Etihad Greenliner on the runway taking off at sunrise.

Etihad inks pact to prevent planet-warming aircraft contrails

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Green Wing logo with white letters against a green backdrop, and leafs on either sideEtihad Airways has taken steps to address the non-CO2 climate impact of its operations by signing a contrail-management agreement with UK-based atmospheric modelling and data analytics firm Satavia.

The two companies had already been working together to trial Satavia’s DECISIONX:NETZERO software platform, which analyzes atmospheric conditions on a flight-by-flight basis and lets airlines know when a proposed flightpath is likely to produce a contrail. This information gives airlines the opportunity to adjust the flight level and prevent the formation of contrails.

Non-CO2 aircraft emissions, including contrails, are estimated to account for as much as two-thirds of the aviation industry’s impact on climate change. Contrails are formed in certain atmospheric conditions when water vapor from jet engines condenses and freezes around soot particles, leaving a trail that is visible from the ground. Over time, persistent contrails can merge together to form heat-trapping contrail-cirrus clouds, which contribute to global warming.

Etihad describes its agreement with Satavia as “the world’s first multi-year commercial production contract to integrate contrail management within routine operations”. Under the agreement, the Abu Dhabi-based carrier aims to scale up the use of Satavia’s contrail-prevention technology across all of its day-to-day flight schedules. 

The two companies have also agreed to collaborate on the possible generation of future carbon credits by calculating the CO2-equivalent savings created through their contrail-prevention activities. Satavia is working with carbon-accreditation specialists to try and make this happen. If it does, the company believes this could incentivize more airlines to invest in contrail avoidance.

“In 2022 alone, Satavia technology has enabled us to eliminate thousands of tons of carbon dioxide-equivalent climate impact,” said Etihad head of sustainability Mariam Al Qubaisi on announcing the agreement earlier this month.

Satavia founder and chief executive Adam Durant added that by implementing “minimal changes to a small percentage of flights”, airlines such as Etihad “can eliminate most of their non-CO2 climate footprint with little to no impact on day-to-day operations, and on shorter timescales than other green aviation interventions”.

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Addressing a Royal Aeronautical Society conference on the non-CO2 effects of aviation in September, Durant explained how aircraft flying through ice super-saturated regions emit clouds of tiny ice crystals which can result in the formation of contrails. However, with the right modelling data, he says, these regions can be avoided with minimal additional air traffic control- and fuel burn-related costs.

“The ice crystals themselves are incredibly small — smaller than the thickness of a human hair — but they’re very numerous, and they’re very effective at absorbing some of the heat that’s trying to escape to space and directing it back downwards,” says Durant. Working with airlines at the flight-planning stage, Satavia’s analysis of atmospheric data and use of artificial intelligence enables it to present the operator with a briefing pack.

This pack, says Durant, “explains for every waypoint [if there are] contrail conditions present, what’s the upper and lower limit, and then that would allow a dispatcher to decide [whether they can] fly above or below these layers — of course keeping a keen eye on fuel burn and ATC costs”. Most flightpaths would be unaffected, he stresses, with just 5% of flights being responsible for 90% of contrails.

“Of the 45 flights we’ve done [with Etihad], we’ve only had a $6,000 ATC charge and, on average, we’re seeing $100-200 [additional] fuel burn, so we’re keeping these penalties, if they do exist, to extremely low values,” says Durant. “We have managed to prevent over 6,000 tons of CO2-equivalent forcing from these contrail-prevention flights and this is one flight per week, on average, that we’re doing with one airline. Just imagine scaling that up across all operators.”

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Featured image of Etihad-flown Greenliner credited to Etihad