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falstaff
Topic Author
Posts: 5744
Joined: Sun Jun 25, 2006 6:17 am

### How Much Does Jet Fuel Weigh?

Last Monday, while I was waiting at the gate, I was was talking with a NW DC-9 captain at MEM and asked him how much fuel does an average DC-9 burn in an hour. He told me 5000-6000 pounds depending on conditions. I was curious how much fuel it would take to go from DTW-STL, which is a route I frequent. He told me it would take about 9000 pounds. Now here is my question; how much is that in US gallons? How much does one gallon weigh?

I am trying to figure out how much fuel it takes to travel from DTW-STL. When I drive it takes me about 38 gallons. (110 gallons once in F-350 with a 460). I want to figure out how many gallons per passenger, assuming it is full, the flight takes. This figure would be different for a DC-9-30/40/50.
My mug slaketh over on Falstaff N503

Newark777
Posts: 8283
Joined: Thu Dec 02, 2004 6:23 am

### RE: How Much Does Jet Fuel Weigh?

I don't know the density of jet fuel, but I know a gallon of water weights about 8.3 pounds. It should be somewhere close to there.

Harry
Why grab a Heine when you can grab a Busch?

dogfighter2111
Posts: 1867
Joined: Tue Nov 09, 2004 3:02 am

### RE: How Much Does Jet Fuel Weigh?

Heya,

9000 pounds = 1326.46 Gallons = 4050kg

1 Gallon = 6.79 pounds

Thanks
Mike

m404
Posts: 1875
Joined: Tue Nov 25, 2003 4:43 pm

### RE: How Much Does Jet Fuel Weigh?

Yup. 6.8 lbs pg is the round number we always used.
Less sarcasm and more thought equal better understanding

widebodyphotog
Posts: 885
Joined: Wed Jun 30, 1999 9:23 am

### RE: How Much Does Jet Fuel Weigh?

Interestingly enough the density of Jet-A varies significantly around the world. The places in the world with the highest typical fuel density is on the US East and West coast and the lowest density fuel is found in Southeast and Australiasia.

For each individual flight operation fuel density is measured and density is calculated, then the appropriate amount is metered into the aircrafts fuel tanks. As I said fuel density vaires by region and typically can range from 6.55 to 6.80 lbs/USG. That is a huge variation in required fuel volume when you consider that a .1/b/USG variation means a difference of up to 1,000 gallons on a 747 loaded up for a 6,000nm trip!

-widebodyphotog
If you know what's really going on then you'll know what to do

nonfirm
Posts: 430
Joined: Mon Sep 12, 2005 3:04 pm

### RE: How Much Does Jet Fuel Weigh?

We use 6.7
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mpdpilot
Posts: 824
Joined: Fri Jul 28, 2006 6:44 am

### RE: How Much Does Jet Fuel Weigh?

so I also have question, I have heard talk of varing densities of jet fuel offering varing performance so how much variation is there in that number like is it always within .1lbs or is it more signifigant than that.
One mile of highway gets you one mile, one mile of runway gets you anywhere.

Vimanav
Posts: 1471
Joined: Thu Jul 31, 2003 4:33 am

### RE: How Much Does Jet Fuel Weigh?

 Quoting Widebodyphotog (Reply 4):Interestingly enough the density of Jet-A varies significantly around the world. The places in the world with the highest typical fuel density is on the US East and West coast and the lowest density fuel is found in Southeast and Australiasia.

To add to what Widebodyphotog has stated, weight of fuel varies from place to place and is dependent on its specific gravity. As an approximation 1000kgs of Jet-A1 is equivalent to 1251 liters.

rgds//Vimanav
Sarfaroshi kii tamannaa ab hamaare dil mein hai, Dekhnaa hai zor kitnaa baazu-e-qaatil mein hai

Lono
Posts: 1136
Joined: Sun Apr 04, 2004 5:47 pm

### RE: How Much Does Jet Fuel Weigh?

 Quoting M404 (Reply 3):Yup. 6.8 lbs pg is the round number we always used

 Quoting Nonfirm (Reply 5):We use 6.7

6.5...6.6....6.7...6.8..... all the way up to 7.0...... depending on the outside temperature
Wally Bird Ruled the Skys!

DualQual
Posts: 749
Joined: Sun Mar 05, 2006 6:10 pm

### RE: How Much Does Jet Fuel Weigh?

A quick way to convert from pounds to gallons is to take ten percent of the total number of pounds, then take half of that and add it to the ten percent. You will be extremely close. Ex - 4000lbs. 10% = 400. Half of that is 200. Adding them together yields 600 gallons. Taking the calculator and dividing 4000 by 6.7 gives me 597 gallons. So while it isn't exact you get pretty darn close.
There's no known cure for stupid

N231YE
Posts: 2620
Joined: Tue Jul 25, 2006 9:24 am

### RE: How Much Does Jet Fuel Weigh?

Close to 100LL, which weighs approximately 6 pounds per gallon.

CPHGuard
Posts: 267
Joined: Fri Jun 09, 2006 8:58 pm

### RE: How Much Does Jet Fuel Weigh?

I do beleive, that the temperature of the Jet-A, plays a significant role.

Regards

memphis
Posts: 129
Joined: Wed Mar 15, 2006 6:39 am

### RE: How Much Does Jet Fuel Weigh?

At my other job, I often get to fuel Flight 58, a DC-10 MEM-AMS. The following is from the fuel receipt from the day that I had the highest total once fueling was completed:

STA: MEM A/C: 1237 Flight: 58

16 Sept. 06

Dispatch-------------------Before-------------After

40100-------Left Wing-------9850------------40250
55300-------Upper Aux.---------0------------56600
64400-------Center----------9700------------63500
40100-------Right Wing------9750------------40400

Totals---199900lbs.-------------------24300lbs.--------200750lbs.

Fuel Density: 6.60
Total U.S. Gallons: 25934
Time Begin: 17:14 Time End 18:12
The center tank almost always shuts off (tops out) early, therefore we add the remaining to the upper aux. We have a 400 lb. overshoot window for the NWA narrow-body A/C in MEM. We usually try to give them a little more than what they want, no complaints so far! On the 10, we usually give 400 -1200 more than what they dispatched.
nocturnal

jetmech
Posts: 2382
Joined: Wed Mar 29, 2006 2:14 am

### RE: How Much Does Jet Fuel Weigh?

The places in the world with the highest typical fuel density is on the US East and West coast and the lowest density fuel is found in Southeast and Australiasia.

In Sydney, Australia, we get the density of fuel in metric units. With the first airline I worked for, we used to have large folders with fuelling charts written for a number of Jet A-1 densities from 0.76 - 0.84 kg/L. In reality, the density usually ranged between 0.785 - 0.805 kg/L.

With my current airline, we get sent a fax with the density for the day. This again rarely goes outside the range of 0.785 - 0.805 kg/L. A good ball-park figure for the density of Jet A-1 in metric units would be 0.795 kg/L

 Quoting Memphis (Reply 12): At my other job, I often get to fuel Flight 58, a DC-10 MEM-AMS. The following is from the fuel receipt from the day that I had the highest total once fueling was completed

Yep, the job I found most interesting was fuelling B744's for long trans-Pacific flights from SYD to LAX. This would often require a departure fuel load of about 175 tonnes (385,175 lbs), which made for a 165 tonne (363,165 lbs) uplift. It was a real test of your skill if you could fill each tank to the exact amount required. In this situation, you also had to fill the Horizontal Stabiliser Tank (HST) which was an additional challenge.

The true test of your skill, and the most satisfying result was the situation where you managed to fuel the plane to 100kg (201 lbs) above the final fuel required, with a discrepancy less than 100 Kg   . The pilots were happy for two reasons, it meant they would be right on MTOW a few minutes after engine start, and the aircraft fuel system was almost in exact agreement with the fuelling truck.

[Edited 2006-10-02 05:42:59]

[Edited 2006-10-02 05:44:39]

[Edited 2006-10-02 05:45:52]

[Edited 2006-10-02 05:47:17]
JetMech split the back of his pants. He can feel the wind in his hair .

arffguy
Posts: 110
Joined: Sat Sep 10, 2005 2:20 pm

### RE: How Much Does Jet Fuel Weigh?

Yes, temperature makes a difference. We usually had 6.70 or 6.75 pounds as an average here in Northern California. When it was cold (30 to 40 degrees F) we could get to 6.80. Sometimes an unusual load would come through that was lighter than that. We would have to take a sample from our trucks before the shift, test it and call some airlines (like United.) Depending on the density, the top off quantity of the tanks would be different and sometimes we could not get the tanks to take the amount the fuel slip specified. That's really a pain when, unlike the above DC-10 story, there were no more tanks to put the fuel in. And if the Volumetric Top Off device (VTO) didn't work or was intentionally overridden then you could get a fuel spill. In certain situations some airlines require the fuel density check to be done at planeside prior to fueling.
Time to spare, go by air.

B6DC10
Posts: 79
Joined: Thu Jul 06, 2006 6:57 am

### RE: How Much Does Jet Fuel Weigh?

1 pound of jet fuel weighs the same as 1 pound of lead - which coincidentally weighs the same as a pound of feathers
TriJet or No Jet At All...

Wsan581
Posts: 174
Joined: Sat Sep 23, 2006 11:52 pm

### RE: How Much Does Jet Fuel Weigh?

 Quoting B6DC10 (Reply 15):1 pound of jet fuel weighs the same as 1 pound of lead - which coincidentally weighs the same as a pound of feathers

3201
Posts: 813
Joined: Sun Oct 10, 2004 4:16 pm

### RE: How Much Does Jet Fuel Weigh?

I've heard that fuel density was an issue for the HKG-LHR "eastbound" 777-200LR flight -- apparently the density of fuel available in HKG is not as high as elsewhere. It can definitely be an issue for the very few flights that require max fuel from stations that don't have very high density.

Fuel density variations also have an impact on fuel cost, since fuel is sold by volume but required fuel is based on weight.
7 hours aint long-haul

nonfirm
Posts: 430
Joined: Mon Sep 12, 2005 3:04 pm

### RE: How Much Does Jet Fuel Weigh?

 Quoting Lono (Reply 8):6.5...6.6....6.7...6.8..... all the way up to 7.0...... depending on the outside temperature

There is no variation in our paperwork it is only 6.7.
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concentriq
Posts: 283
Joined: Mon Jan 24, 2005 11:37 am

### RE: How Much Does Jet Fuel Weigh?

 Quoting B6DC10 (Reply 15):1 pound of jet fuel weighs the same as 1 pound of lead - which coincidentally weighs the same as a pound of feathers

haha! Brilliant! I opened this thread to write exactly that! You beat me to it!

I think they are talking about mass vs weight here. As Vimanav correctly pointed out:

 Quoting Vimanav (Reply 7):As an approximation 1000kgs of Jet-A1 is equivalent to 1251 liters
Mobilis In Mobili

Charliejag1
Posts: 226
Joined: Sun Aug 20, 2006 4:48 am

### RE: How Much Does Jet Fuel Weigh?

When I was flying King Airs, we used 6.7 daily. I realize the density does change depending on a number of factors, but this seems like a nice average, at least for the midwest or the US as a whole. Of course, I wasn't flying for an airline, so it wasn't as much of a concern. If I burn a couple thousand gallons in a King Air, the economics are much different than a major airline's daily fuel burn. It takes fuel to carry fuel . . .

Matt72033
Posts: 1589
Joined: Sat May 14, 2005 10:03 pm

### RE: How Much Does Jet Fuel Weigh?

you americans should adapt a proper mesurement system.....like metric

vivavegas
Posts: 422
Joined: Tue Apr 27, 2004 11:56 pm

### RE: How Much Does Jet Fuel Weigh?

 Quoting Falstaff (Thread starter):Last Monday, while I was waiting at the gate, I was was talking with a NW DC-9 captain at MEM and asked him how much fuel does an average DC-9 burn in an hour. He told me 5000-6000 pounds depending on conditions. I was curious how much fuel it would take to go from DTW-STL, which is a route I frequent. He told me it would take about 9000 pounds. Now here is my question; how much is that in US gallons? How much does one gallon weigh? I am trying to figure out how much fuel it takes to travel from DTW-STL. When I drive it takes me about 38 gallons. (110 gallons once in F-350 with a 460). I want to figure out how many gallons per passenger, assuming it is full, the flight takes. This figure would be different for a DC-9-30/40/50.

 Quoting Dogfighter2111 (Reply 2): 9000 pounds = 1326.46 Gallons = 4050kg 1 Gallon = 6.79 pounds

Anyone care to help fill in the below???....

So rough costs for your DTW-STL trip is as follows???

1,327 gallons @ \$2.00/gal? = \$2654.00
Crew 2hr block (\$160x2cockpit, \$30x3cabin x 2 hours) = \$820.00
Landing Fees = ??
Lease? = Nothing
Hull Insurance = ??
Ground Crew (amitorized) = ??

So would it be safe to say that 2 hour flight with say 70 out of the 100 seats filled would cost \$71.42 to fly from DTW-STL? (based on estimated \$5000 hard costs)?

It's lilke taking my college economics classes all over again....

Craig
MKE
MKE / EYW / LAS - The true trifecta of aviation!

twal1011727
Posts: 449
Joined: Thu Mar 23, 2006 5:36 am

### RE: How Much Does Jet Fuel Weigh?

 Quoting DualQual (Reply 9):A quick way to convert from pounds to gallons is to take ten percent of the total number of pounds, then take half of that and add it to the ten percent. You will be extremely close. Ex - 4000lbs. 10% = 400. Half of that is 200. Adding them together yields 600 gallons. Taking the calculator and dividing 4000 by 6.7 gives me 597 gallons. So while it isn't exact you get pretty darn close.

Just as quick is taking the fuel in pounds, divide in half then add that back into the original lbs then drop the last zero.
Ex: half of 15000 lbs is 7500...added back into it is 22500...drop the last zero and the result is 2250 gallons.
If you take 15000 divided by 6.7 you get 2238 gallons...pretty close huh.

Otherwise, most airlines use 6.7 or have a hydrometer get the density down to the hundredths (i.e. 6.69 ) even further...some airlines want the temperature of the fuel figured in too.

KD

OldAeroGuy
Posts: 3928
Joined: Sun Dec 05, 2004 6:50 am

### RE: How Much Does Jet Fuel Weigh?

A lot of airline flight planning departments in Southeast Asia and Australia use 6.4 lbs/gal when developing airplane performance. This is based on the low end fuel densities in their part of the world.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis

3201
Posts: 813
Joined: Sun Oct 10, 2004 4:16 pm

### RE: How Much Does Jet Fuel Weigh?

 Quoting Matt72033 (Reply 21):you americans should adapt a proper mesurement system.....like metric

Yes, should definitely drop proper English units for those French ones like you guys did.
7 hours aint long-haul

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