Operational performance in sustainable aviation: an in-depth analysis of turnaround times of future commercial narrowbody liquid hydrogen aircraft

Operational performance in sustainable aviation: an in-depth analysis of turnaround times of future commercial narrowbody liquid hydrogen aircraft

The aviation industry is closely associated with the effects of weather conditions on flight safety, but energy efficiency and sustainability issues have also gained importance in recent years. Meteorological data plays a critical role in determining flight routes, increasing fuel efficiency and ensuring flight safety. More efficient flight routes can be planned by considering the impact of meteorological events on the energy consumption of aircraft, in particular factors such as wind, temperature changes, humidity and turbulence during flight. This reduces fuel consumption and minimizes environmental impact. Particular attention should be paid to the use of renewable energy, the energy efficiency of aircraft and the impact of weather conditions on energy production. In addition, the integration of meteorological data with energy efficiency in future aircraft systems should be assessed. In this study, net thrust, fuel consumption, fuel flow and core efficiency factors of a turboshaft engine were predicted by artificial neural networks based on meteorological data such as ambient temperature. The best predicted output parameter, which varies depending on the ambient temperature input, is the core efficiency with 0.9 MAPE. It also investigated the role of aviation meteorology in predicting weather conditions and improving flight safety, and the interface between energy management and sustainable aviation.

The sustainability of aviation in global supply chains is of increasing importance to airline management and policy makers. With mounting environmental pressures and market volatilities, airlines need to find strategies for simultaneously managing their economic and environmental (emissions) performance, two objectives that can support but also contradict each other. This chapter aims to evaluate the relative performance of airlines’ carbon and cost efficiency and how this relationship has changed over time. We compute and compare the carbon efficiency of 14 major European airlines for the period of 1986–2007. As jet fuel is the most important resource in the aviation supply chain, we examine whether there is a relationship between fuel prices and carbon efficiency. We also test whether unit cost, distance flown and load factors have an impact on airline carbon efficiency. The results show that the fuel prices and their volatility have affected and improved carbon efficiency of airlines. Our findings also confirm previous anecdotal evidence suggesting a significant negative relationship between carbon efficiency and unit cost.

Liquid hydrogen (LH2) has long been seen as a technically feasible fuel for a fully sustainable greener aviation future. The low density of the cryogenic fuel would dictate the redesign of commercial aircraft to accommodate the large tanks, which are unlikely to be integrated within the whole internal volume of the wing. In the ENABLEH2 project, the morphological aspects of a LH2 aircraft design are discussed and a methodology for rapid concept comparative assessment is proposed. An exercise is then carried on to down-select short-to-medium range (SMR) and long-range (LR) concepts, able to carry 200 passengers for 3000 nmi and 414 passengers for 7500 nmi respectively. The down-selection process was split into two phases with the first considering 31 potential airframe architectures and 21 propulsion-system arrangements. The second phase made the final down-selections from a short-list of nine integrated design concepts that were ranked according to 34 criteria, relating to operating cost, revenue, noise and safety. Upon completion of the process, a tube and wing design with the tanks integrated into extended wing roots, and a blended-wing-body design were selected as the best candidates for the SMR and LR applications respectively. Both concepts feature distributed propulsion to maximise synergies from integrating the airframe and propulsion systems.

ABSTRACTAircraft performance parameters play a critical role in maintaining economic and environmental sustainability in aviation. Furthermore, the ability to calculate aircraft performance parameters accurately for the cruise range contributes to aviation in areas such as the preliminary design of aircraft and air traffic management. This study is focused on cruise range performance, as this is critical to both the evaluation and understanding of the economic and environmental impacts of commercial aircraft. Quick Access Recorders (QAR) data were used for more accurate analysis of the cruise range. The QAR data used in this study included 6,574 short-distance domestic flights by narrow-body turbofan commercial aircraft between 31 different city pairs. To obtain a more accurate cruise range equation, parameters affecting the cruise range performance were determined and studied. First, the drag polar model was improved to take the cambered profile, compressibility effects and cruise airspeeds of commercial aircraft into consideration using the real flight data. Second, Thrust-Specific Fuel Consumption (TSFC) models were compared and the most suitable one for the cruise phase was selected. After these steps, cruise range values were calculated using the Breguet range equation with these improved parameters. When the results of this enhanced range model were compared with the real flight data, the mean absolute percentage error (MAPE) was found to be 2.5% for all the Aircraft and Engine Type Groups (AETGs) considered in the data. This figure corresponds to a 7.9% smaller error than provided by previous range models based on simple parabolic drag polar and TSFC models. According to these results, the application of a simple parabolic drag polar and TSFC is not appropriate for cruise range calculations.

A variety of related questions is posed. Are the right priorities for future aircraft design being set now? New civil aircraft types could be ‘silent’, i.e. make much less noise than current types. They could be ‘green’, i.e. safeguard the environment. Is silent as important as Green? The crucial answer is that future aircraft design should focus on substantial reductions on climate change impact. The air quality targets proposed by the ‘Sustainable Aviation’ initiative appear very ambitious: they should be pursued only to the extent that they do not affect improved fuel efficiency and reduced climate-changing emissions. Good progress has already been made on the aircraft noise targets proposed by the ‘Sustainable Aviation’ initiative, but again they should be pursued only to the extent that they do not affect improved fuel efficiency and reduced climate-changing emissions. The financial case for designing to reduce aircraft noise in order to deliver novel financial benefits, e.g. increase airport flights at night and/or relocate airports, is weak.

Aircraft Noise Pollution in Communities living close to commercial passenger airports world-wide could have been avoided if, following the Second World War, Governments and Local Planners had built very large commercial airports according to strong directives and regulations preventing the building of residential houses in zones in the vicinity to the airport boundary. Today the challenge is to use the experience gained in recent years on ∞ow and noise control in respect of quiet aircraft noise reduction technology(QAT) and its applications, capable of reducing and even eventually eliminating the aircraft noise problem within communities close to airports. In this study the necessary parameters are set out for the design of such future aircraft having safe ∞ight trajectories at takeofi and approach to landing when over∞ying residential areas close to all airports. To achieve this future noise reduction goal it is necessary to extend the present QAT program, based on an interim solution requiring the refurbishment of existing conventional takeofi and landing (CTOL) aircraft to reduce by 10dB the noise in communities close to the airport. It will be shown that to achieve the extended goal the likelihood is that all commercial aircraft will need to ∞y higher and slower in over∞ying residential areas involving a revolution in the low speed operation of all air transport. Residents, however, would then flnally recognize by sight and sound that technology, supported by Governments and Local Authorities, has at last produced a solution to this long standing aggravation of aircraft noise nuisance and annoyance in residential communities. The difierent types of aircraft capable of meeting this challenge are reviewed in the current study. It is shown that one solution to this problem is to changeover from CTOL aircraft to short takeofi and landing(STOL) aircraft operating with Circulation Control. This would eliminate the need for the flnal approach to landing along the 3 ‐ ILS glide slope, involving over∞ying at low altitude communities living close to an airport. Such a revolution in ATC, ∞y-by-wire and pilot handling in replacing this tried and tested approach, by a slower speed STOL circulation control aircraft ∞ying a new safe steep approach path trajectory with the aircraft ∞ying at a low shallow nose up attitude relative to the ground will need pilot approval with FAA and International acceptance. The flnal approach would follow a continuous descent trajectory from cruise to an altitude near 1000m with a changeover to STOL operation for the flnal approach to landing. Such a STOL approach to landing is similar to that used by helicopters. There exists a vast amount of knowledge and experience on this type of STOL aircraft, which has been used successfully for military and small commercial aircraft on short-haul operations. This approach to landing will allow an increase in the slant distance from aircraft to people on the ground, and thereby reduce the noise in residential communities close to the airport. Current research is now focused on the optimization of this type of aircraft for small, medium and large commercial aircraft to ensure this type of aircraft can not only meet all its cruise and low speed performance and economic goals with safe ∞ight trajectories, but also those specially related to the large noise reduction predictions that will need conflrmation in the communities close to airports at take-ofi and on the approach to landing. Little research has been directed so far to the assessment of the noise, and methods for its reduction, for the circulation control aircraft ∞ying a steep approach trajectory. The aim of this study is to seek a revolution in the optimum design of the STOL circulation control aircraft ∞ying safe and acceptable low speed and ‘low’ noise trajectories for all commercial passenger aircraft, including both subsonic and supersonic aircraft. The aim is to ensure all aircraft over∞ying residential areas maintain a separation distance of at least 1000m.

Liquid hydrogen (LH2) aircraft have the potential to achieve carbon neutrality. However, if the hydrogen is produced using electricity grids that utilise fossil fuel, they have a non-zero carbon dioxide (CO2) emission associated with their well-to-wing pathway. To assess the potential of LH2 in aviation decarbonisation, an energy systems comparison of large commercial LH2, liquified natural gas (LNG), conventional Jet-A and LH2 dual-fuel aircraft is presented. The performance of each aircraft is compared towards 2050, over which three system changes occur: (1) LH2 aircraft technology develops; (2) both world average and region-specific grid electricity, which is used to produce the hydrogen, decarbonises; and (3) the International Air Transportation Association (IATA) emissions targets, which are used to restrict the passenger-range performance of each aircraft, tighten. In 2050, the emissions of all aircraft are thus constrained to 0.063 kg-CO2/p-km, relative to 0.110 kg-CO2/p-km for the unconstrained Jet A fuelled Boeing 787-8. It is estimated that, in this year, an LH2 aircraft powered by fuel cells and sourcing world average electricity can travel 6000 km, 20% further than the conventional Jet A aircraft that is also constrained to meet the IATA targets, but not as far as the LNG aircraft. At its maximum range, the LH2 aircraft carries 84% of the Jet A passenger demand. Analysis using region-specific hydrogen indicates that LH2 aircraft can travel further than LNG aircraft in North America only, accounting for 17% of the global demand. 1.59 times the current aviation energy consumption is required if all conventional aircraft are replaced with LH2 designs. Under stricter emissions constraints than those outlined by the IATA, LH2 outperforms LNG in Europe and the Americas, accounting for 41% of the global demand. Also in these regions, the range, energy consumption and passenger capacity of LH2 aircraft can be improved upon by combining the advantages of LH2 with LNG in dual-fuel aircraft concepts. The use of LH2 is therefore advantageous within several prominent niches of a future, decarbonising aviation system.

The adoption of composite materials in commercial aviation has profoundly transformed aircraft design and performance. This research explores the impact of composites, particularly Carbon Fiber Reinforced Polymers (CFRP) and Glass Fiber Reinforced Polymers (GFRP), on aircraft weight reduction, fuel efficiency, and operational performance. By replacing traditional materials such as aluminum, composite materials enable a 15-30% reduction in structural weight, contributing to a 20-25% improvement in fuel efficiency. Models like the Boeing 787 and Airbus A350 exemplify these advancements, achieving enhanced payload capacity, extended range, and reduced environmental impact. Despite challenges such as high manufacturing costs and complex repair processes, the long-term economic and ecological benefits—lower operational expenses and reduced carbon emissions—underscore the importance of composites in sustainable aviation. This study underscores the necessity for further innovation in composite technologies to optimize performance and cost-effectiveness in the evolving landscape of commercial aviation.

Recent advancements in sustainable aviation fuels

We present a groundbreaking water vapor sensor specifically engineered for autonomous deployment on commercial aircraft. This innovative sensor was recently put to the test aboard a research aircraft, which conducted chase flights aimed at assessing the emissions from sustainable aviation fuel. In this presentation, we will explore the sensor's performance in flight conditions and delve into the key design features that make it suitable for this application. A significant aspect of our study is the potential of this monitoring system to serve as a routine, cost-effective, and highly reliable solution for automated water vapor measurement on commercial flights. The data acquired through this system is expected to significantly enhance now-casting model systems. Specifically, it will provide high-resolution water vapor data crucial for evaluating the Appleman-Schmidt criterion, thereby aiding in the prevention of persistent contrail formation – a major environmental concern in aviation. Our findings demonstrate the feasibility and value of implementing such a water vapor monitoring system in commercial aviation, with implications for both environmental monitoring and the advancement of sustainable aviation practices.

The need for more sustainable aviation has led to various new electric commercial aircraft concepts. This electrification introduces large batteries required for propulsion into the powertrain. Although safety assessments on component level have been conducted, some questions regarding the integration of such batteries into aircraft certified under FAR- or CS-25 regulations remain open. These include the crashworthiness of conceivable battery locations. This paper reviews challenges in state-of-the-art battery-electric aircraft designs, taking into account current developments in battery technologies and regulatory specifications. The aspects are analyzed within the context of conventional crash concepts. Cargo compartment and engine nacelles are identified as the most realistic options for battery storage, as accessibility issues may present a critical obstacle for batteries located in the wing box. Reviewing future battery technologies shows that mechanical deformation should be prevented for lithium-ion batteries as well as for all-solid-state batteries, which often are regarded as inherently safe with respect to thermal runaway. Difficulties in achieving a crashworthy design are therefore evident in particular when placing batteries in the cargo compartment. Still, very few studies have been published on this issue, which is also not covered by current regulations for large airplanes. More research is needed on local battery level as well as on global aircraft level to achieve certifiable battery-electric commercial aircraft.

Present work performs a comparative study of two medium-range commercial jets with future airframe and propulsion technologies powered by hydrogen and kerosene fuel to achieve a substantial reduction in overall aviation emissions. The study aims to investigate the cumulative effect of different energy networks combined with airframe efficiency gains achieved by aircraft-related technologies to suggest a better option for the potential next-generation commercial aircraft similar to the Airbus A320. Advanced airframe and engine technologies include laminar flow control, active load alleviation, new materials and structures, and ultra-high bypass ratio turbofan engines. Two aircraft with hydrogen and kerosene propulsion systems were sized to compare their performance characteristics, equivalent CO2 emission, and direct operating costs. The design was performed using a multi-fidelity approach and included the effects of future airframe technologies and the hydrogen propulsion system. The design comparison showed a significant contribution of airframe and propulsion technologies in achieving more environmentally friendly aircraft. The green hydrogen option showed a 41–63% reduction in overall emissions compared to the kerosene aircraft depending on flight conditions while the blue hydrogen variant achieved a 21–26% reduction level. A rather optimistic price scenario shall be met to enable an operational benefit of green hydrogen while the blue hydrogen variant has more potential of being economically acceptable by the market. In circumstances when operating costs drive the decision-making more than emissions, kerosene may be a more favorable option as a compromise between emission and costs, given the positive effect of airframe and propulsion technologies.

Challenges of future aircraft propulsion: A review of distributed propulsion technology and its potential application for the all electric commercial aircraft

Climate change and global warming pose great sustainability challenges to the aviation industry. Alternatives to petroleum-based fuels (hydrogen, natural gas, etc.) have emerged as promising aviation fuels for future aircraft. The present study aimed to contribute to the understanding of the impact of material selection on aviation sustainability, accounting for the type of fuel implemented and circular economy aspects. In this context, a decision support tool was introduced to aid decision-makers and relevant stakeholders to identify and select the best-performing materials that meet their defined needs and preferences, expressed through a finite set of conflicting criteria associated with ecological, economic, and circularity aspects. The proposed tool integrates life-cycle-based metrics extending to both ecological and economical dimensions and a proposed circular economy indicator (CEI) focused on the material/component level and linked to its quality characteristics, which also accounts for the quality degradation of materials which have undergone one or more recycling loops. The tool is coupled with a multi-criteria decision analysis (MCDA) methodology in order to reduce subjectivity when determining the importance of each of the considered criteria.