Stupid question: water in fuel

[Scott Moore]

Yes, this is a stupid question, and somewhat off topic for IFR.

But I get better answers here than elsewhere.

Question:

Why is it that devices to separate water from fuel are quite
common cars (my F-350 truck has one), but such a device, which
could save lives in an airplane, is not offered for airplanes ?
Even as a retrofit ?

[Jose]

> Why is it that devices to separate water from fuel are quite
> common cars (my F-350 truck has one), but such a device, which
> could save lives in an airplane, is not offered for airplanes ?
> Even as a retrofit ?

To this and other similar questions, the general answer is weight, cost,
and reliability.

Weight - all the gadgets and gizmos weigh something, and this gets
removed from your useful load. If all the safety features people wanted
were included, the airplane would never fly. I guess that would be
pretty safe. :) Cars don't have to fly, so they can be as heavy as it
takes - a few pounds here and there don't really make a difference. But
in the air they do.

Cost - mainly certification cost, since any newfangled gizmo has to go
through the FAA wringer to ensure that there are no unexpected
surprises. Whether this is actually effective or not is subject to
debate (witness the homebuilt arena) but it is necessary.

Reliability - it's another gizmo to go TU, with unpleasant side effects.
Cars can pull over when they break. Planes can't. In the case of
this particular item (fuel/water separators), it would still not relieve
the pilot of the necessity to check for water in the gas, since we all
know that things that "shouldn't" happen, do anyway.

Jose
--
Money: what you need when you run out of brains.
for Email, make the obvious change in the address.

[paul kgyy]

You can use a GATS jar for checking your fuel. It has a screen that
removes water when you pour back into the tank.

My guess is that water separator are rather new, and the volume doesn't
justify anyone producing a certified unit for aircraft?

[RK Henry]

On Fri, 14 Oct 2005 13:28:51 -0700, Scott Moore
> wrote:

>Yes, this is a stupid question, and somewhat off topic for IFR.
>
>But I get better answers here than elsewhere.
>
>Question:
>
>Why is it that devices to separate water from fuel are quite
>common cars (my F-350 truck has one), but such a device, which
>could save lives in an airplane, is not offered for airplanes ?
>Even as a retrofit ?

I wasn't aware that there are any airplanes without water separators.

My Cherokee has quick drains on each tank and each fuel manifold to
check and drain any accumulated water. Checking for water is a
preflight item. Before the fuel enters the carburetor it goes through
a gascolator to separate dirt and water, which can also be tested with
a quick drain. And of course the last chance is the carburetor bowl
itself, which no one ever seems to check at annual, no matter how much
I insist, but there's a drain plug nevertheless.

Most other airplanes I've looked at seem similarly equipped. I believe
the thesis for this topic is flawed.

I never bother checking for water in the fuel on my car. There's no
provision for checking the car for water anyway without disassembling
stuff.

RK Henry

[Matt Whiting]

paul kgyy wrote:
> You can use a GATS jar for checking your fuel. It has a screen that
> removes water when you pour back into the tank.
>
> My guess is that water separator are rather new, and the volume doesn't
> justify anyone producing a certified unit for aircraft?
>

Not new at all. They've been used on diesel engines for at least 25
years. I had a water trapping filter on my fuel pump tank when I owned
a 182 and ran auto gas in it. I definitely didn't want to be adding
water to the tanks beyond what they might collect naturally, although, I
never found water in the fuel in 6 years of flying. However, I was
always expecting it given that the 67 had fuel bladders which were known
for having wrinkles that could trap large amounts of water and let it
loose at inopportune times. My partner and I always did a vigorous wing
rock before draining the sumps, however, we never found anything. We
did have the flush fuel cap upgrade which was supposed to greatly reduce
the change of water ingestion.

I'm not sure why they aren't used on airplanes, other than they add
cost, weight, and another item to get certified. Also, although I never
saw the problem on the diesels I used to operate, it may be that the
filter has a nasty failure mode if it collects enough water. For
example, maybe they clog completely. I don't know, just wondering if
there isn't some downside like that which obviates the benefit for
airplane use.

Matt

[Newps]

Scott Moore wrote:
> Yes, this is a stupid question, and somewhat off topic for IFR.
>
> But I get better answers here than elsewhere.
>
> Question:
>
> Why is it that devices to separate water from fuel are quite
> common cars (my F-350 truck has one), but such a device, which
> could save lives in an airplane, is not offered for airplanes ?
> Even as a retrofit ?


Your F350 is a diesel. Gas engines in cars and trucks don't have water
seperators. Cars and trucks don't have a way to test the fuel like
aircraft.

[Clay]

My 1983 Ford F-250 diesel truck has a water seperator.

[Clay]

My 1983 Ford F-250 diesel truck has a water seperator.

[Mark Hansen]

On 10/14/2005 6:40 PM, Newps wrote:

>
> Scott Moore wrote:
>> Yes, this is a stupid question, and somewhat off topic for IFR.
>>
>> But I get better answers here than elsewhere.
>>
>> Question:
>>
>> Why is it that devices to separate water from fuel are quite
>> common cars (my F-350 truck has one), but such a device, which
>> could save lives in an airplane, is not offered for airplanes ?
>> Even as a retrofit ?
>
>
> Your F350 is a diesel. Gas engines in cars and trucks don't have water
> seperators. Cars and trucks don't have a way to test the fuel like
> aircraft.
>

My 1993 Ford Clubwagon XLT 350 (E350) has a water separator. It's
a 5.8L V8 Gas engine.

--
Mark Hansen, PP-ASEL, Instrument Airplane
Sacramento, CA

[Maule Driver]

I've never encountered water in a/c fuel either. However, I did in an
auto once and I wonder how a water separator would have handled it.

I filled up an almost empty '95 Caravan with fuel that had a great deal
of water in it. The van died before turning out of the station. After
damning my luck at a breakdown on a raining winter evening 100s of miles
from home, we looked for a meal and a hotel. Then I noticed that there
were several people milling about the interstate exit, on foot! No one
walks anywhere in January at an interstate exit. Further observation
found that a number of cars were parked irregularly all over the place.

I put 2 and 2 together and immediately went in the station and suggested
that water was in the fuel and that the pumps needed to be closed. The
confused teenager handling the desk didn't know what to do so insisted
she call the owners and I went out and hung signs closing the station.

Anyway, I concluded that the problem resulted from semi-melted ice all
over the parking lot. They were damming up the cold rain and the water
ran into the tanks during a fill or otherwise overcame whatever
protection is normally in place. Ever seen 3 guys chain smoke while
draining fuel tanks into 55 gallon drums.

How would water sparators work with an 'enormous' quantity of water in
the fuel?

Jose wrote:
>> Why is it that devices to separate water from fuel are quite
>> common cars (my F-350 truck has one), but such a device, which
>> could save lives in an airplane, is not offered for airplanes ?
>> Even as a retrofit ?
>
>
> To this and other similar questions, the general answer is weight, cost,
> and reliability.
>
> Weight - all the gadgets and gizmos weigh something, and this gets
> removed from your useful load. If all the safety features people wanted
> were included, the airplane would never fly. I guess that would be
> pretty safe. :) Cars don't have to fly, so they can be as heavy as it
> takes - a few pounds here and there don't really make a difference. But
> in the air they do.
>
> Cost - mainly certification cost, since any newfangled gizmo has to go
> through the FAA wringer to ensure that there are no unexpected
> surprises. Whether this is actually effective or not is subject to
> debate (witness the homebuilt arena) but it is necessary.
>
> Reliability - it's another gizmo to go TU, with unpleasant side effects.
> Cars can pull over when they break. Planes can't. In the case of
> this particular item (fuel/water separators), it would still not relieve
> the pilot of the necessity to check for water in the gas, since we all
> know that things that "shouldn't" happen, do anyway.
>
> Jose

[john smith]

> How would water sparators work with an 'enormous' quantity of water in
> the fuel?

Try adding alcohol to absorb the water.

[Robert Chambers]

john smith wrote:
>>How would water sparators work with an 'enormous' quantity of water in
>>the fuel?
>
>
> Try adding alcohol to absorb the water.

I wouldn't fly with you.

[john smith]

> >>How would water sparators work with an 'enormous' quantity of water in
> >>the fuel?

> > Try adding alcohol to absorb the water.

> I wouldn't fly with you.

Drain it or ground run it.

[Robert Chambers]

john smith wrote:
>>>>How would water sparators work with an 'enormous' quantity of water in
>>>>the fuel?
>
>
>>>Try adding alcohol to absorb the water.
>
>
>>I wouldn't fly with you.
>
>
> Drain it or ground run it.

That would be the prudent way of doing it. What works for water-in-fuel
in a car is fine for cars.. the engine stops, you roll to the side of
the road and call the tow truck. I don't know how the alcohol would
affect the seals and whatnot in the tanks/lines/pumps/carb so I'd be
hesitant to put anything not specifically approved for use in the plane
into the tanks.

[Stubby]

Robert Chambers wrote:
>
>
> john smith wrote:
>
>>>>> How would water sparators work with an 'enormous' quantity of water
>>>>> in the fuel?
>>
>>
>>
>>>> Try adding alcohol to absorb the water.
>>
>>
>>
>>> I wouldn't fly with you.
>>
>>
>>
>> Drain it or ground run it.
>
>
> That would be the prudent way of doing it. What works for water-in-fuel
> in a car is fine for cars.. the engine stops, you roll to the side of
> the road and call the tow truck. I don't know how the alcohol would
> affect the seals and whatnot in the tanks/lines/pumps/carb so I'd be
> hesitant to put anything not specifically approved for use in the plane
> into the tanks.

Right. The FAA limits the percent of alcohol in gasohol which can be
used in airplanes. I don't believe any of the auto products are low
enough. Draining it is the only way to go and I remember one cold day
when I had to drain out about a pint of water (?) from one tank. Even
taxiing around isn't good -- how long do you go before you conclude
there's no water in the tanks? Do you really want to walk back in the
cold from your plane?

[John R. Copeland]

"Stubby" > wrote in message ...
>
> .... Draining it is the only way to go and I remember one cold day
> when I had to drain out about a pint of water (?) from one tank. Even
> taxiing around isn't good -- how long do you go before you conclude
> there's no water in the tanks? Do you really want to walk back in the
> cold from your plane?

What I *really* hate is when the quick-drain won't budge,
because there's water frozen above it in the sump.

[[email protected]]

: Right. The FAA limits the percent of alcohol in gasohol which can be
: used in airplanes.

Yeah.... 0.0%

I don't believe any of the auto products are low
: enough.

Alcohol can eat rubber seals and such in the Lycontosaurus engines in planes.
Also, it can attack the rubber in bladders, or even the aluminum in wet-wing or
structural in-wing tanks. The alcohol avgas like EG85 (IIRC) requires new seals
all around, and has additives to prevent corrosion.

-Cory

--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

[Stubby]

John R. Copeland wrote:
> "Stubby" > wrote in message ...
>
>>.... Draining it is the only way to go and I remember one cold day
>>when I had to drain out about a pint of water (?) from one tank. Even
>>taxiing around isn't good -- how long do you go before you conclude
>>there's no water in the tanks? Do you really want to walk back in the
>>cold from your plane?
>
>
> What I *really* hate is when the quick-drain won't budge,
> because there's water frozen above it in the sump.
>

It's worse when a little piece of dirt or ice won't let the quick drain
to close fully.

[[email protected]]

: It's worse when a little piece of dirt or ice won't let the quick drain
: to close fully.

I've *still* got some tiny plastic flecks in my fuel tank from the previous
owner's peeling of the "100LL" sticker off the fill hole. Every once in awhile, I'll
get a bit in the sump and it'll weep. I've flushed it a half dozen times, but never
gotten it all out.

Oh well, I've never seen any in the gascolator, and unless there were a
horrendous amount, that'll catch it all just fine.

Frozen water NOT in a clump is worse than in a clump at the bottom. That
*can* clog your gascolator and ruin your day. At least if it's clumped you know it's
there. Also, chances are good that it's colder at altitude so it won't thaw an clog
up the works.

-Cory

--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************