Stages Of Flight Research Articles

In-Flight Infection Prevention and Control Training for Cabin Crew in China: A Qualitative Study

Specific in-flight infection prevention and control (IPC) training was deemed an essential strategy for ensuring the implementation of appropriate measures to protect the health of passengers and crew sustainably during COVID-19 and the post-pandemic period. This study aims to identify cabin crew’s IPC duties and investigate the current status of the in-flight IPC training for cabin crew in China. The snowballing technique was employed with purposeful sampling. A total of 15 participants, including cabin crew of various positions, inspectors, and trainers from eight airlines in China were invited to attend the in-depth semi-structured interview between September and November of 2022. Cabin crew IPC duties can be classified into four phases based on a thematic analysis: before flight, passenger boarding, during flight, and after flight. The findings indicated airlines in China required their cabin crew to carry out strict IPC measures onboard throughout all stages of flight, including in-flight IPC training before flight, being aware of COVID symptoms and monitoring passengers’ conditions during boarding, the standard operating procedure (SOP) of handling suspicious carriers during flight, and so on. Meanwhile, six major themes concerning cabin crew’s in-flight IPC training were extracted: COVID-19 information, IPC Supplies and usage, IPC measures onboard, communication and explanation, information collection and report up, attitude and perceptions toward COVID-19, and IPC measures. Cabin crew were regularly trained on in-flight IPC through online learning, with face-to-face training used as reinforcement. Although training for knowledge and technical skills was deemed comprehensive, non-technical skills such as communication and explanation were viewed as a weak link. Moreover, airlines should make greater efforts to help cabin crew develop a positive attitude towards COVID-19 and overcome their internal fears. This study pointed out the shortcomings of the in-flight IPC training for cabin crew in China and can help the airlines improve the training program so that cabin crew can perform their duties correctly. Furthermore, the result can inform the development of future cabin crew training programs for the post-pandemic period.

The impact of shape and attachment position of biologging devices in Northern Bald Ibises

BackgroundThe impact of biologging devices on the aerodynamics or hydrodynamics of animals is still poorly understood. This stands in marked contrast to the ever more extensive use of such technologies in wild-living animals. Recently, increasing concerns have been raised about the impairing effects of these devices on the animals concerned. In the early days of biotelemetry, attention was focused solely on reducing weight, but now aerodynamic effects are also increasingly being considered. To investigate these effects, we trained Northern Bald Ibises to fly in a wind tunnel in which we measured heart rate and dynamic body acceleration (VeDBA) as proxies for energy expenditure in relation to different logger shapes and wind flow directions.ResultsOur data provide evidence that the position of biologging devices significantly influence the flight distances, and the shape of biologging devices has a considerable effect on heart rate and VeDBA, both of which have been used as proxies for energy expenditure. Unfavorable shape and positioning go beyond merely affecting the effort required during flapping flight. The energetically probably more important effect is that the devices impair the bird’s ability to glide or soar and thus force them to perform the energetically much more demanding flapping flight more frequently. This effect was more pronounced in rising air than in horizontal airflow. A complementary study with wild Northern Bald Ibises during spring migration provides evidence that the position of the devices on the bird’s back affects the length of the flight stages. Birds carrying the devices on the upper back, fixed by wing-loop harnesses, had significantly shorter flight stages compared to birds with a more caudally positioned device, fixed by leg-loop harnesses.ConclusionThe attachment of biologging devices on birds affects their performance and behavior and thus may influence their fitness and mortality. Our results show that detrimental effects can be reduced with relatively little effort, in particular through a strictly aerodynamic design of the housing and increased consideration of aerodynamics when attaching the device to the body. In birds, the attachment of biologging devices via leg loops to the lower back is clearly preferable to the common attachment via wing loops on the upper back, even if this affects the efficiency of the solar panels. Nevertheless, the importance of drag reduction may vary between systems, as the benefits of having a biologging devices close to the center of gravity may outweigh the increase in drag that this involves. Overall, more research is required in this field. This is both in the interest of animal welfare and of avoiding biasing the quality of the collected data.

Dynamic modeling and analysis of compound pendulum motion of projectile

The influence of air lift on the stability of inaccurate precision strike ammunition is studied, and the mechanical analysis of projectile and its flight stage is carried out. The dynamic equation of projectile under the action of air lift is established and simulated. The angular velocity and angular time-history curve of the compound pendulum motion of the projectile are obtained, and the correctness of the mechanical analysis of compound pendulum motion during flight is verified.

Analyzing the operation reliability of aeroengine using Quick Access Recorder flight data

Aeroengine operation reliability (AOR) estimation is important for stakeholders in operating, monitoring, designing, and improving. The Quick Access Recorder (QAR) flight data and failure rate of aeroengine are utilized to analyze AOR. Considering the uncertainty in AOR assessment, a Bayesian neural network (BNN) is trained to evaluate and forecast AOR based on aeroengine status data within a confidence interval. Further, to quantify the degree of each feature on AOR, Shapley Additive ex-Planations (SHAP) values are calculated based on the Light gradient boosting machine (LightGBM) to study the degree and direction of influence feature on AOR. In this study, it is revealed that (i) AOR is closely related to the airplane flight stages; and (ii) after training with eight flights and validation with two flights data from QAR data, BNN can achieve AOR analysis and prediction within a certain confidence interval while obtaining aeroengine state data; and (iii) the feature importance and influence direction are quantified by SHAP values, it demonstrates the sensitive factors in AOR analysis. Based QAR data, this study provide an AOR analysis framework to improve the operation and design, which has the potential to support aeroengine real-time status monitoring and health management.

Improved Generative Adversarial Network Method for Flight Crew Dialog Speech Enhancement

Traditional speech enhancement algorithms are only suitable for dealing with stationary noise, but the noise in the stage of flight is nonstationary noise, so the traditional method is not suitable for dealing with the noise in the stage of flight. This paper proposes a speech enhancement algorithm based on a generative adversarial network: Deep Convolutional–Wasserstein Generative Adversarial Network (DWGAN). Firstly, the model integrates the deep convolutional generative adversarial network and the Wasserstein distance based on the generative adversarial network. Secondly, it introduces a conditional model to improve the enhanced speech quality, and the spectral constraint layer is used to prevent the model from falling too fast and causing collapse. Finally, the L1 loss term is introduced into the loss function to reduce the number of training times and further improve the enhanced speech quality. The experimental results show that the intrusiveness of background noise and overall processed speech quality of DWGAN are improved by about 7.6 and 9.4%, respectively, compared with WGAN in the acoustic environment of simulated aircraft operation.

Conceptual design and optimal sizing of a small unmanned aerial vehicle with fuel cell and battery-powered hybrid propulsion system by meta-heuristic algorithms based on energy consumption

ABSTRACT In this paper, a new conceptual design methodology for a hybrid propulsion system consisting of the battery and hydrogen fuel cells is presented based on the minimum energy consumption of the UAV. In this context, an optimization problem with non-linear constraints is constituted to determine the wing loading, aspect ratio, stall velocity, endurance velocity, battery power, fuel cell power, maximum lift coefficient, and zero-lift drag coefficient of the UAV. The solution to this optimization problem, based on the UAV’s minimum energy consumption for the endurance and cruising flight modes, is implemented by meta-heuristic algorithms: particle swarm optimization, cuckoo search algorithm, artificial bee colony, and genetic algorithm. The results of these algorithms are compared in terms of energy consumption. This article contributes to the literature on sizing fuel cell-powered small UAVs based on minimum energy consumption and comparing different metaheuristics. According to the results, the lowest power consumption of the UAV is obtained by the particle swarm optimization algorithm as 2018.63 W. Additionally, the weight ratios calculated with the parameters obtained from the sizing optimization for the UAV propulsion system components and flight stages are compared with a benchmark study in the literature. Finally, the payload weight ratio is also increased by 28.5% by sizing optimization.

Effects of rotor separation on the axial descent performance of dual-rotor configurations

Rotorcraft can encounter highly unsteady flow when descending at a steep angle, leading to a flow condition called vortex ring state, which is associated with strong oscillatory airloads and substantial losses in mean rotor thrust. This study examines the aerodynamic coupling between closely arranged rotors in vertical flight and assesses the extent to which rotor–rotor interactions affect the rotor performance in this flight stage. Wind tunnel experiments were performed on a small-scale, dual-rotor set-up with adjustable rotor spacing, and the effect of rotor separation on thrust generation was quantified. Pairs of 4 in., 5 in. and 6 in. rotors ( $3.0 \times 10^4< Re<8.1 \times 10^4$ ) were investigated, with load cell measurements showing significant thrust losses and concomitantly increased thrust oscillations as descent rate increased. Peak losses and fluctuations were consistently recorded at descent rates of 1.2–1.3 times the hover induced velocity for all rotor sizes and separations. While tests showed that the mean aerodynamic performance of dual-rotor systems is generally similar to that of single rotors, appreciable changes to the descent characteristics could be observed at low rotor separations. Particle image velocimetry flow visualization suggests considerable changes to the flow field as rotor separation decreases, where individual vortex ring systems merge into a single vortex ring structure.

Reliability of life support systems depending on the degree of their biologisation

Long-range and long-duration autonomous missions of manned transport systems have different objectives depending on the environment. They can be tasks of studying and mastering the depths of the world ocean, Arctic and Antarctic multi-purpose missions, etc. The most complicated of such missions may be manned flights to planets with the purpose of their exploration during long stays. Reliable technologies of life support systems (LSS) of autonomous transport systems (ATS) mastered in space missions can be fully or fragmentarily used in missions of other habitats. The reliability of any long-term manned missions depends on the degree of LSS autonomy, the level of its biologisation, and the efficiency of integrated closed biotechnological cycles. With the help of unmanned interplanetary vehicles, the presence of water reserves on Mars has been proved, the Mars atmosphere has been studied, and methane, the origin of which is yet to be discovered, has been discovered, all of which will undoubtedly contribute to the exploration of the planet. This indicates the possibility of organising human life on Mars and contributes to the preparation of a manned mission with the mission of thorough exploration of the planet. Biotechnology has long ago mastered in Earth conditions biosynthesis of animal microbial protein on the basis of methane, water, and air. If the LSS ATS of the Martian manned mission includes closed biotechnological cycles with the participation of these substances, they will make it possible to provide food for the ATS crew not only at the stage of a long flight to Mars, but also on its surface at the initial stage of colonisation, including the use of planetary resources. The purpose of this paper is to analyse and identify ways to improve the reliability of ATS during long-duration and extended manned missions when there is no possibility of resupply in the LSS.

СОВЕРШЕНСТВОВАНИЕ МЕТОДОЛОГИИ И АППАРАТНО-ПРОГРАММНОГО ОБЕСПЕЧЕНИЯ ПОЛУЧЕНИЯ ТЕЛЕМЕДИЦИНСКОЙ ВИДЕОИНФОРМАЦИИ В КОСМИЧЕСКОМ ПОЛЕТЕ

The paper describes the telemedicine methods of video info acquisition from cosmonauts in the ISS RS using the available hard- and software for ENT, periodentium and teeth imaging and full examination in the course of mission, after extravehicular activities or dynamic flight stages, as well as in the pre-launch and post-landing periods within the program of space experiment LOR. Also, the paper presents the results of computerized examination and tele-imaging of the upper airways tunica mucosa, pariodentium, tooth crown, auricle and middle ear.

Utilizing the KSC Fixation Tube to Conduct Human-Tended Plant Biology Experiments on a Suborbital Spaceflight.

Suborbital spaceflights now enable human-tended research investigating short-term gravitational effects in biological systems, eliminating the need for complex automation. Here, we discuss a method utilizing KSC Fixation Tubes (KFTs) to both carry biology to suborbital space as well as fix that biology at certain stages of flight. Plants on support media were inserted into the sample side of KFTs preloaded with RNAlater in the fixation chamber. The KFTs were activated at various stages of a simulated flight to fix the plants. RNA-seq analysis conducted on tissue samples housed in KFTs, showed that plants behaved consistently in KFTs when compared to petri-plates. Over the time course, roots adjusted to hypoxia and leaves adjusted to changes in photosynthesis. These responses were due in part to the environment imposed by the encased triple containment of the KFTs, which is a requirement for flight in human spacecraft. While plants exhibited expected reproducible transcriptomic alteration over time in the KFTs, responses to clinorotation during the simulated flight suggest that transcriptomic responses to suborbital spaceflight can be examined using this approach.

Study on bottom thermal environment of launch vehicle during high altitude flight

Aiming at the problem of the thermal environment at the bottom of the launch vehicle in the high-altitude flight stage, taking the launch vehicle with core stage four-way machine as the model, the coupled convection / radiation heat transfer problem at the high-altitude of the launch vehicle is deeply studied through the numerical simulation method, the gas jet flow model of the launch vehicle in the high-altitude flight stage is established, and the flow field information of the rocket under different working conditions and the heat flow at the bottom of the rocket are obtained. The numerical results are compared with the experimental data to verify the effectiveness of the selected model and calculation method. The research shows that the external flow field of the rocket body will have a great impact on the thermal environment at the bottom. With the continuous increase of flight altitude, the convective heat flow at the bottom of the rocket body first rises and then decreases. In the high-altitude stage, the total heat flow at the bottom of the rocket body is dominated by radiant heat flow, the convective heat flow outside the main nozzle is dominant, and the radiant heat flow outside the traveling jet nozzle is dominant.

Modeling and Simulation of Flight Profile and Power Spectrum for Near-Space Solar-Powered UAV

Currently, several solar-powered unmanned aerial vehicles (UAVs) have achieved 24 h uninterrupted cruise. However, models that can cruise for weeks or even months without interruption are in the minority. The technological progress requires the improvement of subsystems and also depends on the accurate planning of flight profile and power spectrum in a long working cycle. Combined with the test data obtained during the development of a solar-powered UAV, this paper establishes systematic mathematical and physical models of aerodynamic, energy, and propulsion systems, which can reflect the change in performance parameters with flight conditions and the performance attenuation with time. Further, a track control strategy based on the principle of maximum energy utilization is proposed, and the energy balance model of each flight stage is established. On the basis of the strategy, the typical flight profile and power spectrum of a solar-powered UAV are analyzed. Finally, the input parameters are decomposed into task parameters (takeoff time window, flight season, flight latitude, takeoff weight) and performance parameters (lift–drag ratio, secondary battery density), and their effects on mission feasibility are studied respectively. The research methods and conclusions of this paper have reference significance for the mission and track planning of solar-powered UAVs.

Data-Driven Method for Detecting Flight Trajectory Deviation Anomaly

With the rapid growth of air traffic, it often happens that aircraft deviate from the original flight plan during actual flight. This paper proposes an anomaly detection method for aircraft trajectory deviation to realize single-point and successive multipoint anomaly detection from a data-driven perspective. Given the one-to-many relationship between reporting points of planned and real trajectories, a matching algorithm is used to match these points. Four trajectory deviation features (which are the position deviation, distance deviation, altitude deviation, and flight stage) are defined. On this basis, a one-class support vector machine is trained to detect single-point anomalies using the deviation features as input. Furthermore, successive multipoint anomaly detection of the aircraft is realized by considering the deviation of successive segments of the trajectory. Taking the flights taking off and landing at four Chinese hub airports as examples, the proposed method obtained an F score, which is a balance of the precision and recall, over 0.92, indicating it achieves high accuracy for anomaly detection.

Overview of Flight Planning Optimization Research

<p>From the analysis of different time stages of flight planning optimization, flight planning optimization can be divided into three aspects: static flight planning optimization, flight planning dynamic feedback optimization based on flight delay prediction, and flight planning dynamic adjustment based on airport collaborative decision -making (A-CDM). Then, it analyzes the static scheduling and optimization of flight plans from the preparation links of flight schedules, aircraft type assignments, and flight frequencies; then uses the optimization method of delay spread prediction and data mining prediction to analyze the correlation of flight plan dynamic feedback optimization based on flight delay prediction the study. Finally, according to the complexity analysis of flight plan optimization, the development trend and future research directions of flight plan optimization are given.</p>

Conflict Risk Assessment between Non-Cooperative Drones and Manned Aircraft in Airport Terminal Areas

Recent years have seen an increase in events of drone incursion into airport terminal areas, leading to safety concerns and disruptions to airline operations. It is of great importance to identify the potential conflict, especially for those non-cooperative drones, as their intentions are always unknown. For the safe operation of air traffic, this paper proposes a conflict risk assessment method between non-cooperative drones and manned aircraft in the terminal area. First, the trajectory data of manned aircraft and drones are obtained. Real-time cylindrical protection zones are established around manned aircraft according to the separation interval for safe operation between the drone and the manned aircraft at different altitudes. Secondly, trajectory predictions for the manned aircraft and the drone are conducted, respectively. A quartile regression bidirectional gate recurrent unit neural network is proposed in this research for the trajectory prediction of the drones. The model integrates the bidirectional gated recurrent unit structure and the quartile regression structure. The performance indicators confirm the superiority of the proposed model. Based on the trajectory prediction results, it is then determined whether there is a conflict risk between the drone and manned aircraft by comparing the position distribution of the drone as well as the real-time cylindrical protection zone of the manned aircraft. The conflict probability between the drone and the manned aircraft is then calculated. The prediction accuracy of conflict probability is estimated by Monte Carlo simulation methods. The collision probability prediction accuracy of manned aircraft and drones at different flight stages and altitudes ranges from 73% to 97%, which shows the reliability of the proposed method. Finally, the collision probability between the drone and the manned aircraft at the closest encountering point and the estimated time to reach the closest encountering point are calculated. This paper predicts the conflict risk between the drone and manned aircraft, thus providing theoretical support for the safe operation of air transport in low-altitude environments.

Efficacy of an elasto-flexible morphing wing at high lift using fluid-structure-interaction simulations

The wide field of applications is the driving force behind the scientific interest in unmanned and micro air vehicles. For these aircraft, morphing wing technologies offer the possibility to adapt the aerodynamics to different flight stages. A morphing wing configuration with two elasto-flexible membrane wings is investigated numerically at a low Reynolds number of Re = 264000. The concept enables wing folding over a wide range and it allows the wing to adapt to changing aerodynamic loads. The focus is set on the benefits of the membrane in the high lift regime. Therefore, fluid-structure-interaction simulations are performed for the model equipped with a flexible and with a rigid wing. The comparison of the numerical results to data from previous experimental measurements show a good agreement. Compared with the rigid wing, the elasto-flexible membrane increases the gradient in the linear region and the maximum lift coefficient. In addition, the maximum lift coefficient is shifted to higher angles of attack. For selected wing positions and angles of attack, the aerodynamic behavior of the flexible and the rigid wing are investigated by means of the lift coefficient, the deformation of the membrane, the wall shear stresses and the wing surface pressure distribution. The deformation of the wing surface directly influences the area of flow separation at the extended wing and the separating leading-edge vortex at the folded wing. Both effects increase the generated lift of the wing with a flexible membrane.

The Emissions of Water Vapour and NOx from Modelled Hydrogen-Fuelled Aircraft and the Impact of NOx Reduction on Climate Compared with Kerosene-Fuelled Aircraft

A kerosene fuelled aircraft was modelled within a performance tool and fuel burn and the emissions of nitrogen oxides (NOx) and water vapour at different stages of flight throughout the mission were estimated. Adaptions were made to engine and aircraft parameters within the performance tool to accommodate a liquid hydrogen fuel over the same given mission. Once an iterative design process had been completed to ensure the aircraft could perform the given mission, the performance tool was again used to calculate total fuel burn. Fuel burn results alongside predicted emission indices were used to estimate the emissions of NOx, water vapour from hydrogen-fuelled aircraft. The use of hydrogen fuel over kerosene fuel in the modelled aircraft resulted in the removal of carbon-based emission species alongside 86% reduction in NOx and 4.3 times increase in water vapour emission. The climate impact of this switch with the reduction in NOx emission was assessed by a 3D global atmospheric chemistry and transport model, STOCHEM-CRI, which found a significant reduction in the concentration of a potent greenhouse gas, ozone, and an oxidizing agent, OH, by up to 6% and 25%, respectively. The reduction of OH levels could induce a positive radiative forcing effect as the lifetime of another important greenhouse gas, methane, is increased. However, the magnitude of this increase is very small (~0.3%), thus the overall impact of the reduction in NOx emissions is likely to have a net negative radiative forcing effect, improving aviation’s impact on the environment. However, further work is warranted on effects of other emission species, specifically water vapour, particulate matter and unburned hydrogen.

Development of a novel supervisory controller on a parallel-hybrid powertrain for small unmanned aerial systems

PurposeA hybrid-electric unmanned aerial vehicle (HE-UAV) model has been developed to address the problem of low endurance of a small electric UAV. Electric-powered UAVs are not capable of achieving a high range and endurance due to the low energy density of its batteries. Alternatively, conventional UAVs (cUAVs) using fuel with an internal combustion engine (ICE) produces more noise and thermal signatures which is undesirable, especially if the air vehicle is required to patrol at low altitudes and remain undetected by ground patrols. This paper aims to investigate the impact of implementing hybrid propulsion technology to improve on the endurance of the UAV (based on a 13.6 kg UAV).Design/methodology/approachA HE-UAV model is developed to analyze the fuel consumption of the UAV for given mission profiles which were then compared to a cUAV. Although, this UAV size was used as reference case study, it can potentially be used to analyze the fuel consumption of any fixed wing UAV of similar take-off weight. The model was developed in a Matlab-Simulink environment using Simulink built-in functionalities, including all the subsystem of the hybrid powertrain. That is, the ICE, electric motor, battery, DC-DC converter, fuel system and propeller system as well as the aerodynamic system of the UAV. In addition, a ruled-based supervisory controlled strategy was implemented to characterize the split between the two propulsive components (ICE and electric motor) during the UAV mission. Finally, an electrification scheme was implemented to account for the hybridization of the UAV during certain stages of flight. The electrification scheme was then varied by changing the time duration of the UAV during certain stages of flight.FindingsBased on simulation, it was observed a HE-UAV could achieve a fuel saving of 33% compared to the cUAV. A validation study showed a predicted improved fuel consumption of 9.5% for the Aerosonde UAV.Originality/valueThe novelty of this work comes with the implementation of a rule-based supervisory controller to characterize the split between the two propulsive components during the UAV mission. Also, the model was created by considering steady flight during cruise, but not during the climb and descend segment of the mission.

Research on Separation and Emission Reduction of Regional Airliner Based on Wake Encounter Response Model

To ensure the safety of aircraft operation, the current regional passenger aircraft maintains a large distance from the preceding aircraft in actual operation, which result in reducing the operation efficiency of airports and airspace, and increasing pollutant emissions. To address these issues, in this paper, two aircraft types are selected in which the CRJ-900 encounters the trailing wake vortices of the A380 in front. An improved strip model is developed to build the CRJ-900 overall response wake encounter value. First, the safety of the CRJ-900 longitudinal and lateral wake encounters in different flight stages is analyzed. Second, we calculate the critical safety separation and its impact on air transport efficiency. Third, we use the LTO model to measure the reduction of aircraft fuel consumption and pollutant emissions. The results demonstrated that the medium-sized aircraft CRJ-900 has the potential to reduce the wake separation when following the super-heavy A380 aircraft. In terms of the critical safety separation calculated by the safety index, the operating efficiency of airports and airspace could be effectively improved, allowing the reduction of pollutant emissions during aircraft take-off and landing. During the takeoff, level flight, and landing phase, the results are summarized as follows: when the CRJ-900 is 13km away from the A380, the maximum lift variation is 11334N, 8157N, and 7366N; the maximum rolling moment variation is 43836N•M, 35274 N•M, and 28487 N•M; the maximum value of the rolling moment coefficient (RMC) is 0.0171, 0.0160, and 0.0130; when the RMC critical value is 0.031, the maximum safe separation for different flight stages is 11960m, which is 1040m shorter than the existing separation; when the RMC critical value is 0.05, the maximum safe separation distance of each stage is 10083m, a reduction of 2917m compared with the existing separation; when the RMC threshold is 0.07, the maximum safe separation of different flight stages is 9021m, a reduction of 3979m compared to the existing separation; when the RMC value is between 0.031-0.07, the fuel consumption can be reduced by 7.9%–12.8%, and the pollutant emission can be reduced by 9.1%–12.8%.

Research and Optimization of Aircraft’s Cruising Flight Stage in Civil Aviation in the Vertical Navigation Problem

Research and Optimization of Aircraft’s Cruising Flight Stage in Civil Aviation in the Vertical Navigation Problem