Why can't the French dump fuel?

I'm sure the airlines, EPA, and everyone else would rather the fuel be
burnt as normal rather than dumped into the air and sea.


I heard that the environmental impact of dumping fuel is not as bad as
it might seem. As the volatile fuel is sprayed into the air it tends to
oxidize and the result is similar to burning it in the engine. I am not
too sure of this when considering the complex chemistry of turbofan
combustion in flight. From the combustion chamber, out the nozzle and
through the downwash behind the plane the combustion reaction
continues. Dumping fuel sprays it into turbulent air without the
initial combustion and expansion so it is likely much different. I was
a payload integration engineer in support of the NASA DC-8 (which had
the ability to dump of course) on the SUCCESS mission to fly planes
behind and around each other to sample the exhaust products and
characterize the chemistry. The pilots had to be careful not to get
caught in the tip vortex.

http://cloud1.arc.nasa.gov/success/d...60418.hil.html

In the above photo our engineering group installed the canoe sized
instrument fairing on the side of the plane just forward of the aft
service door. We also installed the pod under the forward fuselage. As
the elevator is tab powered and the fairing is in front of it, we were
crossing our fingers during the taxi test and flight test.

http://uap-www.nrl.navy.mil/dynamics...s2May1996.html

http://raf.atd.ucar.edu/~dcrogers/GRL/grl.html

http://cloud1.arc.nasa.gov/success/

James

"jbaloun" wrote:

I'm sure the airlines, EPA, and everyone else would rather the fuel be
burnt as normal rather than dumped into the air and sea.

I heard that the environmental impact of dumping fuel is not as bad as
it might seem. As the volatile fuel is sprayed into the air it tends
to oxidize and the result is similar to burning it in the engine.

Then why are gas pumps in many places fitted with systems to capture the
vapors from fueling? Why is barbeque lighter fluid banned in many
jurisdictions? Why is there a push to ban oil-based paint and thinners?

The reality is that unburned hydrocarbons are a major source of air
pollution. The occasional fuel dump will not have a huge effect on the
environment, but it is still better if the fuel is burned in a well-
maintained engine.

The reality is that unburned hydrocarbons are a major source of air
pollution. The occasional fuel dump will not have a huge effect on the
environment, but it is still better if the fuel is burned in a well-
maintained engine.

I did not say that it would be better to dump fuel rather than burn it
in the engine. Burning in the very efficient modern turbofan is a
better way to dispose of the high energy fuel, maybe the best way (just
from a chemestry point of view let alone the value of flying a plane).
I did not say there would not be an environmental impact, just that the
fuel dumped in flight is likely oxidized and would not stay in the air
or land on the ground in the form of raw fuel. I understand that fuel
dumping is very rare compared to the number of flights per year. It is
so rare that the any regulatory agencies may not be concerned about the
yearly amount of fuel dumped as compared to the overall amound of fuel
burned. The cumulative impact of automobile (gasoline) refueling vapors
being released is much greater than that due to (kerosene) fuel dumped
in flight. In addition, dumping fuel is almost always done to respond
to an urgent situation on an aircraft where the environmental cost is
outweighed by flight safety.

Aircraft engine manufacturers have made amazing strides in improved
efficiency. And still researchers are considering how to continue to
improve engines while reducing emissions. It would have been
interesting if the SUCCESS mission took measurements of fuel being
dumped in flight. If I had thought of it I would have suggested it
then. Oh well.

James

"jbaloun" wrote

I did not say there would not be an environmental impact, just that the
fuel dumped in flight is likely oxidized and would not stay in the air
or land on the ground in the form of raw fuel.

I think you are making a mistake, in you use of "oxidized" in this case.

"Oxidized" is combining it with oxygen chemically, as in "burning". In this
case, there is no combining chemically, but only vaporization, as in
evaporating. In both cases, no fuel reaches the ground.
--
Jim in NC

Why is barbeque lighter fluid banned in many jurisdictions?

You're kidding, right?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

Jay Honeck wrote:
Why is barbeque lighter fluid banned in many jurisdictions?

You're kidding, right?

California. Aspen also had a shot at it, but I think the law failed to pass.

George Patterson
Drink is the curse of the land. It makes you quarrel with your neighbor.
It makes you shoot at your landlord. And it makes you miss him.

Why is barbeque lighter fluid banned in many jurisdictions?

You're kidding, right?

California. Aspen also had a shot at it, but I think the law failed to
pass.

Wow. Now I've heard everything.

Of course, today I learned that people in the Seattle, WA area cannot smoke
cigarettes *outside* in public areas -- which seem to be defined as pretty
much anywhere in the city.

As much as I hate smoking, that is amazing.

Why is it that so many areas of the country that pride themselves as being
"liberal" and "free" are neither?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

"Jay Honeck" wrote:

Why is barbeque lighter fluid banned in many jurisdictions?

You're kidding, right?

Partially.

As California has tightened up its air pollution regulations for
automobiles, it is approaching the point where cars are no longer the
major source of air pollution in the Los Angeles area. Other types of
pollution are starting to come into the crosshairs of the pollution
control districts, including such things as barbeque lighter fluid,
paint thinners, dry cleaning fluids, contact cement, and exhaust
emissions from small engines used for lawn mowers, leaf blowers, and
weed eaters.

Of particular concern are what they call Volatile Organic Compounds
(VOC) They estimate that something like 400 tons of VOCs are released
into the air in the San Francisco Bay area each day, down from 600 tons
15 years ago. (Compare that to the amount of fuel in a fuel dump)

As such, there have been a number of proposals to ban things that
contain such chemicals outright. In fact, commercial production of
chemicals like carbon tetrachloride, trichlorethane, and certain types
of Freon have ceased by international agreement.

Pressure on the manufacturers has been used instead, so oil-based paints
no longer use much xylene or toluene, water-based paints like latex are
being pushed more and more, contact cement no longer uses methyl ethyl
ketones, ink-jet cartridges use thinners derived from soy, and so on. It
extends to barbeque ligher fluids as well. The lighter fluid you get
today is not what you got 15 years ago. Most people haven't noticed the
difference, but teh fluid no longer contains the traditional chemicals
like naptha. Instead, low VOC solvents are used.

Getting back to fuel dumping. As the quantities of VOCs from other
sources drop to lower levels over time, don't be surprised to see the
air pollution regulators focus in on such things as fuel dumping. It
will become more and more of an issue if it grows in proportion to other
types of VOC emissions.

"James Robinson" wrote

In fact, commercial production of
chemicals like carbon tetrachloride, trichlorethane, and certain types
of Freon have ceased by international agreement.

Freon is not a VOC, is it?
--
Jim in NC

"Morgans" wrote:


"James Robinson" wrote

In fact, commercial production of
chemicals like carbon tetrachloride, trichlorethane, and certain types
of Freon have ceased by international agreement.

Freon is not a VOC, is it?

Certain types of Freon are. Those types are no longer used in new air
conditioning or refrigeration systems. Older systems will still have them,
but you can't replace lost fluid if you have a leak.