French carrier Amelia is expanding a trial of contrail-avoidance technology from partners Thales and Breakthrough Energy Contrails (BEC) that has already shown the ability to limit their production without significantly increasing other greenhouse emissions as a result.
Amelia successfully tested the technology in 2024 on scheduled services between Valladolid in northern Spain and the French capital Paris using an Embraer ERJ-145 regional jet.
But so pleased has the carrier been with the results of the small-scale trial that it is now rolling out the solution across “all eligible flights” in its operation, using both regional and narrowbody aircraft, says head of Adrian Chabot, Amelia’s chief sustainability officer.
The Thales-developed system – which it calls Flights Footprint – “looks at flights before they take off”, says Julien Lopez, head of green operations within Thales’ avionics division. It uses weather data to identify areas on a flightplan where contrails could form and proposes an alternative routing to avoid them.
Rather than changing the aircraft’s lateral trajectory to fly around the widely-spread but relatively-thin areas of super ice-saturated air prone to contrail formation, the system instead changes the aircraft’s altitude.
While this may mean flying several thousand feet lower than is optimal for engine efficiency, increasing emissions of carbon dioxide and nitrogen oxide, the fuel burn – and flight time – are still lower than if the aircraft attempted to fly around.
“To make quite a significant change in terms of route which will increase flight time and fuel consumption is not really a good compromise,” says Chabot.
As contrails have a strong but short-lived effect on the climate, versus CO2’s weaker but much longer-lasting one, the Thales system, dubbed Flight Footprint, attempts to compare the two by converting the former’s impact into a unit called CO2 equivalent (CO2eq).
Using that as a basis, it then calculates the calculates the overall climate impact of the flightplan change – balancing contrail abatement against additional fuel burn – allowing Amelia’s operational control centre to decide whether the switch makes overall environmental sense.
“We need to be sure at the end of the day that the balance between the benefits we have on the contrail side and the drawbacks we have on the CO2 side mean that [the change] is still worth it,” says Chabot.
During the 2024 tests, of the 50 flights in which the system was trialled, it suggested flightplan alterations to five, saving around 20t of CO2eq in the process. The partners believe that 10% level of modified flights will apply more widely.
Although the changes are relatively minor, they still generate strong benefits, Thales says. It points to a representative flight on 5 June where the system recommended cruise at 34,000ft rather than the 36,000ft.
While the 2,000ft altitude change was predicted to cause CO2 and NOx emissions to rise – to 5.84t and 2.33t, respective increases of 2.4% and 4.7% – contrails would be reduced by 86.9% to 0.61t of CO2eq, from 4.5t previously. Overall, the flight’s climate impact fell by 30%, to 8.8t CO2eq from 12.6t.
Once completed, Thales compared the retrospective meteorological data against the forecasts to validate its modelling, says Lopez.
In addition, a camera positioned near Bordeaux to capture the Amelia jet as it passed overhead verified that no contrails were produced, albeit the camera’s limited field of view means this is “not a full validation through observation”, says Lopez.
Amelia has already begun the next phase of the trial, says Chabot, generating further data to help validate Thales and BEC’s predictions. Its first flight using the system to modify the flightplan of an Airbus A320 was completed in January, he notes.
Thales also continues to analyse images recorded by the Bordeaux camera, comparing these against the flight data for other aircraft transiting the region, some of which were producing contrails.
So far, Thales has yet to recruit any other carriers for the trials. “There is still a limited number of airlines that are proactive enough to start an experiment around contrail avoidance,” says Lopez. “It is very rare to find an airline that is motivated to do this.”
Regulatory change may be required to spur greater interest in such a system, he adds. Equally, Thales is working with other operators through air traffic management-based initiatives with a similar contrail-reduction goal.
At an practical level, the biggest challenge to using the system successfully is the “very limited time window” the operational control centre has in which to decide whether to change the flightplan: too early and the weather forecast will not be accurate enough, too late and the routing cannot be altered. “Sometimes we were just too slow,” says Lopez.
“There are a lot of steps. We have tried to make it as efficient as possible and now we have something that’s running very smoothly and that’s why we are ready to deploy [at a larger scale] across Amelia’s fleet.”
Chabot agrees: “Sometimes it is obvious and you can decide quite quickly, but there are times when the balance is more difficult to assess and that can take some time.”
A change in mindset among pilots may also be required, he adds. “You have to be sure that the crew will operate as per the flightplan.
“For decades we have pushed crews to fly as high as possible to lower fuel consumption. So it’s a change for the way for crews to operate these flights.”
