Fuel Tankering

[ulsk]

Good day.
I am looking for a good formula or a method for calculating tankering fuel when the destination fuel price is higher than the departure fuel.
Can anybody help me out on this giving me more info / methods / formulas that you use or know. How can we consider other criteria like wind, weather etc other than fuel prices.

[Tu.114]

This is strongly dependent on company, aircraft type and route structure.

On my current type, 1% of index difference makes up for the costs of carrying 1 hours worth of extra fuel. So for example if the destination is 1,5 hours of flight time away and has a fuel index of 102 while the departure field has an index of 100, it is starting to get economic to tanker for both legs on the departure field.

On other types, there are tables of flight time vs. required fuel index for tankering. And other types will have the flight log show figures for savings/extra costs per unit of fuel tankered.

If I were in Your shoes, I would contact Your companies accountants for guidance, as they should know Your companies cost structure.

[BARKINGMAD]

AFAIK the website Smartcockpit.com has an article on the topic.

However, I lost the will to live after the 1st equation and agree with previous poster, contact your company fleet office first and get their preference and policy.

Once cost index and extra burn (3% per extra carried is a typical figure) are considered, amongst other factors, then it may not be as simple as you would hope.

[SU-GCM]

I think any decent flightplanning software should be able to help you with this subject

Some softwares allow you to enter ip to date fuel prices and can run the maths for you

[Green Guard]

Hi Ulsk, here they are. As how many $ or kg (lb) fuel you will gain or lose

...+/- in $ = Store t *((Arr price $/t) / 1.04^flt time in HRS –(Dep price $/t) )
+/- in fuel = Store / (1.04^hr) – Store / (ArrPrice / DepPrice)

Fuel Price $ / t = 26.42 * (c/Gal) / SG(lb /Gal)
.....................= 3.166 * (c/Gal) / SG(kg / L )

PS the number ~1.04 for Flt tm < 1/2 hr ~1.03 for Flt tm >1.5 hr
Cruize speed changes and FL changes or far from opt are not included

[ulsk]

It seems that your method for tankeing is interesting. Could you please explain the system precisly, giving more datails and an example as well. Actually I could not understand the abbreviations you had given

[Terry Dactil]

The logic is like this:

Get out your flight planning data for somewhere A to B
Pick a weight (W) and look up the fuel burn and time.
Pick another weight (say W + 50 tons) and get the fuel burn and time again.
Do some sums and calculate the extra fuel burn to carry one tone for one hour. (It will be something like 4% per hour iirc).
Get the current fuel price and you can now work out the cost of air-freighting that fuel to any destination if you know the flight time.
Add the air freighting cost to the original fuel price.
If the fuel price at destination is greater than this, then it pays to air freight your own fuel to the destination.

I did this exercise years ago for an airline and Green Guard's numbers look pretty good to me.

[BOAC]

ulsk - in very simple 'ballpark' terms, to pick upon TD's post:

1) You need to know your departure and destination fuel price per unit.
2) Multiply your departure fuel price per unit by 104% for every hour of flight
3) If the resulting price is equal to or more than destination price, there is no economic reason to tanker.
4) There are other reasons, of course, TO tanker, and several reasons NOT TO
5) Never tank EXACTLY to departure fuel needs as it can be VERY EXPENSIVE to have to pick up a few hundred kg at dest if you use a bit more en-route and need them. Fuel companies often have a minimum uplift or a surcharge for small amounts. Better often to 'undertank' to require an uplift of at least a tonne or 'overtank' to allow for holding etc
6) 4% is a pretty reasonable figure to use and more or less takes into account lower levels achieved etc. for 'normal' tanking amounts.
7) As said above, you should NOT be involved in this UNLESS you are managing your own operations - are you?

EG

Dep fuel 102 bananas per bucket full
Flight time 3.5 hours
Dest fuel price 110 bananas per bucket

Do not tank for economic reasons

Dep fuel 102 bananas per bucket full
Flight time 3.5 hours
Dest fuel price 125 bananas per bucket

Economic to tank

[Broomstick Flier]

BOAC

Interesting method.
One question, is the 104% factor valid for any kind of jet aircraft?

[BOAC]

Worked for 737. For others I don't know.

[TopBunk]

3.5 to 4.0% extra burn per tonne carried per hour flown sounds about right to me for 737, 320 and 747 types I have flown.

[BOAC]

Ta TB - we used 3.5 on the 737NG in fact, but I was trying not to over-complicate it for the OP:)

[Linktrained]

Does an aircraft know (or care) whether it is tankered fuel or payload ?

It's just weight, to be carried for some hours, surely.

Just occasionally as crew with an otherwise empty positioning flight, we might find a payload.( A load of soapflakes was one that the airline carried !)

Later I chartered a Britannia to three passengers who were going my way. The money went into my Flight Account. ANY additional revenue was welcomed by some companies.

One of my employers condemned this practice. as it implied that their salesmen were not finding that work. ( That Captain went on to found his own successful airline.)

LT

[BOAC]

I now realise that all my long flying career I had cruelly IGNORED the sensitivities of the aircraft I was flying.................:confused:

[Linktrained]

In those rather less advanced jet days, my Chief Pilot ( A long-haul man) wanted to know why his two short haul fleets regularly flew the same trajectories on a route even though the loads and atmospheric conditions might vary.

"Why don't they fly today's aircraft for today's conditions ?"

( One Captain could and did fly 10,000 ft. higher even on a one hour scheduled sector, if lightly loaded and cold. Others used the "Standard Flight Plan" regardless of the day's circumstances.)

The provision of a simple " Optimum Altitude " graph improved matters.

LT

[g450cpt]

Fuel price is not the only factor in deciding whether to tanker or not. Don't forget to factor in the increased brake and tire wear landing with the increased weight. On our type, one brake costs $60,000 x 4 = $240,000. The more mass they have to stop the faster they wear out. We do tanker sometimes but we look at more than the fuel price.

G450cpt

[Skyjob]

Use of reverse thrust will cost some additional fuel on landing but certainly will save you the wear and tear on the brakes, thus cost in this area.
Just to complicate matters, you could factor this amount into the equation. :8