to operation with a full tank?
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It all depends on the what type of sediment we are talking about. Some debris can be light enough to float around on top of the fuel and get closer to the pick-up lines as the quantity is decreased. Water on the other hand is heavier than gas, so it will go to the lowest point. I am sure that you would be surprised as to what kind of stuff you would find after you pull the tanks out of a twenty something year old plane.
 
Wow a poor guy works a regular 8 hour shift, and a good ol Old Wives Tale debate fires up.


RE: running a fuel tank dry.

Completely harmless in piston engines.

The fuel pick up is at the lowest part of the tank just above the sump. If you have properly drained the tanks then there will be no contaminates of any significant size remaining in the fuel (the filter takes care of the really small stuff). Every time I have heard about a engine quiting due to contamination was a case of truely filthy gas in the tanks and/or rubber bladders coming apart. Durring normal flight, vibrations agitate the fuel keeping any contaminates in suspention slowly.

Other myths about fuel pumps being lubricated by fuel are completely false.


Unsable fuel is the fuel that MAY be remaining when the tank has run dry durring level flight. In all likelyhood you will even be able to burn some of that fuel before the engine quits.

As a pilot you sould know EXACTLY how much useable fuel is in your airplane. Useing the numbers in the POH is a safe starting point, but you need to do some checking yourself.

Procedure for running a tank dry:

Take off & run on one tank for 30 min to 1hr, switch tanks and run that one untill all fuel is exausted in level flight, switch back and continue to a safe landing. If you are observant, you will see the fuel pressure flucuate as the last gallon or so is burned. You should be able to predict this +- 5 minutes.

When you fill up the empty tank you will now know EXACTLY how much useable fuel, endurance and range on one tank.

Repeat this for other tanks and take the time to observe what indications your instruments show durring an actual engine failure.

http://www.avweb.com/news/columns/182044-1.html

Diclaimer, if your POH says not toi run a particular tank dry, then follow the manufactur's instructions.
 
SteveC said:
And I'm saying that it makes no difference whether the tank is full or down on empty. Do you have any reason to refute my stance?

If you're trying to make a point, I'm not following you.
Neither of the two instances you brought up are related to our discussion of whether or not running a tank to empty can cause fuel contamination. Other than the fact that both were fuel contamination accidents. :whatever:

All that you have done so far is prove that fuel contamination accidents and incidents happen. We knew that.

Do you have any basis for saying that running a tank to empty has a higher chance of causing sediment to enter the fuel system when compared to operation with a full tank?
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I think you should give up man. You guys are like two ships, passing in the night...

G
 
JayAre said:
Hey I'm a 210 driver

As you said about running out of fuel
I have a P210 next door in the hanger that was ran out by an 15,000hr ATP Who also passed over one airport as he ran one tank dry and switch to the other to make his destination well tried to make his destination.

http://www.ntsb.gov/ntsb/brief.asp?ev_id=20050119X00075&key=1
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you heard it here first folks!! screw those high time guys! they'll just run you out of fuel, hire me instead! :)

I was told a story once in a safety class about a pair of CFI's that took a cessna of some sort from KGFK to KMSP and back one night late. Apparently they went down, it's right at 250NM one way, flew some friends around, and came back without refueling, and ran out of fuel a few miles short of KGFK, where they landed on the road. Once they landed I guess they tried to restart the engine, and it started, so they taxiid down the highway, up the road to the airport, and up to the gate, called the apt. manager to open the gate and put the airplane away and went home. The next day the line guy noticed he put a ton of fuel into it, and the apt. manager was calling to tell them about this airplane they taxiied through the gate. How true is it? I dunno... just what we were told lol.
 
USMCmech said:
Wow a poor guy works a regular 8 hour shift, and a good ol Old Wives Tale debate fires up.

RE: running a fuel tank dry.

Completely harmless in piston engines.
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Thank you.

And thanks for that link to the avweb article. I had read that one in the past, but forgot about it until you linked it.
http://www.avweb.com/news/columns/182044-1.html

From John Deakin's article:
The Creeping Crud OWT

Then there is the secondary OWT that says something like "But what if some crud gets sucked into the system from the tank bottom?" Give me a break! Think about this, for a moment. There are three areas where "crud" might be a concern. Crud lying on the bottom, crud suspended in the fuel, and crud floating on the surface. When we fuel the airplane, fuel is injected rather violently, stirring up the whole tank. When we fly in turbulence, fuel sloshes rather violently around the tank. Do you really think anything will be peacefully lying on the bottom, year after year? If it were, why would running the tank dry stir it up, and if it's that tenacious, how on earth is running the tank dry going to magically pick it up?
How about suspended crud? It is no more, or less likely to be sucked into the fuel lines at any fuel level. Floating crud, on the surface? Well, maybe, but can you name me something that will do that? And if there is, well, how much of it will you allow, before you rip the tank out for "cleaning," or how WILL you get it out, someday? Just how, and when, will you identify it, detect it, and get rid of it? And, how much fuel do you want as a "buffer" below the floating crud, to keep from sucking it in? In fact, if there is a little something floating on the surface, I WANT it to be sucked into the fuel lines, preferably a little at a time, so that the strainers and filters can catch it, and alert me that something is going on in there. The likelihood of there being enough to cause a problem is remote, at best, and if running a tank dry will pick up a little crud, then running a tank dry often is a very good thing, because you'll catch it a little at a time, and drain it out the strainer. Of course, if you keep the tank full most of the time, and the cap on, and drain the sumps often, there isn't any way for crud to get into, or stay in the tank in the first place.
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(OWT = Old Wives Tale)
 
Did you notice that I did exactly what the author of that article asks you to do. He wants you to argue your point against his opinion by supplying data that supports your argument. In the meantime, he gives you his opinion without supplying data to support his argument. He only gave data from the FAA which said nothing about sediment or contamination. In a side bar there is a little bio that says he has 35,000 hours. Since he has sooo much time, his theory must be correct and we should accept his opinion without facts to back it up.

Go to ntsb.gov and do a querry search using the keywords fuel contamination and see that 29 pages of accidents comes up. If I had more time on my hands, I would go through each and every 29 pages of accidents and disregard the ones where water was the contaminate. Why on earth would such an experienced pilot attempt to dispell " OWT " without supplying data himself to show he has actually researched the subject.
 
bob loblaw said:
Go to ntsb.gov and do a querry search using the keywords fuel contamination and see that 29 pages of accidents comes up. If I had more time on my hands, I would go through each and every 29 pages of accidents and disregard the ones where water was the contaminate. Why on earth would such an experienced pilot attempt to dispell " OWT " without supplying data himself to show he has actually researched the subject.
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as pointed out earlier in the thread, no one is debating that fuel contamination will cause you problems. The issue is whether or not running a tank dry is the causal factor for the contamination. So unless you want us to go search for "fuel starvation" accidents and re-attribute them to "fuel contamination" i dont see where you are going with posting ntsb accidents involving contamination. I can go dump a couple pounds of iron oxide into a tank, fly around and have my engine quit due to contamination and that will make it into your query, but i'll leave it to you to determine how relevant that is to this discussion (the one every one else in the thread is having).
 
As casey mentioned, no one is argueing that fuel contamination isn't a real concern. In fact I highly recomend carrying a filter of some sort anytime you travel outside the USA (Mexico, cariben ect.).

However I have never seen an instance where fuel contamination was caused by running a fuel tank empty.

Contamination stays in suspension inside any airplanes fuel tank. The constant vibration and sloshing back and forth will not allow any contaminates to settle out. This contamition is GRADUALLY feed to the engine. The reason that we drain the sumps durring preflight is that OVERNIGHT (not durring flight) it can settle and cause problems. I recomend not draingin the tanks if you have just been fueled, because you won't find anything, and you are just polouting the ground water.

Also rember that gasoline is a powerful solvent. Any orgainic contamination will be disolved into microscopic particles in minutes. Only metal and rubber can really cause problems.

Consider your car.

You run thousands of gallons of comparitvely FILTHY gas through in a year amounting to thousands of hours of operation. Most car mechanics recomend replacing your fuel filter every 2-3 years. Many people routinely run their tank down to nearly empty. Now, how often do you hear about sombodys car dying suddenly because of fuel contamination.

BTW, my truck is starting to run a little off, I think I need to replace the fuel filter. Check your car too.

Now consider your airplane.

Your AVGAS is stored in tanks which are much more closely monitored. You won't run a fraction of the amount of gas that you do in your car. You drain the sumps before every flight. Fuel filters are (or should be) changed at every annual inspection.


RE: Deakin's articles

I have found these articles to be the most throughly researced, yet the simplest and best explaintions about powerplant managment.

He and several others host a seminar dedicated to explaining to pilots about what is really going on inside their engine.

Read them all, You will learn a TON!

http://www.avweb.com/news/columns/182146-1.html
 
USMC, one again, thanks for the experienced, easy to understand answers!
 
Mech, since you seem to know what you're talking about here, you brought something up. Ground water contamination.

Now, if I go and get one of those GATS jars and dump the fuel back into the plane, is that okay?
 
tonyw said:
Now, if I go and get one of those GATS jars and dump the fuel back into the plane, is that okay?
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The GATS jar is specificly designed to filter out any contamination that is inside, therefore you can safely pour the drained fuel back into the tanks and help save the enviroment. If I got a bunch of contamination and/or water I wouldn't do this, but that is so rare that it wouldn't be a problem to find a gas can for that one time out of a hundred.

Since 99% of the time you get a clean pure sample from the sump anyway drained fuel is a real unesacary polutant.


When I was at FSA in vero, they had to tear up the entire FSA ramp due to the polution that had seeped down through the asphalt.
 
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