Skip to page content
Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

The latest general information on the Coronavirus (COVID-19) is available on Coronavirus.gov. For FAA-specific COVID-19 resources, please visit faa.gov/coronavirus.
United States Department of TransportationUnited States Department of Transportation

The Air Up There Podcast

Reducing Aviation Noise and Emissions

Season 3, Episode 4
Published: Friday, September 17, 2021

Climate change impacts the world we live in today as well as future generations. As with other transportation sectors, aviation plays a role in sustainability. The Federal Aviation Administration (FAA) is rolling out Phase III of its Continuous Lower Energy Emissions and Noise (CLEEN) Program, working with stakeholders to decrease aviation's effects on climate change. Among other things, Phase III of the CLEEN Program introduces new environmental goals, including reducing noise and carbon dioxide (CO2) emissions.

Tune in to this podcast episode where we sit down with Kevin Welsh, FAA's Executive Director of the Office of Environment & Energy, and David Hyde, former Director of Environmental Policy at the Aerospace Industries Association, to discuss what CLEEN is, what success looks like, and what is exciting about this new phase.

Reducing Aviation Noise and Emissions

Reducing Aviation Noise and Emissions

Transcript

Dominique Gebru:
You're listening to The Air Up There, a podcast about the wide world of aviation and aerospace. I'm Dominique Gebru. Before we dive into today's episode, I just want to share a quick note about the show and why we created it in the first place. The aerospace industry continues to grow and in the future, it's going to be a whole lot more complex, but despite the tremendous growth in the sector, we're seeing slower progress when it comes to the workforce. I'll give an example. At the end of 2018, about half of the 330,000 aviation maintenance technicians in the country were between 50 and 70 years old. That means we can expect a lot of folks to retire within a short period of time, and we need people to take their place. Here's where you come in. If you know a young person, share this episode with them. We at the FAA envision a future workforce that's as diverse as our nation.

Dominique Gebru:
With so much exciting innovation in the sector, there's really no better time to consider a career in aerospace. And it's never too early to start thinking about it. All right. Let's start the show. These are the facts. Climate change is affecting the world now and similar to nearly all aspects of our lives, aviation has an impact on that. But what exactly would a more environmentally sustainable aviation industry look like? And what does sustainable mean anyway? All across the agency, the FAA is working hard to answer that question and making significant strides to that end. This year, the agency is rolling out phase three of its CLEEN program. We love a good acronym. The CLEEN program, or Continuous Lower Energy Emissions and Noise program, brings together the FAA and industry around a mutual set of goals aimed at decreasing aviation industry's effect on climate change.

Dominique Gebru:
You can think of it like an accelerator for innovation. From nose to tail, industry partners are looking at ways to reduce noise, fuel consumption, and emissions. So where does the FAA come in? Well, we regulate the industry. Aircraft and engines have to meet a set of environmental standards along with other rigorous safety standards to receive airworthiness certification. And as aircraft technology advances, the FAA has made CLEEN goals even more aggressive. With each new phase of the program, we've added new goals. New for phase three, we've set goals for community noise exposure and aircraft engine particulate matter emissions.

Dominique Gebru:
And the third phase will also include supersonic aircraft, which is pretty cool. We want to pull back the curtain on what exactly the CLEEN program means. So of course, we turn to the experts. Kevin Welsh is the Executive Director of the Office of Environment and Energy at the FAA. Kevin has an extensive background working on climate- and environment-related issues at the FAA, the White House, and in the private sector. Kevin is joined by David Hyde, the Director of Environmental Policy at the Aerospace Industries Association, or AIA. AIA is one of the new partners participating in phase three of the CLEEN program. Our colleague, Sabrina Jones, spoke with Kevin and David about what CLEEN is, what success looks like, and what excites them about this new phase. Let's hear the interview.

Sabrina Jones:
Kevin and David, thank you again for joining us today. To start, Kevin, will you give us a quick overview of the FAA strategy for addressing climate change and other environment-related concerns?

Kevin Welsh:
Yeah. Thanks, Sabrina. It's great to be here and chat with you in the FAA Office of Environment and Energy where I work. And we really think about our role as how to make airplanes cleaner and quieter in very simple terms. And so when it comes to climate change, we focus a lot of our efforts on really reducing greenhouse gas emissions and specifically carbon dioxide from airplanes. There's a couple things to know. One is, it's very difficult and costly to do, in part because airplanes are already very efficient, but also because there are not a lot of readily available alternatives for reducing airplane emissions. So what we do is focus on a range of topics from new technologies, sustainable aviation fuels, and more fuel efficient operations to do as much as we can from the federal government side, working with industry and nonprofits to reduce aviation emissions towards addressing the broader climate change objectives of the Biden-Harris Administration.

Kevin Welsh:
There's a couple of really important things to think about here is, one, the aviation sector really has focused on climate and sustainability for many years now, but there's a lot more work to keep doing. So, as I said earlier, the aviation sector is already highly efficient, but as the sector continues to grow, and even with the recovery from COVID, we expect continued growth in the sector, that can offset some of the gains and efficiency. So really the focus ahead in the years and decades ahead is what action can be taken to reduce the emissions from the sector in line with ambitious goals like this administration's goal of achieving net zero emissions economy-wide by 2050. So what we're focused on when we think about aviation sustainability is how does aviation fit into that picture? And how can we — recognizing the importance of aviation in terms of connecting people and business and commerce — how can we foster the continued role of aviation, but also ensure a step change in how we're addressing sustainability and climate change to achieve those ambitious objectives?

Sabrina Jones:
You touched on this a little, but how has aviation become less harmful to the environment in recent years? Help us understand where we started and where we're at now.

Kevin Welsh:
There's a strong track record in terms of improving technology and fuel efficiency over time. So just, as one example, between the early 1990s and 2018, the U.S. aviation sector improved its fuel efficiency by over 70%. From around the year 2000 to the same time periods of 2018, the number of passengers grew at a much higher rate than the level of emissions showing sort of a decoupling between growth, which is good, and emissions growth, which we don't want. So there has been a lot of progress, but again, looking at that, if the aviation sector continues to grow without more action, without more fuel efficient technologies, sustainable fuels, and other things to address, aviation, we won't be doing enough to achieve really ambitious climate goals.

Kevin Welsh:
So really what we're focused on is how do we build on the foundation that we already have while recognizing that there's a lot more action that needs to be done. And I talked a little bit about that. It's both the technical work that we do, but also the collaboration that we're doing with international partners at the International Civil Aviation Organization, other countries around the world, and importantly, the aviation sector, aerospace manufacturers, airlines, airports, and nonprofit organizations that are representing civil society. So really it's both the technical work that we need to do and also the collaboration globally that's really important.

Sabrina Jones:
Switching to David. Could you provide the airline manufacturer's perspective? How have milestones been achieved through this collaboration?

David Hyde:
AIA represents the manufacturers of aircraft and aircraft engines, and that's where we really provide the most direct contribution to addressing aviation's environmental impact. Kevin gave some figures on sort of this system-wide improvements we've seen over the last years and decades, but to focus in at the aircraft level, modern aircraft are about 80% more fuel efficient than the first generation of jet airliners. And with each new generation of aircraft, we expect to see improvements in efficiency in the region of 15 to 25%. So over time that does add up to significant improvements. We realized as manufacturers that that alone is not going to be enough to reduce the environmental impacts from aviation and meet some of those ambitious goals, which we've set ourselves as an industry in which governments are also setting. So we really view this as a driver of collaboration between different parts of the sector, between governments, and between different elements of society.

David Hyde:
So in addition to those improvements in aircraft technology, as manufacturers, we realize that a really crucial way for us to meet our emissions goals is going to be the use of sustainable aviation fuels. That's something we very much want to see more of. We're working with other associations and stakeholders to try and advocate for policies that will really drive up the use of those fuels, both here in the U.S. but globally, too. Outside of that, we also want to see improvements in air traffic control and things that will enable airlines and aircraft to operate more efficiently. There's really not one solution. It's very much a collaborative effort that we are very happy to play our part in enabling. Way back before I was involved with AIA, airlines for America, and the FAA did start a consortium with a group to really try and drive progress on the use of sustainable aviation fuels.

David Hyde:
We realize that this is a really important area that we do need to see progress in. We've been really pleased to support … efforts over many years. And we're obviously delighted with the attention that these fuels and sustainable aviation, in general, is now getting under this administration. In terms of CLEEN, AIA, I wouldn't say we're directly involved with that, but our members are obviously the ones who contribute to the technology development that takes place under those programs, and it's something which our members value greatly. AIA members contribute 50% of the costs to those programs and with the FAA matching them, but actually I think a sign of how much we do appreciate the work that CLEEN does, and some of the developments it enables is shown by the fact our members have far gone over what's required there in terms of that match. I could speak a bit more about what some of those benefits of CLEEN are, if you'd like.

Sabrina Jones:
Yes. I would love to hear why this work is important to your members.

David Hyde:
Kevin mentioned the fact that the aviation sector is continuing to grow, and that's something which obviously benefits the industry as a whole. It enables the AIA members, air framers, engine manufacturers continue to sell more aircraft, which is obviously something that we want to do, but we realize that that group is depending on maintaining the industry's licensed to operate. And we can only do that by being both good neighbors locally, in terms of making sure we operate in a way which is quiet and does not disturb the communities around airports, but also at a global level we want to ensure that we are doing our part to beat the ambitious goals of the Paris Agreement, to enable the U.S. to meet it's that zero goals. And to do that, we're going to need to see improvements in aircraft technology. What CLEEN really does is help accelerate some of those technologies, which are out there and have potential into the aircraft fleet itself.

David Hyde:
So with the focus on safety and that obviously being a priority for the industry, technologies don't go from the conceptual phase to maturity straight away. It's a long progress and it takes a lot of time and money to do that. Programs like CLEEN programs, like NASA and the government really support some of those developments and technologies maturing faster than would otherwise be the case. Also within companies, those programs can really help make the business case for investments in some of these technologies. Just like other business, there are finite resources and funds available for this, but by the FAA supporting some of these efforts and providing that cost share, it makes those investments much more attractive from an industry perspective and ultimately helps them deliver the environmental benefits sooner than they otherwise would.

David Hyde:
So there's really a wide range of stuff going on within the CLEEN program. There were three goals, actually maybe four goals now, Kevin, because I think supersonic noise is a new one, but traditionally it was subsonic noise, fuel burn, and then other emissions. And there's a whole load of different technologies that CLEEN has supported to try and reduce and sort of improve performance in those areas. They cover everything from the airframe, the bigger infrastructure level improvements right down to what might sound like quite small improvements, but actually can deliver pretty significant improvements in those environmental performance measures.

Sabrina Jones:
This question is for both of you. What are your measurements of success as far as CLEEN and other environmental initiatives are concerned?

Kevin Welsh:
Thank you, Sabrina. I think that's a great question. I want to start with a stepping back a little bit and then I'll get right to the heart of that question, but just following on what David said. In terms of the technologies, right, like I think from the perspective of the lay person or a member of the public, sometimes it might be hard to think about all that goes into making an airplane cleaner and quieter. Right? And I started out saying, that's really what we're focused on. When you think about CLEEN, it really gets down into very specific actions and technologies working with aerospace manufacturers to make those changes. So those could be you take the wing of an airplane. Those could be aerodynamic improvements just to parts of the wing in and of themselves might have an incremental improvement in efficiency, but we're not just working on that.

Kevin Welsh:
We're working on that, but we're also working on something to do with the engine that has a similar improvement and also may lead to the engine being quieter. We're working on a full suite of technologies. And when you take them together, they're going to add to real significant improvements over time. So that's really how we think of the CLEEN program kind of among a wider range of activities. Now, in terms of success, there's two ways you can look at it. One is we have a very limited set of resources as the U.S. government at the FAA working on this particular issue so we think about how do we best use the limited resources we have to facilitate technology gains. And so we can either help aerospace manufacturers move more quickly in terms of technologies that would have taken them longer to develop or potentially develop technologies that were sitting on the shelf and not being developed without government funding.

Kevin Welsh:
So we kind of measure our success both on how quickly we're maturing those technologies and potentially identifying technologies that would not have otherwise made it to market had the government not intervened. And we then kind of assess the program, how much would benefit in terms of emissions reductions and noise. So we've done an assessment. In the first 10 years of CLEEN we've estimated that those technology improvements will save the aviation industry 36 billion gallons of fuel by 2050, reducing costs by over $70 billion and lowering CO2 emissions by over 400 million metric tons, which is people always use this, it's the equivalent of reducing 3 million cars from the road from 2020 to 2050.

Kevin Welsh:
Measuring success, I think, is one of the challenges when you look at specific actions in this area and we try multiple ways to measure that success, and again, a further kind of point I would add here is we're continually thinking how we can be more successful and how we can do more and go beyond what we're currently doing. Where I started the discussion today was thinking about the record the sectors had up until now for recognizing there's a lot more work to do. So we're actively thinking about how do we build on CLEEN? How do we go beyond what is just happening in the CLEEN program to do more, to do more to achieve emissions reductions? A lot going on there, but we're continuing to evaluate what success means and how we can be successful and do better, frankly, from a U.S. government perspective

David Hyde:
From the industry perspective, I think echoing what Kevin said, there are several different ways to measure success. There is the acceleration of technologies and getting them into the fleet and ultimately the environmental benefits that those technologies will deliver. As representatives of the U.S. aerospace industry, one thing that we really value about these programs is that they give our industry a competitive boost against industries that other parts of the world. This really helps us to get technologies to the market quicker, which makes AIA members' products more attractive, which is good for both our members and the wider U.S. economy. So there's some of the more obvious benefits that we see in this program. I think another benefit is maybe less obvious and which people don't appreciate is actually the learning that comes from some of this research and development activity. It's not just the technologies that immediately come to market where the benefit comes from.

David Hyde:
It's also other applications that we made that may be inspired as we go through this process. I think one of the more interesting programs to come out of CLEEN was the adaptive trailing edge, which is a shape-shifting alloy which can change shape during flight to make an aircraft more efficient. The original use of that obviously came through the CLEEN program, but that has begun to work itself into other applications outside of that. And that's all due to some of the lessons learned as a result of CLEEN. And it's also learning about some of the things that maybe don't work. It's learning about some of the trade-offs. If you're looking at a technology to do with emissions that could potentially have a less than optimal output in terms of noise or another environmental factor. And going through it and learning that process allows more intelligent decisions to be made as aircrafts are designed in the future.

Sabrina Jones:
Thank you both for these amazing examples of success. Are there any future milestones that you'd like to share with our listeners?

Kevin Welsh:
Well, I think from the U.S. side, we're relatively early in this administration and we've seen the president frankly take a huge leadership role in climate change, including rejoining the Paris Agreement on day one, convening leaders around the world on April 22nd, on Earth Day, and that commitment extends to aviation and already the secretary of transportation has committed to putting a vision out for how we achieve aviation emissions reductions consistent with that climate vision of President Biden. Working there, we're working very concretely on a vision and a climate strategy for aviation that we hope to announce in the coming months that will really explain and not just explain, set out a course of actions that this administration will take to really enable greater reductions from the aviation sector many years ahead and put us on that path to contributing to the president's net zero goal that I mentioned earlier. There's definitely a lot more to come. CLEEN is a really important part of that.

Kevin Welsh:
It's been very successful as a program. And so what we think about again is building on a foundation of activity that FAA has had for many years now. And where can we do more? How can we accelerate that? I guess two additional topics I'll mentioned today, but we probably don't have time to go in much greater detail is another really important aspect of our work is Ascent Center of Excellence, which is a university led center of excellence that does research and development activities on these same topics, on their 16 universities. It's co-led by Washington State and MIT. And we work with that center of excellence really to address some of these same questions and look from an academic perspective on how we can broadly take on aviation, climate, environment, and noise issues, so that's one really important thing. And then the other thing that we've mentioned several times in this podcast, there's sort of focused as well is sustainable aviation fuels.

Kevin Welsh:
The FAA has worked actually for many years on sustainable aviation fuels. As David mentioned, the commercial aviation alternative fuels initiative is something we founded back in 2006. And in that period of time, we have worked on establishing safe and effective pathways for seven tools that can be used as drop-in replacements for existing petroleum fuels. And what I mean by that is there are sustainable aviation fuels out there today that can be used in the existing airplanes and the existing infrastructure. And in fact, last year in the U.S. nearly 5 million gallons of sustainable aviation fuel were used. So that's a really important step, but we've got a lot more work to do because it turns out that that 5 million gallons is just a very, very small percentage of the total volume used. And so where we're focused on sustainable aviation fuel in the years ahead is how to address the higher costs of sustainable aviation fuel relative to fossil fuel and how to scale up production. So that's another area. Again, it complements the work we're doing in CLEEN and technology where we're focused on how do we address the aviation climate impacts.

David Hyde:
And from an industry perspective, as international industry, we have set a long-term goal to reduce our emissions by 50% by 2050. That's our industry goal. There's also work going on in which the FAA has been really instrumental in driving forward, and that's to set a long-term goal. As an industry we think that's important that that work is done. There's a lot of analysis which needs to inform what that goal should be, and we want it to be both ambitious and achievable, but certainly by the next general assembly of next year, we'd hope that that's something that can be agreed. As manufacturers, long-term, we want to contribute to the fully sustainable aviation system. That's obviously extremely difficult for a sector like aviation, but that's why programs like CLEEN, and other partnerships between industry and government are going to be really important, not just in the next few years, but going forward for some time to enable a fully sustainable aviation system in the future.

Sabrina Jones:
We're going to have to bring this to a close, but before we end, is there anything else that you want our listeners to know?

Kevin Welsh:
Thank you. To close, I hope it's come across that this is an issue that I am personally passionate about and so are my many colleagues at FAA. And it is widely recognized that addressing the climate impacts of aviation are really challenging, that there's a lot of work ahead. But I think the piece of information that I would want to convey more broadly to people who haven't closely followed this topic is that there is a lot of actions area. There is a large commitment. There's a recognition of the need to do more, but one of optimism. There are opportunities here and if the U.S. government private sector non-government organizations work together, this is something we can actually address. And so I'm optimistic about what can happen in this area in the future. And I look forward to contributing and FAA's role, frankly, in contributing to that effort in the years ahead.

David Hyde:
Nothing much more to add for me, Sabrina. Just want to echo Kevin's comments and sentiments there, and thank him and his team for all of the work they do to actually ensure that this issue gets the attention that it deserves and warrants both domestically and internationally. And obviously to thank you both for the opportunity to speak with you today.

Dominique Gebru:
As you heard the FAA and private companies take climate change action seriously, and there's a lot more going on where environmental sustainability is concerned. At the FAA's tech center in New Jersey, which is basically our research hub for the agency, scientists are doing extensive work to test alternate fuel sources. If you'd like to learn more about that work, you'll want to keep an eye on this podcast feed or an ear, I guess. We're working on an upcoming episode about the research that goes on at our tech center so you don't want to miss that. We hope today's episode taught you something new. The Air Up There is a podcast from the Federal Aviation Administration. If you liked today's episode, please subscribe and share it with someone else. You can find the FAA on social media, too. We're @FAA on Facebook, Instagram, and LinkedIn, and @FAANews on Twitter and YouTube. Thanks for listening.