Germany's busiest airport is running short of the one thing every departure needs. Lufthansa has told its crews to bring extra jet fuel into Frankfurt, because supplies at the airport are tight. The measure, first reported by the German tabloid Bild on 14 October and then confirmed by Lufthansa to dpa and aeroTELEGRAPH, is called tankering: fill up somewhere else so you need less where you land.

Lufthansa says no flights will be cancelled. But the explanation it gave differs from the one in the original report, and the episode shows how a sprawling hub that burns millions of litres a day depends on pipelines and river barges most passengers never think about.

What Lufthansa Confirmed

According to Bild, Lufthansa's flight operations told pilots to carry more fuel than the flight needed on selected routes into Frankfurt. That applied mostly to short- and medium-haul flights, and increasingly to long-haul ones too. For the A320 family the paper reported a cap of eight tonnes of extra fuel, and flight planners were told not to offload passengers or cargo to make room for the weight. The instruction runs until further notice.

The two explanations do not quite match. Bild, and aeroTELEGRAPH after it, put the low level of the Rhine first. Lufthansa told dpa that the main cause was reduced capacity on the pipeline connection to the airport, with the river described as a possible additional factor.

A Hub That Drinks From a River

Frankfurt's scale explains why this matters. According to aeroTELEGRAPH, aircraft at the airport take on around 15 million litres of jet fuel on an average day, drawn from ten above-ground tanks with a combined capacity of 186 million litres. A roughly 60-kilometre network of underground pipes carries it from the tanks to the stands. On paper, a full tank farm covers about twelve days without fresh deliveries.

Some of that fuel arrives by barge, unloaded at a terminal on the Main and piped on to the airport. When the Rhine drops, barges can only sail part-loaded, so every trip delivers less. Combine that with a pipeline running below capacity and the margin shrinks quickly.

Why Tankering Is a Last Resort

Tankering is not free. Every extra tonne of fuel makes the aircraft heavier, and a heavier aircraft burns more fuel to carry it. Airlines normally use tankering when fuel is much cheaper at the departure airport. Here they are using it for a different reason, to keep the hub running.

It also comes in a year when jet fuel has already been scarce and expensive across Europe. If the Rhine stays low, the question for Frankfurt is not whether Lufthansa can tanker fuel in, but for how long.

Captain Joe explains tankering: why airliners sometimes carry fuel for the return flight instead of refuelling at every stop.

Sources: Bild; aeroTELEGRAPH; dpa via Tagesspiegel; Lufthansa statement