Update on Sustainability Efforts Throughout Aviation Industry

The challenge of reducing artificial carbon emissions extends well beyond the ground, but thankfully technologies to address this problem are on the rise, quite literally. In early September 2021, the Federal Aviation Administration (“FAA”) awarded more than $100 million to six airline-industry companies to continue development of aircraft technologies, which reduce fuel use, emissions, and noise. (FAA, CLEEN Program Awards). The awards were made to commence the third phase of the agency’s Continuous Lower Energy, Emissions, and Noise (“CLEEN”) program, which is the FAA’s primary sustainability initiative. Id. Although technologies developed under this phase will not be seen on commercial aircraft until the 2030s, the program overall has been a great success, resulting in significant noise and emission reductions due to enhanced engine systems and advanced aircraft wings. Id. 

Congress must recently re-authorized the CLEEN program in 2018, and it was codified into law under 49 U.S.C. 47511, but the program began in 2010 with agreements between the agency and five partners, namely Boeing, General Electric, Honeywell, Pratt & Whitney, and Rolls-Royce. (FAA, CLEEN Program). After ten years of technology development through the initial phases of the program, the third phase proposes more aggressive targets and is open to both subsonic and supersonic innovations. Id. Two areas of renewed interest in aviation sustainability are the use of sustainable aviation fuels and the reduction of noise by supersonic aircraft, both of which could receive attention under the third phase. Because these areas may very well manifest to passengers in the next decade, they are worth further discussion herein. 

Sustainable aviation fuel (“SAF”) is composed entirely of organic materials such as fats, natural oils, algae, and corn grain which is modified into a low-carbon fuel useable by all commercial and private jets, rather than traditional “Jet-A” kerosene fuel. (U.S. Department of Energy, Sustainable Aviation Fuels). Using these fuels significantly reduces an airplane’s carbon emissions and results in less harmful compounds being emitted by an airplane’s engines both in the sky and on the ground. Id. However, this alternative fuel is still a relatively recent innovation, so its distribution to airlines has been limited so far. 

On September 9, 2021, the Biden Administration released a fact sheet outlining the President’s vision for a cleaner aviation industry, a large part of which revolves around the increased adoption of SAFs. (The White House, SAF Fact Sheet). The release detailed the commitment of several national airlines to the adoption of SAFs, although there is no formal agreement between the federal government and the airlines on the targets. Id. With that said, Delta Airlines committed to replacing 10% of its current jet fuel use with industry-developed SAF by 2030, while American Airlines plans to procure 10 million gallons of SAF from a supplier by 2025. Id. Select airports were also lauded by the Administration for pursuing operational efficiency and emission reduction efforts, including building solar farms on-site and undertaking air quality initiatives throughout their facilities. Id. The Administration will release an aviation climate action plan in the coming months, which is a strong indicator that curtailing aviation emissions will be a key goal of the President during his tenure. Id. 

Besides emissions produced during flight and on the ground, noise reduction is another target of the FAA’s CLEEN program, especially given renewed interest in commercial supersonic flights. In 1973, the FAA finalized a rule prohibiting overland supersonic flight in the United States and supersonic flights from a certain distance due to concerns about supersonic noise impacts to local communities. (14 C.F.R. § 91.817). The agency does allow flight testing at supersonic speeds, but the regulation gives the agency broad discretion to deny a flight if there are concerning environmental impacts. (14 C.F.R. § 91.818). Earlier this year, the FAA adopted a final rule amending part of the §91.818 regulation to streamline the application process for supersonic flight tests, but a general prohibition remains on overland commercial supersonic flights. (FAA, Federal Register). The FAA’s recent regulatory action in the area could be a sign that supersonic aircraft may again be authorized to carry passengers in some capacity by the end of the decade. However, there is a long way to go before commercial supersonic aircraft are a common option for passengers at large airports.  

With the rising potential for the return of supersonic passenger flights, two exciting projects are worth mentioning, namely NASA’s X-59 experimental airplane and Boom Supersonics’ commercial supersonic jet, the Overture. The X-59 aircraft is part of NASA’s Low-Boom Flight Demonstrator Program and will fly over communities to test its “quiet” supersonic technology. (NASA, Aeronautics). The X-59 is not designed to be commercially adopted upon conclusion of its test campaign, but the quiet sonic boom technology itself could be used to enable overland supersonic flights because of the reduced noise. Id. NASA will share the program’s noise findings with regulators, primarily the FAA, to inform decisions on current restrictions for supersonic aircraft. Id. For its part, Boom Supersonic, located in Centennial, Colorado, is designing its Overture aircraft to cut the flight time of popular trans-oceanic routes in half at supersonic speeds. (Boom Supersonic, Overture). Additionally, the aircraft will fly on 100% SAF and will be designed for “zero” overland noise impacts. (Boom Supersonic, Sustainability). United Airlines, one of the four major passenger airlines in the nation, clearly sees the value in Boom Supersonics’ aircraft, as evidenced by its commitment to purchase fifteen of the aircraft with an expected commercial entry date of 2029. (Boom Supersonic, United). Time will tell if the Overture begins passenger service flying only trans-oceanic routes at supersonic speeds, as currently permitted, or if the company will push hard for the FAA to permit overland supersonic routes from the start. 

The aerospace community at large, including small operators, should take heed of the FAA’s CLEEN program and President Biden’s push for increased climate action within the industry. Companies should take genuine measures to improve the sustainability of their operations, such as by investing in noise and emission reduction technologies, or risk public outcry and/or decreased customer revenue. To spur widescale adoption of SAF, the FAA could mandate that all future new aircraft types built by Boeing and Airbus operate with 100% SAF, or at least a high percentage worth. It is likely more difficult to adapt existing aircraft to sustainable fuel, but new aircraft types could be designed to accommodate SAF from the start. Although investments in CLEEN-related technologies may be burdensome at first, the public increasingly expects to see genuine climate and sustainability action by companies across the nation, and it would be financially imprudent for the aviation sector to make light of these calls.