Avgeek Alert: Aircraft Fuel Consumption & How It´s Calculated

29/12/2023

Of all the issues related to aviation, how much fuel aircraft consume is one that´s especially sensitive today, for obvious reasons. Sustainability and reducing carbon footprint is an imperative that concerns us all, including airlines. Iberia is deeply committed to this goal, and we´ll talk more about that later. But first, let´s take a look at the factors that influence how fuel is consumed by an aircraft.

How Is Fuel Consumption Calculated?

Although it varies depending on the aircraft model, the number of passengers, and other factors, as a general rule fuel consumption per passenger is around three litres per 100 kilometres (about 6⅓ pints per 62 miles). That compares with cars, which usually consume on average around five liters (10½ pints) to cover that same distance –regardless of whether it´s one passenger or four), but it can consume up to 12l (25⅓).

Under normal conditions, a plane travels about 800 kilometers (497 miles) in one hour, under optimal weather conditions and at cruising speed.

Of all the issues related to aviation, how much fuel aircraft consume is one that´s especially sensitive today, for obvious reasons. Sustainability and reducing carbon footprint is an imperative that concerns us all, including airlines. Iberia is deeply committed to this goal, and we´ll talk more about that later. But first, let´s take a look at the factors that influence how fuel is consumed by an aircraft.

How Is Fuel Consumption Calculated?

Although it varies depending on the aircraft model, the number of passengers, and other factors, as a general rule fuel consumption per passenger is around three litres per 100 kilometres (about 6⅓ pints per 62 miles). That compares with cars, which usually consume on average around five liters (10½ pints) to cover that same distance –regardless of whether it´s one passenger or four), but it can consume up to 12l (25⅓).

Under normal conditions, a plane travels about 800 kilometers (497 miles) in one hour, under optimal weather conditions and at cruising speed.

Factors Affecting Fuel Consumption

That said, there are numerous factors that influence how much fuel an airplane will consume, including:

  • Weather: More or less fuel is consumed depending on varying atmospheric conditions, and this is taken into account when a flight plan is being prepared.
  • Weight: That is, is the weight of the aircraft itself plus the number of passengers on board.
  • Distance. Long-haul flights need to carry more fuel, which makes the plane weigh more – and consequently, consume – more fuel.
  • Propulsion efficiency: The propulsion engine fitted to each aircraft affects the cost.
  • Design: Since aerodynamics of course play a very important role in fuel consumption, the relationship between lift and resistance are factors which define the design of the ship and its energy efficiency.

More About Calculating Fuel Consumption

Taking all this into account, how is it possible to determine how much a plane will consume throughout a given flight? Online simulators do exist, but the amounts they yield can end up being far from reality, since they don´t take into account almost anything other than the aircraft model and the distance to be travelled.

On the one hand, pilots will of course consider the distance, but also needs to take into account flight conditions expected. Therefore they will not calculate the fuel needed for actual kilometres but rather for the route that would be taken in the worst-case scenario (adverse weather, traffic density at the arrival airport, possible detours, etc.). The the age of the aircraft is another factor that can directly influence consumption (older models burning through more).

These and other variables give rise to en-route consumption or burn-off fuel. And then there´s also consumption on the ground – that is, while waiting for take-off at the airport; particularly high densities of air traffic can delay the departure of flights, and so more fuel is consumed while waiting to take off.

How Sustainable Airline Fuels (SAFs) Affect Consumption

These days, yet another variable is introduced to reduce fuel consumption, and therefore each flight´s carbon footprint. SAF´s are a new class of aircraft fuel – some created synthetically, others distilled from biomass and organic waste – which is even now contributing significantly to decarbonisation in the skies.

Iberia’s commitment to reducing the carbon footprint of its fleet has led it to increase the percentages of SAF we use even more than the goals set forth by the European Union.

In addition, we´ve added aircraft to our fleet that have made us the world´s second largest airline in reducing carbon dioxide emissions. Among those additions are two models which have been specifically created to promote more sustainable aviation.

One of them is the A350, designed for long-haul flights and between 30 and 35 perccnt more efficient in terms of fuel use – and consequently CO2 emissions into the atmosphere – thanks in part to the latest generation materials used to build it.

In terms of short- and medium-haul aircraft, the A320 Neo is technologically very advanced, reducing its emissions by up to 20 percent, saving the atmosphere 5,000 tonnes of CO2 per year in addition to emitting just half of the nitrogen oxide of previous models. Furthermore, it Leap-1A type CFM engines make the A320 Neo much quieter, on top of being more sustainable.