Cessna Aircraft and water contamination of fuel.

[3958v]

The latest e pilot electronic news letter I received from AOPA had an article about how Cessna is concerned about the possibility of fuel contamination in the 100 200 and 300 series of aircraft. Latter in the article it mentions a study of 150 170 & 172 aircraft. I was wondering if there was a reason that 170's made that list. I understand that they made lots of 150's and 172's but I was surprised to find the only other model specifically listed to be the 170. Made me wonder if there have been more accidents as a result of contaminated fuel in 170's than other Cessnas. They recommend switching to umbrella style fuel caps. I wish they would engineer a kit to change our 170's over to those caps. The ragwing caps (also used on 195's) seem particularly prone to fuel contamination. Not sure if fuel contamination is quite the issue in the A&B models. Bill K

[jrenwick]

I don't know how many have seen this web site: http://sumpthis.com/ -- it shows that an absolutely amazing amount of water can live in the tanks of a Cessna 150 without reaching the sump drains. The aircraft it's talking about, though, are tricycle gear Cessnas. I can't see how the 170 could fit this pattern.

[1SeventyZ]

I think it's odd that I was taught to watch for water contamination and sump-sample tanks over 15 years ago when learning to fly (many of you much longer ago), and now this statement is made? Isn't this akin to the FAA releasing an official critical statement about pilots not flying beyond the fuel endurance of their aircraft? Duh?

Am I missing something unique about this recent development?

[3958v]

I can tell you from personal experience that you can sump your tanks on a 170 and still have enough water left in your tanks to shut your engine down. When I took my first trip in my 170 and it sat out in the rain I sumped my tanks and found water. I then sumped them again several hours latter and found a little more water. I mistakenly assumed that I got it all. I took off and flew for about 2.5hrs and refueled. My mistake I did not sump after refueling. then about 2 hrs later the engine quite. Paid an A&P to drain the carb and remove all water. Took off and flew home and found more water in gascolator. Took drains out of tanks and drained tanks. Flew again and still had a few drops of water in gascolator for several more flights. That is why Cessna still talks about this and at least the ragwing is not bullet proof in this department just because it is a taildragger. When the plane went down the gascolator was full of water. Since owning the 170 I have found a lot more water in the gascolator then in the tank sumps. Just information that every 170 owner should be aware of so I think its good for Cessna to talk about and owners to be made aware of. Bill K

[canav8]

This is a real important topic. Please understand this is written for the lurker or the inexperienced and is no intention to insult anyone. I just see this as a very common overlooked problem that my private pilot transition students do when they get their tail wheel endorsement. It is a majority of them so this topic is valid.

I see students sample fuel and maybe only put an 1oz. in the gats jar. (I think they were taught by tree huggers or penny pinchers)Remember this is about your life and safety of your passengers as the previous poster disclosed. If you are a nose wheel(training wheel) pilot you can usually get away with doing this. Unfortunately all tailwheel pilots know about this problem because it is significant. You should fill it to the top of the jar as a minimum. The reason why if you look at the location of where the fuel drain is, it is forward of the aft spar(The rear of the tank). The water is heavier then fuel so it will make beads and roll back to the aft of the tank. When you sample fuel and you do not get any water, you are not guaranteed to have no water in the fuel. It will just stay in there till the next time you sample. Over time, you will have enough water accumulate to see it in the fuel sample.

Note to any pilot.
If you see any fuel in the sample- DO NOT FLY IT till you have verified that all water is out of the tank.(In a tailwheel aircraft this means there is a lot of water in there!)

If you find water in the tank, you should assume it is at every drain point. First, you should deflate the opposite aircraft side tire to create a low side and allow the water beads to roll down the traped corner of the tank(aft tank by the Spar). This will generally yield an accumulation to remove it. Then do an extended sample. If you do it for a period of 30 seconds continuosly, you will create a venturi and suck the water out. It gradually sucks debris closest to the drain and works out in a greater curcumference from the drain. Do this to the other side as well.

Another old Taildragger trick if you cant affort to deflate tires in the stix is to get out on the wing tip and shake it then hold it up about three inches higher. The shaking will dislodge the water beads and then it will roll down to the low point more readily.
When I teach my students about fuel sampling I make them do it after the cursary walk around. So basically you walk around it twice. A little overkill but it makes a good habit pattern because when they walk around the wing tip they no longer just look at the light lens to see if it is cracked, they go to shake the wing to help dislodge the fuel beads before the second walk around which is the fuel sample walk.

Then you can sample the other drain points easily. Remember on some aircraft the fuel selector has a drain on it and some do not. For the ones that do not, you should have your mechanic install a drain there. That is the low point in the system not the gasculator. The gasculator is a trapping resevoir and will grab the water before it gets to the engine, but only to a degree.

Also trapping the fuel into a collection jar or other resevoir is good. You can then use a chamois and strain the fuel and reuse it.

For you instructors out there: Do you show your primary students what water looks like in a fuel sample? In the desert here none of my students have ever seen water in the fuel. A good trick is to get a fuel sample then spit into it. Swirl it around a little and the spit ball will drop to the bottom of the sample. Then shake it around and you will see how the water will move in your fuel tank, there by requiring the shaking of the wing to dislodge the water beads.
The other reason why this is good to do is water is corrosive on aluminum, if you dont move those beads and you let them remain, they will over time corrode your fuel tanks.

I would like to hear any other comments on this, as I am always willing to learn. I didnt get this alligator skin for nothing in the desert. Doug

[Bruce Fenstermacher]

I see people sample fuel immediately after refueling. This is pointless. The water that was in the tank is now mixed with the gas and any water in the gas you just put in is also mixed. It needs time to separate. How much time I can't say but I wouldn't be surprised if it's a half hour or more.

In the Army we were talking about JP4 or Jet A and water. There was a table which specified how fast the water would separate from the fuel and then the depth of the tank made even more difference. Our UH-1H tanks were fairly deep at the back. According to the table it could take upwards of 2 hours for fuel to fully separate to the sump.

There is an STC which is sold with the sump valve on E-bay for the fuel selector location. It is only for B models with the new style fuel selector which is all but about the first 34 as I remember. There is also a hole in the belly already through which you can view the plug that you will be replacing with the valve in the bottom of the selector.

If you have an A model there is still a plug at the bottom of the selector that can be replaced with an appropriately threaded valve. You will have to drill a hole in the fuselage though. The previously mentioned STC does not cover A models. But I'd think this a minor alteration. If you don't agree I'd think given this notice and the long history quite frankly of water in the systems that approval from a higher authority would be easy.

The '48 fuel system is completely different from the A and B model and I can't say if a valve in the fuel selector is doable or even warranted.

[GAHorn]

There is no necessity to visit E-barf to shop for this mod. It is sold by C-mods, along with the STC for installation. http://www.c-mods.com/

Note: While I applaud C-mods for bringing this item to market, I am convinced that for the majority of Cessnas which already have provision for a drain, (such as all 170's & 172's with the machined aluminum fuel valve) it's actually a minor alteration. The part which you might order for this is: CAV-110 or CAV-110-H-4, which are 1/8"-27 pipe thread.



CAUTION: Do not overtighten or use teflon tape when installing this or you will run the risk of cracking your fuel valve and/or contaminating your fuel system with tape. Use dry, or carefully with only one thread of fuel/gasket sealant.



Remember, the lowest point of your fuel system is not likely the gascolator, except in flight or in descent. It's your fuel valve, which should be drained (along with your carb bowl) every 100 hr inspection anyway. Make it a simple matter: Install a fuel drain on the belly at the selector valve.

I'm hesitant to critique anyone's personal efforts to remove water, ...extensive efforts are sometimes necessary and admirable.....but in 40 years of flying (including a lot of junk stored outdoors) I've had a few encounters with water in the fuel systems, however none of them required letting air out of tires to detect or address the matter.
Testing immediately after refueling is not usually productive, as Bruce mentions. It's better to test PRIOR to refueling. (The water which condensed within the tank-walls on the previous descent will already be at the sumps and stirring it up with refueling is counterproductive. We are not testing the NEW fuel. With modern fuel storage and delievery systems, It's rare indeed to receive new fuel already contaminated. This may be an exception with jet-fuel (and ethanol-laced mogas) due to the ability of that fuel to carry soluble water, but with avgas, NEW fuel rarely has water.)

Obviously, anytime the aircraft has been washed, rained-upon, or otherwise subjected to water, time must be allowed for it to settle to the sumps.

Zane, the new FAA AC is not a new discovery, I don't think. It's just another reminder, due to the constant re-appearance of age-old problems that continually "pop-up" from carelessness or familiarity (breeds contempt.) I believe that statistics prove improper/incorrect/incomplete Pre-Flight inspections/activities is the NUMBER ONE contributor to aircraft accidents. Checking the fuel for quantity, quality, contamination, and system condition/cleanliness/configuration/security is a pre-flight action.

[HA]

seems to me that there is a Cessna service kit that adds a pile of extra drains to every corner of the fuel tanks, to mirror the new models which have like 5 drains per tank. I haven't had enough problems that I consider that I need that kit. the times I've had engine issues due to water have been fuel theft from the 172 (they left the cap off and we got 3" of rain), deliberate water fouling of my fuel tanks (caught that guy), and once a bad cap o-ring and a lot of rain.

funny thing, our charter dept guys literally NEVER drain the tanks on their airplanes. so when I do test flights or otherwise fly their airplanes I always sump and get lots of water and goo etc, every time. I've mentioned it to them all but it seems to fall on deaf ears - I think that it's a common trait with guys that fly the same planes every day that they get complacent.

[GAHorn]

Private responses to my previous comment lead me to the conclusion that perhaps my previous comment was not well-worded...or perhaps it was misunderstood...but to clarify my previous comments:

I am a proponent of thorough pre-flight inspections, which INCLUDE sampling fuel tank sumps/gascolators for contaminated fuel and water.

The old adage "familiarity breeds contempt" ...means that, being human, we sometimes fall into the trap of believing that because we've rarely/never found water previously... it must be that we will not find water TODAY.... so it's a waste of time to test the fuel at the sumps.

WARNING: Walking up to an airplane and using your thumb to hold the drains open a moment and letting fuel fall to the pavement is NOT a proper inspection for water or contamination. USE A FUEL-SAMPLE JAR/DEVICE. LOOK FOR PROPER COLOR. SMELL THE STUFF. Look for settled water or settling water droplets.

Don't simply go thru the motions. Do the task properly.

FAA sometimes re-publishes safety bulletins when recent events bring their attention to obvious shortcomings in the field. A rash of accidents from water in the fuel will cause them to re-issue a reminder in the form of Advisories and/or Bulletins.

Don't treat those documents like familiar fuel sumps. The only time such documents are a waste of the taxpayer's dollar is if WE disregard them.

[sumpthiscom]

Gentleman,
You can debate undetectable water in the fuel tanks of the Cessna 170 till the cows come home. Fact is MOST if not all Cessna aircraft whether tri-gear or tail dragger hide water in their fuel tanks. Each of you should perform a simple test on you aircraft by taking a 16 ounce Dixie cup of water,add a drop or two of red food coloring, stir and pour into your fuel tank as the aircraft sits in it normal ground attitude. Go to the sump drain see if you can positively detect it and then eliminate the entire 16 ounces of red dyed water you just poured into the fuel tank. I wish each of you the best. Then come back and tell me what you know instead of what you think and have picked through the years. Here below is some insight into NTSB poor investigations that have allowed Cessna and the FAA to continue to pretend the indicated design flaw does not exist.

APR 05 1971 TX Normal cruise engine failure for UNDETERMINED reason 2 ok
APR 07 1969 LA in flight normal cruise engine failure WATER in fuel
inadequate preflight 1 ok
APR 17 1971 MA At takeoff engine failure for UNDETERMINED reason 4 ok
APR 20 1969 VA DESCENDING eng failure carb ice 3 ok
AUG 10 1969 WY ON TAKEOFF eng failure fuel contamination exclusive of WATER
in fuel 1 ok
AUG 13 1967 WI NORMAL CRUISE eng failure for UNDETERMINED REASON 1 ok
AUG 19 1978 RI initial climb engine failure contamination exclusive of WATER
in fuel 4 ok
DEC 13 1969 MI ON TAKEOFF eng failure for UNDETERMINED REASON 1ok
DEC 20 1964 NJ LANDING ENG FAILURE carb ice 1 ok
DEC 25 1969 GA NORMAL CRUISE eng failure for UNDETERMINED REASON 2 ok
DEC 26 1964 OH NORMAL CRUISE eng failure forced landing carb ice 1 ok
FEB 12 1972 VA landing final approach engine failure for UNDETERMINED reason
2 ok
FEB 22 1969 CA normal cruise engine failure WATER in fuel inadequate
preflight 3 injured
JAN 01 1972 CA landing go around engine failure INADEQUATE DESIGN WATER in
fuel 1 OK
JAN 01 1972 CA landing go around engine failure WATER in fuel 2 ok
JAN 02 1979 MO in flight normal cruise engine failure ice WATER in fuel
filter 2 OK
JAN 03 1967 AK NORMAL CRUISE eng failure for UNDETERMINED REASON 3 ok
JAN 07 1965 NY FINAL APPROACH eng failure carb ice 1 ok
JLY 03 1966 FL NORMAL CRUISE eng failure carb ice 1 ok
JLY 22 1970 WA LANDING GO AEOUND eng failure for UNDETERMINED REASON 3 ok
JLY 22 1970 WA landing goaround engine failure UNDETERMINED substantial
damage
JLY 27 1971 NH at takeoff engine failure for UNDETERMINED reason 2 ok
JLY 28 1972 ND CESSNA 170 normal cruise eng failure RUSTY WATER in carb and
sediment bowl 4 ok
JUN 03 1965 TX NORMAL CRUISE eng failure forced landing carb ice 2 ok
JUN 16 1971 MO Landing final approach engine failure ice carb 1 inj 2 ok
JUN 20 1965 CT CLIMB TO CRUISE eng failure forced landing UNDETERMINED
REASON 1 dead 4 serious
JUN 24 1969 NC LANDING GO AROUND eng failure WATER in fuei 1 ok
JUN 24 2006 IL at cruise about to land engine failure carb ice
JUN 25 1969 MI ON TAKEOFF eng failure for UNDETERMINED REASON 2 ok
JUN 30 1974 WI on takeoff partial eng loss rust in carb inlet screen 2 ok
MAR 02 1968 AR ON TAKEOFF eng failure for UNDETERMINED REASON 2 ok
MAR 02 1969 FL ON TAKEOFF eng failure WATER in fuel 2 ok
MAR 02 1969 FL takeoff initial climb engine failure WATER in fuel inadequate
preflight 2 ok
MAR 03 1969 MI INITIAL CLIMB eng failure for UNDETERMINED REASON 2 killed
MAR 25 1972 MN on takeoff engine failure ice carb 3 ok
MAY 07 2000 AK at cruise unable to restore power for UNDETERMINED reason
MAY 15 1978 KS go around engine failure small particles in fuel exclusive of
WATER
MAY 17 1964 KY normal cruise engine failure ice carb 1 ok
MAY 25 1965 LA NORMAL CRUISE eng failure for UNDERMINED REASON 1 ok
NOV 03 1968 ME initial climb engine failure WATER in fuel inadequate
preflight 1 ok
NOV 12 1967 MO INITIAL CLIMB eng failure WATER in fuel 1 ok
NOV 25 1965 CA INITIAL CLIMB eng failure forced landing WATER in fuel 1 ok
OCT 05 1974 NJ CESSNA 170 final approach eng failed for undetermined reason
pilot ok
OCT 23 2004 CO final approach decided too high engine failed carb ice 1
serious
OCT 24 1964 UT normal cruise engine failure WATER in fuel 2 ok
OCT 27 1968 SC ON TAKEOFF eng failure carb ice 2 ok
SEP 02 1968 ME LANDING GO AROUND eng failure carb ice 1 ok
SEP 05 1977 WI in flight normal cruise engine failure WATER in fuel
inadequate preflight 3 ok
SEP 10 1968 AK on takeoff eng failure fuel contamination exclusive of WATER
in fuel 1 ok
SEP 14 1969 TX DESCENDING eng failure carb ice 3 ok
SEP 14 1972 MT CESSNA 170 normal cruise eng failed for UNDETERMINED REASON
1 OK
SEP 16 1964 AK normal cruise engine failure WATER in fuel 2 ok
SEP 19 1969 WA TRAFFIC PATTERN eng failure UNDETERMINED REASON crashed in
lake 1 ok
SEP 29 1968 CA NORMAL CRUISE eng failure for UNDETERMINED reason 3 ok

[canav8]

Gahorn, is this guy for real? Trying to follow this posters comments but I cant figure it out. Anyone that recommends testing by adding water to a fuel tank to check theory should have these types of posts removed as they are not conducive to promoting safety in aviation. Please purge these posts if you can. Thanks

[jrenwick]

Gahorn, is this guy for real? Trying to follow this posters comments but I cant figure it out. Anyone that recommends testing by adding water to a fuel tank to check theory should have these types of posts removed as they are not conducive to promoting safety in aviation. Please purge these posts if you can. Thanks

I think this guy may be the owner of http://sumpthis.com, which is about undetected water in Cessna fuel tanks. They did an experiment using red-dyed water in a tank with the top cut off, to show how much water could be in there without it reaching the sump drains.

Example here: http://sumpthis.com/cessna150andcessna1 ... 24x768.htm

[Bruce Fenstermacher]

Doug,

As perhaps a more silent moderator looking mostly for spam or obvious violations of our rules, my sensors were peaked by this post. Upon investigation this poster has made 4 posts over a period of time. They seem to be all personally written and generally on topic and don't break any of the rules that I can see. He didn't even attempt to link to his web site to promote his cause, which he does have by the way.

While it seems to me the poster is a bit driven by the cause of water contamination and I might not agree with some of his data or perhaps cringe a bit at the notion to purposely put water in a tank, is it really any worse than allowing the opinion stand that ethanol laced gas is OK or discussions on the use of MMO a non certified product just to name a few. I think not.

To be honest putting a known amount of water in the system and finding out if you can really get it out is an interesting idea, one I've thought of before but not acted on. Perhaps a bit more warning that of course if you do put water in your tank you've made your aircraft unairworthy until you have rid the tank of all the water. And to be honest just getting the known quantity of water added, out of the tank doesn't prove you don't have water in the tank. What if you already had water in the tank before the experiment? But then you wouldn't be any worse of than had you not done anything. I think the only thing wrong with the posts proposition is more caution might have been included rather than implied.

So while I reserve the right to change my opinion I see nothing wrong with the post at this point.

[canav8]

Doug,

As perhaps a more silent moderator looking mostly for spam or obvious violations of our rules, my sensors were peaked by this post. Upon investigation this poster has made 4 posts over a period of time. They seem to be all personally written and generally on topic and don't break any of the rules that I can see. He didn't even attempt to link to his web site to promote his cause, which he does have by the way.

While it seems to me the poster is a bit driven by the cause of water contamination and I might not agree with some of his data or perhaps cringe a bit at the notion to purposely put water in a tank, is it really any worse than allowing the opinion stand that ethanol laced gas is OK or discussions on the use of MMO a non certified product just to name a few. I think not.

To be honest putting a known amount of water in the system and finding out if you can really get it out is an interesting idea, one I've thought of before but not acted on. Perhaps a bit more warning that of course if you do put water in your tank you've made your aircraft unairworthy until you have rid the tank of all the water. And to be honest just getting the known quantity of water added, out of the tank doesn't prove you don't have water in the tank. What if you already had water in the tank before the experiment? But then you wouldn't be any worse of than had you not done anything. I think the only thing wrong with the posts proposition is more caution might have been included rather than implied.

So while I reserve the right to change my opinion I see nothing wrong with the post at this point.

Thanks Bruce, I dont disagree with you. If the guy has a business as suggested by another on this thread, Is this a nonmember for personal gain? is he a member? dont know how to check. I looked his website up, I see his passion and his vain and intent. I dont see why he responded the way he did to any previous poster except maybe the flogging George has recieved. The comments here support his theory minus food coloring. Sorry I could never make a suggestion to add water to fuel to anyone. All he would have to have said is that he has personal knowledge as he has done it in testing rather then suggesting to the public at large that they do it. Sorry I stand by my post. I also suggest you modify it here as there could be questions of liable with the 170 Association. Sorry its the world we live in. Doug

[sumpthiscom]

For those of you that have a problem with my post about not believing in the FAA certification when it comes to positive detection read the series of posts below from your own website. Notice the two posts by Voorhees who is with the FAA in Fresno. He is responsible for the SAIB CE=10-40R1 just released by the FAA. What prompted Harlow Voorhees to push this safety bulletin through is going to my website and then speaking to fellow FAA who can attest to the validity of my tests on real aircraft just like yours. Do not blindly believe in the preflight procedure to work...unless you have tested it for yourself.

What if by chance, your aircraft was sabotaged tonight when some one poured water into your fuel tank. In the morning before you and family takeoff do you want to positively detect and then eliminate any water in the fuel tank? Think about it for a minute. Do you really know if the preflight procedure really works. Okay, instead of testing the aircraft just ask yourself, how many times I have ever seen water in my sump cup on a Cessna fuel tank? If there is no problem, then why did Cessna and the FAA just put out the SAIB covering almost a quarter of a million aircraft?

Moderator's Note: OK, sumpthis, .. this particular msg-post was indeed a little "over-the-top" to the point of being unwwieldy, so I have edited it. (Please do not copy/paste "wholesale". If you wish to reference another discussion, simply post the url-link to it, or use the "quote" feature. Thanks.)

The discussion referenced and deleted from this msg is found at:
http://www.cessna170.org/forums/viewtop ... att+Taylor