# What does the term "tanker" mean when used in regards to a passenger airliner?

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?

• 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. Nov 19, 2015 at 21:42
• @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. Nov 21, 2015 at 1:46

## 3 Answers

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.

• Was this primarily about hijacks? Less fuel means lower wait which means lower fuel burn, with rather significant impact on the overall operating cost. Nov 20, 2015 at 11:23
• @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 Nov 20, 2015 at 15:00
• @BenVoigt, yes, I meant weight. Unfortunately comments cannot be corrected. Nov 20, 2015 at 15:13

Tankering fuel means that an aircraft carries not only the fuel quantity required for the flight to the destination, but also the fuel, or a part of it, required for the next leg of the trip. The aircraft is therefore its own tanker.

### Tankering means reduced cost

This practice can be used when the difference in fuel price at departure and destination airports makes the operation less expensive than refueling at destination. The time to refuel can be also a factor. More: The benefits of tankering considering cost index flying and optional refuelling stops.

From the previous article:

• Fuel expenses remain one of the major components of an airline operational cost, depending on the aircraft size, it may approach from 20% up to 70% of its total flight cost.

• Fuel tankering has been studied and applied by airlines at least since the oil crisis in the 1970 decade. It has become an excellent fuel saving strategy for airliners proving costs reductions up to 10%.

Example of price difference in Europe:

Difference in fuel prices in Europe, source Eurocontrol

Example of savings by fuel tankering:

Savings by fuel tankering for airports distant by 300 NM. Eurocontrol

How to read: For a round trip between airports distant by 300 NM, if fuel is 20% cheaper at the departure airport, then by performing a full tankering, 45 kg of additional fuel will be needed, but this will save 196 € (8%) for the round trip.

### Tankering means also more CO2

Tankering means burning more fuel than strictly required, this can provide an economical advantage, but this operation is usually not neutral for our environment, depending on how fuel is delivered to airports. From the study by Eurocontrol:

[...] it was estimated that fuel tankering could result in a net saving of 265M€ per year for the airlines. However, it would generate 286,000 additional tonnes of fuel burnt and 901,000 tonnes of CO2 emissions at ECAC level per year.

This represents about 2,800 round-trips between Paris and New York or the annual emissions of a European city of 100,000 inhabitants.

(ECAC is the European conference for civil aviation)

Hence:

• +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. Nov 21, 2015 at 2:56

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.