Reducing the environmental footprint of civilian jetliners is one of the biggest challenges facing the commercial aviation industry today. However, a new surface technology jointly developed by Lufthansa Technik and BASF dramatically reduces frictional resistance on aircraft, thereby improving fuel efficiency and lowering emissions.
AeroSHARK is the first fully aviation-proof series application for sharkskin technology, and in February, SWISS, the national carrier of Switzerland, became the first passenger airline worldwide to sign up for the innovative surface technology which improves fuel consumption and reduces emissions by 1%. SWISS has set a goal of becoming carbon neutral by 2050.
Dieter Vranckx, CEO, SWISS, said that the airline is keen to actively promote and invest in new technologies, and the decision to sign up for the innovative surface technology was another significant contribution towards sustainable air travel in the future.
Dr Johannes Bussmann, CEO, Lufthansa Technik, said, “Due to the long lifecycles in our industry, we cannot only rely on new aircraft generations to reduce our environmental footprint, but also need to specifically optimise existing fleets towards sustainability. AeroSHARK makes a significant contribution to this, and I am very pleased that SWISS is leading the way.”
Uta Holzenkamp, Head, BASF’s Coatings Division, said that SWISS was convinced by the solution showed that economic action and sustainability go hand in hand.
Smooth Operator
SWISS has announced that its entire fleet of Boeing long-haul jetliners will receive the fuel-saving AeroSHARK surface technology, starting in the middle of the year. The riblet films will be installed on the fleet of 12 777-300ERs in a phased manner during suitable maintenance layovers. Each aircraft will receive a coating of approximately 950 square meters of film on its surface.
The modification will significantly reduce frictional resistance, improve fuel efficiency by 1.1%, and reduce emissions. When one considers the annual operating profile of SWISS’ fleet of twelve Boeing 777-300ERs, it will generate annual savings of more than 4,800 tonne of kerosene and roughly 15,200 tonne of carbon dioxide. This is the equivalent of CO2 generated on approximately 87 long-haul flights between Zurich to Mumbai.
BASF has delivered the first series production batch of the jointly developed riblet films with the material, successfully clearing the mandated ‘First Article’ and ‘Incoming Inspections.’ Experts from Lufthansa Technik and BASF have now approved AeroSHARK’s use as an approved material for aircraft installation. The AeroSHARK material is now ready for EASA supplemental type certification. Another milestone successfully passed on our way to the start of the series application later this year.
Both companies state that the coating will have general durability of four years. However, removing the material after reaching this time frame is not mandatory, and various test patches of the technology already flying in normal daily operations have exceeded four years. The film’s durability will also depend on its location on the aircraft surface, and areas exposed to higher stresses may have more erosion.
Innovative Approach
Co-developed by Lufthansa Technik and chemicals and coatings manufacturer BASF, AeroSHARK surface technology comprises ribs around 50 micrometres in size, known as riblets. These riblets imitate the properties of sharkskin, which have particularly favourable flow characteristics. First concepts and studies regarding the use of sharkskin go back several decades, but it remained largely in the theoretic realm with progress only on small scale test applications of only a few square meters. However, both companies have finally advanced this technology to a certifiable solution that can be applied on a large scale over the last decade.
The technology was first applied on a Lufthansa Boeing 747-200 jetliner in 2019, and the aircraft was extensively flight tested in 2020. The previous issues related to dirt accumulating on the riblet surface did not negatively affect the 1,500+ flight hours accumulated on the Boeing 747-400 sharkskin testbed. According to Lufthansa Technik, single test patches of riblet film have several years of flight testing and the material composition proven in daily operations.
The results were encouraging enough for Lufthansa Cargo to emerge as the launch customer for AeroSHARK, placing an order for its entire fleet of Boeing 777 freighters. Lufthansa Cargo will equip all Boeing 777 freighters with AeroSHARK from 2022. A coating of riblet film of approximately 800 square meters will be installed on each aircraft. Once installed on these aircraft, AeroSHARK will result in each of the ten aircraft using 3,700 tonne less fuel and saving almost 11,700 tonne less CO2 emissions every year.
SWISS had already supported Lufthansa Technik and BASF during the development phase of AeroSHARK. It had provided a Boeing 777 jetliner in the summer of 2021, whose wing was precisely measured for the entire duration of a regularly scheduled flight between Zurich and San Francisco. From the data collected during these flights, Lufthansa Technik subsequently created highly accurate 3D models for flow simulations, based on which the AeroSHARK modification for the Boeing 777 was finalised.
SWISS will also provide one of its aircraft to STC flight to obtain the required Supplemental Type Certificate (STC) from the European Union Aviation Safety Agency (EASA). In addition, Lufthansa Technik and BASF will develop the new technology further for use on other aircraft types and even larger surfaces. According to Lufthansa Technik’s initial model calculations, the sharkskin technology in its maximum expansion stage could even reduce CO2 emissions to the tune of up to 3%.