Why can't the French dump fuel?

Don Hammer wrote

The FAA certification requirement for a fuel dump system is a takeoff
weight that is greater than 135% (I think) of the max landing weight.
They don't add the complexity and cost of a dump system unless it is
required for certification.

Don, the rules have changed since you and I flew those old Boeings. :-)

Section 25.1001: Fuel jettisoning system.
(a) A fuel jettisoning system must be installed on each airplane unless
it is shown that the airplane meets the climb requirements of §§25.119
and 25.121(d) at maximum takeoff weight, less the actual or computed
weight of fuel necessary for a 15-minute flight comprised of a takeoff,
go-around, and landing at the airport of departure with the airplane
configuration, speed, power, and thrust the same as that used in meeting
the applicable takeoff, approach, and landing climb performance
requirements of this part.

(b) If a fuel jettisoning system is required it must be capable of
jettisoning enough fuel within 15 minutes, starting with the weight
given in paragraph (a) of this section, to enable the airplane to meet
the climb requirements of §§25.119 and 25.121(d), assuming that the fuel
is jettisoned under the conditions, except weight, found least favorable
during the flight tests prescribed in paragraph (c) of this section.

(f) For turbine engine powered airplanes, means must be provided to
prevent jettisoning the fuel in the tanks used for takeoff and landing
below the level allowing climb from sea level to 10,000 feet and
thereafter allowing 45 minutes cruise at a speed for maximum range.
However, if there is an auxiliary control independent of the main
jettisoning control, the system may be designed to jettison the
remaining fuel by means of the auxiliary jettisoning control.


Bob Moore
ATP B-707 B-727
PanAm (retired)

"Robert M. Gary" wrote

Then why did Jet Blue fly around for 3 hours burning fuel before
landing back in LAX? It seems like if there is a real reason to want to
burn off fuel there would be a real way to get rid of the fuel. I can
dump fuel even in my Mooney.

The plane would be able to land at the weight that it was at, but that would
have been two negative things. One, it would have meant extra weight on the
already overstressed nose gear. Two, it would have meant a faster landing
speed, and faster speed that the nose would have been let down.
--
Jim in NC

"Robert M. Gary" wrote in message
ups.com...
As to why no provision for fuel dump, I suspect it is a cost driver:

Of course, everything is a cost driver. Whether or not to have carpet
is a cost decision. The real question is what the benefit side looked
like in their cost/benefit talks.

Why is dumping fuel needed? It can still climb at engine out with full
fuel, no need to dump there. If they can get up, and stay up, no need to
dump; they are safe.

What in this case? Were they in danger, flying around? No? Why dump,
then? Could they have landed immediately, in a case of immediate danger?
Absolutely. Still, you are asking. Why would they need to dump? They were
in no danger.
--
Jim in NC

"Robert M. Gary" wrote in message
oups.com...
In the case of the A320, or the 737, they can both land with a full load
of fuel.

Then why did Jet Blue fly around for 3 hours burning fuel before
landing back in LAX? It seems like if there is a real reason to want to
burn off fuel there would be a real way to get rid of the fuel. I can
dump fuel even in my Mooney.

The crew is paid by the hour?

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

If you put a fuel dump system in an airplane that doesn't need it, and it
does an inadvertent dump, who is liable for the subsequent water landing?

Seth
N8100R

"George Patterson" wrote in message
news:tbl_e.21584$Fh4.12558@trndny03...
Robert M. Gary wrote:

Does anyone have any insight into why the A320 isn't able to dump fuel.

Because it has no need to.

George Patterson
Give a person a fish and you feed him for a day; teach a person to
use the Internet and he won't bother you for weeks.

On 27-Sep-05 13:29, Robert M. Gary wrote:
Does anyone have any insight into why the A320 isn't able to dump fuel.
What factors would go into such a design compromise?
-Robert


It almost sounds as if you would be believing that Airbus is French. :-)

It is not. It is rather a product of an international consortium
(British, German, French, Italian) in which French does not have
the largest financial stake anyway...

The making of an Airbus is literally like the caricature about
the bureaucracy in the "United Europe." It is a maze of parts and
subcomponent tourism (Super Goopies and Belugas are being used.)
For example wings for the A320 are being made in Bremen, Germany.
Many wing components come from Britain, after which they ship the
wings to Toulouse, France in a Goopy. etc etc. You name it, every
Airbus model has its own subdivision of manufacturing sites and
different logistics.

Thomas

ThomasH wrote:

The making of an Airbus is literally like the caricature about
the bureaucracy in the "United Europe." It is a maze of parts and
subcomponent tourism (Super Goopies and Belugas are being used.)
For example wings for the A320 are being made in Bremen, Germany.
Many wing components come from Britain, after which they ship the
wings to Toulouse, France in a Goopy. etc etc.

and who makes the nose gear specifically? :-)

--Sylvain

Does anyone have any insight into why the A320 isn't able to dump fuel.
What factors would go into such a design compromise?

After listening to you in this thread, I'll bet you're one of those people
who thinks its a good idea for ATC to be able to take over flying an
airplane in an emergency.

("Morgans" wrote)
What in this case? Were they in danger, flying around? No? Why dump,
then? Could they have landed immediately, in a case of immediate danger?
Absolutely. Still, you are asking. Why would they need to dump? They
were
in no danger.


Then why not fly on to London, er...NY?

I wonder how far they would have gotten at half speed ...Iowa?


Montblack