Aircraft Operations Research Articles

Can airports be a catalyst for reducing aviation’s effect on the climate?

The aviation ecosystem is increasingly coming under pressure to decarbonise from the public and governments. Airports are at the leading edge of transforming their operations, alongside airlines and aerospace companies. While, however, the levers to reduce Scope 1 and 2 airport emissions are well understood, how to address Scope 3 emissions (which account for the bulk of an airport’s emissions) remains a major challenge. This paper provides an overview of potential Scope 3 decarbonisation levers across aircraft operations, ground transport and infrastructure construction. The paper then assesses the potential impact on emissions, and ease of implementation of these levers, highlighting aircraft operations as the area with highest potential to reduce ecosystem emissions. Next, the paper looks at how some of these levers have been implemented in practice, based on the case study of Geneva Airport, focusing on supporting sustainable mobility, energy support for aircraft and financial incentives for airlines to use latest-generation aircraft. The paper then identifies and discusses key barriers that must be overcome, including the ability of airports to influence domains outside their direct control, competing governmental policies and need for investment, highlighting the need for collaboration between a wide range of stakeholders. Based on this, the paper suggests a number of actions that airports should take to satisfy stakeholders and catalyse the aviation ecosystem towards its goal of achieving net zero.

Numerical study on the thermodynamic behavior of de-icing liquid droplets impacting walls

Spraying de-icing fluid is a key method to ensure the safe operation of aircraft in icy and snowy weather. The film aggregation and internal mixing of de-icing fluid droplets on the aircraft skin during a collision are crucial. Considering the rheological properties of the molecular viscosity change of the de-icing fluid droplets during the collision and the heat transfer model of the heat loss after the impact, the phase field method is used to capture the gas–liquid interface, and a thermal pressure/viscous coupling model is constructed. The thermodynamic behavior of different axial distances is calculated. The results show that, as the dimensionless axial distance of the droplet increases, the spreading length of the fused droplet decreases instead, and the heat transfer rate of the droplet increases with the increase in spreading length. After stabilizing, the increase or decrease in the heat transfer rate depends on the strength of the heat transfer between the liquid layers. As the dimensionless axial distance increases, the internal flow of the droplet weakens and, between the droplet and the wall, the heat flux density gradually decreases and the average temperature drop of the droplet becomes gradual.

Pilot Perceptions of Wire Strikes in Agricultural Aviation Operations.

INTRODUCTION: Agricultural aircraft operations are associated with unique challenges. In particular, these include maintaining awareness of obstacles associated with flight at very low altitudes. Wire strikes are a common cause of accidents in these operations.METHODS: Focus groups were completed during the 2022 Ag Aviation Expo hosted by the National Agricultural Aviation Association with pilots who had experienced wire-strike events (N = 22). The researchers coded the transcripts using a human factors framework.RESULTS: Notably, unplanned "trim passes" were a key stage of flight during wire-strike events. Cognitive risk factors that may have affected their performance included situation awareness, decision-making choices, and pressure to perform. Over half of subjects reported being aware of the wire before collision. Possible prevention strategies include not spraying the field due to safety risks, paying better attention to where they were in the field, and avoiding deviation from the planned route.DISCUSSION: Wire-strike events often occur due to momentary lapses in attention, even when the pilot is already aware of the wire. This study shows that targeted approaches to prevent wire strikes in agricultural aviation operations require addressing a number of cognitive risks and human factors, rather than implementing increased preflight surveillance. These results have implications for preventing future wire-strike accidents based directly on pilot perceptions, both within agricultural operations and general aviation more broadly.Baumgartner HM, DiDomenica R, Hu PT, Thomas S. Pilot perceptions of wire strikes in agricultural aviation operations. Aerosp Med Hum Perform. 2024; 95(6):305-312.

Very Low Level Flight Rules for Manned and Unmanned Aircraft Operations

An analysis of the development of legal regulations regarding unmanned civil aviation leads to the conclusion that the current air traffic rules are among the key issues that require amending. Are drones allowed to fly at any height? Can drones fly freely over a person’s house or garden, several meters above the ground? What is the minimum allowable height for drone flights? The method of study consisted of content analysis of the existing legislation. Current doctrines were confronted with the existing regulations, documents, materials, safety reports, and statistics. The results of the study show that the existing air traffic rules, precisely in the case of aircraft operations performed by manned and unmanned aviation at very low heights, are definitely practical in nature. First, in most countries violations of air traffic rules are prohibited acts subject to criminal penalty. Second, determining the principles of air traffic for air operations is of crucial importance for determining legally permissible interference in property ownership. The urban air mobility is outside the scope of this research.

Aircraft routing using dynamic programming and reinforcement learning: A customer-centric approach

Over the past few decades, the airline industry has evolved into a sophisticated business, with conventional objectives such as operational efficiency, effective fleet assignment, flight punctuality, and equitable crew scheduling being the primary focus. Nevertheless, given the growing accessibility to customer feedback (either through public forums or private data), it is crucial to make business decisions that cater to the customers’ requirements in addition to conventional goals. Within aircraft operations, there is a series of decisions to be made, such as flight scheduling, fleet assignment, aircraft routing, and crew scheduling. After designating a fleet type to each flight leg, airlines ascertain the sequence of flight legs, or strings, to be operated by individual aircrafts, while complying with obligatory maintenance checks. This constitutes the aircraft routing problem.We introduce a novel approach to aircraft routing problem, by infusing traditional methodologies with insightful customer feedback to create a more responsive and customer-centric model. Unlike conventional techniques of constructing routes, in our work, we construct maintenance feasible strings. Traditional aircraft routing methodologies typically concentrate on minimizing propagated delay. However, by integrating customer feedback, more effective prioritization to minimize delays for flight legs with higher customer dissatisfaction can be achieved. We propose an optimization model that strives to minimize propagated delay while prioritizing flights based on customer feedback, thus resulting in customer-aware routes. To solve the proposed optimization model, we design an iterative alternating optimization scheme where feasible strings are first constructed from the pool of available flight legs using a string generation procedure, followed by solving an integer linear optimization problem over only the feasible set of strings obtained in the first stage. To construct feasible strings of flights at each iteration, we use two different methods. The first method is based on a dynamic programming approach which is useful for mean delay information. To handle practical cases where delays are uncertain, we propose a reinforcement learning (RL) approach to construct the strings. We provide experiments of our proposed methods on synthetic and real data sets and demonstrate the effectiveness of our RL model in comparison to dynamic programming based model. Our experiments affirm that routing decisions informed by customer feedback prioritize minimizing delays for specific flight legs, resulting in routes that are inherently customer-friendly.

A Simulation Study on Utilizing in Airbus380 fuel Tanks for Thrust and Fuel Efficiency

This paper explores the potential benefits of using nanofluids within the fuel system of an Airbus A380 to enhance engine thrust and reduce fuel consumption. By analyzing the Nusselt and Reynolds numbers, the study aims to understand the heat transfer and fluid dynamics that could lead to more efficient aircraft operation. The integration of nanotechnology in aviation fuel systems represents a promising frontier for improving aircraft performance. the nanoscale as a fluid whose particles are suspended between 1-100 nanometers and permanently in the particle. Adding nanoscale increases heat transfer. In this research used silicon carbide nanofluid (sic nanofluid) with a percentage of (1,2,3,4%) the base fluid (Jet A1) as well as thermal properties including Nusselt number and thermal conductivity coefficient and... It's been studied.

A Decision Support Framework for Aircraft Arrival Scheduling and Trajectory Optimization in Terminal Maneuvering Areas

This study introduces a decision support framework that integrates aircraft trajectory optimization and arrival scheduling to facilitate efficient management of descent operations for arriving aircraft within terminal maneuvering areas. The framework comprises three modules designed to tackle specific challenges in the descent process. The first module formulates and solves a trajectory optimization problem, generating a range of candidate descent trajectories for each arriving aircraft. The options for descent operations include step-down descent operation, Continuous Descent Operation (CDO), and CDO with a lateral path stretching strategy. The second module addresses the assignment of conflict-free trajectories to aircraft, determining precise arrival times at each waypoint. This is achieved by solving an aircraft arrival scheduling problem. To overcome computational complexities, a novel variable neighborhood search algorithm is proposed as the solution approach. This algorithm utilizes three neighborhood structures within an extended relaxing and solving framework, and incorporates a tabu search algorithm to enhance the efficiency of the search process in the solution space. The third module focuses on comparing the total cost incurred from flight delays and fuel consumption across the three descent operations, enabling the selection of the most suitable operation for the descent process. The decision support framework is evaluated using real air traffic data from Guangzhou Baiyun International Airport. Experimental results demonstrate that the framework effectively supports air traffic controllers by scheduling more cost-efficient descent operations for arrival aircraft.

Infrastructural and operational availability for air taxi operations at German aerodromes

According to Flightpath 2050, door-to-door travel times of less than four hours are aspired for journeys within Europe. To accomplish this goal, on-demand air mobility (ODAM) can improve the conventional means of transportation with short travel times and comfort gains. This paper outlines a methodology for analyzing the availability of German aerodromes for air taxi operations. Analyses are based on the usage of hybrid-electric fixed-wing aircraft under visual flight rules (VFR) for ODAM. This future use-case is applied for the evaluation of infrastructural availability (quality) and operational availability in Germany. An aerodrome database and METAR weather database are developed and evaluated for the availability analyses. The main research finding is the availability of German aerodromes for small fixed-wing aircraft (according to EASA CS-23) operation under VFR for ODAM. The lack of suitable infrastructure for air taxi services (e.g., terminals, paved runways) at many small airfields limits the availability of the service. Furthermore, unsuitable weather conditions reduce operational availability, especially in winter, due to lack of visibility, e.g., snowfall. Current ODAM research has assumed continuous availability, causing an overestimation of availability. This paper provides a holistic approach in which the current state of aerodrome infrastructure and operational constraints are considered by the example of German aerodromes. Minimal infrastructure needed for this use-case is determined, main weather parameters causing operational constraints are detected and possibilities for increasing operational availability at aerodromes are revealed.

Enhancing System Predictability and Profitability: The Importance of Reliability Modelling in Complex Systems and Aviation Industry

Predicting the future has always been a human endeavor, ranging from antiquated methods such as monitoring aquariums for indications of earthquakes to contemporary techniques that evaluate system probabilities and capacities. Taking into account the current emphasis on improving product reliability by customer demands and global competitiveness, we introduce the idea of reliability in the context of the Airbus A320 airplane in this paper. When it comes to business and commercial aircraft, timetable compliance and punctuality are critical components of an aircraft’s profitability. For many operators of commercial aircraft, reaching the 98% reliability criterion is a typical objective. This study examines the Airbus A320 in great detail, concentrating on a particular system scenario that has two possible failure modes, one where gears do not retract after takeoff and the other being when landing, the gears fail to extend. The organization bears specific costs as a result of these shortcomings. The purpose of the study is to examine these expenses and offer insights into the financial ramifications by performing a profit analysis. We examine the failure and repair patterns by utilizing the Markov Process and Regenerative Point method. This study adds to our understanding of the reliability issues facing the aviation sector and has applications for improving the Airbus A320 aircraft’s operational effectiveness and financial performance.

A Comprehensive Review on the Global Aviation Industry and Aircraft Maintenance Management Processes

The vision of the Turkish Republic is to surpass the level of contemporary civilization, and one of the main principles to achieve this is "The future is in the skies." To make this a reality, it is imperative to establish a national and domestic aviation industry. The first step towards this goal is to ensure the safe operation of aircraft, which requires a maintenance management system. To create and use the necessary maintenance documents, an international standard management process should be followed for airframe manufacturers and component and part manufacturers in the aviation industry. Airline operators should then create their maintenance documentation according to this system and work with airplane maintenance organizations to ensure the airworthiness of their aircraft. This study discusses and evaluates the documents used within the essential management and organization principles framework, primarily focusing on the aircraft maintenance management system.

Comprehensive Investigation of Unmanned Aerial Vehicles (UAVs): An In-Depth Analysis of Avionics Systems.

The evolving technologies regarding Unmanned Aerial Vehicles (UAVs) have led to their extended applicability in diverse domains, including surveillance, commerce, military, and smart electric grid monitoring. Modern UAV avionics enable precise aircraft operations through autonomous navigation, obstacle identification, and collision prevention. The structures of avionics are generally complex, and thorough hierarchies and intricate connections exist in between. For a comprehensive understanding of a UAV design, this paper aims to assess and critically review the purpose-classified electronics hardware inside UAVs, each with the corresponding performance metrics thoroughly analyzed. This review includes an exploration of different algorithms used for data processing, flight control, surveillance, navigation, protection, and communication. Consequently, this paper enriches the knowledge base of UAVs, offering an informative background on various UAV design processes, particularly those related to electric smart grid applications. As a future work recommendation, an actual relevant project is openly discussed.

Representation of Thermomechanical Damage in Fiber-Reinforced Ceramic Composites at High Thermal Gradients

Ceramic matrix composites (CMCs) are the core strategic materials for the thermal structure of new-generation hypersonic aircraft. The unclear understanding of the cross-scale thermomechanical behavior and failure mechanism of materials and structures in high-temperature transient environments is a key scientific issue that restricts the reliable design and safe operation of hypersonic aircraft. In this study, a high-temperature test module in a supersonic wind tunnel with integrated various test systems was independently designed to systematically investigate the thermal mechanical damage evolution of CMCs used in astronautics applications under high-temperature transient conditions. Furthermore, a numerical method for fluid-heat-solid coupling based on an iterative solution strategy was developed and compared with an algorithm based on a wall modification strategy in terms of computational efficiency and accuracy. Besides, a comparative analysis was conducted with the temperature field distribution of the sample obtained in the hypersonic wind tunnel integration test to verify the correctness of the developed thermal-fluid-solid coupling calculation method. Finally, through thermoelastic coupling computational models, the high-thermal-gradient-induced thermomechanical damage mechanism of the CMCs was revealed, providing support for further optimizing the material system and thermal structure design of the CMCs.

Population health implications of exposure to pervasive military aircraft noise pollution.

While the adverse health effects of civil aircraft noise are relatively well studied, impacts associated with more intense and intermittent noise from military aviation have been rarely assessed. In recent years, increased training at Naval Air Station Whidbey Island, USA has raised concerns regarding the public health and well-being implications of noise from military aviation. This study assessed the public health risks of military aircraft noise by developing a systematic workflow that uses acoustic and aircraft operations data to map noise exposure and predict health outcomes at the population scale. Acoustic data encompassing seven years of monitoring efforts were integrated with flight operations data for 2020-2021 and a Department of Defense noise simulation model to characterize the noise regime. The model produced contours for day-night, nighttime, and 24-h average levels, which were validated by field monitoring and mapped to yield the estimated noise burden. Established thresholds and exposure-response relationships were used to predict the population subject to potential noise-related health effects, including annoyance, sleep disturbance, hearing impairment, and delays in childhood learning. Over 74,000 people within the area of aircraft noise exposure were at risk of adverse health effects. Of those exposed, substantial numbers were estimated to be highly annoyed and highly sleep disturbed, and several schools were exposed to levels that place them at risk of delay in childhood learning. Noise in some areas exceeded thresholds established by federal regulations for public health, residential land use and noise mitigation action, as well as the ranges of established exposure-response relationships. This study quantified the extensive spatial scale and population health burden of noise from military aviation.We employed a novel GIS-based workflow for relating mapped distributions of aircraft noise exposure to a suite of public health outcomes by integrating acoustic monitoring and simulation data with a dasymetric population density map. This approach enables the evaluation of population health impacts due to past, current, and future proposed military operations. Moreover, itcanbemodified for application to other environmental noise sources and offers an improved open-sourcetool to assess the population health implications of environmental noise exposure, inform at-risk communities, and guide efforts in noise mitigation and policy governing noise legislation, urban planning, and land use.

Jet noise of a low bypass turbofan with internal mixing and external plug

Jet noise generated by turbofan engines which are designed for supersonic aircraft operation is expected to remain a challenge for the aerospace industry. For civil supersonic transport, low bypass ratio engines with internal mixing and external plugs are currently seen as promising exhaust architecture to meet aircraft mission and certification requirements. Measurements of the noise from a representative low-bypass ratio long duct mixed flow with external plug exhaust configuration were made, along with corresponding steady-RANS and LES analyses. The measured data showed excess high frequency noise across a wide range of operating conditions as compared to an equivalent single stream jet, or an equivalent uniform jet with internal plug. The absolute levels of the excess noise were relatively insensitive to forward flight, and the excess noise was most dominant when the primary and secondary streams had large velocity and temperature mismatch just upstream of the internal mixer. Preliminary indications from the LES analysis also indicated that significant pressure fluctuations, at the same frequencies which are insensitive to forward flight, develop inside the nozzle as the internal shear layer from the mixer grows and gets accelerated by the external plug. Parametric study test measurements on the fan and core operating conditions were performed, providing support for the hypothesis that the excess noise is generated as the internal shear layer, starting inside the nozzle, gets accelerated by the plug and passes through the weak shock at the nozzle exit where the flow accelerates more and turns over the external plug.

Preliminary Performance Analysis of Medium-Range Liquid Hydrogen-Powered Box-Wing Aircraft

This paper proposes a performance analysis of a medium-range airliner powered by liquid hydrogen (LH2) propulsion. The focus is on operating performance in terms of achievable payload and range. A non-conventional box-wing architecture was selected to maximize operating performance. An optimization-based multidisciplinary design framework was developed to retrofit a baseline medium-range box-wing aircraft by designing and integrating the fuel tanks needed to store the LH2; several solutions were investigated for tank arrangement and layout by means of sensitivity analyses. As a main outcome, a performance analysis of the proposed LH2-powered box-wing aircraft is provided, highlighting the impact of the introduction of this energy carrier (and the integration of the related tank systems) on aircraft operating performance; a comparative study with respect to a competitor LH2-retrofitted tube-and-wing aircraft is also provided, to highlight the main possible operating differences between the two architectures. The findings reveal that the retrofitted box-wing can achieve long-range flights at the cost of a substantially reduced payload, mainly due to the volume limitations imposed by the installation of LH2 tanks, or it can preserve payload capacity at the expense of a significant reduction in range, as the trade-off implies a reduction in on-board LH2 mass. Specifically, the studied box-wing configuration can achieve a range of 7100 km transporting 150 passengers, or shorter ranges of 2300 km transporting 230 passengers. The competitor LH2-retrofitted tube-and-wing aircraft, operating in the same category and compatible with the same airport apron constraints, could achieve a distance of 1500 km transporting 110 passengers.

Comprehensive Evaluation of Anti-icing Performance and Operational Efficiency of Superhydrophobic Propellers.

The icing of propellers is a critical factor that affects the safe operation of aircraft. A superhydrophobic surface, with its extremely low wettability, is highly valuable in the field of anti-icing. This study investigates the distribution pattern of ice on propeller surfaces by employing spray coating to create superhydrophobic surfaces. Additionally, it conducts a comparative analysis of thrust and power under icing and non-icing conditions to comprehensively assess the impact of superhydrophobic surfaces on propeller operation efficiency. The results show that superhydrophobic surfaces not only diminish the ice formation area on propeller surfaces but also enhance the traction of propellers under icing conditions, reducing the power consumption of the propeller. The generated thrust can reach up to 1.6 times that of non-superhydrophobic propellers while consuming only one-third of the power. Furthermore, under non-icing conditions, superhydrophobic surfaces exhibit minimal impact on propeller performance.

Experimental studies of the influence of elastic-dissipative parameters of engine mounting units on the dynamic characteristics of the “wing model – elastic pylon – engine” system

A feature of modern heavy transport aircraft is their layout with engines on elastic pylons under the wing, with the fuel tanks located in the wing consoles. In this case, the main elastic tones of the aircraft’s own oscillations, which determine its dynamic response to external disturbing influences, include the so-called motor tones (vertical and horizontal (lateral) oscillations of engines on elastic pylons). A new type of flutter has appeared – pylon, which for some aircraft determines the critical flutter speed of the aircraft as a whole. The main reason for this phenomenon is the low oscillation damping of the engine on the pylon under the wing. Therefore, research aimed at modernizing the engine mounting points on the pylon in order to reduce the level of elastic oscillations during aircraft operation seems relevant. One of the possible ways to solve this problem is to use the concept of a freed engine, when the engine attachment points to the pylon are modernized, providing more effective damping of engine oscillations. In order to confirm the possibility of practical implementation of these solutions, corresponding experimental studies were carried out on an experimental setup developed by the authors. A design of engine mounting units has been developed that allows specified displacements of the engine relative to the pylon during forced elastic oscillations of the system, which includes a hinged suspension, installation of additional elastic elements and hydraulic dampers.The article presents the results of studies of the influence of elastic-dissipative parameters (partial frequency of natural oscillations and partial decrement of oscillations) of an engine mount on an elastic pylon on the dynamic characteristics of the dynamic system “wing model – elastic pylon – engine”. It is shown that by introducing specially designed engine suspension units on pylons, it is possible to significantly change the dynamic characteristics (frequencies and amplitudes of natural oscillations) of the elastic system as a whole. Thus, the amplitudes of oscillations of the engine’s center of mass in the region of motor tones decrease by 3...7 times during forced harmonic oscillations.

Image fusion algorithm for the collaborative use of unmanned aerial vehicles

Currently, the applicable scope of unmanned aircraft application is increasingly expanding. The promising field of unmanned aircraft enhancement is the implementation of some collaborative actions during controlled flight. This paper considers some issues of the group application of unmanned aerial vehicles (UAV) related to the coordinated planning and control of UAVs performing surveillance missions. Performing aerial search operations is technically complicated by the requirement to recognize a search object in arbitrary conditions, which can be both simple and severe environment. The search area is limited by the UAV capabilities, so, in order to improve the efficiency of search operations, UAVs are combined into groups. An algorithm for solving the problem of object search in arbitrary conditions by a group of unmanned aircraft is proposed. The advantage of search by a group of unmanned aircraft is the coverage of the larger search area in a conventional unit of time. This paper addresses the unmanned aircraft configuration, containing both the means of collaborative flight operation and a synthetic vision system. The image obtained by the synthetic vision system is both a source of navigation information and a means which reliably determines the result of search operations. Depending on the conditions of search operations, the image obtained by the synthetic vision system may require additional processing to use as intended. A fusion algorithm is proposed, which is characterized by adaptive adjustment of parameters in each frame individually for different image fragments. Based on the results obtained, it is planned to create a new product for commercial operation of unmanned aircraft.

PELAYANAN STAF BOARDING GATE CITILINK BERDASARKAN MANAJEMEN ISLAM DI YOGYAKARTA INTERNATIONAL AIRPORT

This study aims to analyze the service of Citilink's boarding gate staff at Yogyakarta International Airport based on Islamic management. The research method used is qualitative with a case study approach. Data collection was conducted through interviews, observations, and documentation. The results show that Citilink's boarding gate staff at YIA are able to organize and manage boarding procedures quickly and efficiently, allowing passengers to board the aircraft on time without any hindrance. The staff's compliance with established SOPs is a major factor supporting passenger satisfaction. In addition to compliance with SOPs, other supporting factors in improving service quality include the availability of additional facilities that facilitate staff performance. However, this study also identifies several inhibiting factors, such as operational aircraft issues causing delays and passenger dissatisfaction with staff services. To address these obstacles, this study proposes several solutions, one of which is providing compensation to passengers in case of delays as a form of responsibility and fairness. In general, the service aligns with the principles of Islamic management, such as shiddiq (honesty), amanah (trustworthiness), tabligh (good communication), and fathanah (intelligence). However, there are still some aspects that need improvement, such as empathy and responsiveness in serving passengers.

Sensitivity analysis of urban air mobility aircraft design and operations including battery charging and swapping

Urban Air Mobility (UAM) is an evolving concept of passenger transportation providing on-demand flights within metropolitan environments, wherefore typically fully electric vertical take-off and landing aircraft are designed. Due to the underlying battery energy constraints, the design of UAM aircraft is very sensitive. Apart from the design considerations, the impact of aircraft operations on the entire UAM transport network must be examined. As there is no data from real-world operations available, this research article utilizes a system of systems simulation framework combining aircraft design with an agent-based simulation. The underlying approach offers the possibility of studying several parameters concerning UAM aircraft design and operations. In a case study focused on intra-city transport, aircraft design aspects regarding the payload capacity, the mission profile, and the reserve requirement are studied for a multirotor configuration. Furthermore, the aircraft operations aspects are focused on the turnaround procedures, the passenger demand, and the cruise speed. The multi-level sensitivity analysis ranging from the subsystem over the system of interest to the system of systems level allows us to trace the most sensitive aspects. Especially, the sensitivity analysis of battery fast-charging and swapping shows the importance of the holistic system of systems investigations for the successful development of UAM aircraft and services.