Fuel Tankering Economy
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Fuel Tankering Economy
Dear All,
I here again request your help. This time it deals with fuel tankering.
In my company, (737classic operator), we calculate a recommendation about fuel tankering for each flight (mentioned in the flight plan delivered to crews).
The problem is that it only takes account of fuel price differences between the two planned stations (departure and arrival) and the extra fuel burn (associated to the extra fuel carried).
Even though, it is most of the time a loss. No extra fuel should be carried.
Time to time, it is a gain but no credit is taken into account for heavier take off and landing weights.
Further more, if you carry 6t of extra fuel on a 3h flight sector, you may not have the same optimum vertical flight path... the economy is then worse than the one calculated (and it is not definitively an environment friendly practice).
To carry extra fuel may lead also to other problems (wing icing on ground after landing…), even if it is a rare event on 737Classic.
Without considering impact on commercial load, let's take an example: 50€ gain per ton of extra fuel carried... and you carry 6t of extra fuel. This represents 300€... Almost nothing compared to the overall operation cost. (the 50€ gain is calculated for the 1st extra ton, so carry the 2nd is less than 50€ gain and the 3rd even less...).
People justify fuel tankering because:
1/ you cannot evaluate precisely the impact of the other parameters (heavier weights...) so we should not take consideration of it.
2/ the theoretical Gain x Number of annual sectors when you can "earn" (even if it is a reduced number of flights) represents a large amount of annual saving...
As you understand, I believe it is an erroneous analysis.
I strongly believe fuel tankering should be considered only when abnormal fuel price differences are encountered or for operational reasons. I have asked Boeing help to complete the study but they have no data to carry out such calculation.
Could someone share their practice and the reasons behind?
(we used to say that below a 15€ gain, we do not carry extra fuel. This is a value I am not comfortable with neither because I cannot solve an equation to come out to that result).
In advance, thank you!
Fin
I here again request your help. This time it deals with fuel tankering.
In my company, (737classic operator), we calculate a recommendation about fuel tankering for each flight (mentioned in the flight plan delivered to crews).
The problem is that it only takes account of fuel price differences between the two planned stations (departure and arrival) and the extra fuel burn (associated to the extra fuel carried).
Even though, it is most of the time a loss. No extra fuel should be carried.
Time to time, it is a gain but no credit is taken into account for heavier take off and landing weights.
Further more, if you carry 6t of extra fuel on a 3h flight sector, you may not have the same optimum vertical flight path... the economy is then worse than the one calculated (and it is not definitively an environment friendly practice).
To carry extra fuel may lead also to other problems (wing icing on ground after landing…), even if it is a rare event on 737Classic.
Without considering impact on commercial load, let's take an example: 50€ gain per ton of extra fuel carried... and you carry 6t of extra fuel. This represents 300€... Almost nothing compared to the overall operation cost. (the 50€ gain is calculated for the 1st extra ton, so carry the 2nd is less than 50€ gain and the 3rd even less...).
People justify fuel tankering because:
1/ you cannot evaluate precisely the impact of the other parameters (heavier weights...) so we should not take consideration of it.
2/ the theoretical Gain x Number of annual sectors when you can "earn" (even if it is a reduced number of flights) represents a large amount of annual saving...
As you understand, I believe it is an erroneous analysis.
I strongly believe fuel tankering should be considered only when abnormal fuel price differences are encountered or for operational reasons. I have asked Boeing help to complete the study but they have no data to carry out such calculation.
Could someone share their practice and the reasons behind?
(we used to say that below a 15€ gain, we do not carry extra fuel. This is a value I am not comfortable with neither because I cannot solve an equation to come out to that result).
In advance, thank you!
Fin
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It is a fairly inexact science, and the factors taken into account in the decision WILL in general reflect the degraded performance due to the extra weight. They probably do NOT allow for ATC rouite changes, if any, at the lower achievable levels, but I am sure they are pretty reliable overall. Wing icing is normally covered by Captain's discretion on tanking, as are runway conditions at destination.
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Companies should be able to include many of the terms you referred e.g. lower derate in TO, higher brakes gear wearing, etc.
Avoiding fire brigade for a refuelling with pax on board could compensate the fuel penalty to carry on unadvantageus extra fuel as like as deicing requirement in some destination environment could revert a positive tankering into a loss.
As BOAC told "It is a fairly inexact science".
Avoiding fire brigade for a refuelling with pax on board could compensate the fuel penalty to carry on unadvantageus extra fuel as like as deicing requirement in some destination environment could revert a positive tankering into a loss.
As BOAC told "It is a fairly inexact science".
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As far as I'm concerned, the fuel tankering analysis are included to avoid unnecessarily extra fuel taken from crews, showing them that 90% of cases it results in a loss of money.
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flight plan info
My believe is fuel tankering should be done only for operational reasons and not be driven by economic consideration.
One of those situation is positionning flights (no load).
Here you can uplift from the beginning the fuel for the 2 next flights (without having to call for fueller at the next station). You will in this case (if the fuel is cheaper at the first station) uplift much more than 1t.
The indicated information of gain or loss for 1 extra ton is then erroneous as you will extrapole from 1t to 5 or 6 or even more... but the gain is not linear...
Thanks for your contribution
Fin
One of those situation is positionning flights (no load).
Here you can uplift from the beginning the fuel for the 2 next flights (without having to call for fueller at the next station). You will in this case (if the fuel is cheaper at the first station) uplift much more than 1t.
The indicated information of gain or loss for 1 extra ton is then erroneous as you will extrapole from 1t to 5 or 6 or even more... but the gain is not linear...
Thanks for your contribution
Fin
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Plenty of fuel
My personal experience with fuel tankering, were my years flying ACMI B-707 and DC-8 based in Jeddah for Saudia in the early 1980s... Particularly for the European DC-8 cargo flights to/from Jeddah.
xxx
Operating cargo flights, we were as a rule, always empty, no payload, out of Saudi Arabia. As a matter of fact, I recall having full tanks on all flights to Europe, our only concern were the max landing weight. Fuel reserves, bad weather, low visibility in Europe, we never were concerned, we could hold for hours, and use Amsterdam as Rome alternate...
xxx
The Saudi culture "our jet fuel is cheap" even was common for short local flights, domestic or even international, to gain time, and for convenience. We would load a 707 or DC-8 with sufficient fuel for 3 or 4 stops without refueling for some passenger flights. Shut-down engines nº 1 and 4 for taxi on arrival, that procedure did not exist... What a waste.
xxx
Outside of the aviation subject, I remember buying gasoline for my car, an old Chevrolet Impala in Jeddah. They charged your tank fill-up by "car size" regardless of how many liters you actually bought. A big car, Chevrolet, was 20 Riyals, a small car, i.e. Toyota, was 15 Riyals...
xxx
Happy contrails
xxx
Operating cargo flights, we were as a rule, always empty, no payload, out of Saudi Arabia. As a matter of fact, I recall having full tanks on all flights to Europe, our only concern were the max landing weight. Fuel reserves, bad weather, low visibility in Europe, we never were concerned, we could hold for hours, and use Amsterdam as Rome alternate...
xxx
The Saudi culture "our jet fuel is cheap" even was common for short local flights, domestic or even international, to gain time, and for convenience. We would load a 707 or DC-8 with sufficient fuel for 3 or 4 stops without refueling for some passenger flights. Shut-down engines nº 1 and 4 for taxi on arrival, that procedure did not exist... What a waste.
xxx
Outside of the aviation subject, I remember buying gasoline for my car, an old Chevrolet Impala in Jeddah. They charged your tank fill-up by "car size" regardless of how many liters you actually bought. A big car, Chevrolet, was 20 Riyals, a small car, i.e. Toyota, was 15 Riyals...
xxx
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Fuel tankering has always been cost consideration first. While the price per litre/gallon may be cheaper at your intermediate stop, there is usually a price per litre/gallon from the delivery system into the jet... Thus tankering may be the way to go.
Then there are operational considerations... such as turn times. Some airports charge by the hour for parking. In some instances if you go 1 minute into the next hour... your company gets charged for the full hour. Then there is a matter of downline delays to avoid curfews too.
Alot goes into deciding whether or not to tanker.
Then there are operational considerations... such as turn times. Some airports charge by the hour for parking. In some instances if you go 1 minute into the next hour... your company gets charged for the full hour. Then there is a matter of downline delays to avoid curfews too.
Alot goes into deciding whether or not to tanker.
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Just remember that some serious companies like SIA do their tankering based on fuel "hedging", meaning that they will buy huge amounts of cheap fuel now, to be tankered some time later when prices go up, so all flights leaving SIN for example are tankered to places with expensive fuel prices. They have a very well figured out program for their brake even point.
Warning Toxic!
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You do have the option of saving the company money. If it is considered a worthwhile tanking sector, you must consider the maximum fuel you can land with for landing purposes and also ground icing. For a positive sector, yoou should take up to the maximum. It may not be much saving, but you are one flight of many that day that could contribute over a year to a significant saving. It takes a reasonable amount of pragmatism and common sense, but they have given you a figure for guidance. They think it's worth it. They pay your salary. Your job is to do as you are requested by the company, following their guidelines, as long as it's safe and what your flight manager thinks is 'sensible'. If you disagree, you should not just disobey your guidance. You should go in and discuss it with the flight manager to see what you should do. You may well find that if you are not prepared to follow company guidance, you will be invited to leave! They pay you, it is their ball. You do it their way, not yours.
You must always remember far more knowledgeable people than you in the company have worked this out. You should not just ignore guidance- if you disagree, go discuss it with them. There are a lot of other factors involved. Local contracts for a minimum amount of fuel over a period, other fuelling costs, fuel shortages etc. They are not paying you for you to decide you don't want to do it their way!
You must always remember far more knowledgeable people than you in the company have worked this out. You should not just ignore guidance- if you disagree, go discuss it with them. There are a lot of other factors involved. Local contracts for a minimum amount of fuel over a period, other fuelling costs, fuel shortages etc. They are not paying you for you to decide you don't want to do it their way!
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Guidance and Procedures
Dear Rainboe,
I absolutely agree with your position.
The thing is I am in charge of reviewing some internal procedures of my company. I am not agains the current ones, I try to improve it, as I am paid for that purpose.
Fuel tankering practice is one of those I concentrate lately because it is a very sensitive subject and because a large amount of money is involved.
As previously mentioned per the collegues, fuel tankering involves more parameters than fuel cost at each planned station and extra fuel burn. Unfortunately, this are the only parameters on which my company base its computation (currently). Other parameters are very hard to take into account, especially automatically. I wondered how other operators solved this, reason of my thread in this forum.
Any suggestion leading to a procedure improvement starts with a strict application of current procedures.
Again, for all of you, thanks for your contribution.
Fin
I absolutely agree with your position.
The thing is I am in charge of reviewing some internal procedures of my company. I am not agains the current ones, I try to improve it, as I am paid for that purpose.
Fuel tankering practice is one of those I concentrate lately because it is a very sensitive subject and because a large amount of money is involved.
As previously mentioned per the collegues, fuel tankering involves more parameters than fuel cost at each planned station and extra fuel burn. Unfortunately, this are the only parameters on which my company base its computation (currently). Other parameters are very hard to take into account, especially automatically. I wondered how other operators solved this, reason of my thread in this forum.
Any suggestion leading to a procedure improvement starts with a strict application of current procedures.
Again, for all of you, thanks for your contribution.
Fin
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The time-honoured 737 Classic 'rule-of-thumb' is 4% per hour. If the computed flight time x 4% is less than the price differential you tank if you can. Take a 3 hour flight: it will cost you 12% of the fuel you tank. If the price at the other end is 15% more than departure, you win. This 'magic' figure is well-proven and takes into account extra burn and lower levels. You need to decide the differential gain at which it becomes non-economical to tank (but as mentioned before, sometimes other factors like turn-round times come into play).
It is fairly easy to write an Excel sheet to do the work for you, but things to remember:
Do not tanker a lot more than you need to return!
Take into account minimum uplifts if any at destinations - some refuellers have a minimum amount rule, so you will finish up paying heavily for 400kg say. Better sometimes to 'undertank'.
Publish the recommended figure on the pilot's plan OR let them work it out from accurate and up-to-date price differentials. They will decide what is 'practical' and should have a feel for how much they need for the return.
If the return is another crew, give the outbound crew the return tank requirement. We've done it for ages this way, and I'm sure it has worked.
It is fairly easy to write an Excel sheet to do the work for you, but things to remember:
Do not tanker a lot more than you need to return!
Take into account minimum uplifts if any at destinations - some refuellers have a minimum amount rule, so you will finish up paying heavily for 400kg say. Better sometimes to 'undertank'.
Publish the recommended figure on the pilot's plan OR let them work it out from accurate and up-to-date price differentials. They will decide what is 'practical' and should have a feel for how much they need for the return.
If the return is another crew, give the outbound crew the return tank requirement. We've done it for ages this way, and I'm sure it has worked.
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you will burn 10% of your fule just carrying it. so 10% of your extra fuel will be burnt away just for carrying it. we use the rule of thumb that the fuel price needs to be 10% less in order to tanker. our company does this whenever possible. now those who take extra fuel just to make themselves feel better burn away the money saved by those who tanker. so i don't think we ever save money do to others wasting a lot of fuel be it by carrying extra when not needed or flying technique such as decending early and not doing idle decents.
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Finzolas
- I suggest you ignore this. A moment's thought shows it to be ludicrous.
you will burn 10% of your fule just carrying it. so 10% of your extra fuel will be burnt away just for carrying it.
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Finzolas,
I am slightly surprised that you think this is difficult. For a pilot down trip it is true that the various rules of thumb and back of the envelope calculations make it an inexact science. But since you say that you are involved in the back-office planning for a 737 operator, you presumably have access to all the data you could possibly need to make this a highly exact science.
Assuming you have access to some proper performance based planning tools, you just run the trip plan for every trip based on (1) the intended payload and (2) a payload 1 ton higher. The second trip plan will take a little bit longer and wil cost a little bit more, and the difference is what people are calling the "cost" of tankering a ton of fuel. You can then compare this to the cost of a ton of fuel at the next stop, and immediately see whether it is of benefit to tanker the fuel.
Like all these things it is dependent on having good initial data to get good answers. If you flight planning program incorrectly calculates the true cost of a flight, then you will not get the right answer - but you should probably be fixing that anyway for the sake of the overall operation. And, speaking from personal experience, if you make a mistake on the actual price of fuel at the two locations, you can wipe out the whole benefit in one horrible mistake.
But on the assumption that you are starting with good data, then it can be very satisfying to scrape the odd 50 euros here and there on every sector, and for a busy operator that soon justifies the original investment in the flight planning software, the fuel price database, and the Excel spreadsheet to tell you the answer.
I am slightly surprised that you think this is difficult. For a pilot down trip it is true that the various rules of thumb and back of the envelope calculations make it an inexact science. But since you say that you are involved in the back-office planning for a 737 operator, you presumably have access to all the data you could possibly need to make this a highly exact science.
Assuming you have access to some proper performance based planning tools, you just run the trip plan for every trip based on (1) the intended payload and (2) a payload 1 ton higher. The second trip plan will take a little bit longer and wil cost a little bit more, and the difference is what people are calling the "cost" of tankering a ton of fuel. You can then compare this to the cost of a ton of fuel at the next stop, and immediately see whether it is of benefit to tanker the fuel.
Like all these things it is dependent on having good initial data to get good answers. If you flight planning program incorrectly calculates the true cost of a flight, then you will not get the right answer - but you should probably be fixing that anyway for the sake of the overall operation. And, speaking from personal experience, if you make a mistake on the actual price of fuel at the two locations, you can wipe out the whole benefit in one horrible mistake.
But on the assumption that you are starting with good data, then it can be very satisfying to scrape the odd 50 euros here and there on every sector, and for a busy operator that soon justifies the original investment in the flight planning software, the fuel price database, and the Excel spreadsheet to tell you the answer.
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Confession
CJ Driver,
I believe I am a little bit forward from the situation you describe.
Our flight planning system already computes automatically fuel tankering recommendation based on fuel price differences for the intended stations and cost of tankering.
Even if I assume this is the method used largely in the industry, fuel prices and cost of transport are not the sole parameters to take into account.
If you take into account additional costs (impossible to list al theses but let say heavier take off & landings weights, fuel service, parking fees, delays...), you can reverse the previous recommendation (which was only based on fuel price and cost of transport) and this is in my opinion, tragic.
Most of my colleagues argue that pilot experience will do the rest. I do not give up in building up a tool which helps pilots to take the decision based on a maximum of relevant parameters (we are a charter operator and this does not help)
My English is "not very good looking", sorry for that. I hope my situation is easier to understand now with the additional information I brought above.
Best regards,
Fin
I believe I am a little bit forward from the situation you describe.
Our flight planning system already computes automatically fuel tankering recommendation based on fuel price differences for the intended stations and cost of tankering.
Even if I assume this is the method used largely in the industry, fuel prices and cost of transport are not the sole parameters to take into account.
If you take into account additional costs (impossible to list al theses but let say heavier take off & landings weights, fuel service, parking fees, delays...), you can reverse the previous recommendation (which was only based on fuel price and cost of transport) and this is in my opinion, tragic.
Most of my colleagues argue that pilot experience will do the rest. I do not give up in building up a tool which helps pilots to take the decision based on a maximum of relevant parameters (we are a charter operator and this does not help)
My English is "not very good looking", sorry for that. I hope my situation is easier to understand now with the additional information I brought above.
Best regards,
Fin
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Fin -your English is fine!
Taking the list you provided (yes, I know it is not all)
heavier take off & landings weights - do you mean the extra wear on brakes and engines, because take-off and landihg fees will NOT be affected by tanking as they are based on declared Max values from your Certifictae of Airworthiness?
fuel service - I don't understand this - 95% of your tanking will be from your base or bases, where you will have time to put the tanking fuel on before departure - can you explain more?
parking fees - turnround at destination will probably be limited by passengers on/off time BUT you will not be held up by refuelling and fire service cover if needed etc.
delays - again, I cannot see where these will come from? Can you explain?
I do believe that the 'fine-tuning' you are seeking will not be productive in real terms, and I do not think any of the other parameters will actually 'reverse' the economy of tanking.
Taking the list you provided (yes, I know it is not all)
heavier take off & landings weights - do you mean the extra wear on brakes and engines, because take-off and landihg fees will NOT be affected by tanking as they are based on declared Max values from your Certifictae of Airworthiness?
fuel service - I don't understand this - 95% of your tanking will be from your base or bases, where you will have time to put the tanking fuel on before departure - can you explain more?
parking fees - turnround at destination will probably be limited by passengers on/off time BUT you will not be held up by refuelling and fire service cover if needed etc.
delays - again, I cannot see where these will come from? Can you explain?
I do believe that the 'fine-tuning' you are seeking will not be productive in real terms, and I do not think any of the other parameters will actually 'reverse' the economy of tanking.
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so you don't think you burn more fuel when you are heavier? 10% is not far off on the fuel you waste just carrying it. if you carry 2000 extra pound then you will burn 200 pound of that just carrying it. i do not think this is ridiculus.