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In a comment on this answer:

Airlines will tanker fuel if it's substantially cheaper at another airport

I've wondered what that term meant before, and now this comment leads me to think that airliners will carry more fuel than what's required for a trip, because carrying the fuel might be cheaper than buying it at the next airport.

Can someone provide more detail on why and when an airline might do this, the calculations that are involved, and any other interesting information on this topic?

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    $\begingroup$ Back in the 1990s, tankering was also an option to avoid refueling at outlying fields where there were fuel contamination worries or to avoid delays due to having to use over-the-wing refueling. The rough rule of thumb for 747-100/200 aircraft was that if you tankered fuel, it would take 20% of that fuel to do it. In other words, if you wanted an extra 40,000 lbs available at your destination, you had to load 50,000 lbs. $\endgroup$ – Terry Nov 19 '15 at 21:42
  • $\begingroup$ @mins I've never been aware of that distinction. Perhaps meanings have changed since I retired, a lot of things have. All I can offer is that at the two 747 carriers I flew for, in the common parlance between dispatcher and captain, carrying any fuel not required to fly the leg was spoken of as tankering, except of course fuel loaded for ballast purposes. $\endgroup$ – Terry Nov 21 '15 at 1:46
  • $\begingroup$ @Terry: Ok, then you must be right and I'll delete my comment. $\endgroup$ – mins Nov 21 '15 at 2:37
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Since the 1960's and 1970's when political hijackings were a problem, airplanes started to only carry the fuel required for the flight. This means a typical fuel load will be something on the order of:

  • taxi fuel at the departure airport
  • fuel to fly and land at the destination at a given altitude and forecast winds
  • if an alternate is needed:
    • fuel to fly to the alternate airport
  • 45 minutes of reserve fuel
  • perhaps a bit extra for contingency and to keep captains happy (e.g. 5-15 minutes worth of fuel).

For a normal flight this means you'll land with around 45-60 minutes of fuel on board, sometimes less. You'll fill up for the next leg at this airport while you deplane and enplane passengers.

Fuel at the hub airports is sometimes a bit cheaper due to the fuel contracts the airline can secure when they order massive amounts of fuel every day. Fuel at outstations that don't see a huge volume of fuel may be quite a bit more expensive. In this case, and if your weights allow, the airline may elect to load extra fuel that isn't needed. The purpose of this is so you do not need to buy as much fuel at higher prices at the outstation.

I only saw this happen operationally when we were going to be very light and the outstation fuel was very expensive. Usually our loads were high enough that we were struggling to get all 50 passengers, bags, and especially jumpseaters on board with the required fuel load. In that case it would not be economical to take more fuel because we'd have to take fewer passengers.

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    $\begingroup$ Was this primarily about hijacks? Less fuel means lower wait which means lower fuel burn, with rather significant impact on the overall operating cost. $\endgroup$ – Jan Hudec Nov 20 '15 at 11:23
  • $\begingroup$ @JanHudec: While less fuel can be loaded faster (less wait indeed), I wonder from your comment on fuel consumption, if you didn't mean weight $\endgroup$ – Ben Voigt Nov 20 '15 at 15:00
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    $\begingroup$ @BenVoigt, yes, I meant weight. Unfortunately comments cannot be corrected. $\endgroup$ – Jan Hudec Nov 20 '15 at 15:13
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Tankering fuel means that an aircraft carries more fuel than required for the flight to the destination, because difference in fuel price at airports makes this operation less expensive than natural refueling at destination.

Wikipedia:

Tankering fuel

When fuel prices differ between airports, it might be worth putting in more fuel where it is cheap, even taking into account the cost of extra trip fuel needed to carry the extra weight.

A flight planning system can work out how much extra fuel can profitably be carried.

Note that discontinuities due to changes in flight levels can mean that a difference of as little as 100 kg (one passenger with luggage) in zero fuel weight or tankering fuel can make the difference between profit and loss.

While there is sometimes an economical advantage to burning more fuel than strictly required, this operation is not neutral for our environment. See:

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  • $\begingroup$ +1 for adding While there is sometimes an economical advantage to burning more fuel than strictly required, this operation is not neutral for our environment. $\endgroup$ – Steve Nov 21 '15 at 2:56
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It basically means they will take on more fuel than necessary because the cost of doing so is cheaper than getting the fuel at the destination airport.

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