bennett123
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Fuel Dumping

Fri Dec 10, 2004 2:55 am


I know that fuel is dumped in an emergency.

Someone I know in Stevenage reckons that aircraft flying into Luton routinely
arrive with excess fuel and simply dump it.

I find this hard to credit financially or environmentally.

Any info or comments welcome.
 
OPNLguy
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RE: Fuel Dumping

Fri Dec 10, 2004 3:00 am

>>>Someone I know in Stevenage reckons that aircraft flying into Luton routinely arrive with excess fuel and simply dump it.

Given that most aircraft don't even have a fuel dump system installed to begin with, I agree with your doubts...  Big grin

This subject has been covered extensively in the past; you might want to try a search to get more-detailed information from past threads...
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
air2gxs
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RE: Fuel Dumping

Fri Dec 10, 2004 3:49 am

Oh yeah, fuel is so cheap that carriers just load extra to dump.

Let's think a little here, people.
 
Rick767
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RE: Fuel Dumping

Fri Dec 10, 2004 4:57 am

Load of rubbish, and for the record fuel is not necessarily dumped even in an emergency, as OPNLguy stated most aircraft can't do it anyway and those which can (and have the option installed) will not waste time dumping fuel in a serious emergency, they are able to land up to MTOW in this case.
I used to love the smell of Jet-A in the morning...
 
vneplus5
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RE: Fuel Dumping

Fri Dec 10, 2004 7:47 am

I think that wingtip/flap vortecies are the main origin of this myth, and it's often told by people who don't know about aircraft in that much depth (I am not being a snob or anything, just recognising that some 'enthusiasts' don't have a lot of technical knowledge).

I've heard it many times before too...
 
LimaFoxTango
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RE: Fuel Dumping

Fri Dec 10, 2004 9:23 am

As Vneplus5 said, someone not too educated in aviation looking at the photos below would probably think that fuel is being dumped from the wings.


View Large View Medium
Click here for bigger photo!

Photo © Ryan Hemmings
View Large View Medium
Click here for bigger photo!

Photo © Micheil Keegan



It's just condensation!!
You are said to be a good pilot when your take-off's equal your landings.
 
SlamClick
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RE: Fuel Dumping

Fri Dec 10, 2004 10:01 am

I was deadheading into SFO one humid morning and we were pulling these vortices off the ends of both flaps. Some little kid behind me asked what it was and his dad told him the pilots were "dumping fuel so they could land."

Common misconception. Right up there with the people who slept through middle school science and think the plane is on fire when the air conditioning vents are blowing fog into the cabin.
Happiness is not seeing another trite Ste. Maarten photo all week long.
 
OPNLguy
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RE: Fuel Dumping

Fri Dec 10, 2004 10:11 am

>>>Common misconception. Right up there with the people who slept through middle school science and think the plane is on fire when the air conditioning vents are blowing fog into the cabin.

...or the folks who believe that aircraft routinely dump the content of the lavs while on short final, or another time during the flight...

[Edited 2004-12-10 02:13:02]
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
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HAWK21M
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RE: Fuel Dumping

Fri Dec 10, 2004 3:40 pm

With the cost of ATF as it exists,No Airline unless in an emergency will want to dump fuel unnecessary.Thats where Flight planning is so important.
Speaking about Vortices mistaken for Fuel Dumping in progress....Thats a very common problem.People dont realise that Some Aircraft dont have a Fuel Dump system installed in the First place.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
airbusA346
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RE: Fuel Dumping

Sat Dec 11, 2004 3:05 am

Does anybody actually have any good photos of fuel dumping.

Like the one of a CX A346, but i can not find itb in the database

airbusA346  Smile

[Edited 2004-12-10 19:45:43]
Tom Walker '086' First Officer of a A318/A319 for Air Lambert - Hours Flown: 17 hour 05 minutes (last updated 24/12/05).
 
SlamClick
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RE: Fuel Dumping

Sat Dec 11, 2004 3:16 am

AirbusA346 check the "chemtrails" sites. They just might have.  Smile
Happiness is not seeing another trite Ste. Maarten photo all week long.
 
airbusA346
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RE: Fuel Dumping

Sat Dec 11, 2004 3:50 am

Thanks SlamClick, but what is the URL for the website

airbusA346  Smile
Tom Walker '086' First Officer of a A318/A319 for Air Lambert - Hours Flown: 17 hour 05 minutes (last updated 24/12/05).
 
SlamClick
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RE: Fuel Dumping

Sat Dec 11, 2004 4:21 am

Don't know. Don't normally bookmark BS, but try googling it. There are many of them.
Happiness is not seeing another trite Ste. Maarten photo all week long.
 
Venus6971
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RE: Fuel Dumping

Thu Dec 16, 2004 1:40 pm

Any aircraft that weighs more at takeoff than it's permissible landing weight by FAA FAR must have a fuel dump system. The fuel you see sometime coming from the vents on the wingtips are coming from the surge tanks that deal with fuel expansion during temperature change or defective automatic fuel tank shut offs. On Boeings I have worked on if fuel was found in a surge it was to be drained completely before flight. If it seems a endless supply of fuel is in the surge tank you have a plumbing problem some where and need to have it repaired.
I would help you but it is not in the contract
 
OPNLguy
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RE: Fuel Dumping

Thu Dec 16, 2004 7:21 pm

>>>Any aircraft that weighs more at takeoff than it's permissible landing weight by FAA FAR must have a fuel dump system.

Can I ask where you came up with this, or cite the FAR? Our 737-700s can (and often do) takeoff at the max 153,000 lbs, with a max landing weight of 128,000 lbs, and I can assure you that they don't have a fuel dump system involved.

The FAR -used- to say that if an aircraft's max takeoff weight exceeded it's max landing weight by more than 105%, then you had to have a fuel dump system. That explains why the 727 had one, and the then-new 737-100 and DC-9-10 didn't. That 105% figure was later dropped (as 737/DC-9 families were stretched starting in the mid-late 1960s, IIRC.

ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
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Starlionblue
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RE: Fuel Dumping

Thu Dec 16, 2004 11:12 pm

I was deadheading into SFO one humid morning and we were pulling these vortices off the ends of both flaps. Some little kid behind me asked what it was and his dad told him the pilots were "dumping fuel so they could land."


Did you resist the temptation to correct him?  Big grin Hearing that would have killed me.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
OldAeroGuy
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RE: Fuel Dumping

Fri Dec 17, 2004 12:21 am

It's not true that a fuel jettison system is required if takeoff weight exceeds max. landing weight. FAR 25.1001 says a jettison system is required if the climb requirements of 25.119 (Landing Climb) and 25.121(d) (Approach Climb) can be met assuming a 15 min. flight.

Since most twins can meet these requirements, many twins do not have fuel jettison systems. Long range twins do tend to have them due in part to practical operational matters such is the desirability of reducing landing weight quickly if you need to land soon after takeoff.

Quads have difficulty meeting 25.119 near MTOW, so most Quads have jettison systems.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
 
SlamClick
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RE: Fuel Dumping

Fri Dec 17, 2004 12:28 am

Big misconception there Venus6971.

ALL airliners take off at weights far greater than their allowable landing weights. Only time it is not true is on a very short flight with extremely light loads.

Airliners are certificated under FAR Part 25. If you have a copy, check out 25.1001 which will refer you to 25.119 and 25.121(d)

Those are the rules. The upshot of the whole thing is that very few two-engine jetliners have fuel dumping. The A-330 has it as an option and there is a thread here about that. Fuel dumping capability is more common on three and four-engine planes.

Welcome to Tech/Ops
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Venus6971
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RE: Fuel Dumping

Fri Dec 17, 2004 3:40 am

To oldaeroguy, OPNLguy and SlamClick I stand corrected, my experience is with 4 to 8 engine Boeings never working anything smaller than a 707. My AMT FAR book does not have FAR 25 in it but I will take your word for it. Darn it, I learned something today.
I would help you but it is not in the contract
 
OPNLguy
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RE: Fuel Dumping

Fri Dec 17, 2004 5:22 am

Not a prob...

Back in the 1960s when Boeing was growing the 737-100 into the 737-200, and Douglas was growing the DC-9-10 into its various versions (all with increasingly powerful variants of the JT8D), the spreads between max structural takeoff weights and max structural landings grew to the point where the 105% rule would be busted.

Naturally, they just changed the rule...  Big grin
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
SlamClick
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RE: Fuel Dumping

Fri Dec 17, 2004 6:35 am

Rather like the problem of growing the 747 and having difficulty placing emergency exits. Piece of cake, we'll just make a couple of them wider and, as if by magic, more people could exit in the same time. Voila! a new class of emergency exit.

If your pants are on fire, perhaps you can exit faster.
Happiness is not seeing another trite Ste. Maarten photo all week long.
 
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HAWK21M
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RE: Fuel Dumping

Fri Dec 17, 2004 4:43 pm

Would carrying out Overweight Landing be a possibility on such Aircrafts [B737],if it exceeds the 105% limit.
Understandable that the situation would decide it.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
OldAeroGuy
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RE: Fuel Dumping

Sat Dec 18, 2004 2:53 am

Landings at weights higher than 1.05*MLW are rather common for all air transport models, even those with fuel jettison systems, under emergency situations.

Most are returned to service after a structural (usually visual) inspection.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
 
SlamClick
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RE: Fuel Dumping

Sat Dec 18, 2004 4:16 am

The "structural" maximum landing gross weight of a typical airliner may be exceeded all the time if permitted by the nation's government. Nations other than the USA may operate a 737 at higher landing weights. They may do this in part by requiring more frequent inspection of, and shorter replacement cycle for landing gear components. Peformance-limited safety considerations will also apply.

The weight limitations on airliners are normally the lowest of a long list of calculated weights. Exemptions can be granted, even in airline operations if "an equivalent level of safety" can be demonstrated.
Happiness is not seeing another trite Ste. Maarten photo all week long.
 
OPNLguy
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RE: Fuel Dumping

Sat Dec 18, 2004 6:20 am

FAA/Company requirements change as well...

We used to have a 1 per cent buffer on the 103,000 lb. MLW of our 737-200s, meaning you could land (at most) 1,030 lbs over that 103,000 lbs, but that disappeared, and 103,000 is a hard limit, emergencies excepted, of course...
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
JAM747
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RE: Fuel Dumping

Sat Sep 24, 2005 11:18 pm

Quoting OldAeroGuy (Reply 16):
It's not true that a fuel jettison system is required if takeoff weight exceeds max. landing weight. FAR 25.1001 says a jettison system is required if the climb requirements of 25.119 (Landing Climb) and 25.121(d) (Approach Climb) can be met assuming a 15 min. flight.

What is landing climb and approach climb?
 
mrocktor
Posts: 1388
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RE: Fuel Dumping

Sun Sep 25, 2005 12:19 am

Quoting JAM747 (Reply 25):
What is landing climb and approach climb?

Performance speak for a go-around with full landing flaps and all engines operative and at approach flap setting and one engine inoperative, respectively.

mrocktor
 
OPNLguy
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RE: Fuel Dumping

Sun Sep 25, 2005 5:47 am

I see someone has dug up a REALLY old thread...  Wink

More recently, someone just mentioned this link, which lists various Boeing and McD models and whether they have fuel dump systems. I don't have a similar one for Airbus, but there's probably one out there, somewhere...

http://www.boeing.com/assocproducts/aircompat/faqs/fueldump.pdf
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