Jeff Shaknaitis, senior engineer for customer technical programs, has worked at GE Aviation for 10 years. Yet in December, for the first time in a decade, Shaknaitis saw his personal passion to combat climate change and his professional life mix when United Airlines operated the aviation industry’s first passenger flight using 100% drop-in Sustainable Aviation Fuel (SAF).

It started with a customer meeting early last year. During that call with United Airlines, Shaknaitis showed a PowerPoint page listing ideas for how the companies might look to collaborate to reduce flight CO2 emissions. SAF testing, one of the bullet points, caught the United team’s attention. That led to months of planning and eventually what became the first passenger flight with 100% SAF on December 1.

The flight from Chicago to Washington, D.C., carried more than 100 passengers. The Boeing 737 8 aircraft used 500 gallons of SAF in one of the CFM LEAP-1B engines* and the same amount of conventional jet fuel in the other LEAP-1B engine to show there are no operational differences between 100% SAF and petroleum-based jet fuel.

“Stopping climate change and achieving environmental sustainability is imperative, it’s possible, and I plan to do everything I can to help,” said Shaknaitis, who is also one of the leaders of GE Aviation’s Green Team, a group of employees empowered to share best practices and lead projects to reduce energy waste in the company’s operations.

SAF is jet fuel made from alternative sources and processes than those for fossil-based fuels, such as plant oils, algae, greases, fats, waste streams, alcohols, sugars, and captured CO2. By making SAF with alternative feedstocks instead of fossil-based feedstock, lifecycle CO2 emissions can be reduced during production.

Top: The aviation industry’s first passenger flight using 100% Sustainable Aviation Fuel was powered by CFM LEAP-1B engines.

Currently, SAF approved for use is a blend of petroleum-based Jet A or Jet A-1 fuel and a SAF component with a maximum blend limit of 50%. United had to get special permission from the U.S. Federal Aviation Administration to operate the 100% SAF flight for testing purposes.

GE has been actively involved in assessing and qualifying SAF since 2007 and works closely with SAF producers, regulators, and operators to ensure that SAF can be widely adopted for use in aviation. In fact, Gurhan Andac, GE Aviation’s engineering leader for fuels and fuel additives, leads an industry committee helping define standards for 100% SAF so it can be approved for industry use. The United flight contributes to the research and development activities to standardize 100% SAF that doesn’t require blending with conventional jet fuel, further reducing lifecycle CO2 emissions.

“This flight was tremendously important. This was not just the first 100% SAF flight with passengers on it, but it had great practical value regarding increasing the SAF blend ratio above the current limit we have at 50%,” Andac said.

“There have been other 100% SAF flights in the past, including with GE and CFM engines, but in this flight we were able to blend two different SAF types together to get to a drop-in fuel that is fleetwide and infrastructure compatible fuel at 100%,” Andac said. “What we learned from this flight is that we can actually blend two different distinct SAF types together to get to a fully drop-in sustainable synthetic jet fuel to replace conventional jet fuel.”

From left to right: John Martinez, Mohamed Ali, Jeff Shaknaitis and Gurhan Andac of GE Aviation pictured in front of the LEAP-1B-powered Boeing 737 8 operated December 1, 2021, for the first passenger flight using 100% Sustainable Aviation Fuel.

*LEAP-1B engines are a product of CFM International, a 50-50 joint company between GE and Safran Aircraft Engines.