GRantham Scholar Su Natasha Mohamad who researches plastic, planes and LCA.

Planes, plastic and LCA: Su Natasha Mohamad interview

Grantham Scholar Su Natasha Mohamad works on planes, plastic and LCA. LCA –  Life Cycle Analysis – is one the best ways to produce evidence about sustainability claims. At the Grantham Centre we have a special research project which uses LCA to create better systems of reuse for plastic, and Su Natasha is supervised by members of that team.

Can you explain your project on planes, plastic and LCA?

I look at the life cycle of an airplane. Specifically the plastic parts: where the plastic comes from, what it does and what will happen to it afterwards.

I look at both how plastic can be more sustainable in current designs and what we can do with plastic parts coming down the pipeline. Alongside this, I am examining the way policy is set about these things.

Is there much plastic in airplanes?

About a decade ago the major aircraft manufacturers like Airbus and Boeing, decided to use more plastics into planes. And they did this because they wanted to make planes lighter. Because when they’re lighter, planes don’t need as much energy to fly. So fuel consumption is reduced.

However, metal is usually easy to reuse. Planes were sent to ‘plane graveyards’ for people to pull out what’s recyclable.

So plastic waste from planes is a new problem

A plane usually lasts about 25 years. So in the near future we’ll have these new plastic parts of planes to dispose of.

But the spotlight has been on making fuel more sustainable. Also, for decades, concern about plastic waste wasn’t much of an issue because the percentage of plastics-made parts are small and most parts of an aircraft are metals.

However, now Airbus and Boeing have introduced more plastic, concern about where these plastic parts will end up urges us to pay more attention. We need to know how these plastic parts of the aircraft will impact us and we need to know before more plastic-made aircrafts go into retirement. Understanding this would also encourage aircraft designers to build more sustainably.

What is Life Cycle Analysis?

LCA (Life Cycle Analysis) evaluates the environmental impacts of a product or system throughout its entire life cycle, from raw material extraction to disposal or recycling.

Find out more about Life Cycle Analysis in this interview with an expert from the Grantham Centre.

How does policy, LCA and engineering work together?

Grantham Scholar Su Natasha stands in front of a poster about her work on planes, plastic and LCA.
Su Natasha Mohamad presenting her work at SETAC. ‘I take great pride in being able to tell the little girl I used to be, ‘look where we are now’.

Overall, the use of LCA in policy can help to ensure that policies are evidence-based, effective, and targeted to address the most significant environmental impacts of a product or system.

For example, if the LCA identifies a significant impact on air quality from the manufacturing process, policymakers can develop regulations to reduce air emissions from manufacturing facilities.

Also, as I understand it, LCA can be used to evaluate the effectiveness of existing policies and regulations. By comparing the environmental impact of a product or system before and after the implementation of a policy, we can determine whether the policy is effective.

What factors influence plane design beyond engineering?

Airplane design is influenced by various factors and one of the key ones is how profitable an aircraft could be. This includes the cost of raw materials, manufacturing, assembling the parts and even down to how much maintenance costs after years in service.

Also, manufacturers have to pay to dispose of old airplanes. So they want to recoup those costs if they can.

What about regulations?

All airplanes must meet strict safety and performance standards and this is decided by regulatory bodies such as the Federal Aviation Administration (FAA) in the United States or the European Union Aviation Safety Agency (EASA) in Europe.

Regulations can impact airplane design in terms of factors such as weight, size, and performance.

And then there’s customer based considerations

Customer demand affects the life cycle of a plane. For example, recently Airbus built one of the largest aircraft in the world. It can hold up to 500 passengers. But because of the decline in demand for travel recently they put them into early retirement. Each of the aircrafts is only 10 years old, brand new, and perfectly working.

I also notice that passenger comfort and aesthetic values is becoming crucial. Airliners increasingly want to provide a comfortable and enjoyable experience. This can include factors such as seating arrangements, cabin layout, and in-flight entertainment systems.

Airplanes can also be seen as symbols of national identity and pride, and as such, their design can be influenced by cultural and aesthetic factors.

What about sustainability and planes?

Aviation is paying attention to environmental concerns as there’s increasing pressure to design more environmentally friendly planes.

And this is where my project could help. I am addressing which part of the aircraft’s life cycle – for example assembly or production – is not sustainable or in other words has high carbon leakage. And by identifying these hotspots, aircraft designers could decide on a more sustainable approach.

There’s also a growing research on alternative fuel sources such as Sustainable Aviation Fuel (SAF) where biofuel is used to power aircraft that has similar properties to conventional jet fuel but with a smaller carbon footprint.

What specifics does a Life Cycle Analysis of a plane consider?

A good way of thinking about this is looking at claims that are made. So say a manufacturer says this plane is more sustainable than that one. A Life Cycle Analysis can say if that is true.

For example, with the lighter planes, an LCA can compare the materials used to make the lighter one with the materials used with the heavier one. It doesn’t just compare fuel use, but looks at how component parts were made, and the embodied carbon of plastic vs metal. An LCA can ask what is the balance of using more plastic but less fuel.

You’re looking at specific parts of the plane for your LCA?

Su Natasha using scientific equipment to help make a Life Cycle Analysis of plastic plane parts.
Su Natasha in the lab.

Yes, we are focusing on the fuselage of the aircraft where we as passengers sit in an aircraft. In an LCA study, this is called defining system boundary.

System boundary is where we identify stages of a product or process life cycle that are included or excluded from the analysis. This allows us to define the scope of the assessment and determines the accuracy and completeness of the results. The system boundary can be defined based on the goal and scope of the LCA, which determines the purpose of the study and who are the intended audience for the results.

In practical terms I am looking at the cabin wall, passenger windows, cabin door, cabin floor and overhead compartment.

So what you exclude from an LCA is as important as what you include

Aircraft parts can number into the millions depending on the size of the aircraft. So I might need an entire lifetime if I were to include every single one!

Hence the system boundary helps define the direction and scope of the project. From this point, I then start collecting samples and this process we call building an inventory. We are lucky to have our industrial partner, Aircraft Interior Recycling Association (AIRA) who provide aircraft samples and insights on these samples.

People might assume manufacturers already have to justify their claims about sustainability

It’s true that LCA is not yet a requirement for all manufacturers, however, there is a growing awareness of the importance of sustainability and environmental impact. And whilst many companies are voluntarily doing LCAs to understand the full impact of their products and make more informed decisions about sustainability, many still don’t.

In my opinion, this is where academia comes in. Our work could help demonstrate how some practices are necessary and worth conducting.

Companies will soon realise they want scientific data to back up their claims. Conducting an LCA allows them to verify those claims and provide evidence to support them. I notice that this is particularly important in today’s market, where consumers are increasingly concerned about sustainability. People look for products that have a lower environmental impact.

But at COP I heard people speak about ‘sustainable planes’ only in terms of fuel, not LCAs. I want to help people make the right choices.

You were one the University of Sheffield official observers at COP27, how was that experience?

Going to COP was a once in a lifetime opportunity. I would never have imagined being there. COP27 was emotional and I got to do amazing things.

For instance, we were there when a 10 year old, beautiful Ghanaian girl read an appeal to world leaders asking for climate actions. She received a standing ovation and I could feel my heart pump louder and harder as we stood. And we were there when newly appointed President Lula promised to restore the Amazon.

I also got an opportunity to be on Thailand national TV speaking to the Minister of Natural Resources and Environment about how youth can be part of climate solution. And I met a group of medical practitioners who shared their grave concerns on climate justice.

My appreciation towards my project amplified after COP. It’s was a strong push to be more driven towards sustainability. I also noticed that I’m more careful when making purchases. With that said, I’m far from a good green practitioner! I believe a lot of people out there are greener than me but I’m grateful that COP boosted a sustainable consciousness in me.

Grantham Scholars including Su Natasha standing in front of a plane on their way to COP27.
Grantham Scholars on their way to COP27.

What were you doing in medical engineering and how did that lead you to planes, plastic and LCA?

Basically a medical engineer is the doctor of the machines that medical doctors use. After completing my previous role at a hospital, I decided to embark on a PhD. My former supervisor recommended that I create an ink capable of detecting microplastics.

However, as I got into the topic of microplastics, I became captivated by the lack of attention paid to plastic pollution within the medical engineering field. I was compelled to shift my focus.

So I made the bold decision to change supervisors and refocus my studies on understanding the impact of plastic on our environment.

Was it difficult to move into this type of research?

I must admit, shifting from the medical field to aviation has had challenges. However, I firmly believe that challenges exist regardless of whether we remain in our current field or explore new ones. I like a quote that was on my school wall by Aristotle ‘learning is not child’s play, we cannot learn without pain’.

Despite the difficulties, I relish the challenge and use it as an opportunity to expand my horizons and explore new possibilities.

Besides that, I came from a tiny town in Northern Malaysia where we don’t even have an airport –  I grew up with the idea that aircraft are a luxury, beyond the reach of ordinary people. And in my country to be a girl in aerospace with engineering skills is rare. So having the opportunity to learn about aviation represents a significant personal accomplishment.

So I take great pride in being able to tell the little girl I used to be, ‘look where we are now’.

Do you have hope for the future?

YES! A million times yes. The world continues to revolve, so we might as well be optimistic.

Creating a holistic solution isn’t easy. Rome wasn’t built in a day and this saying applies to all – be it in aviation or home waste management.

However, if we continue then little by little we will build a habit of wanting everything to be sustainable. We will realise how important sustainable living is. We will channel our needs toward sustainable life and we will soon find it is not impossible.