Safely above the clouds – plastics in aviation

Around 10,000 m altitude, speeds of almost 1,000 km/h, outside temperatures as low as -60°C. One of the reasons why we as airline passengers don't notice any of this is because of plastics. These are not only mechanically and chemically resistant, but also lightweight. And lighter aircraft cause fewer CO₂ emissions, which is of great importance for achieving climate targets.

Almost all components of an aircraft today are made of fiber-reinforced plastics (FRP). These are synthetic resins reinforced with glass or carbon fibers. This material meets the stringent requirements of the aviation industry. The fact that aircraft are becoming lighter, more powerful and more reliable is therefore also a credit to the chemical and plastics industry.

Today, the aviation industry is particularly in the public eye when it comes to environmental and climate protection. The aviation industry has set itself the goal of halving CO₂ emissions by 2050 compared with 2005. One approach to saving fuel and thus CO₂ is lightweight construction and the associated use of lightweight materials that also meet all the requirements relevant to aviation - and today these are primarily FRP made of carbon. With optimum design, a weight reduction of around 50 percent can be achieved with this material compared with aluminum.

In addition to fuel savings, the reduced weight has another effect: lighter aircraft require more filigree landing gears and smaller tanks. This saves material and compensates for additional costs incurred by FRP. Other advantages of the material include better processability compared with other materials, high chemical and corrosion resistance, high mechanical stability, good sliding properties, low maintenance, temperature resistance and inherent flame retardancy.

Plastic is found in a wide variety of places in aircraft: GVKs have become established in the aircraft interior, while CFRPs are used in the fuselage. Fiber-reinforced plastics are used in fastening elements, seals, cabin fittings and trim parts as well as in propulsion or drinking water systems.

Plastics processing companies such as Röchling SE & Co. KG, igus GmbH or Ensinger GmbH offer materials that meet the high requirements applicable to aviation and also fulfill the fire protection standards FAR 25.853 and UL94 V0.

The aviation industry is growing - and growing rapidly. This naturally poses a number of challenges for the industry. For one thing, passenger aircraft have to be manufactured at rates of sometimes more than 70 deliveries per month. For this reason, intensive research is now being carried out to optimize series production – for example, with the development of new resins that cure faster.

On the other hand, the aviation industry must strive to significantly reduce CO₂ emissions in order to achieve climate targets. Lufthansa Technik and BASF achieved a breakthrough in a joint project last year: Thanks to the new surface film "AeroSHARK," which is modeled on the fine structure of shark skin, an aircraft's frictional resistance in the air is to be reduced, thereby also lowering fuel consumption. A friction reduction of more than one percent is expected for use on ten Boeing 777F aircraft operated by Lufthansa Cargo. What sounds little corresponds to an annual saving of almost 11,700 tons of CO₂.

3D printing also offers great potential. It can be used to produce aircraft components from a single casting, eliminating fasteners. Since a solid construction method can be replaced by a ribbed construction method, an aircraft with parts from the 3D printer becomes much lighter.

But there are already successes to report today, too: German airlines have been able to reduce their fuel consumption per passenger per 100 kilometers by a good 43 percent since 1990. Whereas this figure was 6.3 liters in 1990, in 2019 it averaged just 3.56 liters per passenger. This success is due in no small part to plastics.