Contrail Busters

Welcome back to Jump Seat. This week’s article was written by Raimund Zopp, the co-founder and Director of Innovation at our partner company FLIGHTKEYS. The robust system developed by FLIGHTKEYS powers the back end of the ARINCDirect Flight Planning engine and other features like NOTAMs. FLIGHTKEYS is committed to sustainability efforts and is a thought leader on the subject. Keep reading to learn more about a new challenge to aviation: contrail avoidance.

Aviation’s climate impact is estimated to contribute about 3-4% to the total man-made warming of the atmosphere under the current conditions, with 0.4% attributable to business aviation. While global air traffic is on a continuous growth path, climate impact from CO₂ emissions is expected to be reduced due to technical improvements in many areas – like new engine and aircraft technology and sustainable aviation fuel (SAF). Unfortunately, CO₂ is not the only effect of air traffic on climate warming. Worldwide, scientists working on the topic agree that cloud formation triggered by aircraft’s condensation trails (contrails) contributes more to climate warming than the CO₂ created from burning the fuel. There is still a large margin of uncertainty on the magnitude, but the evidence is already strong enough to start working on mitigation strategies. 

Figure 1: Example from Orca Science’s contrail map application

FLIGHTKEYS is working in close cooperation with several research institutes like Orca Sciences, Imperial College London, DLR, and UC3M to develop models and algorithms suitable for integration into flight planning systems.

A first trial in the FLIGHTKEYS lab system with contrail probability data from Orca Sciences shows significant potential to model flight trajectories that avoid the creation of critical contrails to the maximum possible extent. Only a small number of flights need to be modified, with an acceptable increase in additional fuel and time costs but a big reduction in climate impact. A rough initial estimate indicates that only 5-10% of flights create 80% of the contrail impact. In many cases, only a small portion of the route needs to be planned at altitudes that avoid the ice-supersaturated air volumes indicated in weather forecasts. In some cases, the areas can also be avoided laterally and FLIGHTKEY’s optimizer will automatically find the least-cost solution in both dimensions. 

As a first step, FLIGHTKEYS will treat contrail-sensitive air masses like restricted areas that the route optimizer will avoid, creating a 4D least-cost trajectory around those airspaces. Since these airspaces are evolving over time, presentation on a static map shows how difficult it would be to achieve avoidance manually.

In the next step, FLIGHTKEYS will receive pre-calculated climate cost forecasts from weather providers in gridded format, allowing a more refined mitigation strategy and – as one of the most significant advantages – the deliberate creation of cooling contrails whenever possible. After that, it will be up to the flight operator to define the cost it is willing to invest in reducing contrail climate impact.

Together with weather forecast providers, FLIGHTKEYS helps define the necessary data standards and products to become the first flight planning system to integrate cost-based contrail avoidance in 2023 entirely. Since ARINCDirect is using FLIGHTKEYS 5D as its flight plan calculation engine, customers will get the option to benefit from these developments, too. The ARINCDirect Flight Planning and Navigation team is dedicated to managing the system on behalf of users and has the ability to make adjustments where needed to improve things like routing and aircraft performance upon request.

While the roadmap is already clear from the flight planning side, there are challenges ahead: Bring the necessary awareness to the flight deck and get ATM flexible enough to facilitate avoidance trajectories. Therefore, EFBs will need to integrate contrail probability into their apps, and FLIGHTKEYS will be taking a lead here as well with their new Loretta app.

Contrail avoidance offers a vast potential to quickly reduce aviation’s climate warming input and since discovering this fact, FLIGHTKEYS has been working with all key players to bring it into operation.

This is the first of several sustainability-related topics we’d like to cover. To provide insight on what you would like to hear from us, please fill out our topic survey here: Jump Seat Sustainability Survey

• It’s estimated that two-thirds of aviation’s climate impact is attributable to non-CO₂ effects – mainly to contrails. 
• A single persistent contrail at night can have a warming effect equal to hundreds of non-contrail flights.
• Contrails can cool the atmosphere during the daytime.
• Clever flight planning can eliminate the creation of persistent contrails.

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