Passenger Aircraft Research Articles

A contribution to mitigate NOx and H2O emissions for a hydrogen-powered hypersonic vehicle

AbstractHypersonic transport fueled with liquid hydrogen (LH2-HST) is currently considered as long-term future technology of civil aviation to fly with speeds greater than Mach 5 at stratospheric altitudes of 25–38 km. In this paper, we present a comprehensive methodology to assess the emission mitigation potential (via NOx and H2O) of future LH2-HST through operational measures, considering realistic constraints such as the sonic boom carpet as well as tolerable g-forces acting on the passengers while flying with hypersonic speeds. Both NOx- and H2O-optimal 4D-trajectories are identified by a brute-force algorithm that varies the initial cruise altitude from 30 to 36 km. As case study, the Mach 8 passenger aircraft STRATOFLY-MR3, which was conceptually developed in the framework of the H2020 STRATOFLY project, is operated on a single route from Brussels (BRU) to Sydney (MYA). The findings are highlighted as relative changes regarding MR3's design flight altitude set at 32 km, respectively, 105 000 ft. As scientific contribution, 3D emission inventories are calculated and made publicly available for a world fleet of MR3 aircraft operated along the BRU-MYA route on both NOx- and H2O-optimal mission profiles in the year 2075.

Ultra-high-rate Manufacturing of Thermoplastic Window Plug using Hybrid Overmolding

Highly loaded complex parts are machined from a solid block of metal by removing material through cutting, boring, drilling, and grinding to obtain the three-dimensional shape. Most cases, this involves removing as much as 80 percent of the material from a billet, which is time-consuming and inefficient considering the cost of the materials. Alternatively, these complex parts can be manufactured using hybrid overmolding process which involves injecting plastics over a reinforced substrate with continuous fiber-reinforcement eliminating subtractive machining or joining of multiple parts. The substrate is typically heated using an infrared (IR) oven and preformed over a solid mold to a three-dimensional shape using thermoforming. Injection overmolding material can also be reinforced with discontinuous fibers based on the design requirements. Both thermoforming and injection molding are matured automotive ultra-high-rate manufacturing processes. Adopting these technologies to aerospace requires advanced aerospace-grade thermoplastic material systems and developing the hybrid overmolding process that combines both thermoforming and injection molding processes. Material compatibility is one of the key enablers for the fusion across the overmolded interfaces. To demonstrate the overmolding technology for an aerospace application, Victrex AE250 low-melt polyaryletherketone (LM-PAEK) system reinforced with AS4 fibers and a 30% carbon fiber-reinforced polyetheretherketone (PEEK) were used to overmold aircraft window plugs to be used for cargo conversion of passenger aircraft. The fully automated overmolding process was demonstrated using KraussMaffei multi-robotic thermoforming and injection molding system. Thermal and mechanical test evaluations were employed to assess the material compatibility and overall part quality. Photomicrographs and flexure tests conducted on test samples extracted from the window plugs indicated satisfactory fusion across the overmolded interface and optimized holding of PEEK materials.

The carbon footprint of vegetable imports into Aruba: A closer look at sea and air transport

This study aimed to give insights into low-carbon vegetable import strategies for Aruba, a Dutch Caribbean island. Our selected products were potatoes, lettuce, onions, tomatoes, and green beans. The products originated from 13 different countries, and 25 product-country combinations were identified. The system boundaries were from the farm until arrival at the supermarket. We identified actual maritime transport routes, and calculated greenhouse gas (GHG) emissions of passenger aircrafts flying from Amsterdam to Aruba. Vegetables imported by air had significantly higher GHG emissions (4.2–8.3 kg CO2eq per kg) than products imported by sea (0.4–2.3 kg CO2eq per kg). GHG emissions of road transport generally contributed more than those of other life cycle stages, except when products showed a high contribution of agriculture. Although sea transport was calculated with much detail, it usually did not contribute much to the GHG emissions. We recommend Life Cycle Practitioners to consider aircraft characteristics when calculating GHG emissions of air transport, and to include the weight of the 80 kg AKE container, used for cooled airfreight, when allocating impacts between passengers and freight. For this case study, GHG emissions of specific passenger aircrafts always resulted in lower GHG emissions compared to generic calculations.

Acoustical properties of the new sandwich structures for aircraft cabin interiors with integrated vacuum insulation

AbstractAny modern passenger aircraft must provide a high level of comfort for passengers who spend considerable time inside the cabin. The cabin's climate and interior noise levels contribute to this comfort. Vacuum insulation panels (VIP) have been explored as insulation materials to improve these factors due to their extremely low thermal conductivity. When integrating VIPs into the aircraft cabin's interior, it was discovered that the thermal conductivity of the entire sandwich structure was 3–6 times lower than conventional structures. This finding has generated much interest in using VIPs for aircraft cabin insulation. This article delves into the acoustic properties of these new structures featuring integrated VIPs. Tests were carried out to analyze the sound insulation capabilities of these structures. The results showed that the new interior structures exhibited promising acoustic properties.

Integrated aircraft routing and cargo routing problem for combination airlines

The combination airlines operate both passenger aircraft and freighter aircraft to meet passenger and cargo demand. At present, combination airlines employ a sequential approach to allocating their capacity for passenger and cargo demand. Nevertheless, implementing an integrated resource allocation procedure has the potential to improve overall resource allocation efficiency. In this paper, we introduce an integrated model to help combination airlines integrate their aircraft routing and cargo routing decisions to maximize the expected overall profits derived from both passenger and cargo demand. We considered the stochastic nature of passenger baggage and proposed a set of individual chance constraints to ensure the robustness of the integrated solution. We reformulate the chance constraints using piecewise linear approximation to ensure solution efficiency. In addition, we proposed a column-and-row generation based solution approach that removes the through-connection related constraints at the beginning of the solution process and then adds the columns and rows during the iterations as needed. We proved that the proposed column-and-row generation approach can obtain an optimal solution for the LP relaxation problem. The model and the solution approach were tested in a number of scenarios obtained from a major Chinese combination airline. The computational results show that the combination airline can improve their expected profits by integrating capacity allocation. The results also demonstrated that the proposed column-and-row generation solution approach can decrease the solution time of the integrated model. These findings indicate that the model and the solution method are useful and efficient tools for combination airlines when planning their aircraft and cargo routes.

The Greenhouse gas Observations of Biospheric and Local Emissions from the Upper sky (GOBLEU): a mission overview, instrument description, and results from the first flight

BackgroundThe Greenhouse gas Observations of Biospheric and Local Emissions from the Upper sky (GOBLEU) is a new joint project by Japan Aerospace Exploration Agency (JAXA) and ANA HOLDING INC. (ANAHD), which operates ANA flights. GOBLEU aims to visualizes our climate mitigation effort progress in support of subnational climate mitigation by collecting greenhouse gas (GHG) data as well as relevant data for emissions (nitrous dioxide, NO2) and removals (Solar-Induced Fluorescence, SIF) from regular passenger flights. We developed a luggage-sized instrument based on the space remote-sensing techniques that JAXA has developed for Japan’s Greenhouse gas Observing SATellite (GOSAT). The instrument can be conveniently installed on a coach-class passenger seat without modifying the seat or the aircraft.ResultsThe first GOBLEU observation was made on the flight from the Tokyo Haneda Airport to the Fukuoka Airport, with only the NO2 module activated. The collected high-spatial-resolution NO2 data were compared to that from the TROPOspheric Monitoring Instrument (TROPOMI) satellite and surface NO2 data from ground-based air quality monitoring stations. While GOBLEU and TROPOMI data shared the major concentration patterns largely driven by cities and large point sources, regardless of different observation times, we found fine-scale concentration pattern differences, which might be an indication of potential room for GOBLEU to bring in new emission information and thus is worth further examination. We also characterized the levels of NO2 spatial correlation that change over time. The quickly degrading correlation level of GOBLEU and TROPOMI suggests a potentially significant impact of the time difference between CO2 and NO2 as an emission marker and, thus, the significance of co-located observations planned by future space missions.ConclusionsGOBLEU proposes aircraft-based, cost-effective, frequent monitoring of greenhouse emissions by GOBLEU instruments carried on regular passenger aircraft. Theoretically, the GOBLEU instrument can be installed and operated in most commercially used passenger aircraft without modifications. JAXA and ANAHD wish to promote the observation technique by expanding the observation coverage and partnership to other countries by enhancing international cooperation under the Paris Agreement.

Examining the determinants of Indian airlines’ revenues

The Indian aviation sector has undergone remarkable growth, driven by the emergence of low-cost carriers and diverse business models. This has resulted in a surge in passenger numbers and aircraft orders, establishing India as a vibrant global aviation market. However, this rapid expansion is accompanied by significant financial challenges, leading to distress and insolvency among numerous airlines. Despite optimistic growth forecasts, high operating costs and relatively low revenue returns pose substantial hurdles. Motivated by these challenges, this study aims to uncover the key factors influencing revenue generation in the Indian aviation industry by analysing expenditure components and their impacts on costs. The objective of this study is to address the research gap stemming from the lack of previous studies on Indian airlines that address endogeneity issues related to airline expenditures. By utilising data from 2007 to 2022 sourced from the audited annual reports of each airline, we aim to provide essential insights into the revenue dynamics of Indian airlines through the application of various econometric models including instrumental variables (IV) regression and generalised method of moments (GMM) models for improving causality and addressing endogeneity. Our findings reveal a positive correlation between unit revenue and factors such as unit expenditure, staff numbers, and passenger volume, while also highlighting the positive impacts of airline alliances and regional connectivity schemes. This research not only sheds light on industry intricacies but also underscores the imperative to address key variables to enhance the sector's sustainability and resilience in the face of ongoing challenges, offering valuable contributions to both academia and industry stakeholders for informed decision-making and strategic planning.

Strategies for Increasing Passenger Aircraft Capacity: A Comprehensive Review

This review explores various strategies to increase the passenger and cargo capacity of aircraft while maintaining safety and efficiency. The study focuses on four main areas of modification: wing structures, center of gravity management, landing gear upgrades, and engine enhancements. We examine the challenges associated with increasing aircraft capacity, including structural limitations, performance impacts, and fuel efficiency concerns. The paper provides insights into potential design modifications that could allow for increased load-carrying capacity in commercial aircraft, potentially leading to improved operational efficiency and profitability in the aviation industry.

Measuring the fire growth potential of combustible solids using a cone calorimeter

The fire growth rate of interior linings, furnishings, and construction materials is measured in full-scale fire tests such as the ASTM E84 Steiner Tunnel, the ISO 9705 room fire, and a passenger aircraft fuselage as the flame-spread rate, time-to-flashover, or time to incapacitation, respectively. The results are used to indicate the level of passive fire protection afforded by the combustible material or product in the test without providing any insight into the burning process. These large-scale tests require many square meters of product, are very expensive to conduct, and can exhibit poor repeatability–making them unsuitable for product development, quality control, product surveillance, or regulatory compliance. For this reason, smaller (0.01 m2) samples are tested in bench-scale fire calorimeters under controlled conditions, and these one-dimensional burning histories are correlated with the results of the two- and three-dimensional burning histories in full-scale fire tests by a variety of empirical and semi-empirical fire propagation indices, as well as analytic and computer models specific to the full-scale fire test. The approach described here defines the potential of a material to grow a fire in terms of cone calorimeter data obtained under standard conditions. The fire growth potential, λ (m2/J), is the coupled process of surface flame spread and in-depth burning that is defined as the product of ignitability (1/ E ign) and combustibility (Δ Q/Δ E) obtained from a combustion energy diagram measured in a cone calorimeter at an external radiant energy flux [Formula: see text] (W/m2) above the critical flux for burning, [Formula: see text]. However, the potential for fire growth, λ≡ (1/ Ei gn)(Δ Q/Δ E) is only realized as a hazard when the heat of combustion of the product per unit surface area, Hc (J/m2), is sufficient to grow the fire. The dimensionless fire hazard of a combustible product of thickness b is therefore, Π = λ Hc, while the fire hazard of the component materials is an average over the product thickness, π = Π/ b. The measurement of λ, Π, and π from combustion energy diagrams of heat release Q (J/m2) versus incident energy E (J/m2) is described, as well as a physical basis for a fire growth potential that provides simple analytic forms for λ in terms of the parameters reported in cone calorimeter tests. Experimental data from the literature show that rapid fire growth in full-scale fire tests of combustible materials occurs above a value of Π determined by the severity of the fire test.

Reparation of Civil Aerial Accidents Under International Air Law: A Case Study of the 2020 Ukrainian Plane Incident in Iran

International Air Law, encompassing both national and international legal norms, plays a critical role in defining state sovereignty in airspace and ensuring the safety of passenger aircraft. This paper highlighted the evolution of airspace law, emphasizing key treaties and conventions such as the Chicago and Montreal Conventions, which have shaped the legal landscape of modern aviation. It thoroughly examined the role of Aviation Law in addressing contemporary challenges, with a focus on the downing of Ukraine International Airlines Flight PS752 in Iran on January 8, 2020. This incident, a non-warfare act of force, presented a complex legal challenge and led to recent legal controversies. It examined precedents from international and domestic court decisions and directives of relevant organizations, contributing to a modern legal framework. Key discussions included the implications of human error in aviation incidents, particularly in terms of criminal liability and financial compensation. The paper made efforts to evaluate such situations within the framework of international air law, advocating for continuous legal adaptation to safeguard global civil aviation. This study particularly suggests the possible resolutions for aerial accidents, specifically those caused by human error.

Cyber Resiliency of Aircraft Systems: A Literature Review

Aircraft have an important role in the overall defense of almost every country. However, military aircraft are not only susceptible to traditional kinetic weapons but also to constantly developing cyber weaponry. There has been global growth in the number of cyber threats in recent years, and the field of military aviation is not outside the growing threat. The war in Ukraine and recent military aircraft procurements in Europe make the topic very timely. A highly skilled and resourced adversary is able to conduct complex long-term attacks that penetrate even well-protected systems, such as military aircraft systems. Even air-gap does not protect aircraft from cyber threats as modern aircraft have complex and networked avionics and support systems. The study aims to find the current trends of cyber security research related to aircraft systems. The included topics are, for example, cyber resiliency and cyber protection in the system life cycle. The study concentrates particularly on forming an overall view of the most vulnerable military aircraft systems. The study presents a non-systematic literature review based on public data sources, such as research reports, articles, etc. A set of nine relevant sources was chosen for detailed qualitative analysis. Because of the lack of detailed military sources, applicable study materials related to commercial passenger aircraft were included. The results suggest that the most vulnerable aircraft systems from the viewpoint of cyber security are those that are exposed to threats via communication and satellite systems. Other vulnerable systems are sensors and avionics systems that transfer, or process critical data related to the functions of the aircraft. In addition, the study found that it is difficult to protect aircraft systems from cyber threats because of their complexity, maintenance operations, and supply chains, which also increase the size of the attack vector. To tackle the issue, it is important to follow the development of regulations and policies related to cyber security in aviation and to study the methods of managing the threat in a holistic and cost-effective manner.

Fabrication, machining (dry vs. cryogenic) and life cycle analysis of hybrid titanium composite laminates (HTCL)

Titanium-based fiber metal laminates, also known as hybrid titanium composite laminates (HTCL), are new-age potential materials used in the field of supersonic and high-speed passenger aircraft due to their better corrosion resistance, higher stiffness, fatigue and impact resistance at both elevated and room temperature. However, the difficult-to-machine nature mandates using effective but sustainable coolant during machining. Therefore, in the present study, drilling of HTCL is done in a dry and cryogenic LCO2 environment, considering various responses such as thrust force, torque, surface roughness, tool wear, chip analysis, power consumption and specific cutting energy. Further, a life-cycle analysis was carried out to evaluate the impacts of these two cutting conditions. The results indicate that cryogenic cooling improved the hole surface finish (up to 25%) by reducing the torque values significantly by 25–30%. Furthermore, tool life is improved (up to 48.6%), and power consumption is reduced (up to 13.3%). These outcomes make cryogenic with LCO2 more favorable to use over dry conditions for this novel material. Nevertheless, condensing CO2 into liquid form necessitates a higher consumption of energy and natural resources. Furthermore, its direct release into the environment results in environmental impacts (up to 17–20%) compared to dry machining.

Stosunki niderlandzko-rosyjskie w kontekście inwazji na Ukrainę

The Kingdom of the Netherlands is the only Western state, a member of the European Union, which has tense relations with Russia comparable to Polish-Russian ones after 2010. They have collapsed because of air disasters on the Russian controlled territories. Although the way they were played by politicians of both countries in a different manner, the final results were similar – close to zero. In the years 2011–2014, bilateral relations were going well, and their climax was reached during the winter Olympics in Sochi. The annexation of Crimea in 2014 worsened them. The Netherlands joined the sanctions announced against Russia. The collapse of the relations of the Kingdom of the Netherlands with Russia took place at the end of May 2018. It was the result of the shooting down of the Malaysia Airlines passenger aircraft (code: MH-17) over the Donetsk region on its route from Amsterdam to Kuala Lumpur route. It caused the death of 298 people on the board. The international investigation team found Russia guilty of this barbarian act. As a result of the trial, the Dutch courts ruled the fault of three people and sentenced them to life imprisonment.Diplomatic relations of the Netherlands with Ukraine were established in 1992. Since the Russian invasion of the Kingdom of the Netherlands, the policy of supporting Ukrainians in the fight against the invader has been consistent. The Dutch government favors a hard approach to Russia. The Netherlands participates in the economic sanctions of the European Union towards this country. The Dutch government offers Ukraine significant humanitarian, military and financial assistance. In 2024 it will reach an amount of around 2 billion Euro. The resignation of the government of Prime Minister Mark Rutte in September 2023 will not change the principles of foreign policy of the state, regardless of the composition of a new cabinet, almost all parties still want to continue the support of Ukraine.

Experimental evaluation of alternative ceiling-based ventilation systems for long-range passenger aircraft

Alternative ventilation technology bricks, such as ceiling-based, sidewall-based or floor-based ventilation, are of high interest in terms of manufacturing and customization benefits for passenger aircraft. Two novel ventilation systems and state-of-the-art Mixing Ventilation (MV) were experimentally investigated under static conditions in a ground-based research facility. In case of Micro-Jet Ventilation, a perforated ceiling brings the air into the cabin as localized micro-jets with high momentum. Further, Low-Momentum Ceiling Ventilation characterized by a low-momentum air supply through planar and large-surface inlets is investigated. The measurement techniques and the test matrix were designed in order to quantify and evaluate thermal comfort, local air quality and energy efficiency of the ventilation concept. The results proved that there is not one single ventilation concept which optimizes all challenges: air quality, thermal comfort and energy efficiency. Both advantages and disadvantages were found for each ventilation system. In terms of technology bricks, the following main results were found: The average local age-of-air was between 5 and 14%, depending on the boundary conditions. It was lower for the ceiling-based concepts compared to state-of-the-art MV. At the same time the average CO2 concentration decreased by 7–14% for the ceiling-based concepts compared to MV. The local velocities in the vicinity of the passengers were similar for cruise conditions, whereas they decreased by up to 38% in case of hot-day-on-ground conditions for ceiling-based ventilation compared to MV. On the other hand, the heat removal efficiency was low for all concepts and the temperature stratification increased in case of ceiling-based ventilation.

Analysis and Experimental Study on Vibration Isolation Performance of Full-scale Turbofan Engine Mounting

At present, most of the turbofan engine use the articulated link mount to connect the engine to the wing, and the analysis and experimental research of articulated link mount are important means in the development of engine mount. In this paper, the vibration isolation performance analysis of a certain turbofan engine mounting was carried out, and a full-scale turbofan engine mounting vibration isolation test platform was established based on the four-terminal parameter method, and the engine simulation device - eccentric rotation excitation tester was developed, which simulates the real engine vibration through rotor imbalance, and the vibration isolation efficiency of a certain type of engine mount at the high and low pressure rotor frequency was obtained. The results show that the simulation and test results are very close, the error is within 15% at the low-frequency, and the error is within 5% at the high-frequency. The research of this paper can provide test evaluation means for my country to independently carry out the design and improvement for large passenger aircraft engine installation devices, and provide test basis for its design and finalization.

Analysis and verification of vibration isolation performance of engine mount based on low-frequency approximation method

At present, most of the turbofan engine use the articulated link mount to connect the engine to the wing. The mechanical modeling, analysis and experimental research of articulated link mount are important means in the development of engine mount. In this paper, multibody dynamics method is used to establish the dynamic theory equation for a certain type of turbofan engine mount, and the low-frequency approximation method of the MNF file is proposed, which greatly improves the calculation speed on the basis of ensuring the calculation accuracy. In addition, a full-scale engine mounting system vibration isolation performance test platform was developed, and the vibration isolation efficiency of a certain type of engine mount at the high and low pressure rotor frequency was obtained. The results show that the simulation and test results agree well, the error is within 15% at the low-frequency, and 5% at the high-frequency. This work provides theoretical method and test evaluation means for the design and improvement of large passenger aircraft engine installation devices.

Properties and Processing of Aviation Exhaust Aerosol at Cruise Altitude Observed from the IAGOS-CARIBIC Flying Laboratory.

The characteristics of aviation-induced aerosol, its processing, and effects on cirrus clouds and climate are still associated with large uncertainties. Properties of aviation-induced aerosol, however, are crucially needed for the assessment of aviation's climate impacts today and in the future. We identified more than 1100 aircraft plume encounters during passenger aircraft flights of the IAGOS-CARIBIC Flying Laboratory from July 2018 to March 2020. The aerosol properties inside aircraft plumes were similar, independent of the altitude (i.e., upper troposphere, tropopause region, and lowermost stratosphere). The exhaust aerosol was found to be mostly externally mixed compared to the internally mixed background aerosol, even at a plume age of 1 to 3 h. No enhancement of accumulation mode particles (diameter >250 nm) could be detected inside the aircraft plumes. Particle number emission indices (EIs) deduced from the observations in aged plumes are in the same range as values reported from engine certifications. This finding, together with the observed external mixing state inside the plumes, indicates that the aviation exhaust aerosol almost remains in its emission state during plume expansion. It also reveals that the particle number EIs used in global models are within the range of the EIs measured in aged plumes.

Functional and technological concepts of airports (past and present)

The article discusses the impact of security factors, economic and social conditions of public life, and the development of technology, which leads to many changes in the functional and technological schemes of air passenger services. This, in turn, affects the planning and volumetric-spatial solutions of airport terminals and changes in the organization of airport master plans. It is logical to assume that these changes are not the last, and there is a need to predict further possible solutions. But this is not possible without reviewing and systematizing the changes that have already taken place in the design and construction of airports. The article discusses several concepts of functional and planning passenger service, namely: The concept of runways in the form of a circle. The takeoff and landing of the first passenger airplanes depended heavily on wind speed and power. The airfield configuration in the form of a circle allowed solving this problem. Now this solution is outdated and not used. The concept of containerization of passenger transportation. An assumption was made about the construction of large-capacity passenger aircraft with up to 1000 passengers. Accordingly, it was proposed to first place passengers in specialized containers and then attach these containers to specialized aircraft to save time during handling. The concept remained futuristic due to the fact that passenger aircraft of this capacity are not produced, but it may happen in the future. The concept of urban airports. For the comfort of air passengers, it was proposed to build airports directly in the city. After a certain period of time, this concept was forced to be abandoned due to modern requirements and air traffic safety measures. The concept of centralized or decentralized air passenger service. The concept has been evolving throughout the history of airport construction. At the present stage, the concept of centralized service is more widespread, as it is the most comfortable and economically feasible. The concept of additional (non-transportation) passenger services. The commercial industry of air passenger services at the airport, in the form of shops, cafes, hotels, and much more, is now successfully developing. This allows airports to increase the level of comfort and affects the reduction of costs and lower prices for the transportation of each individual air passenger. The article notes that some concepts are outdated, some are too futuristic, some have ceased to exist due to inconsistencies with modern security measures, and some have stood the test of time and become dominant in modern airport design. Analysis, comprehension and summarization of the consequences of the introduction of certain functional and technological concepts of air passenger service leads to changes in the organization of airports. The process of scientific research of these phenomena is the key to the future life of airports and their efficient operation. This task is quite complex and requires a lot of studies, not only in the field of architecture and design, but also in sociology, economics, marketing, and management.

LaterAnalysis of the energy efficiency of an environmental control system of a passenger aircraft by using the entropy-statistical method

BACKGROUND: Aviation designers are striving to increase fuel efficiency of aircraft, including by increasing the efficiency of aircraft environmental control systems by reducing losses in its components.
 AIM: This study performs an entropy-statistical analysis of the environmental control system of a passenger aircraft assesses efficiency losses in the units included in it.
 MATERIALS AND METHODS: A static mathematical model of an environmental control system with moisture content control was developed to calculate the system parameters in various operating modes, for which an entropy-statistical analysis was performed.
 RESULTS: Using entropy-statistical analysis, the main units of the system were examined, their influence on the overall efficiency of the environmental control system was assessed, and the advantages of the given method of entropy-statistical analysis for such systems were outlined. The mathematical model was developed using the Matlab Simulink software package.
 CONCLUSIONS: A static mathematical model of an environmental control system with a three-wheel air cycle machine unit and a “loop” high-pressure dehumidification system was developed. An entropy-statistical analysis of the system was performed. The influence of the units included in the system on the efficiency of the system as a whole was assessed.

An Event-Driven Link-Level Simulator for the Validation of AFDX and Ethernet Avionics Networks

Aircraft are composed of many electronic systems: sensors, displays, navigation equipment, and communication elements. These elements require a reliable interconnection, which is a major challenge for communication networks since high reliability and predictability requirements must be verified for safe operation. In addition, their verification via hardware deployments is limited because these are costly and it is difficult to try different architectures and configurations, thus delaying design and development in this area. Therefore, verification at early stages in the design process is of great importance and must be supported with simulation. In this context, this work presents an event-driven link-level framework and simulator for the validation of avionics networks. The tool presented supports communication protocols commonly used in avionics, such as Avionics Full-Duplex Switched Ethernet (AFDX), as well as Ethernet, which is used with static routing. Also, the simulator provides accurate results by employing realistic models for various devices. The proposed platform was evaluated in the Clean Sky’s Disruptive Cockpit for Large Passenger Aircraft architecture scenario, showing the capabilities of the simulator. Verification speed is a key factor in its application, so the computational cost was analyzed, proving that the execution time is linearly dependent on the number of messages sent and that the increase in the number of nodes has few quadratic components.