Cost of jet fuel-The Answer! +HOW much to carry a tonne extra?
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Cost of jet fuel-The Answer! +HOW much to carry a tonne extra?
Had a chat with a refueller in London today.
27p per litre (depending on the contract). Not much, hey?
The Boeing 737 uses 70kg to carry every extra tonne of weight (from the burn correction on the nav log). Therefore, 70 times 27p is £18.90! About the cost of a business class meal.
Makes a mockery of those carriers which supposedly discourage pilots taking extra fuel (re: the recent CAA SRG survey).
I'm not suggesting everyone should carry an extra tonne every flight, but there should be no feelings of guilt at carrying a sensible extra amount to allow for holding / wx. etc.
As they say, only time you've got too much fuel is when you're on fire!
27p per litre (depending on the contract). Not much, hey?
The Boeing 737 uses 70kg to carry every extra tonne of weight (from the burn correction on the nav log). Therefore, 70 times 27p is £18.90! About the cost of a business class meal.
Makes a mockery of those carriers which supposedly discourage pilots taking extra fuel (re: the recent CAA SRG survey).
I'm not suggesting everyone should carry an extra tonne every flight, but there should be no feelings of guilt at carrying a sensible extra amount to allow for holding / wx. etc.
As they say, only time you've got too much fuel is when you're on fire!
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Propellorhead
Whilst I agree that the fuel carried shoud be down to the captain, I suggest you mulitply that £18.90 by 180 flights per day by 365 days a year. I think you will agree that a £1.25m per annum increase in fuel costs is a bit excessive if the fuel is not necessary.
Whilst I agree that the fuel carried shoud be down to the captain, I suggest you mulitply that £18.90 by 180 flights per day by 365 days a year. I think you will agree that a £1.25m per annum increase in fuel costs is a bit excessive if the fuel is not necessary.
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Agreed, but if each of those flights burns an avergage of 5000 litres, then the total fuel bill is £87 million eg) this is only 1.4% extra. Plus, how many pax. meals get wasted every flight? Often at least 2, which myself and my collegue personally take care of 
I'm not saying everyone should bung on an extra tonne, but it is interesting. Also, the cost of a diversion is tens of thousands of pounds, which would easily cancel out years of being 'frugal'.
I'm not saying everyone should bung on an extra tonne, but it is interesting. Also, the cost of a diversion is tens of thousands of pounds, which would easily cancel out years of being 'frugal'.
Sensible PPRuNer?
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Propellorhead, not being picky, but in your example I think you've taken one litre of fuel to equal one kilo?
Not quite correct. one litre of fuel is more like .80 of a kilo (specific gravity of .8)
So 70kg/.8 = 87.5 Litres
Multiply that by the 27p and you get £23.62
Not quite correct. one litre of fuel is more like .80 of a kilo (specific gravity of .8)
So 70kg/.8 = 87.5 Litres
Multiply that by the 27p and you get £23.62
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If you are looking for real fuel cost savings then reduce the cost index in the FMC the speed wont suffer much but this must be balanced with the hourly costs on the aircraft.
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Yes 1.25million pounds a year is a lot of money, but just remind yourselves of how much of a bonus management in your airline got last year. And how hard they worked to earn it.
They're fuel tanks, not air tanks!.
They're fuel tanks, not air tanks!.
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HPSOV
As a professional pilot, I see my job as operating the aircraft safely and efficiently.
When I go to work I don't think to myself these sods I work for are overpaid therefore I'm going to put an extra 5 tonnes of fuel on.
The decision is based on the minimum amount comensurate with safety.
Carrying extra because they are fuel tanks not air tanks sounds iresponsible both to your employer and to the environment which is receiving a few hundred kg of extra CO2 for every extra tonne you carry
As a professional pilot, I see my job as operating the aircraft safely and efficiently.
When I go to work I don't think to myself these sods I work for are overpaid therefore I'm going to put an extra 5 tonnes of fuel on.
The decision is based on the minimum amount comensurate with safety.
Carrying extra because they are fuel tanks not air tanks sounds iresponsible both to your employer and to the environment which is receiving a few hundred kg of extra CO2 for every extra tonne you carry
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Quite right, Captain Sensible.
Capt. Sandl, I should elaborate:
The 'burn correction' is of course dependent on the length of time airborne, and varies from 19 to 87 across our route structure (Western Europe).
Therefore, it equates to 23.8 to 109 litres per trip per tonne.
So, on a short domestic flight (30min), an extra tonne costs £6.43 to transport, whereas on a 2:15 hour Europe trip, it would cost £29.43. An hour is 34kg (42.5litres), or £11.47, so it doesn't seem to be an exact linear relationship - not sure why.
A rough average is £12 per hour for every extra tonne of fuel. Compared to the cost of a diversion, it isn't much.
Bally Heck, your not a management pilot are you?
I believe there are areas of most airlines which could (and probably should) be cost cut, but fuel isn't one of them. It's false economy not to carry enough to allow for anticipated holding etc.
Capt. Sandl, I should elaborate:
The 'burn correction' is of course dependent on the length of time airborne, and varies from 19 to 87 across our route structure (Western Europe).
Therefore, it equates to 23.8 to 109 litres per trip per tonne.
So, on a short domestic flight (30min), an extra tonne costs £6.43 to transport, whereas on a 2:15 hour Europe trip, it would cost £29.43. An hour is 34kg (42.5litres), or £11.47, so it doesn't seem to be an exact linear relationship - not sure why.
A rough average is £12 per hour for every extra tonne of fuel. Compared to the cost of a diversion, it isn't much.
Bally Heck, your not a management pilot are you?
I believe there are areas of most airlines which could (and probably should) be cost cut, but fuel isn't one of them. It's false economy not to carry enough to allow for anticipated holding etc.
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Let me try to set the wtra fuel record straight here. Some of you used parameters and data very close to reality in their posts, some others have been trying to draw conclusions with source info miles away from real life.
1. I agree with those who say the correct parameter to be used is kg of fuel used per ton (of fuel) transported during one hour, or =kg/ton/hr. Which btw produces linear results for any flight duration, or at least quasi linear results given the higher fuel consumption at take off.
2. I agree that for a 737-300 series the consumption number is close to 40 kg/ton/hr. It may range in the 42-44 kg area for A300B4 or DC10-30 aircraft, and in the mid thirties for the most fuel efficient engines as installed on A340 etc.
But 27kg/ton/hr for a 757 has to be incorrect; that should also be close to 40kg.
3. The extra fuel, over and above the trip fuel (which already has a 5% reserve), one has to carry for safety purposes (holding, diversion, etc.)is normally known fm the flight planning data, with the ultimate decision up to the captain.
4. Any extra fuel to be taken on top of the preceding is a mgmt decision based on the company fuel policy (which would typically provide for bunkering at cheaper airports to avoid or minimize refueling at more expensive airports). If one accepts that 40 kg/ton/hr is a good average for jet aircraft, it means the cost of bunkered fuel increases by 4% (=40/1000) per flight hour. Very easy to compare your cost of bunkered fuel with the fuel cost at destination.
Hope this helps.
1. I agree with those who say the correct parameter to be used is kg of fuel used per ton (of fuel) transported during one hour, or =kg/ton/hr. Which btw produces linear results for any flight duration, or at least quasi linear results given the higher fuel consumption at take off.
2. I agree that for a 737-300 series the consumption number is close to 40 kg/ton/hr. It may range in the 42-44 kg area for A300B4 or DC10-30 aircraft, and in the mid thirties for the most fuel efficient engines as installed on A340 etc.
But 27kg/ton/hr for a 757 has to be incorrect; that should also be close to 40kg.
3. The extra fuel, over and above the trip fuel (which already has a 5% reserve), one has to carry for safety purposes (holding, diversion, etc.)is normally known fm the flight planning data, with the ultimate decision up to the captain.
4. Any extra fuel to be taken on top of the preceding is a mgmt decision based on the company fuel policy (which would typically provide for bunkering at cheaper airports to avoid or minimize refueling at more expensive airports). If one accepts that 40 kg/ton/hr is a good average for jet aircraft, it means the cost of bunkered fuel increases by 4% (=40/1000) per flight hour. Very easy to compare your cost of bunkered fuel with the fuel cost at destination.
Hope this helps.
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HOW MUCH WOULD IT COST TO RUN OUT OF THE OPTIONS, THAT CARRYING A LITTLE EXTRA AFFORDS A CREW,IT'S THINKING TIME IN LIQUID FORM... "PRICELES"...just one diversion costs more than all the fuel one could save in a career...
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So, if you carry one extra tonne each way to the Ibiza and back, how much extra is that going to cost me. Please feel free to round up to the nearest whole penny. 
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This thread is taking two distinct lines and they are contradictory. Sure it costs something (in both fuel and money terms) to carry "extra" fuel. Wether this is 40 kg/ton/hr or any other figure is type / trip dependant and is not the point. Wether this "extra" fuel" costs 27p/ltr or some other figure is also a blind. Depending upon your company and the arrangements / deals it has you can pay from US$400+ to US$260 per ton for the good stuff. It is so geographically varied and so changed by hedging arrangements and other financial wizardry that it is very hard to second guess.
However the main point is what is "extra" fuel ?
An casual 5 tons for the "wife and kids" is extra fuel.
I am unhappy with the management so put another 10 tons on is extra fuel.
etc etc
The weather at XXXX is very average today, they will be doing full instrument approaches - I will take another 30 mins holding - is not extra fuel.
En route Wx is poor and a good amount of off route diversion may be required - I will take another 30 minutes of cruise fuel - is not extra fuel.
etc etc
I am sure you take my point. If your experience and judgement tell you that the "standard fuel" is in anyway inadequate, take more. But make it a quantifiable and justifiable amount. No one can possibly question that - this is what you are paid for. Some people are more cautious than others - and that is fine too. Experience and professional judgement will allow them to refine their assessments with time. Equally valid, though thankfully less often, there are people who tend the other way and do not take enough sometimes. The latter is more of a management worry than the former I will agree.
The professional approach is surely to take what you need (or figure you do). If you carry justifiable additional fuel and don't use it then you can consider yourself lucky. If you take it and use it - then you can bask in the satisfaction of a good call. But just taking extra for the feelgood factor is a very amateur approach to the problem.
MG
However the main point is what is "extra" fuel ?
An casual 5 tons for the "wife and kids" is extra fuel.
I am unhappy with the management so put another 10 tons on is extra fuel.
etc etc
The weather at XXXX is very average today, they will be doing full instrument approaches - I will take another 30 mins holding - is not extra fuel.
En route Wx is poor and a good amount of off route diversion may be required - I will take another 30 minutes of cruise fuel - is not extra fuel.
etc etc
I am sure you take my point. If your experience and judgement tell you that the "standard fuel" is in anyway inadequate, take more. But make it a quantifiable and justifiable amount. No one can possibly question that - this is what you are paid for. Some people are more cautious than others - and that is fine too. Experience and professional judgement will allow them to refine their assessments with time. Equally valid, though thankfully less often, there are people who tend the other way and do not take enough sometimes. The latter is more of a management worry than the former I will agree.
The professional approach is surely to take what you need (or figure you do). If you carry justifiable additional fuel and don't use it then you can consider yourself lucky. If you take it and use it - then you can bask in the satisfaction of a good call. But just taking extra for the feelgood factor is a very amateur approach to the problem.
MG
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My company has a very revolutionary way to calculate the minimum block fuel: from A to B to C plus 30 minutes plus a statistical amount that would put the aircraft at its destination with enough fuel to proceed from B to C with a probability of either 90 or 99 %, depending on weather and runways available. This statistical amount is at least 15 minutes (regulation), but can be as high as anything for flights with a history of lengthy holdings or extended radar vectoring.
If the old man wants to take extra he is always at liberty to do so. Also calculated is what it would cost to take extra fuel, taking into account fuel price differences, lenght of the flight and weight of the aircraft. A flight accross the atlantic, for instance, would burn approximately 300 KGs per ton extra fuel for a B767.
Sometimes carrying extra fuel even gives a profit when arrival airport fuel is very expensive.
Then at the bottom of the flightplan is calculated how much fuel you actually burn per ton extra weight at take-off. This might be when ZFW is up or when taking extra fuel. So it is easy to calculate how much fuel to take along to arrive at destination with a certain amount of fuel (in minutes) extra in the tanks.
SJ
If the old man wants to take extra he is always at liberty to do so. Also calculated is what it would cost to take extra fuel, taking into account fuel price differences, lenght of the flight and weight of the aircraft. A flight accross the atlantic, for instance, would burn approximately 300 KGs per ton extra fuel for a B767.
Sometimes carrying extra fuel even gives a profit when arrival airport fuel is very expensive.
Then at the bottom of the flightplan is calculated how much fuel you actually burn per ton extra weight at take-off. This might be when ZFW is up or when taking extra fuel. So it is easy to calculate how much fuel to take along to arrive at destination with a certain amount of fuel (in minutes) extra in the tanks.
SJ
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There certainly seems to be some professional thinkers out there, whilst there also appears to be a element of conservatism / lack of understanding that could be costing your particilar company a fortune.
I think bally hack and master green have made some good points here. If what you are doing is safe, then surely the next consideration is commercial awareness. Irrespective of how incompetent your management may appear to be, I would be very surprised if we had professional pilots trying to antagonise them with amateur behaviour like taking "feel good fuel".
Let's face it. The weather most of the time is not too bad in most parts of Europe during the summer. Even the winter has good patches. If your destination has 2 or more runways, and the forecast is CAVOK, why on earth would you want to carry more than minimum required fuel? refer JAR OPS. Your company minimum req'd will still get you to an ALT with 30 holding will it not?
Sometimes, I think we pilots tend to get a bit too melodramtic about these issues. How many times over the past 10 years or so could you honestly say that you needed all that extra gas? Our company have determined that we are costing ourselves a fortune each year by the lack of prudence when uplifting fuel. Day after day, pilots are landing with a ton extra in cavok conditions, "just in case". This to me is farcical and totally unprofessional. Management or not, I think most good pilots take their job a bit more seriously than that.
I would never question a pilot carrying extra fuel when the wx is marginal, or based on local knowledge he decided to carry a bit extra. However most of the time, I do not believe that is required.
I think bally hack and master green have made some good points here. If what you are doing is safe, then surely the next consideration is commercial awareness. Irrespective of how incompetent your management may appear to be, I would be very surprised if we had professional pilots trying to antagonise them with amateur behaviour like taking "feel good fuel".
Let's face it. The weather most of the time is not too bad in most parts of Europe during the summer. Even the winter has good patches. If your destination has 2 or more runways, and the forecast is CAVOK, why on earth would you want to carry more than minimum required fuel? refer JAR OPS. Your company minimum req'd will still get you to an ALT with 30 holding will it not?
Sometimes, I think we pilots tend to get a bit too melodramtic about these issues. How many times over the past 10 years or so could you honestly say that you needed all that extra gas? Our company have determined that we are costing ourselves a fortune each year by the lack of prudence when uplifting fuel. Day after day, pilots are landing with a ton extra in cavok conditions, "just in case". This to me is farcical and totally unprofessional. Management or not, I think most good pilots take their job a bit more seriously than that.
I would never question a pilot carrying extra fuel when the wx is marginal, or based on local knowledge he decided to carry a bit extra. However most of the time, I do not believe that is required.
My crowd operates ultra long haul ex Oz.
If the wx is forecast above alt criteria, we carry, for LHR say, 30 min final reserve (the law), 3000Kg arrival allowance (for ports with known/expected lengthy arrival proceedures) and 2000Kg for the approach and landing. Our VFR is 10% of flight fuel, but if wt limited (not unusual ex SIN for LHR) we carry 10% flight fuel from PNR. The extra burn for additional fuel/ZFW is about 360Kg/ton for SIN-LHR.
BTW 300Kg/ton sounds high for a B767 trans Atlantic to my ears (3 years B767)
If the wx is forecast above alt criteria, we carry, for LHR say, 30 min final reserve (the law), 3000Kg arrival allowance (for ports with known/expected lengthy arrival proceedures) and 2000Kg for the approach and landing. Our VFR is 10% of flight fuel, but if wt limited (not unusual ex SIN for LHR) we carry 10% flight fuel from PNR. The extra burn for additional fuel/ZFW is about 360Kg/ton for SIN-LHR.
BTW 300Kg/ton sounds high for a B767 trans Atlantic to my ears (3 years B767)
