Oct. 11, 2021, © Leeham News: EcoAviation was the Number One topic at the Oct. 3-5 IATA AGM in Boston.
IATA, the International Air Transport Assn., set a number of lofty goals to remove carbon emissions from commercial aviation by 2050. Interim goals were also set.
Tim Clark, the president and COO of Emirates Airline, didn’t mince words about these goals.
“People are expecting us… by the end of this decade, to take out 40% of our emissions… We are in la la land if you think we are going to do this,” Flight Global reported.
Sustainable Aviation Fuel (SAF) is here now. It is biofuel, which may be compared with the ethanol blended into gasoline in the US. In most places, gasoline contains a blend of 10% ethanol made from corn. SAF has been made with a variety of bio-sources.
But there is not nearly enough feedstock available to make more than a small dent in the global commercial aviation fuel requirements.
Battery and hybrid-battery power is suitable, with caution, for only small airplanes. Hydrogen powered aircraft are at least 15 years in the future.
There is one technology that is available now, one that’s been under study since the Boeing 727/McDonnell Douglas MD-80 days: Open rotors.
The noise and blade failure issues are understood, as have some solutions. Fuel economy is improved by at least 20%, if not more. Basic airplane configurations have been designed.
Clark talked down the open rotor technology at IATA, saying designing the engines, wings and technology will be “astronomical.”
Well, not really.
Any new airplane that makes a step change to justify a new design is going to cost billions in any event. “Astronomical” is a highly subjective term. But if the commercial aviation industry is serious about reducing emissions, greenwashing goals with unrealistic feedstock supplies, pie-in-the-sky technology and the absence of hydrogen infrastructure isn’t the way to go about it.
Open Rotors have been studied for some 30 years. There’s another decade at least of research underway. Solutions are being found. It’s time for regulators in Europe, the US, Canada, the UK and elsewhere to step up with mandatory emissions standards that force the aviation industry to get off the pot. These can force the issues on Open Rotor.
It’s been done before. In the 1960s and 1970s, regulators required the aviation industry to eliminate the black smoke trailing the first generation of jet engines. During the same era, noise regulations forced solutions to meet standards known as Stage 2 and Stage 3. Today, there are Stage 4 noise standards. Pratt & Whitney, CFM and Rolls-Royce met them. London airports required another level of noise reduction for engines powering the Airbus A380 and proposed Boeing 747 derivatives. The engines on today’s Boeing 787s, Airbus A330neos and A350s had to meet new standards.
ICAO’s guidelines—which must be adopted by governments to mean anything—say that airplanes like the Boeing 767 and 777 Classic now in production can’t be built from 2028 because these won’t meet emission standards.
The main limitation to Open Rotors now appears to be a slower cruise speed. This wouldn’t work well for intercontinental flights. But in the US, the average length of flight is 800nm. The lower speed wouldn’t be material on this length. Even on trans-continental trips, 10% lower speed may be an acceptable trade for lower emissions.
Likewise, within the European Union, the short distances wouldn’t have a meaningful impact on flight times.
No special infrastructure will be required for Open Rotor engines. There are no battery production and disposal issues. There are no SAF feedstock requirements, although obviously SAF would be an added benefit. There are no hydrogen-induced infrastructure issues.
Another major limitation is passenger acceptance. Studies say passengers won’t like propeller airplanes. Maybe the issues need to be recast in surveys. Ask if “new, open rotor technology will reduce fuel consumption and emissions and the impact on global climate change by up to 30%,” and see what they answer might be.
This is the best, near- to mid-term solution. It’s time for regulations to adopt the standards that will force aviation to move forward without greenwashing.