Fuel Tankering Formula
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LC,
Assuming that OB's figure of 5% is good for each hours extra fuel burn (sounds logical) then we would say that if destination was 4 hrs away then for the fuel tankering to be economical the destination fuel would have to be 120% of the departure price.
If doing a multi sector day from A via B to C where the prices were 100% / 120% /160% then the economics would be favourable if the comparison price were 160/120% = 133%.
Just what we do!
idg
Assuming that OB's figure of 5% is good for each hours extra fuel burn (sounds logical) then we would say that if destination was 4 hrs away then for the fuel tankering to be economical the destination fuel would have to be 120% of the departure price.
If doing a multi sector day from A via B to C where the prices were 100% / 120% /160% then the economics would be favourable if the comparison price were 160/120% = 133%.
Just what we do!
idg
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Los Cabos,
Your easiest solution is to go to your flight plan provider, most of them have the ability to input the departure and destination fuel prices together with the percentage of fuel required to carry that additional fuel, you will then get an economic tankered fuel quantity. Otherwise, use the fuel differential and tankering charts in the AOM and work it out.
OldeBloke, "tankering to landing weight" isnt the simple solution that it appears! You need to know the fuel prices, remembering that it costs fuel to carry fuel, you have to make sure that you have a sufficient price differential to pay for the additional fuel.
Then there is the subject of "de-icing", if you land with additional fuel, is your aircraft prone to upper wing icing?
idg, the 5% is aircraft specific and doesnt multiply by the hour. Or least it doesnt in the aircraft which we operate.
Mutt.
Your easiest solution is to go to your flight plan provider, most of them have the ability to input the departure and destination fuel prices together with the percentage of fuel required to carry that additional fuel, you will then get an economic tankered fuel quantity. Otherwise, use the fuel differential and tankering charts in the AOM and work it out.
OldeBloke, "tankering to landing weight" isnt the simple solution that it appears! You need to know the fuel prices, remembering that it costs fuel to carry fuel, you have to make sure that you have a sufficient price differential to pay for the additional fuel.
Then there is the subject of "de-icing", if you land with additional fuel, is your aircraft prone to upper wing icing?
idg, the 5% is aircraft specific and doesnt multiply by the hour. Or least it doesnt in the aircraft which we operate.
Mutt.
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Gents(and ladies)the 5% was a standard we used in Canada(for 37 years)as the penalty..Operations would add Tanker fuel when they came across a Bargain(the prices of course)..As flight crew we worried about the logistics(landing weights.etc)..Wing deicing only became a concern on the DC9....The cold fuel(-0)cooled the ambient air to create clear icing on the top o' the wing..
But when one adds up the savings per flight(660a day)Tankering is a worthwhile consideration
as a parttime Metro pilot recently,loading the return \'burn\'if weight allowed, saved us $250 a trip(1 crew wages)
But when one adds up the savings per flight(660a day)Tankering is a worthwhile consideration
as a parttime Metro pilot recently,loading the return \'burn\'if weight allowed, saved us $250 a trip(1 crew wages)
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Many pilots just carry a copy of the Fuel Tankering Fuel Price Differential graph from the Flight Planning and Performance Manual or use the table below for break-even fuel price based on LRC/.79M cruise and step climb:
****************************************
TRIP DISTANCE (NM)/ BREAK-EVEN PRICE RATIO
200 / 1.015
400 / 1.032
600 / 1.046
800 / 1.062
1000 / 1.078
2000 / 1.179
3000 / 1.313
4000 / 1.500
*****************************************
****************************************
TRIP DISTANCE (NM)/ BREAK-EVEN PRICE RATIO
200 / 1.015
400 / 1.032
600 / 1.046
800 / 1.062
1000 / 1.078
2000 / 1.179
3000 / 1.313
4000 / 1.500
*****************************************
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Gents, 5% per hour is way to high it worked for old low to medium bypass ratio engines with 60's and 70's technology airfoils, but the modern aircraft is way more efficient than that.
Unfortunately, I don't have any numbers for the B737NG type aircraft and no ability to access flight planning data for the type to run the flight plan data points to give you the fuel carriage penalty for this type. Its an interesting exercise and with good flight planning software takes about two hours to get enough data points to calculate the percentage to carry and develop a mathematical representation of the data in the form of an equation.
The difficulty is that the fuel carriage penalty is not linear over time, in fact some are quadratic or cubic functions and using a rule of thumb is if little value for this type of exercise.
The key elemts in the equation are the price at departure point, the price at destination, the stage length of the trip from departure to destination AND the stage length of the onward trip from the first destination. Complex stuff for the average line pilot and really can't be effectively done using a calculator.
The latest state of the art flight planning software available today generally all have "Tankering Modules". This takes all the above information and provides you with a tankering fuel amount and the monetary savings this will generate.
Lots of great tools out there so no need to rely on a rule of thumb.
Richard
Unfortunately, I don't have any numbers for the B737NG type aircraft and no ability to access flight planning data for the type to run the flight plan data points to give you the fuel carriage penalty for this type. Its an interesting exercise and with good flight planning software takes about two hours to get enough data points to calculate the percentage to carry and develop a mathematical representation of the data in the form of an equation.
The difficulty is that the fuel carriage penalty is not linear over time, in fact some are quadratic or cubic functions and using a rule of thumb is if little value for this type of exercise.
The key elemts in the equation are the price at departure point, the price at destination, the stage length of the trip from departure to destination AND the stage length of the onward trip from the first destination. Complex stuff for the average line pilot and really can't be effectively done using a calculator.
The latest state of the art flight planning software available today generally all have "Tankering Modules". This takes all the above information and provides you with a tankering fuel amount and the monetary savings this will generate.
Lots of great tools out there so no need to rely on a rule of thumb.
Richard
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mutt
Definitely per hour on long range airplanes. (3%)
Taking a nearly empty 744F ex LAX recently the refueller tried to load the ZFW instead of required fuel (360000lbs instead of 270000lbs) he stopped when he could get no more in at about 356000lbs. The new FPL had an increased burn of about 35000lbs. After about 13 hours in the air we still had 90000+ in the tanks on landing. Total endurance 19 hours +
Not a very efficient way to take 11000lbs of freight 6000 miles!
Definitely per hour on long range airplanes. (3%)
Taking a nearly empty 744F ex LAX recently the refueller tried to load the ZFW instead of required fuel (360000lbs instead of 270000lbs) he stopped when he could get no more in at about 356000lbs. The new FPL had an increased burn of about 35000lbs. After about 13 hours in the air we still had 90000+ in the tanks on landing. Total endurance 19 hours +
Not a very efficient way to take 11000lbs of freight 6000 miles!
Per Ardua ad Astraeus
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I'd like to re-open this thread with a question for the 'Tecchies' in Flt Planning departments. It has plagued me for years!
Tankering generally means you cannot achieve the cruise level you would have done non-tankering. Is this taken into account in the 3% or 3.5% (or 5%) rule-of-thumb?
Diving into my 737-400 fuel tables I find:
If I depart on an out-and-back at 54T on a 3hr flight, my optimum cruise is initially at FL360, at 1165kg/hr/engine
If I tanker, say 6T extra, my optimum is now FL340 at 1296kg/hr/engine
That is over 11% extra fuel. Taken, then over a 3 hr cruise, I will burn:
Approx 786kg more for the lower levels at the new weight
Tankering will be decided (by 'established rule of thumb' = 3.5% per hour) on a price diff of around 10.5%
Are we still saving money?
Now I'm on a NG, and can get ALL my return fuel on at departure, so I carry somewhere around 10T extra........................
Should that 3/3.5% be a higher figure?
Tankering generally means you cannot achieve the cruise level you would have done non-tankering. Is this taken into account in the 3% or 3.5% (or 5%) rule-of-thumb?
Diving into my 737-400 fuel tables I find:
If I depart on an out-and-back at 54T on a 3hr flight, my optimum cruise is initially at FL360, at 1165kg/hr/engine
If I tanker, say 6T extra, my optimum is now FL340 at 1296kg/hr/engine
That is over 11% extra fuel. Taken, then over a 3 hr cruise, I will burn:
Approx 786kg more for the lower levels at the new weight
Tankering will be decided (by 'established rule of thumb' = 3.5% per hour) on a price diff of around 10.5%
Are we still saving money?
Now I'm on a NG, and can get ALL my return fuel on at departure, so I carry somewhere around 10T extra........................
Should that 3/3.5% be a higher figure?
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This subject has been brought up again on the NBAA Airmail list. Someone mentioned a program called "Tanker-Cranker". Does anyone here have it, or know where to get it? I've googled like nuts and I can't find any reference to it at all!
My curiosity is driving me crazy...
My curiosity is driving me crazy...
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Concerning fuel transport it all depends what kind of aircraft you are flying
B747: 4000 NM Coef transport around 1.500
However A330 on the same distance is around 1.330.
There is a good formula for small airplane like 320 737 .
That is roughly tenth of the air distance.
i.e 2000 NM on A320 is 1.200
500 NM = 1.050 etc.........
B747: 4000 NM Coef transport around 1.500
However A330 on the same distance is around 1.330.
There is a good formula for small airplane like 320 737 .
That is roughly tenth of the air distance.
i.e 2000 NM on A320 is 1.200
500 NM = 1.050 etc.........
Tanker Cranker?
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B707, 4%
L1011, 3%
Standard across most weights, in my experience.
The L10 has a very efficient wing design, so tankering has many obvious advantages, in most circumstances, all things considered. SVA had an increased landing weight to take most advantage of tankering, with the L10.
L1011, 3%
Standard across most weights, in my experience.
The L10 has a very efficient wing design, so tankering has many obvious advantages, in most circumstances, all things considered. SVA had an increased landing weight to take most advantage of tankering, with the L10.
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Tankering Formula
Hi ... I have a program Called "Tanker Cranker" which is quite a bit more than a formua. If you are interested please contact me at [email protected]
Thanks
Don MacLean
Thanks
Don MacLean
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Tankering fuel is full of pitfalls, not least the difficulty in finding a simple price differential/distance/flight level formula.
Another consideration is the likelihood of wing ice accumulation if you land with a lot of fuel in your wing tanks. Destination weather or flight through iceing conditions in the latter stage of the flight can result in rapid and heavy build-up of ice. If you are landing in foggy but frost free airport (hence no de-icing equipment) at a temp of a few degrees above freezing, it will be a very long wait before the aircraft can make a subsequent take.
Another consideration is the likelihood of wing ice accumulation if you land with a lot of fuel in your wing tanks. Destination weather or flight through iceing conditions in the latter stage of the flight can result in rapid and heavy build-up of ice. If you are landing in foggy but frost free airport (hence no de-icing equipment) at a temp of a few degrees above freezing, it will be a very long wait before the aircraft can make a subsequent take.
