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In the field of civil aviation, the nose landing gear is a critical component that is prone to damage during taxiing. With the advent of new technologies such as towing taxi-out and hub motors, the nose landing gear faces increasingly complex operational environments, thereby imposing higher performance demands. Ensuring the structural safety of the nose landing gear is fundamental for the successful application of these technologies. However, current research on aircraft nose landing gear under these new conditions is somewhat lacking, particularly in terms of reliable analysis models for real-world scenarios. This study focuses on a typical Class C aircraft, specifically the B-727 model, for which a finite element model of the nose landing gear is developed. Modal testing of the aircraft's nose landing gear is conducted using the impact hammer method, and the results are compared with those from the simulations. The experimental data indicate that the error range for the first seven natural frequencies is between 0.23% and 9.27%, confirming the high accuracy of the developed landing gear model. Furthermore, with towing taxi-out as the primary scenario, a dynamic model of the aircraft towing system is established, and an analysis on the structural strength and topological optimization of the nose landing gear under various conditions, including high speeds and heavy loads, is performed. The results show that the developed model can effectively support the analysis and prediction of the mechanical behavior of the nose landing gear. Under high-speed, heavy-load conditions, the nose landing gear experiences significantly increased loads, with the maximum deformation primarily occurring at the lower section of the shock strut's outer cylinder. However, no damage occurred. Additionally, under these conditions, an optimized structural design for the landing gear was identified, which, while ensuring structural strength, achieves a 22.32% reduction in the mass of the outer cylinder, also ensuring safety in towing taxi-out conditions. [ABSTRACT FROM AUTHOR]

The global warming is amplified in the Arctic. To collect data that help to constrain weather and climate models, which often do not realistically represent the enhanced Arctic warming, the HALO-(AC)³ aircraft campaign was conducted in March and April 2022 over the Norwegian and Greenland Seas, the Fram Strait, and the central Arctic Ocean. Observations were made over areas of open ocean, the marginal sea ice zone, and the central Arctic sea ice. Two low-flying and one long-range, high-altitude research aircraft have been employed. Whenever possible, the three aircraft were flown in collocated formation. The campaign focused on one specific challenge posed by the models: The reasonable representation of transformations of air masses during their meridional transport into (northward by moist and warm air intrusions, WAIs) and out of (southward via marine cold air outbreaks, CAOs) the Arctic. To observe the air mass transformations, a quasi-Lagrangian flight strategy using trajectory calculations was realized enabling to sample the moving air mass parcels twice along their trajectories. Eight distinct WAI and 12 CAO cases were probed extensively. From the quasi-Lagrangian measurements, we have derived the diabatic heating and moistening of the moving air masses during CAOs and WAIs, the development of cloud macrophysical and microphysical properties along the southward pathways of the air masses during CAOs, and the moisture budget of WAIs. As an example result, we have obtained typical values of the surface-driven diabatic heating between 1–3 K h-1 and of the near-surface moistening between 0.05–0.3 g kg-1 h-1 within the lowest about 0.5 km. From the observations of WAIs, a weak diabatic cooling of up to 0.4 K h-1 and a moisture loss of up to 0.1 g kg-1 h-1 from the ground to about 5 km altitude were derived. In addition, we discuss the frequency of occurrence of the different thermodynamic phases of Arctic low-level clouds, the interaction of Arctic cirrus with sea ice, water vapor, and aerosol particles, and the characteristic microphysical and chemical properties of Arctic aerosol particles. Finally, we provide proof of a concept to measure mesoscale divergence and subsidence in the Arctic using data from dropsondes released during circular flight patterns. [ABSTRACT FROM AUTHOR]

Most of the aircraft skin is assembled by riveted structural parts, and the riveted holes are prone to cracks due to stress concentration, so it is urgent to carry out non-destructive testing research on aircraft riveted components. In this paper, a planar remote-field eddy current focusing detection probe was designed to study the hidden defects around the holes of aircraft riveted components, and a 3D simulation model was established for the detection of hidden defects in aircraft riveted components. The structural parameters of the focused remote-field eddy current probe were optimized by combining simulation and experiment, and the planar remote-field eddy current focusing detection test was carried out. The simulation and results showed that: When the inclination angle of the excitation coil is 10° and the coil spacing is 0 mm, the optimized focused remote-field eddy current probe can effectively detect the defect in length × width × depth of 10 mm × 0.2 mm × 1 mm under the buried depth of 9 mm. When the buried depth of the defect is 6–9 mm, the focused remote-field eddy current probe has a better detection capability than the non-focused remote-field eddy current probe. [ABSTRACT FROM AUTHOR]

This research study aimed to identify the factors influencing manned aircraft pilots' willingness to operate in AAM/UAM integrated airspace using a hypothesized model grounded in the Technology Readiness Index (TRI) and Technology Acceptance Model (TAM). Advanced Air Mobility (AAM) is the concept of using novel aircraft to transport cargo and passengers in and around regional and urban areas. Urban Air Mobility (UAM) is a subset of AAM. Currently, there is a lack of empirical research on manned aircraft pilots' willingness to operate in the vicinity of autonomous AAM/UAM aircraft. The study used a quantitative correlational design and a survey instrument to collect data from 254 participants. The findings from the study indicated support for five of the ten hypotheses, and the model explained 63% of the variance in willingness to pilot an aircraft (WTPA) in UAM/AAM integrated airspace. Perceived ease of use and trust had a positive influence on willingness to pilot, while risk had a negative influence. [ABSTRACT FROM AUTHOR]

For the semi-physical simulation test process of the coordinates of aircraft landing points, the concept of a completeness test for landing point simulation data is proposed, and a completeness test criterion based on field test data and expert estimation information is established. An integrity detection method for semi-physical simulation data, including data dimensionality reduction, data expansion, and regularization, drawing the envelope of the confidence region and establishing the completeness test criterion steps, is proposed. For landing points that do not satisfy the requirements of completeness, a surrogate model of the semi-physical simulation system was constructed based on a backpropagation neural network method, and the test conditions for data of this point were supplemented. Finally, application verification was carried out. Through the field and semi-physical simulation test research of a 534A aircraft, it was verified that the method can well realize the inspection of the completeness of the semi-physical simulation test data and the design of supplementary test conditions. It lays a good foundation for the fusion of subsequent semi-physical simulations and field test data. [ABSTRACT FROM AUTHOR]

This paper presents the results of a study on the use of different tropospheric correction models in SBAS positioning for air navigation. The paper, in particular, determines the influence of the Saastamoinen troposphere and RTCAMOPS models on the determination of aircraft coordinates and mean coordinate errors in the SBAS positioning method. The study uses real kinematic data from a GPS navigation system recorded by an onboard GNSS satellite receiver as well as SBAS corrections. In the experiment, the authors include SBAS corrections from EGNOS and SDCM augmentation systems. The navigation calculations were performed using RTKLIB v.2.4.3 and Scilab 6.1.1 software. Based on the conducted research, it was found that the difference in aircraft coordinates using different troposphere models can reach up to ±2.14 m. Furthermore, the use of the RTCA-MOPS troposphere model improved the values of mean coordinate errors from 5 to 9% for the GPS+EGNOS solution and from 7 to 12% for the GPS+SDCM solution, respectively. The obtained computational findings confirm the validity of using the RTCA-MOPS troposphere model for SBAS positioning in aerial navigation. [ABSTRACT FROM AUTHOR]

To accurately predict the amount of fuel needed by an aircraft for a given flight, a performance model must account for engine and airframe degradation. This paper presents a methodology to identify an aero-propulsive model to predict the fuel flow of an aircraft in cruise, while considering initial modeling uncertainties and performance variation over time due to degradation. Starting from performance data obtained from a Research Aircraft Flight Simulator, an initial aeropropulsive model was identified using different estimation methods. The estimation methods studied in this paper were polynomial interpolation, thin-plate splines, and neural networks. The aero-propulsive model was then structured using two lookup tables: one lookup table reflecting the aerodynamic performance, and another table reflecting the propulsive performance. Subsequently, an adaptative technique was developed to locally and then globally, adapt the lookup tables defining the aeropropulsive model using flight data. The methodology was applied to the Cessna Citation X business jet aircraft, for which a highly qualified level D research aircraft flight simulator was available. The results demonstrated that by using the proposed aero-propulsive performance model, it was possible to predict the aerodynamic performance with an average relative error of 0.99%, and the propulsive performance with an average relative error of 3.38%. These results were obtained using the neural network estimation method. [ABSTRACT FROM AUTHOR]

An Earth system model (ESM) aerosol–cloud diagnostics package is developed to facilitate the routine evaluation of aerosols, clouds, and aerosol–cloud interactions simulated by the Energy Exascale Earth System Model (E3SM) from the US Department of Energy (DOE). The first version focuses on comparing simulated aerosol properties with aircraft, ship, and surface measurements, which are mostly measured in situ. The diagnostics currently cover six field campaigns in four geographical regions: eastern North Atlantic (ENA), central US (CUS), northeastern Pacific (NEP), and Southern Ocean (SO). These regions produce frequent liquid- or mixed-phase clouds, with extensive measurements available from the Atmospheric Radiation Measurement (ARM) program and other agencies. Various types of diagnostics and metrics are performed for aerosol number, size distribution, chemical composition, cloud condensation nuclei (CCN) concentration, and various meteorological quantities to assess how well E3SM represents observed aerosol properties across spatial scales. Overall, E3SM qualitatively reproduces the observed aerosol number concentration, size distribution, and chemical composition reasonably well, but it overestimates Aitken-mode aerosols and underestimates accumulation-mode aerosols over the CUS and ENA regions, suggesting that processes related to particle growth or coagulation might be too weak in the model. The current version of E3SM struggles to reproduce the new particle formation events frequently observed over both the CUS and ENA regions, indicating missing processes in current parameterizations. The diagnostics package is coded and organized in a way that can be extended to other field campaign datasets and adapted to higher-resolution model simulations. [ABSTRACT FROM AUTHOR]

Through the integration of advanced sensors, actuators, and micro-processors, aircraft smart skin technology can improve the structural performance of aircraft and make them self-perception, self-diagnosis, self-adaptation, self-learning, and self-repair. Aircraft smart skin for structural health monitoring (SHM) is an important type of aircraft smart skin and has received extensive attention in recent years. Large-scale, lightweight, and low-power consumption are three key problems hindering the realization and engineering applications of aircraft smart skin for SHM. In view of these problems and restrictions of practical aircraft onboard applications, this article reviews the current research progress on aircraft smart skin for SHM, introduces their design, materials, manufacturing process, and monitoring principles in detail, and discusses how they study above problems from these aspects. Finally, perspectives are proposed on the opportunities and future developments of aircraft smart skin for SHM. [ABSTRACT FROM AUTHOR]

In this paper, a dual-loop active disturbance rejection attitude controller design method is proposed for the attitude control of aircraft. Firstly, based on the nonlinear dynamic model of aircraft, the control system model with inner loop as angular velocity and outer loop as attitude angle is established. Secondly, the extended state observer for the inner loop is established to estimate and compensate the state of the system in real time. The controller of the compensated series integral system is designed by using the linear PD control method. Thirdly, the extended state observer and controller for the outer loop are designed by the same method. Finally, the stability proof of the dual-loop attitude control method is given based on the Lyapunov theorem of stability. Simulation results show that compared with the traditional PID attitude control method, the dual-loop ADRC attitude control method has better control quality in tracking speed, tracking error, and system anti-interference ability. The control parameters to be adjusted in this method have distinct physical significance. So this method has a wide range of engineering application prospects. [ABSTRACT FROM AUTHOR]

Transferring part of the separation assurance responsibilities from air traffic controllers to pilots during en route phases of flight can reduce the controllers' workload while ensuring operational safety and improving operational efficiency in the airspace. For this new generation of distributed air traffic management mode, firstly use the conflict detection algorithm to determine whether a potential conflict exists between two aircraft, introduce cooperative game theory to autonomous separation assurance model for horizontal cross-conflict in a static wind field by forming a coalition of all aircraft involved in the potential conflict. The convex combination of minimum yaw angle and maneuver flight time is used as the strategic gain of the aircraft, and the welfare function of the coalition is maximized by changing the behavioral strategy of the aircraft. Finally, a horizontal cross-conflict scenario is set up for simulation experiments and compared with a centralized separation assurance strategy. The simulation results show the effectiveness of cooperative game theory, which is applied in distributed autonomous separation assurance. [ABSTRACT FROM AUTHOR]

Flight safety and airlines operation have been at the center of research since aircraft were first invented, as even slight errors in aircraft maintenance may cause serious accidents. Thus, aircraft maintenance is critical to the aviation industry all the time. To prevent maintenance errors, it is important to train for aviation maintenance. Therefore, an aircraft maintenance virtual reality (AMVR) system was developed in this study. For a Dornier-228 aircraft, a walk-around visual inspection of its fuel system was designed and tested in a virtual environment. For the system, CATIA V5 and Unity 3D software were used for designing the 3D model of the aircraft and developing the visual environment, respectively. With the software, the visual environment of the aircraft hangar was created for the system. The developed system was tested by students to validate the effectiveness of using the AMVR system in training. The students acknowledged that the system was beneficial to their learning, which proved that the developed system is highly effective for training students to improve aircraft maintenance skills. [ABSTRACT FROM AUTHOR]

The conventional aircraft layout will contain the elevator, aileron, rudder three control surfaces, and thus generate three control moments to adjust the aircraft trajectory and flight attitude. However, the aircraft with multi-control plane flying wing layout needs to choose redundant new control plane configuration, which is quite different from the conventional aircraft layout in both control method and operation mode. Since there are many problems in the aircraft motion mathematical model during the ownership period, which will directly affect the control effect of the flight control system, in order to reduce dynamic error and improve the robustness and accuracy of the flight control system, this paper proposes an adaptive neural network algorithm. Combined with the current operating status of tailless flying wing aircraft and the research status of aircraft control system analysis, this paper mainly discusses the design differences between the adaptive control system and the original control system, based on the empirical case, to clarify the compensation effect of the adaptive control system. [ABSTRACT FROM AUTHOR]

The increased number of accidents in general aviation due to loss of aircraft control has necessitated the development of accurate aerodynamic airplane models. These models should indicate the linear variations of aerodynamic coefficients in steady flight and the highly nonlinear variations of the aerodynamic coefficients due to stall and post-stall conditions. This paper presents a detailed methodology to model the lift, drag, and pitching moment aerodynamic coefficients in the stall regime, using Neural Networks (NN). A system identification technique was used to develop aerodynamic coefficients models from flight data. These data were gathered from a level-D Research Aircraft Flight Simulator (RAFS) that was used to execute the stall maneuvers. Multilayer Perceptrons and Recurrent Neural Networks were used to learn from flight data and find correlations between aerodynamic coefficients and flight parameters. This methodology is employed in here to optimize neural network structures and find ideal hyperparameters: training algorithms and activation functions used to learn the data. The developed stall aerodynamic models were successfully validated by comparing the lift, drag, and pitching moment aerodynamic coefficients predicted for given pilot inputs with experimental data obtained from the Cessna Citation X RAFS for the same pilot inputs. [ABSTRACT FROM AUTHOR]

This paper investigated a nonlinear control algorithm for flight dynamics of aircraft using an integrator backstepping–based design. The paper focused on two points. Firstly, a systematic procedure was presented for formulating an integrator-backstepping law for a strict-feedback form of nonlinear dynamic system. In this approach, a set of coordinate transformations including a definition of modified tracking error and state feedback laws is provided to transform a strict-feedback model into a state-decoupled linear model. This process of control design is implemented using a backstepping recursive design in which a backstepping control law is formulated for further study. Secondly, successful applications of roll dynamics of L-59 aircraft model and longitudinal dynamics of F-16 aircraft model were restructured in a strict-feedback form of nonlinear dynamic system under a series of less restrictive assumptions. A direct applicability of the proposed control theoretic framework was used to derive backstepping control laws for the achieved models. To show advancement, improvement, and validation of the proposed control method, both simulation and experimental studies were implemented, which used the numerical simulation of the flight path angle control of the longitudinal motion of an F-16 aircraft model and an experimental study of roll angle control of an L-59 aircraft model to validate the proposed control approach. [ABSTRACT FROM AUTHOR]

Aircraft is a crucial mode of transport with several strategic objectives. It is important to detect the position and number of aircraft in remote sensing images accurately. Most of the current research on aircraft detection focuses on improving algorithms or networks based on public datasets or a single remote sensing image, with limited application to large-scale remotely sensed scenes. Moreover, the detection of small and weak targets is challenging for current detection algorithms. This paper proposes a top-down method for aircraft detection in large-scale scenes. First, multi-source data and spatial constraint rules are used to search for potential airport areas in a wide range, and U-Net is then used to extract the airport area. Finally, this paper proposes a feature enhancement faster R-CNN (FEF-R-CNN) by adding a feature enhancement module to the original Faster R-CNN to improve target detection. This can enhance the aircraft feature while suppressing the background information to a certain extent, for effectively detecting small and weak aircraft targets in the airport area. Top-down aircraft detection experiments were conducted on Hainan Island and Shanghai, and 10 of the 12 airports were accurately detected. Meanwhile, the average precision (AP) of aircraft detection by FEF-R-CNN in the public dataset and four large airports in the study area reached 97.71% and 95.63%, respectively, which are 2.14% and 11.31% higher than that of the traditional Faster R-CNN, respectively. Experimental results verify the effectiveness of the proposed method for aircraft detection in large-scale remotely sensed scenes. [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to provide a detailed review of the experimental research on the prediction of aircraft spin and recovery characteristics using dynamically scaled aircraft models. Design/methodology/approach: The paper organizes experimental techniques to predict aircraft spin and recovery characteristics into three broad categories: dynamic free-flight tests, dynamic force tests and a relatively novel technique called wind tunnel based virtual flight testing. Findings: After a thorough review, usefulness, limitations and open problems in the presented techniques are highlighted to provide a useful reference to researchers. The area of application of each technique within the research scope of aircraft spin is also presented. Originality/value: Previous reviews on the prediction of aircraft spin and recovery characteristics were published many years ago and also have confined scope as they address particular spin technologies. This paper attempts to provide a comprehensive review on the subject and fill the information void regarding the state of the art aircraft spin technologies. [ABSTRACT FROM AUTHOR]

To prevent aircraft from running off the runway during landing, this paper uses a BP neural network model to predict the aircraft landing distance. In this study, based on the five main influencing factors of airport height, aircraft landing quality, airport runway slope, wind, and ambient temperature, the B737-800 was selected as the reference aircraft and the relevant operational data were collected using Boeing's LAND software for the study. In addition, this study uses LM (Levenberg–Marquardt) algorithm and GA (genetic algorithm) to optimize the training process, accelerate the computation speed, and improve the shortage of local optimization of BP (back propagation) neural network model and then construct the GA-LM-BP neural network optimization model. Finally, it makes the BP neural network have the ability of global search for optimal solutions. The results show that the predicted landing data are in good agreement with the measured landing data. The maximum absolute error is within 6.66 m and the maximum relative error is within 0.038%. [ABSTRACT FROM AUTHOR]

To realize innovative transportation systems for intercontinental flight and orbital spaceflight, it is essential to establish the necessary aerodynamic, structural, propulsion, and control technologies for a vehicle to fly at high altitudes and speeds within the atmosphere and to verify those technologies by using small unmanned supersonic experimental aircraft. This paper describes the switching conditions at waypoints from one flight mode to another for fully autonomous flight and the verification results of the flight path from takeoff to landing via a circuit by a 3 kg low-speed model airplane. It is confirmed that the switching conditions worked well and thereby the airplane flew on the designated flight path. Based on the results, a flight path is designed for a small unmanned supersonic airplane. [ABSTRACT FROM AUTHOR]

The article describes the proposition for developing the similar dynamically downscaled model of a medium range passenger aircraft and its application for researches in area of aerodynamics and flight dynamics. Computer simulations of aerodynamic flows are commonly used in advanced aircraft designing. Numerous data on the characteristics of an airplane can be obtained from tunnel tests of geometrically scaled models. To get complete characteristics from both stable and unstable flight conditions, dynamically scaled models are constructed and applied in static or dynamic tests. The dynamically similar scaled model is, in fact, a reduced model of the real airplane which has specific qualities similar to qualities of a real aircraft and these relations are strictly defined with specific similarity numbers (factors). The article presents methodology for determining scale factors in relation to geometric, aerodynamic, and structural properties (mass, stiffness) of the aircraft. The methodology will be presented on the example of Tu-154 aircraft that crashed in April 2010 with the President of the Republic of Poland and many military and government officials on board. Dynamically similar downscaled model was designed in Faculty of Mechatronics and Aerospace of the Military University of Technology (FMA MUT, Warsaw, Poland) and is still being developed in the framework of ongoing research project. This paper presents only general assumptions taken for the process and the current stage of successively developed model. [ABSTRACT FROM AUTHOR]

Advanced Air Mobility (AAM) represents a collaborative vision shared by NASA, regulatory agencies, and global industry leaders, aimed at establishing a robust and reliable air transportation ecosystem, which is expected to facilitate safe and efficient movement of both people and cargo within urban, suburban, and regional environments. This paper presents a holistic review and analysis encompassing various aircraft designs, including different propulsion system designs and architectures (electric, hybrid electric, turboelectric, etc.), for different AAM aircraft applications, and state-of-the-art air traffic management, cybersecurity, and infrastructure strategies. Recent academic and industry literature on these aspects is critically reviewed and summarized, and a compilation of the aircraft models currently in development is also provided. The aircraft designs are categorized into a set of core groups, which include lift + cruise, tilt-wing, tiltrotor, multirotor, and rotorcraft, to analyze the existing literature systematically. For each of these core groups, literature on different propulsion system designs and architectures is reviewed and analyzed. Next, these core groups, including their variations based on propulsion system designs and architectures, are analyzed through a set of evaluation lenses. This provides a comprehensive insight into their respective strengths, weakness, and gaps in design considerations. The identified lenses include range and payload, performance, environmental impact, feasibility, traffic and infrastructure, noise, vehicle safety, and cybersecurity. Finally, directions for future research in AAM aircraft and overall ecosystem development are identified. In general, a more in-depth, quantitative analysis on the various evaluation lenses identified in this study and appropriate consideration to all these evaluation lenses at the design and development stage are highly recommended. This type of holistic approach will drive AAM aircraft designs towards convergence and help build an efficient, affordable, and sustainable AAM ecosystem. • A compilation of state-of-the-art AAM aircrafts developed by the industry. • Comprehensive evaluation of various AAM aircraft designs, including rotor configuration and propulsion architectures. • Evaluation of the key components of the overall AAM ecosystem specific to vehicle operation. • Discussion on the research outlook for all the evaluation lenses analyzed in the study. [ABSTRACT FROM AUTHOR]

This paper presents a design application of Interval Type-2 (IT2) Takagi–Sugeno (T–S)​ Fuzzy Model Based (FMB) control system for generic aircraft. The IT2 T–S FMB flight control system consists of an IT2 T–S fuzzy model and a fuzzy controller connected in a closed-loop. The IT2 T–S​ fuzzy model is obtained by linearizing the nonlinear aircraft dynamics about various representative points (equilibrium points) of the flight envelope with some fuzzy rules. The aircraft flight envelope parameters, i.e., operating altitude and aircraft speed are characterized as premise parameters and elements of stability and control derivative matrix are identified as consequent parameters of fuzzy model. Longitudinal dynamics of X-29A research aircraft is selected for design of IT2 T–S FMB control system. To achieve the optimum design flexibility, an imperfectly matched premise and membership function dependent (MFD) stability analysis is considered. In MFD stability conditions, the information of flight envelope parameters is included to capture the nonlinearity pertaining to variation in flight conditions. The closed-loop response of IT2 T–S FMB controller is presented at trim equilibrium points by taking four initial angle of attack flight conditions. The performance analysis of designed controller is also presented and discussed in comparison with Fuzzy LQR and LQR based optimal controllers. The simulation results reveal that proposed IT2 T–S FMB controller not only stabilizes the aircraft dynamics but also provides improved transient performance as compared with Fuzzy LQR and LQR based optimal controllers. This demonstrates the utility of IT2 T–S FMB control system for aircraft/ UAV's related application. • A systematic approach for design of an Interval Type-2 T–S Fuzzy Model Based (FMB) flight control system is presented. • Demonstrates how designer can embed the qualitative and quantitate knowledge of aircraft dynamics for design of FCS. • The novel concept for mapping of flight envelop parameters are explored as premise parameters of IT2 T–S fuzzy model. • The performance of IT2 T–S FMB controller is presented in comparison with Fuzzy LQR and LQR based optimal controllers. • The effect of noise disturbances on the performance of designed IT2 FMB controller is also presented and discussed. [ABSTRACT FROM AUTHOR]

Transmission of SARS-CoV-2 between passengers on airplanes is a significant concern and reducing the transmission of SARS-CoV-2 or other viruses aboard aircraft could save lives. Solving the Airplane Seating Assignment Problem (ASAP) produces seating arrangements that minimize transmission risks between passengers aboard an aircraft, but the chosen risk model affects the optimal seating arrangement. We analyze previous risk models and introduce two new risk models, masked and unmasked, based on previous experiments performed aboard real aircraft to test aerosol dispersion of SARS-CoV-2 sized particles. We make recommendations on when each risk model is applicable and the types of seating arrangements that are optimal for each risk model. • SARS-CoV-2 may be transmitted between passengers on airplanes. • Aerosol models for SARS-CoV-2 can be used to reduce risk in seating arrangements. • Different risk models lead to distinct types of optimal seating arrangements. • Passengers should always be spaced as far apart as possible to minimize transmission. [ABSTRACT FROM AUTHOR]

Aircraft directional control effectiveness is analyzed through experiments in wind tunnel. Control surfaces on low aspect ratio lifting surfaces exhibit different lifting capabilities compared to those with high aspect ratio. Such behavior must be carefully considered in the preliminary design phase to avoid any overestimation in size, weight, costs and emissions. Traditional sizing methodologies are based on coupling the effects of the wing planform (e.g. aspect ratio) at low angles of control surface deflection with the effects of wing section (e.g. chord ratio) evaluated on section data in the full range of control surface deflection, so that the non-linear aerodynamics is inherited from 2D data, completely neglecting the different aerodynamic behavior of a low aspect ratio wing at high angles of deflection. To fill this gap, an experimental wind tunnel test campaign on a generic regional turboprop aircraft model with a modular vertical tail with rudder has been performed. Results indicate that the aircraft design methodologies present in public literature underestimate the control surface effectiveness at high angle of deflections by 15% to 25%, leading to an average overestimation of control surface size. [ABSTRACT FROM AUTHOR]