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Atmospheric turbulence poses a major risk to aviation. Besides airframe damage, it can cause injuries of passengers and crew when encountered unexpectedly. The Singapore Airlines flight SQ321 was on its way from London to Singapore when severe turbulence was encountered over Myanmar on 21 May 2024. In this study, it is analyzed how well the turbulence was predicted by the turbulent eddy dissipation rate (EDR) forecast index of the ECMWF integrated forecasting system (IFS). It was found that ECMWF IFS was able to predict the convection and associated turbulence 24 hr in advance. The state‐of‐the‐art probabilistic EDR forecasts based on IFS ensemble members predicted probabilities for EDR >0.18 ${ >} 0.18$m2/3 ${\mathrm{m}}^{2/3}$s−1 ${\mathrm{s}}^{-1}$ between 10% and 40% over Myanmar with higher values for shorter lead time (8‐hr forecast). Individual members predicted EDR >0.3 ${ >} 0.3$m2/3 ${\mathrm{m}}^{2/3}$s−1 ${\mathrm{s}}^{-1}$. Knowledge about the characteristics of convection in the IFS forecasts is required to make proper use of the probabilities determined from the ensemble for such cases. Plain Language Summary: Atmospheric turbulence is a threat to aircraft because it is invisible to pilots in the absence of clouds and therefore often encountered unexpectedly. Turbulence is usually found close to mountains, near the atmospheric jet streams, or thunderstorms. A severe turbulence encounter can damage the airframe and cause injuries of passengers and crew. The Singapore Airlines flight SQ321 was on its way from London to Singapore when severe turbulence was encountered over Myanmar on 21 May 2024. Abrupt rapid changes in flight altitude including a drop of 178 ft left one passenger dead and dozens injured. In this study, it was found, that the turbulence forecast of the European Centre for Medium‐Range Weather Forecasts (ECMWF) was able to predict the convection in the area and the associated turbulence 24 hr in advance. However, convection cannot be exactly predicted in time and space, so knowledge about the characteristics of the forecast of convection is needed to properly interpret such turbulence forecasts. Key Points: Singapore Airlines flight SQ321 encountered severe turbulence in an area where developing convection was presentECMWF IFS was able to predict the occurrence of convection and associated convectively induced turbulence more than 24 hr in advanceProbabilities from ensemble forecasts must be taken with care when convection is involved because of the variability in time and space [ABSTRACT FROM AUTHOR]

This study addresses the scientific and technical challenge of evaluating the integrative properties of the complex technical system comprising an aircraft's airframe and power plant during the phase of work on the preliminary design or modernization of passenger and transport aircraft. A novel "integration index" is proposed, which quantifies the degree of subsystem integration or compatibility by considering thrust, aerodynamic, and geometric characteristics, alongside design and layout solutions. The integration index may streamline early-stage parametric studies, by reducing design variants. The integration index's dependencies on the characteristics of the aircraft engine and airframe are examined. The proposed approach can be used to conduct parametric studies at the stages of preliminary variant design of aircraft subsystems. This, in turn, will reduce the cost and time of designing new, significant upgrades of existing aircraft and their components. The methodology offers a practical tool for evaluating hybrid-electric and conventional aircraft systems, thus guiding the development of innovative and competitive aviation technologies. [ABSTRACT FROM AUTHOR]

Despite children being vulnerable aircraft passengers, children's safety on aircraft does not attract enough public attention as it does in the automotive industry. Current regulations about Child Restraint Systems (CRSs) used on aircraft differ in various countries. This study introduces the potential injuries, injury mechanisms, and injury criteria for children on an aircraft. The protective effects of different CRSs are summarised. Among the four types of CRSs, automotive child seats are the most practical CRSs used on an aeroplane today. The airworthiness regulations and operation regulations of CRSs are also presented. The lack of injury criteria for the neck and abdomen in current regulations should be addressed. Finally, the social effects of mandatory regulations of using CRSs on an aircraft are discussed, and advice on the future improvement of children's safety in aircraft is provided. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

A method is proposed for quickly estimating the sonic boom characteristics from supersonic passenger aircraft under standard atmospheric conditions. The piecewise linear temperature profile and absence of atmospheric wind make it possible to completely reduce the problem of the geometry of sonic boom wave propagation to an algebraic form. For acoustic pressure, an analytical solution is formulated using the nonlinear geometrical acoustics approach. The dependence of the geometry of sonic boom wave propagation on the cruising flight parameters of a supersonic passenger aircraft is analyzed. Under the conditions of SBPW (Sonic Boom Prediction Workshop) 2020, the overpressure signatures on the ground from the X-59 demonstrator were calculated. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to examine the incidence of scheduled training provided to develop the leadership skills of pilots, prior to their operation as the captain of an aircraft in scheduled airline operations, and the subsequent maintenance of their leadership skills after becoming a captain. Method/Approach: The approach used in this paper involved a survey of suitably qualified aviation captains and co-pilots. A total of 741 usable responses were received. The differences between the Captains and Co-pilots responses to the questions related to leadership training were examined using the chi square test. Results/Findings: The majority of both captains (51.0%) and co-pilots (57.1%) had not received training in leadership theory -- this did not systematically differ between the two groups (χ² = 5.88279). In response to the question on leadership practical training the majority of both captains (63.3%) and co-pilots (72.6%) had not received practical training -- this did not systematically differ between the two groups (χ² = 6.2756). In response to the question on ongoing or recurrent leadership training the majority of both captains (52.9%) and co-pilots (69.8%) had not received ongoing or recurrent training -- this however, did systematically differ between the two groups (χ² = 18.106). Implications: The paper provides a review of the issues related to the training requirements of leadership skills for captains of aircraft in commercial passenger operations of aviation. [ABSTRACT FROM AUTHOR]

Article on determining airport area accessibility, flight timeliness and check-in process time on airplane passenger satisfaction (Study at Soekarno Hatta Airport) within the scope of marketing management science. This article aims to create hypotheses regarding the relationship between factors, which can then be used for further research in the field of marketing management. The research method used in this research is descriptive qualitative. The data used in this research comes from previous research which is still relevant to the current investigation. Data was collected from leading academic online platforms, including Publish or Perish, Google Scholar, digital reference books, and Sprott journals. The results of this literature research include: 1) Accessibility influences aircraft passenger satisfaction at Soekarno Hatta Airport; 2) Punctuality of flight times influences aircraft passenger satisfaction at Soekarno Hatta Airport; and 3) The speed of the check-in process influences the satisfaction of airplane passengers at Soekarno Hatta Airport. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to investigate the design and optimization of landing gear buffers to improve the landing-phase comfort of civil aircraft. Design/methodology/approach: The vibration comfort during the landing and taxiing phases is calculated and evaluated based on the flight-testing data for a type of civil aircraft. The calculation and evaluation are under the guidance of the vibration comfort standard of GB/T13441.1-2007 and related files. The authors establish here a rigid-flexible coupled multibody dynamics finite element model of one full-size aircraft. Furthermore, the authors also implement a dynamic simulation for the landing and taxiing processes. Also, an analysis of how the main parameters of the buffers affect the vibration comfort is presented. Finally, the optimization of the single-chamber and double-chamber buffers in the landing gear is performed considering vibration comfort. Findings: The double-chamber buffer with optimized parameters in landing gear can improve the vibration comfort of the aircraft during the landing and taxiing phases. Moreover, the comfort index can be increased by 25.6% more than that of a single-chamber type. Originality/value: To the best of the authors' knowledge, this study first investigates the evaluation methods and evaluation indexes on the aircraft vibration comfort, then further conducts the optimization of the parameters of landing gear buffer with different structures, so as to improve the comfort of aircraft passengers during landing process. Most of the current studies on aircraft landing gear have focused on the strength and safety of the landing gear, with very limited research on cabin vibration comfort during landing and subsequent taxiing because of the coupling of runway surface unevenness and airframe vibration. [ABSTRACT FROM AUTHOR]

The object of research is a civil mainline aircraft with a transonic truss-braced wing. The problem of designing an aircraft of this scheme at the preliminary design stage is being solved in the work. The results of the work include the concept of designing aircraft with a transonic truss-braced wing, the main advantages of such a scheme, the process of determining the geometric parameters of the truss-braced, features of the preliminary design of an aircraft with an extremely high aspect ratio truss-braced wing, possible approaches to the arrangement of units and their mutual arrangement. The results are explained by the difference in the design model (the cantilever beam is replaced by a beam on two supports) in mass analysis and the increased wing aspect ratio in aerodynamic calculation. The final data are based on a statistical study to determine the basic geometric parameters of assemblies of modern mainline passenger aircraft, synthesis of parameters of analog aircraft. For example, an aircraft capable of carrying 250 passengers over a distance of 13.000 km is considered. In the design process, values of aspect ratio, taper ratio, wing area, vertical tail and horizontal tail area ratio, and fuselage dimensions are accepted. Drawings of the general appearance of the aircraft have been developed and, based on it, a master geometry of the theoretical contour has been constructed. Graphs of first-order polar and maximum lift-to-drag ratio have been plotted, the reduction of aerodynamic drag in percentage terms has been determined, and the increase in aerodynamic lift-todrag ratio in percentage terms for an aircraft with an extremely high aspect ratio truss-braced wing compared to similar characteristics of an aircraft with a conventional non-braced wing has been calculated. The approximate mass savings when using a truss-braced wing on the aircraft are determined in percentage terms. The expediency of using wings of greater aspect ratio, than modern aircraft currently have, has been justified. The expediency of using a brace for the aircraft with an extremely high aspect ratio wing has been justified. The obtained results can be used in practice in the process of developing the preliminary design of an aircraft with a truss-braced wing or in the modifications of existing aircraft to increase their fuel efficiency or increase the durability of wing elements due to reduced loads acting on them. [ABSTRACT FROM AUTHOR]

Evaluating global chemistry models in the upper troposphere–lower stratosphere (UTLS) is an important step toward an improved understanding of the chemical composition in this region. This composition is regularly sampled through in situ measurements based on passenger aircraft, in the framework of the In-service Aircraft for a Global Observing System (IAGOS) research infrastructure. This study focuses on the comparison of the IAGOS measurements in ozone, carbon monoxide (CO), nitrogen reactive species (NOy) and water vapour, with a 25-year simulation output from the LMDZ-OR-INCA chemistry–climate model. For this purpose, we present and apply an extension of the Interpol-IAGOS software that projects the IAGOS data onto any model grid, in order to derive a gridded IAGOS product and a masked (sub-sampled) model product that are directly comparable to one another. Climatologies are calculated in the upper troposphere (UT) and in the lower stratosphere (LS) separately but also in the UTLS as a whole, as a demonstration for the models that do not sort out the physical variables necessary to distinguish between the UT and the LS. In the northern extratropics, the comparison in the UTLS layer suggests that the geographical distribution in the tropopause height is well reproduced by the model. In the separated layers, the model simulates well the water vapour climatologies in the UT and the ozone climatologies in the LS. There are opposite biases in CO in both UT and LS, which suggests that the cross-tropopause transport is overestimated. The NOy observations highlight the difficulty of the model in parameterizing the lightning emissions. In the tropics, the upper-tropospheric climatologies are remarkably well simulated for water vapour. They also show realistic CO peaks due to biomass burning in the most convective systems, and the ozone latitudinal variations are well correlated between the observations and the model. Ozone is more sensitive to lightning emissions than to biomass burning emissions, whereas the CO sensitivity to biomass burning emissions strongly depends on location and season. The present study demonstrates that the Interpol-IAGOS software is a tool facilitating the assessment of global model simulations in the UTLS, which is potentially useful for any modelling experiment involving chemistry climate or chemistry transport models. [ABSTRACT FROM AUTHOR]

Very high concentrations of ultrafine particles (UFP) were measured at Heathrow Airport London. Exposure to UFP is strongly linked to adverse health effects and guidance for exposure limits has recently been provided by the World Health Organization (WHO). Using 1 s resolution UFP measurements and aircraft GPS data, measurements were assigned to individual aircraft and their operating mode, and this information was used to model UFP emission rates. In all cases, the highest emission rates were associated with departing aircraft, with rates for larger aircraft higher than smaller aircraft. Emission rates per passenger is influenced by the number of passengers carried, especially for arriving aircraft. Calculated emission rates are significantly higher than stated literature values, due to the inclusion of condensable particles in the measurements. These condensable particles are specifically not included in the regulated emission rates. Measured UFP concentrations within the airport boundary (and therefore not accessible to the general public) exceed the WHO guidance, indicating that UFP concentrations outside of the airport boundary could also be of concern. Assessing population exposure close to airports will be of increasing importance in future. [ABSTRACT FROM AUTHOR]

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After an aircraft is forced to land, it is easy for it to become stuck in a tilt state of pitch or roll. The pitch/roll state of the aircraft cabin is a critical factor affecting the safe evacuation of the cabin. However, evacuation therein deserves more attention. In this research, an aircraft cabin simulator was developed to study the impact of pitch and roll on the individual and group evacuation speed. The values of the pitch angle θ and roll angle γ considered in the experiments were both 0, ±5, and ±10°. It was found that the average individual passenger speed could be attenuated in an aircraft cabin in pitch or roll conditions, but a pitch angle less than 0 had an acceleration effect on the walking mode. The results of the group evacuation experiments showed that, in addition to affecting the speed of individual passengers, the pitch/roll state also affected the evacuation interval time between a passenger and the preceding one. In addition, the linear fitting models introduced in this paper, which linked the motion of individual and group passengers, could predict the movement speeds accurately. This study provides a valuable benchmark for simulating the evacuation of an aircraft cabin and a reference for the safety design of actual aircraft cabins. [ABSTRACT FROM AUTHOR]

The object of research is the process of remotorization of a regional passenger aircraft to increase its fuel efficiency. Based on the conceptual requirements for the remotorization of the An-158 aircraft with turbojet bypass engines, a parametric appearance of three modifications of this aircraft with turboprop engines for 80, 100, and 120 passenger seats was formed. The study was carried out on the basis of the well-known modular software systems «Integration 2.1» and «Air propeller 2.2» for typical flight profiles of the An-158 aircraft. Improved procedures of weight design and determination of the takeoff characteristics of aircraft with different types of power plant engines have made it possible to identify the most advantageous flight speeds of aircraft modifications with a turboprop engine corresponding to different flight masses. The results of the study of flight performance for optimal and «non-optimal» modifications of the aircraft are reported. The parametric appearance of the propeller was formed, the shape of the propeller blade for the cruising flight mode was determined for modifying the aircraft with a maximum number of passengers – 120 people. It is shown that the propeller for this modification of the aircraft cannot have less than 8 blades since with a smaller number of blades, the maximum chord of the propeller blade increases. The inductive power costs increase significantly due to the small elongation of the blades and, as a result, the flight efficiency of the propeller decreases. It is shown that the total fuel consumption for the entire typical flight of all modifications of the aircraft with turboprop engine at all studied flight speeds is less than the total fuel consumption of the An-158 base aircraft. [ABSTRACT FROM AUTHOR]

Synthetic aperture radar (SAR) is an active ground-surveillance radar system, which can observe targets regardless of time and weather. Passenger aircrafts are important targets for SAR, as it is of great importance for accurately recognizing the type of aircraft. SAR can provide dynamic monitoring of aircraft flights in civil aviation, which is helpful for the efficient management of airports. Due to the unique imaging characteristics of SAR, traditional target-detection algorithms have poor generalization ability, low detection accuracy, and a cumbersome recognition process. Target detection in high-resolution SAR images based on deep-learning methods is currently a major research hotspot. You Only Look Once v5 (YOLOv5) has the problems of missed detection and false alarms. In this study, we propose an improved version of YOLOv5. A multiscale feature adaptive fusion module is proposed to adaptively assign different weights to each scale of the feature layers, which can extract richer semantic and textural information. The SIOU loss function is proposed to replace the original CIOU loss function to speed up the convergence of the algorithm. The improved Ghost structure is proposed to optimize the YOLOv5 network to decrease the parameters of the model and the amount of computation. A coordinate attention (CA) module is incorporated into the backbone section to help extract useful information. The experimental results demonstrate that the improved YOLOv5 performs better in terms of detection without affecting calculation speed. The mean average precision (mAP) value of the improved YOLOv5 increased by 5.8% compared with the original YOLOv5. [ABSTRACT FROM AUTHOR]

In-flight sitting comfort has become a key selection criterion for aircraft passengers when choosing their travel options among available flight services. This comfort feeling can often be associated with the ease of passengers in performing their typical in-flight activities. In view of this notion, having an appropriate height of the seat tray table that aptly matches the passengers' body anthropometry is imperative to enable them to adopt comfortable sitting posture while doing their in-flight activities. In this study, an activity-based sitting comfort experiment is conducted in an aircraft cabin mock-up where the participants were asked to rate their comfort level when they used the seat tray table during eating, writing and typing activities at seven different settings of the tray table's height: 66 cm, 69 cm, 72 cm, 75 cm, 78 cm, 81 cm and 84 cm. A total of 15 volunteers participated in the experiment and the collected sitting comfort data is then statistically analyzed through ANOVA method using the MINITAB software. The analysis results have indicated that the height of seat tray table and several passengers' anthropometry parameters have high influences on their in-flight comfort level while performing their common in-flight activities. Additionally, the findings also suggested that there is a potential optimum setting of seat tray table's height that can maximize the passengers' comfort level. [ABSTRACT FROM AUTHOR]

Wing-body assembly is a key part of aircraft manufacturing, and during the process of wing assembly, the 3D point cloud data of the components are an important basis for attitude adjustment. The large amount of measured point cloud data and the obvious noise affect the quality and efficiency of the final assembly. To address this problem, research on the pre-processing method of the component point cloud data is carried out. Firstly, a feature-enhanced point cloud resampling method is proposed to preserve key features such as part contours in the resampling process. Then, a multi-scale point cloud data noise filtering method is proposed, which can effectively filter out the outliers. The experimental results show that the proposed method improves the speed and accuracy of the subsequent point cloud analysis effectively and is successfully applied to the assembly process of a large passenger aircraft, laying the foundation for high-quality assembly. [ABSTRACT FROM AUTHOR]

In this paper, we present the results of direct numerical modeling of the process of susceptibility of a supersonic boundary layer over an unswept wing with a thin parabolic profile to acoustic noise of various intensities. It was demonstrated that acoustic noise can cause a laminar–turbulent transition over the unswept wing of a supersonic passenger aircraft. [ABSTRACT FROM AUTHOR]

The paper briefly reviews a recent initiative on the application of hydrogen as a fuel for future commercial aircraft. Special attention is paid to the benefits of using liquid hydrogen (LH2) to power aircraft engines. A comparison of LH2 to other fuels is presented, as well as a comparison of LH2 hazard to hazard imposed by typical jet fuel. Major attention is focused on the combustion of hydrogen benefits in turbine engines with classic deflagrative combustion chamber and engines utilizing detonative combustion of the hydrogen-air mixture. Benefits and problems with the utilization of LH2 are discussed in this paper. [ABSTRACT FROM AUTHOR]

The article is devoted to consideration of passenger service on aircraft board as a basis for forming the image and ensuring the airline's competitiveness. The role of passenger service quality for airlines in the context of fierce global competition is defined; an analysis of the on-board product of the world's leading airlines was carried out, and the most influential ratings of airlines for the service quality were considered. The key criteria for evaluating the passenger service quality on the aircraft board in terms of the quality of the on-board product and the efficiency of the cabin crew are substantiated. Recommendations are provided for flight attendants to improve service in the context of passenger expectations, and steps that airlines should implement to improve the passenger service quality are identified. [ABSTRACT FROM AUTHOR]

The aircraft environmental control system (ECS) is the second-highest fuel consumer system, behind the propulsion system. To reduce fuel consumption, one research direction intends to replace conventional aircraft with more electric aircraft. Thus, new electric architectures have to be designed for each system, such as for the ECS. In this paper, an electric ECS is modeled and then sized and optimized for different sizing scenarios with the aim of minimizing fuel consumption at the aircraft level. For the system and for each component, such as air inlets and heat exchangers, parametric models are developed to allow the prediction of relevant characteristics. These models, developed in order to be adapted to aircraft design issues, are of different types, such as scaling laws and surrogate models. They are then assembled to build a preliminary sizing procedure for the ECS by using a multidisciplinary design analysis and optimization (MDAO) formulation. Results show that the ECS design is highly dependent on the sizing scenario considered. An approach to size the ECS globally with respect to all the sizing scenarios leads to an ECS that accounts for around 200 N of drag, 190 kW of electric power, and 1500 kg of mass for the CeRAS aircraft. [ABSTRACT FROM AUTHOR]

Microphysical, optical, and environmental properties of contrail cirrus and natural cirrus were investigated by applying a new, statistically based contrail–cirrus separation method to 14.7 h of cirrus cloud measurements (sampling frequency 1 Hz, max. ∼ 290 m s -1 , total length of sampled in-cloud space ∼ 15 000 km) during the airborne campaign ML-CIRRUS in central Europe and the northeast Atlantic flight corridor in spring 2014. We find that pure contrail cirrus appears frequently at the aircraft cruising altitude (CA) range with ambient pressure varying from 200 to 245 hPa. It exhibits a higher median ice particle number concentration (Nice), a smaller median mass mean radius (Rice), and lower median ice water content (IWC) (median: Nice=0.045 cm -3 , Rice=16.6 µ m, IWC = 3.5 ppmv), and it is optically thinner (median extinction coefficient Ext = ∼ 0.056 km -1) than the cirrus mixture of contrail cirrus, natural in situ-origin and liquid-origin cirrus found around the CA range (median: Nice=0.038 cm -3 , Rice=24.1 µ m, IWC = 8.3 ppmv, Ext = ∼ 0.096 km -1). The lowest and thickest cirrus, consisting of a few large ice particles, are identified as pure natural liquid-origin cirrus (median: Nice=0.018 cm -3 , Rice=42.4 µ m, IWC = 21.7 ppmv, Ext = ∼ 0.137 km -1). Furthermore, we observe that, in particular, contrail cirrus occurs more often in slightly ice-subsaturated instead of merely ice-saturated to supersaturated air as often assumed, thus indicating the possibility of enlarged contrail cirrus existence regions. The enlargement is estimated, based on IAGOS long-term observations of relative humidity with respect to ice (RH ice) aboard passenger aircraft, to be approximately 10 % for Europe and the North Atlantic region, with the RH ice threshold for contrail cirrus existence decreased from 100 % to 90 % RH ice and a 4 h lifetime of contrail cirrus in slight ice subsaturation assumed. This increase may not only lead to a non-negligible change in contrail cirrus coverage and radiative forcing, but also affect the mitigation strategies of reducing contrails by rerouting flights. [ABSTRACT FROM AUTHOR]

Although the blended wing body aircraft has been long speculated to be the next-generation passenger aircraft, its boarding processes remains relatively unexplored. In this study, we investigate possible boarding strategies for the blended wing body aircraft. The uncertainty in the design of the blended wing body aircraft and future civil aviation industry requires that boarding strategies must be evaluated from multiple perspectives, including adaptability, practicality, boarding rate, occupancy rate, passenger compliance, etc. We propose a novel boarding strategy specifically designed for the blended wing body aircraft, which can be used for different blended wing body aircraft. Performances of boarding strategies adapted from those commonly used today are also evaluated. As a result, while the performance of the novel boarding strategy is limited by operational constraints, it demonstrates better efficiency and robustness compared to conventional boarding strategies. [ABSTRACT FROM AUTHOR]

Models of air freight are often constrained by a lack of available data. This study brings together different sources of air freight supply and demand data to address this gap. To study air freight operations, we combine schedules, flight tracking data and country-level databases of passenger and freight movements to produce estimates of global flight segment-level capacity and load factors in freighter aircraft and passenger holds for 2019–2021. To study true origin-ultimate destination air freight demand, a freight mode choice model by commodity group is developed for 2019 to fill gaps in mode information in international and national trade datasets, and estimates are made for 2019 and 2021. Initial comparisons of supply and demand data demonstrate that air freight journeys differ significantly from passenger journeys, typically including more flight legs (roughly, around 2, compared to 1.2 for passengers) and greater leg distances (2.2–2.5 times average passenger distance), with significant asymmetry in commodity flows and operations to and from individual countries and regions. These differences persist in 2021, despite COVID-19 induced shifts towards carrying more air freight in freighter aircraft. This research forms a first step towards making available an integrated database of estimated global air freight flows by commodity. [Display omitted] • We combine different sources of 2019–2021 air freight demand and supply data. • Air freight trips are longer, more complex, more asymmetric than passenger ones. • The average passenger trip has 1.2 flight legs, compared to 2 for freight. • Covid19 increased freighter use, other system metrics stayed similar to 2019. • Policy impacts on air freight will differ by route group due to commodities carried. [ABSTRACT FROM AUTHOR]

In graph theory, a set consisting of vertices of a graph that are incident to at least one of the edges is called a vertex covering set for that fuzzy graph. Facility location problems are represented as fuzzy graphs, and a model is designed with multi-objective optimization programming problems. These problems are solved using the Particle Swarm Optimization approach combined with the covering concept of fuzzy graphs. An algorithm is designed for finding fuzzy vertex covering set of fuzzy graphs. The definitions of covering speed, covering time, and coverage impact for a fuzzy vertex cover are introduced and used to develop the model. This model uses a fuzzy graph with vertices as demand and facility nodes. In case of a sudden change in the total demand of the system, there is a change in the fuzzy covering radius or capacity of facility nodes. The problem is to cover up the fuzzy network by placing facilities with maximizing demand and optimizing unknown fuzzy parameters. These studies solve a real-life problem: emergency aircraft landing with minimum time and nearest landing place. Also, the method minimizes the loss of aircraft and passengers. The proposed methodology is a new approach to solving such complex problems. • Introducing coverage impact, time, speed, cover-break cost of a vertex covering set. • Reliability analysis to use covering concept of fuzzy graphs with PSO algorithm. • Developing programming problems (objectives and restrictions) with solutions. • Evaluate Pareto-optimal solution for the model. • Comparison study between the proposed model with existing models for optimization. [ABSTRACT FROM AUTHOR]

Technologies related to the passenger aircrafts equipped with turbofan engines and carbon fiber composite materials have made remarkable progress. Also, air passengers and freight have been steadily increased. However, due to the effects of the world economy, the number of passenger aircraft orders for aircraft manufacturers has been considerably fluctuated. Large fluctuations in orders make it difficult to manage the supply chain and formulate production plans, and to determine the timing of capital investment. To stabilize the management of aircraft manufacturers and suppliers, it is important to predict the number of passenger aircraft orders to some extent. In this study, by using the Fourier transform, the periodicity of the passenger aircraft ordering trends since 1960 were analyzed. As a result, it was found that the passenger aircraft ordering trends could be simulated, and the periods of the waveform of the ordering trends of passenger aircraft were approximately 8 to 10 years. Further, it was clarified that the waveforms were synchronized with the expansion and recession periods of United States economies. [ABSTRACT FROM AUTHOR]

The article presents the discussion on presence of gold jewelry at the Boves site provides compelling evidence of the social status of the occupants. Topics include archaeological findings are rare and are only exceptionally subjected to archaeometric studies; and measurement of their trace element contents enables comparisons with contemporary gold reserves.

In this work, the enhanced correction factor technique (ECFT) is modified for a subsonic wing–body interference model, which can consider the forces on both the lifting boxes and the body elements of an idealized airplane, termed the advanced ECFT method. A passenger aircraft model is chosen as the simulation model, and the longitudinal static aeroelasticity at the transonic situation for two-degree freedom, including the α (angle of attack) degree and ϕ (angle of horizontal tail) degree, is simulated in this paper. The corresponding CFD results are used to correct the aerodynamic influence coefficients (AIC) matrix, which is then simulated by MSC.NASTRAN. The pressure distribution results of different aircraft components received by the advanced ECFT method indicate that it is suitable for the subsonic wing–body interference model. Compared with the uncorrected linear method and the diagonal corrected method, it is generally more consistent with the CFD/CSD coupling method, not only for the lifting boxes, but also for the body elements. In addition, the aerodynamic derivative results also show good agreement with the flight test data, which solidly verifies the advance ECFT method. [ABSTRACT FROM AUTHOR]

In China, airports have a profound impact on people's lives, and understanding their dimensions has great significance for research and development. However, few existing airport databases contain such details, which can be reflected indirectly by the built-up land in the airport. In this study, a deep learning-based method was used for extraction of built-up land of airports in China using Sentinel-2 imagery and for further estimating their area. Here, a benchmark generation method is introduced by fusing two reference maps and cropping images into patches. Following this, a series of experiments were conducted to evaluate the network architectures and select the positive impact bands in Sentinel-2 imagery. A well-trained model was used to extract the built-up land for China airports, and the relationship between China airports' built-up land and the carrying capacity of air transportation was further analysed. Results show that ResUNet-a outperformed U-Net, ResUNet, and SegNet, and the B2, B4, B6, B11, and B12 bands of Sentinel-2 had a positive impact on built-up land extraction. A well-trained model with an overall accuracy of 0.9423 and an F1 score of 0.9041 and 434 China airports' built-up land was extracted. The four most developed airports are located in Beijing, Shanghai, and Guangzhou, which matches China's political and economic development. The area of built-up land influenced the passenger throughput and aircraft movements. The total area influenced the cargo throughput, and we found a certain correlation among the built-up land, carrying capacity, and nighttime light. [ABSTRACT FROM AUTHOR]

A physics-based optimisation framework is developed to investigate the potential advantages of novel technologies on the energy efficiency of a midrange passenger aircraft. In particular, the coupled-adjoint aerostructural analysis and optimisation tool FEMWET is modified to study the effects of active flow control at different load cases for conventional and unconventional wing configurations. This multidisciplinary design optimisation (MDO) framework presents the opportunity to optimise the wing considering static aeroelastic effect and, by its gradient-based method, save substantial computational time compared to high-fidelity tools, keeping a satisfying level of accuracy. Two different configurations are analysed: a forward- and backward-swept wing aircraft, developed inside the Cluster of Excellence SE2A (Sustainable and Energy-Efficient Aviation). The forward-swept configuration is sensitive to the aeroelastic stability effect, and the backward configuration is influenced by the aileron constraint. They may lead to a weight increment. Sensitivity studies show the possible role of key parameters on the optimisation results. The highest fuel weight reduction achievable for the two configurations is 5.6% for the forward-swept wing and 9.8% for the backward configuration. Finally, both optimised wings show higher flexibility. [ABSTRACT FROM AUTHOR]

Introduction/Purpose: Aircraft present one of the safest and most frequently used means of transport. However, despite taking many security measures, accidents happen. No matter a damage level, if the aircraft somehow manages to land, the most important is to evacuate passengers from the aircraft, fast and safely. Evacuation of aircraft is very complex and depends on many different factors such as a damage degree, presence of fire, speed of passengers, presence of panic and fear, etc. So, it is important to, somehow, as much as possible, predict potential ways of evacuation and potential evacuation strategies and routes. Landed aircraft can be in different conditions so fast and safe evacuation of passengers is very important. The only way to predict safe evacuation routes, to determine proper evacuation strategies and to calculate potential evacuation times needed to leave the aircraft is to use some adequate simulation software. Methods: In this paper, for calculating needed evacuation times and potential evacuation routes, the simulation method was used. Simulations of evacuation scenarios and calculations of evacuation times were realized in Pathfinder software. The simulation model created in Pathfinder was a model of the A 321 aircraft related to its real dimensions. Results: The results of this paper, obtained on an appropriate simulation model of the aircraft with stairs and emergency slides, have shown the evacuation times for two different evacuation scenarios with different speeds of passengers/occupants. Conclusion: A proper evacuation strategy and the fastest evacuation of occupants are crucial for saving lives. Simulation software use in evacuation problems presents a very effective way in terms of safety, cost-effectiveness and prediction. This kind of software presents an obligatory engineering tool for more effective and more precise dealing with evacuation and similar problems. This paper was written to show how simulation software can be used for calculating evacuation times from an airplane on land. [ABSTRACT FROM AUTHOR]

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The air distribution system is one of the key systems for ensuring the safety and comfort of the passenger aircraft. The large number of components poses a severe challenge to the efficiency, accuracy, and convergence of system simulation. For the 3D CFD method, the complex and large number of meshes leads to low computational efficiency. The 1D simulation has high efficiency, but the local accuracy is inadequate. To solve this problem, the 1D Fluid System Simulation Software Flomaster with the linearization algorithm is used to establish the system-level model. The flow characteristic curve is obtained by the CFD (computational fluid dynamics) method for the local irregular ducts and introduced into the 1D system model for iteration. The effects of local flow resistance and thermal insulation on the flow distribution and thermal performance of the system are studied using this simulation model. The results show that the local flow resistance affects the total flow and uniformity of the cabin distribution, the improvement of insulation performance is weakened with increasing insulation layer thickness, and the application of thicker insulation layers on the downstream pipeline is more advantageous to limit the maximum temperature change of the conditioned air. [ABSTRACT FROM AUTHOR]

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The application of the wings with a high aspect ratio for future-oriented transport category aircraft is being considered. Such a solution makes it possible to increase fuel efficiency by reducing induced drag. This goal is achieved by increasing the wingspan, when the wings made of composite materials are used. The wings of an increased span complicate the arrangement of the aircraft in the existing infrastructure of airports. To eliminate this drawback, the application of folding wingtips was considered. The effect of such a folding device on the mass of the airplane was estimated. The approach to estimating the mass of composite structures with folding wingtips has been proposed. A conceptual assessment of the Boeing 737 and A-320 aircraft with higher aspect ratio composite wings was performed. [ABSTRACT FROM AUTHOR]

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