CPH-R
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What Happens To Remaining Fuel After A Flight?

Sun Nov 08, 2009 4:45 pm

Perhaps a somewhat stupid question, but it just occured to me that I've found out what happens to the remaining fuel after a flight.

I suppose it's mostly an issue for long-haul flights, where there may be a difference between the fuel quality at origin and destination (BA38 comes to mind, IIRC there was a theory that the fuel ex-PEK had been contaminated), and where there may be a fairly substantial amount of fuel left in the tanks.

Will the fuel remain in the tank and used for the next flight? Or is the plane de-fuelled (if that's even possible), or does it depend on how long the plane is on the ground? Ie. something like the day-stoppers at LHR, FRA and JNB, where the plane usually sits on the ground for 10+ hours.
 
zanl188
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RE: What Happens To Remaining Fuel After A Flight?

Sun Nov 08, 2009 5:10 pm



Quoting CPH-R (Thread starter):
Will the fuel remain in the tank and used for the next flight?

Yes this is what happens to the remaining fuel.

Quoting CPH-R (Thread starter):
Or is the plane de-fuelled (if that's even possible),

Yes planes can be defueled. Usually only happens for maintenance reasons or if too much fuel is put aboard.
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tb727
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RE: What Happens To Remaining Fuel After A Flight?

Sun Nov 08, 2009 6:55 pm

And sometimes, at least in our situation, you "tanker" fuel to land with enough fuel to buy little or no fuel at destination and fly on to the next airport. We typically tanker fuel if it's cheap or company gas at one of our bases.

An example the other day was I flew LRD-GRR and we only required about 31,000 pounds of fuel but on our flight release we were authorized to carry 38,000 to make a short leg back to base 120 miles away and not buy any fuel in GRR and still land in Detroit with the required minimum amount of fuel.
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Fabo
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RE: What Happens To Remaining Fuel After A Flight?

Sun Nov 08, 2009 11:18 pm



Quoting Tb727 (Reply 2):
...

Typical in Kosice. With quite much pricier fuel than either Bratislava, Vienna or Prague, there is practically always a note "FUEL NOT REQ" with dispatch message from departing field.
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tb727
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RE: What Happens To Remaining Fuel After A Flight?

Sun Nov 08, 2009 11:32 pm

Yeah, the FBO fueler guys are usually relieved but the owners and managers, not so much!
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CanadianNorth
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RE: What Happens To Remaining Fuel After A Flight?

Mon Nov 09, 2009 2:18 am

Generally it's just left in the tank and added to for the next flight. De-fueling can easily be done, but that feature is usually only used for the occasional maintenance purpose (accessing the inside of the tank for structural inspections, troubleshooting, etc). Can also be used if too much fuel has been pumped in, but I've never seen that happen myself.


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KELPkid
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RE: What Happens To Remaining Fuel After A Flight?

Mon Nov 09, 2009 3:53 am



Quoting Tb727 (Reply 2):
An example the other day was I flew LRD-GRR and we only required about 31,000 pounds of fuel but on our flight release we were authorized to carry 38,000 to make a short leg back to base 120 miles away and not buy any fuel in GRR and still land in Detroit with the required minimum amount of fuel.

Flying seatbelts around?  Wink (I'm guessing based on the origin and destination).
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HAWK21M
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RE: What Happens To Remaining Fuel After A Flight?

Mon Nov 09, 2009 8:51 am

Normally the Fuel remaining is left in the tanks & topped up for the next sector unless Maintenance or sector operated requires defuelling.

With costs playing a big role in aviation these days.Tankering policies are reinforced strictly as it does contribute to a lot in cost savings over time.Some places have various ATF costs due to local taxes of that area & it can help in savings if tankered well.

regds
MEL.
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tb727
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RE: What Happens To Remaining Fuel After A Flight?

Mon Nov 09, 2009 2:35 pm



Quoting KELPkid (Reply 6):
Flying seatbelts around?

No, believe it or not it was door trim! Only 2900#'s on a 727? Heck yeah! I hate seatbelts, that stuff is heavy! Although I guess it doesn't matter because I don't have to load it anymore.

Quoting HAWK21M (Reply 7):
With costs playing a big role in aviation these days.Tankering policies are reinforced strictly as it does contribute to a lot in cost savings over time.

We have a program that puts our savings if we tanker on our flight release vs buying fuel just as we need it. It was quite the chunk of change on the one leg.
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EMBQA
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RE: What Happens To Remaining Fuel After A Flight?

Mon Nov 09, 2009 2:49 pm

The only thing you can't do with fuel is cross use it. If a plane is de-fueled, it must go back on that plane.. or at least onto the same airline.
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KELPkid
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RE: What Happens To Remaining Fuel After A Flight?

Mon Nov 09, 2009 8:43 pm



Quoting EMBQA (Reply 9):

The only thing you can't do with fuel is cross use it. If a plane is de-fueled, it must go back on that plane.. or at least onto the same airline.

Hehehe, recalling my lineboy days....many times when the maintenance guys had to de-fuel a bird, we'd get offered a free jerry can or two of 100LL...used that to run the lawn mower at the apartment complex where I lived  Wink
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HAWK21M
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RE: What Happens To Remaining Fuel After A Flight?

Tue Nov 10, 2009 9:55 am



Quoting EMBQA (Reply 9):
The only thing you can't do with fuel is cross use it. If a plane is de-fueled, it must go back on that plane.. or at least onto the same airline.

Thats correct.Unless it goes thru the oil refuellers QC sequence process.
regds
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Faro
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RE: What Happens To Remaining Fuel After A Flight?

Tue Nov 10, 2009 10:53 am

What about the moisture accumulated in that leftover fuel? How do you get rid of it?

Faro
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fr8mech
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RE: What Happens To Remaining Fuel After A Flight?

Tue Nov 10, 2009 8:21 pm



Quoting Faro (Reply 12):
What about the moisture accumulated in that leftover fuel? How do you get rid of it?

At some specified interval, usually daily, but may be longer, maintenance will sump the tanks. The sump is plumbed to the lowest point in a fuel tank. Since water is heavier than fuel, it will eventually make its way to the sump.
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tdscanuck
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RE: What Happens To Remaining Fuel After A Flight?

Wed Nov 11, 2009 12:37 am



Quoting Faro (Reply 12):
What about the moisture accumulated in that leftover fuel? How do you get rid of it?

Besides sumping, several aircraft also have water scavenge systems that will burn most of the water through the engines. The little bit that the scavenge system doesn't catch should come out with regular sumping.

Tom.
 
KELPkid
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RE: What Happens To Remaining Fuel After A Flight?

Wed Nov 11, 2009 5:06 am



Quoting Tdscanuck (Reply 14):
Besides sumping, several aircraft also have water scavenge systems that will burn most of the water through the engines.

Not to be pedantic, but,

(okay, let's be completely pedantic here Big grin )

Substances (like water) which are already oxidized don't tend to do much burning...they might come out the tailpipe as steam, though...which is okay (to a degree) in jets. It is far easier (and much lest costly) to deal with jet fuel's water-absorbing tendencies than it is to treat small amounts of water as unacceptable contamination.

Jets which have cold soak/ice crystal fuel system problems might require fuel additives, though, to keep ice crystals from plugging up the fuel system.

The fuel is also sumped and sloshed at many points throughout the distribution cycle, before it goes from truck to plane, to get as much water as possible out.
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Faro
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RE: What Happens To Remaining Fuel After A Flight?

Wed Nov 11, 2009 9:41 am



Quoting Tdscanuck (Reply 14):
Besides sumping, several aircraft also have water scavenge systems that will burn most of the water through the engines. The little bit that the scavenge system doesn't catch should come out with regular sumping.

What about non-water contamination? Is it relevant in the first place or only specific to non-mainstream suppliers?

Faro
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fr8mech
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RE: What Happens To Remaining Fuel After A Flight?

Wed Nov 11, 2009 2:15 pm



Quoting Faro (Reply 16):
What about non-water contamination? Is it relevant in the first place or only specific to non-mainstream suppliers?

Aviation fuel is filtered everywhere in the pipeline. Everywhere. But, the last real filter is usually at the engine fuel pump. This filter (as I recall, 10 or 15 microns. That's an old, fuzzy number) is the last chance to stop anything big.
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HAWK21M
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RE: What Happens To Remaining Fuel After A Flight?

Wed Nov 11, 2009 5:19 pm



Quoting Faro (Reply 12):
What about the moisture accumulated in that leftover fuel? How do you get rid of it?

Regular draing of fuel prior to refuelling is carried out after letting the Fuel & water seperate by not being disturbed for a while.
regds
MEL.
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tdscanuck
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RE: What Happens To Remaining Fuel After A Flight?

Thu Nov 12, 2009 6:25 am



Quoting Faro (Reply 16):
What about non-water contamination?

Liquid non-water contamination will either float (never get burned), sink (get scavenged and/or sumped with the water), or be neutral and just go through the engine with the fuel.

Solid contamination can get caught by the inlet screens (only for big pieces), the fuel filters (all the way down to some microns), or the screen after the HP fuel pump (mostly to catch bits of a dying fuel pump). The fuel filters are your major filtering point.

There are several filters in the delivery system so, by the time it's on the plane, all you should have is FOD from the plane itself, and dust inhaled by the tank vents.

Quoting Faro (Reply 16):
Is it relevant in the first place or only specific to non-mainstream suppliers?

Well, if it's got any solids/water/non-hydrocarbon contamination of any importance, it's doesn't meet the specification (all the jet fuel specs are fairly similar in this regard). In theory, it could show up from any supplier but it would take an aweful lot of serial QA & equipment failures.

Tom.
 
MD11Engineer
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RE: What Happens To Remaining Fuel After A Flight?

Thu Nov 12, 2009 10:19 pm



Quoting KELPkid (Reply 10):
Hehehe, recalling my lineboy days....many times when the maintenance guys had to de-fuel a bird, we'd get offered a free jerry can or two of 100LL...used that to run the lawn mower at the apartment complex where I lived Wink

Older diesel cars and trucks run quite well on JET A1  Wink... but don´t tell it to the tax man!

Jan
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KELPkid
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RE: What Happens To Remaining Fuel After A Flight?

Thu Nov 12, 2009 11:12 pm



Quoting MD11Engineer (Reply 20):


Older diesel cars and trucks run quite well on JET A1 ... but don´t tell it to the tax man!

Jan

Yep, our Jet-A truck used to run on...Jet-A Big grin (you did have to mix a slight amount of diesel in there, apparently the kerosene has insuffecient lubricating properties for a diesel engine's fuel pump to be happy)  Wink
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