MIAMI – An airline’s biggest environmental impact is its carbon emissions. And that is why increasing fuel efficiency is one of the most effective ways of reducing aviation’s environmental footprint. Finnair (AY) has been investing in this sector for many years.

On February 17, Finnair, in collaboration with Fintraffic ANS, flew an A319 from Helsinki to Kittilä. The company orchestrated the flight to maximize all its aspects as fuel-efficiency is concerned, calculating the drop in fuel consumption.

Achieving a reasonable fuel efficiency is possible in many ways. For instance, some methods include designing a fuel-efficient airway, optimizing aircraft load and weight, minimizing queuing and unnecessary stops when taxiing, as well as efficiently using the airspace.

Finnair’s website described the A319 flight in a press release. The flight utilized biofuel ordered by AY’s customers in 2019 via the Drive for Progress initiative. Since biofuel is not available at Helsinki Airport (HEL), AY’s is developed in California and it would not be a sustainable project to export it to Finland.

Instead, San Francisco International Airport (SFO) will receive biofuel equivalent to 50% of the fuel consumption of the carrier’s HEL-KTT route. According to industry best practice, AY can claim a reduction in the resulting emissions.

“During every flight, we make several decisions that impact fuel consumption. Even decisions that might appear small have a large impact when they’re repeated on thousands of flights every year.” Says Tom Hakala, technical lead responsible for the fuel efficiency of AY’s flight operations.

Finnair PH-LVD Airbus A319-112. Photo: Alberto Cucini/Airways

A Collaborative Approach

Good cooperation between air traffic control teams, the airport, and the airline is the product of best practices in fuel efficiency management.

Finnair’s VP of Sustainability, Anne Larilahti says, “It’s crucial that the organizations actively share data with each other. When all parties know the same things, we can make decisions that lead to bigger emissions decrease than if everyone just optimized their own area,” Larilahti adds that the pandemic is an opportunity. “When there’s less traffic, it’s easier to do things as planned.”

On their part, airlines can optimize their fuel management through the following stages of the flight: Before the flight, Taxi, Takeoff, Cruise, approach, and landing. We take a look at these in more detail.

Flight Planning

Finnair’s routes are as fuel-efficient as possible. This means, the airline usually aims to take the shortest possible route to its destination while taking into account the weather.

For a couple of minutes, moving away from the airway will consume hundreds of kilos of more fuel. Contrary to intuition, the most direct path is not necessarily the most energy-efficient.   For instance, sometimes the wind is against you. Often, by taking a slightly longer route, you can achieve better fuel economy.

As Finnair Flight Planning Manager Riku Kohvakka suggests, flight planning plays a vital role in optimizing fuel efficiency. The optimal path to fly depends on the real conditions of each flight. These include the prediction of upper air winds and temperatures, the volume of payload, and the constraint of airspace.

Managing Fuel

An AY’s flight planning tool named Pilot Briefing Fuel Dashboard is now in practice. This offers information to assist pilot decisions on fueling. Based on an evaluation of the flight plan, the captain adopts fueling decisions.

There is already enough fuel and the application considers any delays, such as parking at another airport or a go-around.

Adjusted Payload

As a rule of thumb, The lighter the aircraft, the less fuel it burns. Catering and water are calibrated and modified by aircraft loading specialists according to the number of passengers.

Apart from this, the center of gravity of the aircraft should be as far back as possible to reduce aerodynamic drag and thereby maximize fuel efficiency.

Cold Weather Operation

Pilots visually inspect the need for de-icing before takeoff. Ay’s pilots can use the SureApp application to consider a suitable level of anti-icing that provides sufficient weather protection for take-off.

In addition, a precise decision-making mechanism would make it easier for pilots to reduce the de-icing treatment period that occurs while burning fuel.

Taxi Wisely

At HEL, the airline procedure is normally to taxi out for takeoff and taxi in for landing using the one-engine procedure.

The CDM production management system at HEL provides departing aircraft with a time window so that they do not need to queue or make unwanted stops. Taxiing with one engine at departure would save a total of 100kg of fuel on the A350 aircraft.

Precise and timely Take-offs

The exact departure is quite critical. Passengers may affect departure times by not being on schedule for their trip. Often, flights have to wait for passengers from other flights.

As a result, the delay of one incoming flight may affect other departures. Offsetting missing minutes by traveling quicker would raise fuel burns, and this is expensive. Catching up any minute wasted on the ground burns an average of 100kg of fuel.

Route Management

Pilots can optimize fuel burn by controlling their altitude and velocity. One AY A350 aircraft is fitted with software that calculates the optimum fuel efficiency flight profile focused on speed and altitude.

Wind impacts fuel consumption, so AY looks for favorable winds (headwind and tailwind). When the wind is favorable, fuel burn will decrease without losing speed. According to the airline, it is not always worth it to get to a destination as fast as possible. Flying slowly – when possible – can save fuel considerably.

Finntraffic ANS focuses on making air travel as optimized as possible. It achieves this by optimization of flight paths, continuous descent, and strong international cooperation. As Osmo Liimatainen from Finntraffic ANS says, the weather, of course, has a huge impact on the fuel efficiency of a flight.

A Safe Landing

A continuous descent route is the most fuel-efficient way to land a plane. AY’spilots use a continuous approach technique for more than 90% of flights to HEL. This technique is known as the Continuous Descent Final Approach (CDFA).

The procedure entails lowering the altitude from the cruising speed to the landing path without the level flight segment. Each level-off section inside the approach patch would increase the engine thrust, thereby increasing fuel consumption and aircraft noise.

Passenger’s Share

Any passenger will affect fuel efficiency. For instance, being on time at the airport and the gate is critical, so the flight will depart on time. Moreover, the passenger’s role plays a part in the sum of luggage.

The airline states that the fuel saved if any Finnair client had 1kg less luggage in 2019 could have been used for 20 flights from Helsinki to Tokyo.

Photo: Kochan Kleps/Airways

Final Thoughts

For flight operations and preparations, several of the above phases are important. On the other hand, aircraft manufacturers also recommend that airlines take certain steps to ensure a smooth flight and to reduce fuel usage in terms of aircraft maintenance activities. In authorized maintenance data, such as the Aircraft Maintenance Manual (AMM), these activities are identified and outlined.

In the AMM, aircraft manufacturers often discuss the washing of aircraft fuselage and exterior surfaces, depending on the operating environment in which the aircraft flies. The polishing of aerodynamic surfaces, such as the leading edges of the wing and stabilizers and the cowlings of the engine, also has a major impact on reducing fuel consumption.

Furthermore, as required by the ongoing airworthiness regulations of the FAA or EASA, each operator shall have an aircraft weighing program throughout each fleet and shall track the weight of each aircraft during its service life. That’s to say, as it ages, every aircraft gains weight. In addition, the aerodynamic smoothness of the fuselage that influences fuel consumption will be compromised by any structural damage or tooth that needs to be repaired by the AMM.

Finnair OH-LVA Airbus A319-112. Photo: Alberto Cucini/Airways

A Digital Transformation in Aviation

These defects also require precise monitoring. Today, aircraft dent and buckle management of any size are enhanced through using drones. These drones fly over the whole aircraft’s external surfaces and capture and record all dents, damages, and existing repairs in a linked database.

Global trends are towards digital transformation and applying data science in the context of aviation.

As a consequence, data gathering from the flight, and maintenance is an ocean of valuable data that can be extracted. As a result, these data then can be analyzed through several optimization algorithms, taking to account reducing fuel consumption. This provides airlines a clear path towards fuel-efficiency and more sustainable air transport.

Featured image: Brandon Farris/Airways