The boss of GE Aviation, John Slattery, expressed confidence that everybody across the air transport business, including airlines, believes in the “noble cause” of reducing carbon dioxide (CO2) emissions. Credit: Handout.

Narrow-body jetliners with CFM Rise open fan jet engines running on sustainable aviation fuel (SAF) or liquid hydrogen?

Why the heck not, says GE Aviation boss, John Slattery.

Even though, if Lufthansa or Air France-KLM fleets flew on SAF, they would burn the world’s available SAF in one single day.

But hey, it’s coming, it’s gonna happen, Slattery insists, and people will want it.

Even “Glum Greta” will like it.

The boss of GE Aviation expressed confidence that everybody across the air transport business, including airlines, believes in the “noble cause” of reducing carbon dioxide (CO2) emissions, not least because customers increasingly want it, AINonline reported.

Well, some customers want it. Some don’t really care. They just want to get from A to B, and if it’s efficient and reduces an airline’s carbon footprint, then fine.

Still, Slattery, speaking at the Eurocontrol Straight Talk session, insisted people will want to know each of their flights’ carbon footprint — either out of environment concerns, or, to know how much tax they will need to pay on their carbon production.

“Collectively the industry will get there,” he said, stressing GE Aviation is playing its role to achieve the industry’s challenge to halve carbon emissions by 2050.

Slattery, an Irishman and former head of commercial aviation at Brazilian jet maker Embraer, pointed to the recently announced Rise (Revolutionary Innovation for Sustainable Engines) development program of its engine joint venture with Safran, CFM International, which aims for a 20% improvement in fuel burn and CO2 emissions compared with today’s CFM Leap family, the report said.  

“This will be the single largest leap in fuel burn reduction ever seen,” he said. “If you would apply this to the narrow-body fleet, it would be equivalent to removing more than 17 million cars from the roads.”

The CFM Rise hybrid electric advanced open fan demonstrator would run on either 100% SAF or liquid hydrogen.

The new CFM gas-turbine engine design will be open rotor, which dispenses with the conventional pod around the rotating fan blades. This allows a larger fan, sweeping backward a greater volume of air.

Similar in look to a propeller — with carbo composite scimitar-shaped rotating blades, and behind that a circle of fixed blades, or stators, that straighten the air flow — it is also called an “unducted fan.”

In contrast, the large fans at the front of today’s jet engines are entirely encased in a protective pod called a nacelle, which is armored to contain any fan blade that breaks off.

“If you would apply this to the narrow-body fleet, it would be equivalent to removing more than 17 million cars from the roads.”

John slattery

The CFM open fan engine also has big implications for Boeing and for Airbus, which in the past have relied upon significant improvements in engine efficiency to launch any all-new airplane design.

CFM’s latest engine — the LEAP, launched in 2008 — powers Boeing’s 737 MAX and about 60% of the rival A320 family of jets built by Airbus.

“Hundred percent SAF will result in an 80 percent reduction in lifecycle CO2 emissions, while green hydrogen would reduce CO2 by 100 percent. Hydrogen will get us to the nirvana of flight with zero carbon emissions,” he said.

Slattery, who joined GE Aviation as CEO last September 1, acknowledged it will require a lot of work to industrialize a hydrogen-burning engine but that a clear technology path exists, the report said.

“The actual physics are very doable,” he said.

However, he cautioned that making hydrogen, like SAF, viable will require the support of policymakers and regulators.

“I know the airlines want to do it … but the regulators, the policymakers, they may need to play a role here,” Slattery said.

“As they look around encouraging incentives to help people generate SAF and SAF can come from a multitude of sources, including synthetic SAFs.

“If we bring up the supply, the price will come down and that supply-demand equation will help bring the price down, but regulators are also looking at potentially regulating the percentage of SAF that would need to be used onboard an aircraft.”

SAF is “clearly a first step” to a meaningful reduction of carbon emissions, he said, adding that the industry is working with regulators to define standards for a 100% use of SAF, or double the blend now allowed.

“What people get confused about is the difference between COemissions and the fuel burn,” Slattery said.

“If we can change the type of fuel that goes into the engine, we can reduce those emissions a lot more than the initial 20 percent we’re talking about.”

A big advantage to using SAF is that aircraft today do not need to be modified in any way to use a 50% blend of SAF. The current in-production engines developed by GE Aviation are certified to operate with a blend of up to a 50% blend of SAF.

To be able to use 100% SAF, some modifications to the aircraft engine will be necessary, but these modifications will be small, Slattery said.

The Covid-19 crisis and the Boeing 737 MAX grounding had a “very meaningful” effect on GE Aviation’s business, Slattery said, while stressing he sees a clear improvement in the sector with a rise in new aircraft and engine orders and the return of travel demand.

“We’re at an inflection point in our industry,” Slattery said. “We need to win the right to continue to grow and that’s going to be rooted, in my humble opinion, in our commitment to drive down CO2 emissions.”

Sources: AINonline, Aviation Today, Aviation Pros