Irregular Flight Research Articles

Research on Irregular Flight Recovery Strategy Under Different Flight Route Types With Big Data Computing

During periods of extreme weather conditions, airport closures, or other unforeseen circumstances, air-lines frequently encounter disruptions in their flight schedules, posing flight recovery as a recurrent operational challenge. This paper aims to explore the impact of passenger transfer costs on flight recovery across various route types. Drawing on established methods used to calculate aircraft maintenance and crew assignment costs, this study utilizes an improved large-scale neighborhood search algorithm to perform a large number of calculations on a realistic dataset of airlines, meticulously analyzes the amalgamation of passenger transfer costs across different route types and proposes tailored strategies to mitigate disruptions. Through simulation experiments, the research evaluates the influence of various passenger transfer methods on flight recovery across diverse route types, with the goal of furnishing airlines with more adaptable and targeted decision support.

Time-band network model and binary tree algorithm for multimodal irregular flight recovery

Recovery of irregular flights caused by various reasons such as aircraft failures and airport closures is studied in this research and a multimodal time-band network model for solving the issue is proposed. It transforms the flight routing problem into a time-based network, which is used to obtain the delay and cancellation costs of each flight. With delay and cancellation costs as variables, the proposed model aims to minimize recovery costs under constraints. This research also suggests a developed binary tree algorithm, which improves the efficiency of model solving. The results show that the rescheduled flights and re-selected flight routes are at the lowest cost and helpful to achieve a balance of flight flow without affecting flight safety. This method used in this work shows its certain value in helping airlines restore flight operations in the shortest possible time and at the lowest cost, improving operational efficiency and service quality.

A distributionally robust optimization approach for airline integrated recovery under in-flight pandemic transmission risks

The COVID-19 pandemic has hit the airline industry hard, leading to heterogeneous epidemiological situations across markets, irregular flight bans, and increasing operational hurdles. Such a melange of irregularities has presented significant challenges to the airline industry, which typically relies on long-term planning. Given the growing risk of disruptions during epidemic and pandemic outbreaks, the role of airline recovery is becoming increasingly crucial for the aviation industry. This study proposes a novel model for airline integrated recovery problem under the risk of in-flight epidemic transmission risks. This model recovers the schedules of aircraft, crew, and passengers to eliminate possible epidemic dissemination while reducing airline operating costs. To account for the high uncertainty with respect to in-flight transmission rates and to prevent overfitting of the empirical distribution, a Wasserstein distance-based ambiguity set is utilized to formulate a distributionally robust optimization model. Aimed at tackling computation difficulties, a branch-and-cut solution method and a large neighborhood search heuristic are proposed in this study based on an epidemic propagation network. The computation results for real-world flight schedules and a probabilistic infection model suggest that the proposed model is capable of reducing the expected number of infected crew members and passengers by 45% with less than 4% increase in flight cancellation/delay rates. Furthermore, practical insights into the selection of critical parameters as well as their relationship with other common disruptions are provided. The integrated model is expected to enhance airline disruption management against major public health events while minimizing economic loss.

A Data-Driven Heuristic Method for Irregular Flight Recovery

In this study, we develop a data-driven heuristic method to solve the irregular flight recovery problem. Based on operational data from China South Airlines, Beijing, China, we evaluate the importance of a flight in the flight network and the influence of a delay on a flight and its subsequent flights. Then, we classify historical states into three scenarios according to their delay reasons and investigate the recovery patterns for each scenario. Inspired by the results of the data analysis, we develop a heuristic algorithm that imitates dispatcher actions. The algorithm is based on two basic operations: swapping the tail numbers of two flights and resetting their flight departure times. The algorithm can provide multiple recovery plans in real time for different scenarios, and we continue to refine and validate the algorithm for more robust and general solutions through a cost analysis. Finally, we test the efficiency and effectiveness of the recovery method based on the flight schedule, with real and simulated delays, and compare it with two other methods and the recovery actions of dispatchers.

Ghostbusters: Hunting abnormal flights in Europe during COVID-19

The impact of the COVID-19 pandemic is unprecedented in airline history, with irregular flight bans, the inability for accurate demand estimation, several turns in the epidemiological evolution, and a wide range of downstream effects on all aviation stakeholders. While most airlines have increasingly entered a recovery stage, compared to the utmost disruption around April 2020, the airline business is far from back-to-normality. Throughout the past two years, recurrent statements have been made regarding the existence of so-called ghost flights, where airlines operate nearly empty aircraft on markets with insufficient demand, partially with the aim to avoid losing precious airport slots. This study investigates the extent of such abnormal market service during the COVID-19 pandemic through an explorative, data-driven analysis, based on actual load factor data of European airlines for the years 2017 to 2021. We break down the observed deviations by airlines, markets, and airports. We find that low-cost carriers are most-likely to have performed abnormal flights during the pandemic; and that abnormal flights have mostly occurred on frequently-served markets. In addition, we show that airline responses, in terms of departure and yield changes, are largely heterogeneous across the 24 airlines in this study. Our study is the first one to shed light on the important issue of load factor deviations, and we hope that our findings can contribute to a better understanding of the existence of abnormal flights during the pandemic, as well as deriving appropriate policies for dealing with the ubiquitous threat and impact of ghost flights in the future.

Robust Airport Gate Assignment Based on the Analysis of Flight Arrival Time

At present, hub airport is facing a lot of emergency situations, e.g., the management of irregular flight, which affects the sustainable development of the airport. Most of the methods for evaluating the robustness of airport gate assignment have been proposed by giving an independent evaluation function based on their experience, and thus, subjective factors are involved in varying degrees. Therefore, this paper puts forward an objective evaluation method based on the analysis of airport flight arrival, which gives a digital transformation strategy for the airport resource scheduling. A novel evaluation method based on data analysis of flight arrival time, and a mathematical model are formulated accordingly. In order to solve the proposed NP-hard problem, a new hybrid genetic algorithm combined with a heuristic algorithm is designed. In numerical experiments, the actual flight data of an international hub airport are used to analyze and verify the effectiveness of the proposed method. The results showed the advantages in scheme stability, operating cost savings, and risk reduction of the proposed method.

Y2O3\u2013Al2O3 microsphere crystallization analyzed by electron backscatter diffraction (EBSD)

The crystallization of glass microspheres in the Y2O3–Al2O3-system produced from precursor powders of four different nominal compositions via flame synthesis is analyzed in detail by electron microscopy with a focus on electron backscatter diffraction (EBSD). Growth models are formulated for individual microspheres crystallized during flame synthesis as well as after an additional heat treatment step. 16 different types of crystallized bodies are cataloged for future reference. They are presented without regard for their relative occurrence; some are extremely rare but illustrate the possibilities of flame synthesis in the analyzed system. All three phases in the binary Y2O3–Al2O3-phase diagram (Y3Al5O12, YAlO3 and Y4Al2O9) and α-alumina are located by EBSD. Energy dispersive X-ray spectrometry results obtained from these microspheres show that their chemical composition can deviate from the nominal composition of the precursor powder. The multitude of differing microsphere types showing polygon and dendritic crystal growth as well as phase separation indicate that flame synthesis can lead to a wide variety of parameters during microsphere production, e.g. via irregular flight paths through the flame, contaminants or irregular cooling rates.

Decision support system for the irregular flight recovery problem

In this paper, we describe a data-driven approach to the irregular flight recovery problem. By imitating the decision process of dispatchers, we develop a quantitative mechanism to evaluate the disrupted flight and to provide easily adopted recovery suggestions. Our method consists of two steps. The first step is to establish a scoring system based on interviews, questionnaires, and operational data. Specifically, an irregular flight will be assigned a real-time score representing the importance of the flight and the impact of its current status. This score is also used to evaluate the necessity of the immediate recovery of the irregular flight. The second step is to generate feasible adjustment plan, which decrease the total scores of the related flights. Having validated by 306 manually recorded recovery actions, the scoring system successfully explains most of the recovery actions from dispatchers, meaning that the scoring system is consistent with the airline recovery strategy. To further demonstrate the recovery method's feasibility and response time, we also conducted tests based on one-day flight schedule simulation containing 92 flights and 7 historical cases from one Chinese airline. These tests prove the feasible adjustment plans can be generated in real-time, help airlines mitigate disruption effects to the network and reduce their decision process by 5–10 min in each delay scenario.

Stereo three-dimensional particle image velocimetry measurement and aerodynamic force analysis of non-spinning soccer balls

A knuckle shot, resulting from non-spinning kicking, is an essential technique in soccer. The irregular flight path of the knuckle shot is caused by the aerodynamic force from the three-dimensional twin vortices generated in the wake behind the ball. However, the detailed behavior of the twin vortices and relation between the jet flow and the acting forces on the balls is still not understood. In addition, a more thorough understanding of the effect of ball panels on the formation of twin vortices and jet flow is important to develop balls with high controllability. To study the effect of the ball panel shape on the flight path, stereo three-dimensional particle image velocimetry wake flow measurements and synchronized force measurements were performed on various soccer balls. It was confirmed that the aerodynamic force on the ball is produced by the jet flow generated by the vortices in the wake flow. The directions of the force followed the changes of the jet flow, and the magnitude of the force was strongly associated with the flow rate of the jet. Moreover, the shape of the ball panels, especially the groove volume, determines the critical Reynolds number and the fluttering of the balls.

Pros and Cons in Helicopter-Borne GPR Data Acquisition on Rugged Mountainous Areas: Critical Analysis and Practical Guidelines

We critically discuss both advantages and limitations of helicopter-borne GPR surveys in rugged mountainous areas by analyzing a pseudo 3D data set acquired over the Marmolada Glacier, which constitutes the largest ice body in the Dolomites (Eastern Alps) and contains several peculiar features both in terms of the internal structures and the surrounding topography. In this paper we analyze several possible issues that can be encountered when performing airborne surveys in mountain regions, related to both the local conditions in the particular survey areas, and the general performance of the data acquisition equipment, which includes the GPR device, the GPS system, and the helicopter itself. Based on our analyses and observations, we propose a few guidelines and optimization strategies in order to address several issues, including the choice of various data acquisition parameters, interpretation problems related to curvilinear or irregular flight paths, and trace positioning errors caused by GPS malfunctioning or oscillating antennas. Such results have general validity and can be used for helicopter-borne survey planning, as well as for data analysis and interpretation.

The application of abundance sensitivity filters to the precise and accurate measurement of uranium series nuclides by plasma mass spectrometry

Application of retardation filters has revolutionized the use of multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS) for the measurement of U-series disequilibria. Here, we present an evaluation of the application of retardation energy filters coupled with ion counting detectors for the measurement of U-series disequilibria by MC-ICPMS. We show that: 1) The RPQ minimizes backgrounds caused by ions experiencing irregular flight paths at high masses of uranium series nuclides. This reduced background is important for low count rate measurements and has enabled us to develop an improved method for the determination of 226Ra/228Ra ratios using a dual SEM/RPQ collector block. 2) Systematic biases exist for isotope ratios of 234U/238U and 230Th/232Th without the use of RPQs; thus, the RPQ is important for measurement of both of these isotope ratios. 3) That the RPQ makes possible 210Pb measurements in geologic samples using MC-ICPMS, but that this application is limited to samples that have low common Pb, such as carbonates and silica sinter. Additionally, we present mass spectrometric and gamma counting data for U-Th-Ra disequilibria in rock standard reference materials including AGV-2, AThO, BCR-1, BCR-2, BHVO-2, BIR-1a, DTS-1, PCC-1, RGM-2, TML, and W-2a. Comparing this new data with values from published literature enables us to provide consensus or recommended values for U, Th, and 226Ra concentrations and 230Th/232Th ratios for each of these standards. We note that this is the first compilation of recommended radium concentrations for rock standard reference materials.

Integrated fleet assignment and aircraft routing based on delay propagation

Airlines’ expensive resources, especially aircraft, are to be optimally scheduled to cover flights of timetables. However, the irregular flight, due to bad weather, mechanical fault and so on, is inevitable. Moreover, flight delays become more severe with the rapid development of the air transport industry in China and have huge irregular flight cost. In order to alleviate flight delays impact on the flight plan, we present a double objective multi-commodity network flow model of flight delay propagation-based aircraft scheduling and minimize the total delay propagation and airline operation cost as the optimization objective. Branch-and-price solution and column generation algorithm are used to solve the problem. Computational results obtained by using data from a major domestic airline show that our approach can reduce delay propagation significantly, thus improving on-time performance and robustness of aircraft scheduling, and decreasing the total cost simultaneously.

Modeling and simulation of passenger mass violence event derived from irregular flights in the airport terminal

Purpose – The purpose of this paper is to analyze and access the extent that emotion contagion (EC) affects the passenger aggressive behavior, and then reveal key factors triggering the passenger mass violence event (MVE) under an irregular flight situation. Design/methodology/approach – This paper presents the group behaviors simulation framework based on multi-agent. The EC model is put forward to explore the EC effect among passengers, integrating the influence of intervention measures, power difference and intimacy. Moreover, the authors propose the aggressive behavior decision-making model tailed to the passenger MVE by combining the improved social force model and adaptive neuro-fuzzy inference system. Findings – The experiment results show that the method proposed in this paper can simulate the realistic evolution process of passenger MVE .The EC effect among passengers is the catalyst for the quick spreading of MVE. The intervention measures, such as providing food and endorsing service, can effectively prevent from the MVE situation deterioration. Originality/value – The research of this paper has important practical significance for the evolution analysis of passenger MVE and provides the basis for airport safety management.

Evaluation of an mHealth intervention aiming to improve health-related behavior and sleep and reduce fatigue among airline pilots.

The aim of this study was to evaluate the effects of an mHealth intervention (intervention using mobile technology) consisting of tailored advice regarding exposure to daylight, sleep, physical activity, and nutrition, and aiming to improve health-related behavior, thereby reducing sleep problems and fatigue and improving health perception of airline pilots. A randomized controlled trial was conducted among 502 airline pilots. The intervention group was given access to both the MORE Energy mobile application (app) with tailored advice and a website with background information. The control group was directed to a website with standard information about fatigue. Health-related behavior, fatigue, sleep, and health perception outcomes were measured through online questionnaires at baseline and at three and six months after baseline. The effectiveness of the intervention was determined using linear and Poisson mixed model analyses. After six months, compared to the control group, the intervention group showed a significant improvement on fatigue (β= -3.76, P<0.001), sleep quality (β= -0.59, P=0.007), strenuous physical activity (β=0.17, P=0.028), and snacking behavior (β= -0.81, P<0.001). No significant effects were found for other outcome measures. The MORE Energy mHealth intervention reduced self-reported fatigue compared to a minimal intervention. Some aspects of health-related behavior (physical activity and snacking behavior) and sleep (sleep quality) improved as well, but most did not. The results show offering tailored advice through an mHealth intervention is an effective means to support employees who have to cope with irregular flight schedules and circadian disruption. This kind of intervention might therefore also be beneficial for other working populations with irregular working hours.

An Irregular Flight Scheduling Model and Algorithm under the Uncertainty Theory

The flight scheduling is a real-time optimization problem. Whenever the schedule is disrupted, it will not only cause inconvenience to passenger, but also bring about a large amount of operational losses to airlines. Especially in case an irregular flight happens, the event is unanticipated frequently. In order to obtain an optimal policy in airline operations, this paper presents a model in which the total delay minutes of passengers are considered as the optimization objective through reassigning fleets in response to the irregular flights and which takes into account available resources and the estimated cost of airlines. Owing to the uncertainty of the problem and insufficient data in the decision-making procedure, the traditional modeling tool (probability theory) is abandoned, the uncertainty theory is applied to address the issues, and an uncertain programming model is developed with the chance constraint. This paper also constructs a solution method to solve the model based on the classical Hungarian algorithm under uncertain conditions. Numerical example illustrates that the model and its algorithm are feasible to deal with the issue of irregular flight recovery.

Research on Indirect Cost of Irregular Flight

To release the delayed cost caused by irregular flight, this paper puts forward a new model and optimization algorithm on the basis of the extenics. A part of the delayed cost is indirect cost, but few authors considered it and all of models rarely solved it. In this paper, based on membership function and fuzzy language operator, a evaluation model for indirect cost has been proposed to solve how to reduce indirect cost and improve the service after irregular flight. The feasibility of the model is verified by the simulation results.

Airlines' Optimization Decision of Slot Allocation in CDM

With the rapid development of civil aviation in China, increasingly serious irregular flights problem arise wide attention. Though the air transport systems are composed of air transport control, airlines and airports, solving the irregular flight problem is still depend upon air transport control at present. The paper presents the method of airlines free-assignment between flight and slot with collaborative decision-making mechanism. A flight-slot assignment model is developed and an indexing heuristic arithmetic is designed. An empirical example proves that this method can reduce the total delay time and improve regular flight ratio. It also shows the importance of slot allocation decisions when the airlines is involved.

Males do not catch up with females in pursuing flight inCalopteryx splendens(Odonata: Calopterygidae)

Abstract In high densities males of Calopteryx splendens showed alternative reproductive behaviour at the river Oker in northern Germany. One of several tactics was to pursue females. Pursuing flight was filmed in summer 2006 in slow motion. Frame by frame analysis showed that males fly in irregular flight patterns: they showed different lengths of wing beat phases in comparison to females which fly more steadily. Females had significantly lower wing beat frequencies than males. The flight patterns of males depended on their position to other pursuing males and to the pursued female. The possible causes of these flight differences are discussed.

Leveling aerogeophysical data using a moving differential median filter

We describe a new technique that can be used to level data collected along regular and irregular line patterns with or without tie-line control. The technique incorporates a moving differential median filter to minimize line-level errors, to level survey-line data, and to microlevel data with no tie-line control. This overcomes the problem of standard leveling methods that lose their effectiveness with irregular flight patterns. To validate the method, we use it to level very-low-frequency (VLF) electromagnetic (EM) data from a helicopter survey where flight lines are parallel. Leveling is also performed on a set of vintage aeromagnetic data from the North Sea, gathered from nonparallel flight lines. Results show that the differential median filter leveling technique is superior to the standard leveling method because it results in fewer line errors and less distortion of high-wavenumber anomalies when processing irregular survey lines, making the method suitable for a wide variety of data sets.

The Forces which lift Aeroplanes

PROF. BJERKNES, in his Royal Institution lecture (NATURE, September 27, p. 472; October 4, p. 508), introduces the phenomenon of “acoustic repulsion” before going on to the accepted circulation theory of aeroplane lift. Both these are discussed in Rayleigh's “Collected Papers,” Nos. 52 and 53 respectively; “Note on Acoustic Repulsion” (Phil. Mag., 1878, also 1902, 1905), and “On the irregular Flight of a Tennis Ball” (Mess. of Maths., 1877).