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4AIR business aviation analysis finds small changes to aircraft routings could reduce environmental impact

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In one of the largest international studies of its kind, 4AIR, aviation sustainability solutions, has found that small altitude adjustments on business aviation flights could have a substantial impact on reducing their contrail impact on the environment without CO2 trade-offs.

Contrails, or condensation trails, are a product of aircraft engine emissions interacting with the right combination of temperature and humidity in the upper atmosphere.

Depending on the location and time of day, long-lasting or “persistent” contrails can have an outsized warming impact, trapping and absorbing heat that otherwise would radiate back into space.

Studies have estimated the overall net impact from contrails and non-CO2 emissions to be about twice that of CO2 alone, contributing to two-thirds of aviation’s total warming impact.

The study, the largest flight-by-flight contrail footprint in business aviation, encompassed over 16,000 flights and over 27,000 flight hours and identified specific opportunities to mitigate contrails to reduce the impact from non-CO2 emissions.

According to the analysis, adjustments on just 50 flights out of 16,888 would have reduced the non-CO2 impact from this sample by more than 50% overnight.

In conjunction, 4AIR has also completed six months of a contrail avoidance pilot program, launched in collaboration with Flexjet in Europe.

The program incorporated contrail forecasts into the dispatch process to optimize flight paths and minimize the time spent in contrail forming regions.

Where possible, flight paths were adjusted to modify cruising altitudes above these regions and notes were shared with pilots to calibrate climbs or descents to minimize time spent in the contrail regions.

Kennedy Ricci, 4AIR President, said: “The results of this study demonstrate both the challenges and opportunities with reducing aviation’s footprint from contrails.

“Effectively reducing our contrail warming impact requires considering contrails on every flight, but successfully avoiding contrails on just a handful of flights would have a major impact, potentially without CO2 trade-offs.”

Normally these contrail regions are thin, extending just 2,000 – 4,000 feet, but exist at the upper end of a commercial aircraft’s service ceiling.

These business aviation aircraft, which have higher service ceilings, were found to have the unique opportunity to fly higher than the contrail formation region, reducing both CO2 emissions and their contrail impact instead of needing a trade-off between the two.

Flying higher does come with a slightly higher impact from NOx, but more research is needed to better understand the NOx emissions lifecycle as well as its comparison to CO2.

The analysis also found that contrails were at their lowest levels during the months of July and August, when demand to travel is usually at its peak.