Number Of Take-offs Research Articles

Using ADS-B Trajectories to Measure How Rapid Exit Taxiways Affect Airport Capacity

The capacity of an airport can be specified with a so-called capacity envelope, which indicates how many take-offs and landings an aerodrome is capable of handling per unit time. In this study, the capacity envelope of an airport is determined on the basis of Automatic Dependent Surveillance-Broadcast aircraft trajectories obtained via the Opensky Network. Trajectories are classified as departures and arrivals by using rule-based algorithms. Subsequently, the time of landing or take-off is determined for all these flight movements. Since some of the trajectories used in this study are not entirely covered near the ground, an XGboost model is used to improve the determination of the take-off and landing times. In a final step, the capacity envelope is determined. To this end, the number of take-offs and landings operated at an airport within 15-minute intervals are counted first. Then, the 92.5th percentile of departures is computed for all observed arrival counts. Finally, a concave, non-increasing piecewise-linear function is fitted to these quantile values. The method introduced in this study is subsequently applied to Lisbon Airport in order to evaluate if and how the construction of an additional rapid exit taxiway has affected its capacity. The results suggest that Lisbon Airport benefits from this rapid exit taxiway. Indeed, especially when the airport handles a high number of landings, the additional rapid exit taxiway appears to allow for a slightly higher number of departures.

An integrated vertiport placement model considering vehicle sizing and queuing: A case study in London

The increasing level of congestion and infrastructure costs in cities have created a need for more intelligent and flexible transport systems. Urban Air Mobility (UAM) introduces the third dimension to intra-urban transport at a minimal infrastructure cost, bypassing congestion and providing reliable travel times to users through the provision of air passenger transportation. The performance of UAM systems is highly dependent on vertiport locations, vehicle sizing and infrastructure specifications, which themselves are intrinsically linked. This study takes a holistic approach to UAM network optimisation by considering the inter-relatedness of these decisions in a three-stage algorithm. In the first stage, a linear vertiport placement model with vehicle sizing constraints is developed to determine the optimal vertiport configuration while considering eVTOL performance. The vertiport configuration serves to determine the operational requirements of the aircraft and are incorporated in the vehicle sizing models. The resulting network configuration and vehicle sizing constraints are used as inputs in the infrastructure model, which utilises open network theory to determine the service rate requirements and the allowed loiter and waiting times based on the number of take-off, landing, and charging pads at each vertiport. These stages are executed sequentially through a feedback mechanism, which balances the infrastructure, operational costs as well as passenger waiting times. The algorithm optimises the profitability of the UAM network ensuring all operational constraints are satisfied. A case study based on the hypothetical implementation of UAM in the city of London is presented using Rolling Origin and Destination Survey data to estimate demand patterns. Our results suggest that ignoring vehicle sizing and infrastructure modelling in the network optimisation stage results in infeasible UAM networks. Furthermore, reducing waiting times and loiter times are critical to reduce operational costs of the UAM network, with all optimal configurations yielding waiting times below 5% of the total flight time. The proposed method can be used to plan future UAM developments whilst ensuring operational viability.

The effects of COVID-19 pandemic on the performance of airport renovation projects: the case of Pulkovo Airport

This paper explores the effects of the COVID-19 pandemic on the performance of airport renovation projects. The research examines the case of the renovation project of the Saint Petersburg's Pulkovo Airport in Russia, which started in 2010 within the concession agreement of the Northern Capital Gateway and the Government of Saint Petersburg until 2040, and raises the question of how this pandemic influenced the performance of Pulkovo airport renovation project. A Cost-benefit analysis and its sensitivity analysis were used to determine how restrictive measures against the spread of COVID-19 affected the profitability and social indicators generated by Pulkovo Airport. The social effect of infrastructure renewal was determined in accordance with the Efficient Time Allocation and Generalized Cost of Travel theories. The study reveals a decrease in the Net Present Value (NPV) of the renovation project due to changes in the trends of passenger traffic and the number of take-off and landing operations, a decrease in the growth rate of airport revenue and a partial reduction in operating costs. The expected Social NPV of the project decreased by 94.32 percent, and the benefit-cost ratio drastically reduced to 1.33, from a 4.06, had the pandemic not developed. The sensitivity analysis suggests a shift in the key variables that affect the performance of the analysed infrastructure project.

An integrated model of aircraft routing and crew rostering problems to develop fair schedule for the crew under COVID-19 condition

This paper focuses on aircraft routing and crew rostering problems simultaneously considering the risk of COVID-19 infection. As airports are among high-risk places in COVID-19 pandemic, the crew prefer to spend less sit time in airports and come back to their home base at the end of each duty day. In this research, an integrated model is developed to assign crew and aircraft to flights in order to achieve a fair schedule for the crew. The objective function is minimisation of the difference between crew sit times. Moreover in this model, a framework including flight hours, number of days and number of take-offs is considered for maintenance requirements. Particle swarm optimisation (PSO) is used as the solution approach. To validate the solution approach, 20 test problems were solved using GAMS and PSO. The results show that PSO improved CPU time significantly (98.279% in average) in turn of 1.902% gap with GAMS in optimum solution.

Analysis of operating parameters of the aircraft piston engine in real operating conditions

The article presents the results of analysis of operational parameters of piston engine CA 912 ULT which is a propulsion system of ultralight gyroplane Tercel produced by Aviation Artur Trendak. Research was conducted under normal operating conditions of the autogyro and data was collected from 20 independent tests including a total of 28 flight hours, divided into training flights and competition flights.Engine speed, manifold air pressure and temperature, fuel pressure, injection time, and head temperature were recorded at 9 Hz during each flight. Collective results were presented to show the statistical analyses of the individual parameters by determining the mean values, standard deviations and histograms of the distribution of these parameters. Histograms of operating points defined by both engine speed and manifold air pressure were also determined. Analyses of the engine dynamics as a distribution of the rate of change of the engine rotational speed were also carried out. It was shown that the engine operating points are concentrated mainly in the range of idle and power above 50% of nominal power. The most frequent range is 70-80% of nominal power. It was also shown that the dynamics of engine work in real operating conditions is small. It was also shown that the way of use significantly influences the distribution of operating points. During training flights, an increase in the number of take-offs and landings causes an increase in the amount of engine work at take-off and nominal power and at idle.

Exhausted with foraging: Foraging behavior is related to oxidative stress in chick-rearing seabirds

To understand foraging strategies and behavioral flexibility in wild animals, it is important to evaluate the physiological costs imposed by foraging efforts and how these costs affect foraging and provisioning behavior. Oxidative stress is a possible physiological indicator associated with foraging behavior in wild seabirds, and may also affect their reproductive performance. However, no previous study has simultaneously recorded foraging behavior and the associated oxidative stress in wild seabirds. Using an integrative approach based on oxidative stress measurements and bio-logging techniques (i.e., the use of animal-borne sensors), we determined the relationships between foraging behavior and oxidative stress in chick-rearing streaked shearwaters Calonectris leucomelas in 2018 and 2019. To quantify their oxidative stress, we measured reactive oxygen metabolites (d-ROMs) and biological antioxidant potential (BAP) in their plasma. We found that the d-ROMs levels were positively related to the maximum distance from the colony and the number of takeoffs, especially in 2019 when shearwaters flew further to forage. In 2018, when they flew relatively short distances, the BAP levels were positively related to the levels of their physical activity (overall dynamic body acceleration; ODBA). We conclude that longer and less successful foraging may lead to increase oxidative stress, while successful foraging may mitigate the oxidative stress of foraging by providing dietary antioxidants. Our results highlight that the combined data from bio-logging and oxidative stress measurements aid in evaluating the underlying physiological costs of foraging behavior in wild animals.

A reinforcement learning-based algorithm for the aircraft maintenance routing problem

With recent developments in the airline industry worldwide, the competition among the industry has increased largely with many key players in the market. In order to generate profits, the industry has paid much attention to generate optimal routes that are maintenance feasible. The main aim of operational aircraft maintenance routing problem (OAMRP) is to generate these optimal routes for each aircraft that are maintenance feasible and follow the constraints defined by the Federal Aviation Administration (FAA). In this paper, the OAMRP is studied with two main objectives. First, to propose a formulation of a network flow-based Integer Linear Programming (ILP) framework for the OAMRP that considers three main maintenance constraints simultaneously: maximum flying-hour, limit on the number of take-offs between two consecutive maintenance checks and the work-force capacity. Second, to develop a new reinforcement learning-based algorithm which can be used to solve the problem, quickly and efficiently, as compared to commonly available optimization software. Finally, the evaluation of the proposed algorithm on real case datasets obtained from a major airline located in the Middle East verifies that the algorithm generates high-quality solutions quickly for both medium and large-scale flight schedule dataset.

СУЧАСНИЙ СТАН ПРОБЛЕМИ РОЗРОБКИ ЗВУКОПОГЛИНАЮЧИХ КОНСТРУКЦІЙ ДЛЯ ГАЗОТУРБІННИХ ДВИГУНІВ

A review of current international aviation noise requirements is provided. It is shown that international requirements for aircraft noise levels are constantly increasing. The rapid growth of the international fleet leads to an increase in the number of take-offs and landings of aircraft at airports, and as a result, the problem of aircraft noise still relevant. To reduce noise levels at airports, various methods are used, one of which is the operational limitations of aircraft concerning the levels of noise they create. In European Union countries there are operational restrictions for aircraft meeting the requirements of Chapter 3 with a noise margin of less than 10 EPNdB. For already established aircraft that have passed certification, again it is necessary to look for methods to reduce noise. The main type of aircraft in operation in the world is an aircraft with turbofan engines. For such an aircraft, the main sources of noise during take-off will be the noise of the fan and jet, while landing, the noise of the landing gear, flaps, slats, and fan noise. When choosing a method of reducing aircraft noise, it should determine the source that most affects the overall noise level. It has been determined that fan noise is one of the main sources of noise. Acoustic liners constructions are widely used to reduce the noise level created by the fan. They are one of the most priority areas for reducing fan noise. Achievements in the use of acoustic liners to decrease the noise of domestic aircraft An-124-100, An-148-100 are considered. It is noted that due to the increasing requirements for aircraft noise, it is necessary to use new acoustic liners with improved sound-absorbing properties. It was determined that it is possible to improve the sound-absorbing properties of the acoustic liners by expanding the frequency range of sound absorption of such structures.Modern methods for improving the acoustic properties of the acoustic liners are presented: the use of multilayer resonant acoustic liners makes it possible to customize the design for an increased number of calculation parameters; the use of modified variants of the acoustic liners core such as corrugated core, oversized perforated core; the use of porous and porous fiber materials in the design of the acoustic liners to provide additional sound-absorbing ability, the use of low-frequency acoustic liners to reduce the noise of promising turbofan engines with a high and ultra-high bypass ratio.

A systematic approach to assess the effectiveness of airport noise mitigation strategies

Regional airports are often located very close to the urban area they serve and the increasing traffic rate that many of them have experienced in the last years has produced several impacts on the communities living close to the airport area, mainly aviation noise. If not properly managed, noise impacts produced by airport operations can cut down significantly the development of airport air traffic with direct effects on the economic and territorial systems. Aeronautical noise has greatly reduced in the last decade, due to aircraft design technological improvements and more severe regulations. However, the noise reduction during a single event does not make the issue of the airport location – and then the whole noise impact – less significant. This paper proposes an assessment process to evaluate the effects of actions adopted to reduce airport noise impacts on populated areas. Both airport-related factors – such as number of take-off; day-evening-night distributions of movements; aircraft type; flying paths – and land-use characteristics have been considered and combined in a density index that synthesizes the impacts of airport noise on the territory. The assessment process has been tested on a real case, the airport of Bologna in Northern Italy. The predicted results, compared with available real data for the test case, are significant and encourage the use of the proposed assessment process as decision support system for the airport management.

Effects of Carbon Trading on Operating Costs of the Civil Aviation Industry

This study investigates carbon emission inventory from the local civil aviation industrys aircrafts, airport ground service vehicles and power consumption within an airport. With the existing data of five years, the operating costs probably added into civil aviation industrys operating costs are estimated and sensitivity of six variables are evaluated with Monde Carlo simulations herein to construct a basis for the policy of carbon trading. The dominant two factors contributing to variation in the cost of carbon trading per takeoff & landing at the Taoyuan Airport and the Taipei Airport are carbon price (71.1%) and number of takeoffs & landings (14.4%) as well as number of takeoffs & landings (38.7%) and carbon price (35.3%), respectively.

DYNAMICS OF PASSENGER TRAFFIC FLOW AT VILNIUS, RIGA, TALLINN AND KRAKOW AIRPORTS

The article contains the results of an analysis of the dynamics of passenger traffic flow at Vilnius, Riga, Tallinn and Krakow airports during a period of ten years. The variation in the number of take-off and landing operations in the airports is analyzed as well. The current situation and prospects for the technical development of the airports are presented. Subjective and objective reasons related to insufficient activities at Vilnius Airport are presented. Possibilities for changing the location of the main airport in Lithuania are mentioned.

Effects of Cave Tours on Breeding Myotis velifer

Human activity in caves can affect bats adversely, especially bats that assemble in maternity colonies where appropriate roosts are restricted to areas with a narrow range of microclimates necessary to raise young. We assessed behavioral responses of a maternity colony of about 1,000 cave myotis (Myotis velifer) to experimental cave tours by manipulating 3 factors: size of tour groups, whether tour groups talked, and a combination of light intensity and color used to illuminate trails. We also considered the effects of distances between bat roosts and the tour group as well as season. We measured 4 behavioral responses of bats: number of takeoffs, number of landings, activity level, and vocalization intensity. Light intensity affected bat behavior most; all bat responses were highest in trials with high-intensity white light and lowest in trials with no light. When tour groups talked, takeoffs, landings, and activity level increased. Size of tour groups and treatment interactions did not affect bat behaviors. When bats roosted near the tour route, takeoffs and activity level increased. In addition, all behavioral responses increased as the maternity season progressed. Designing cave tours to minimize short-term effects on bats will require careful consideration of cave lighting and tour frequency, route location, and noise levels.

Queuing Model for Taxi-Out Time Estimation

Flights incur a large percentage of their delays on the ground during the departure process between their scheduled departure from the gate and takeoff. Because of the large uncertainties associated with them, these delays are difficult to predict and account for, hindering the ability to effectively manage the Air Traffic Control (ATC) system. This paper presents an effort to improve the accuracy of estimating the taxi-out time, which is the duration between pushback and takeoff. The method was to identify the main factors that affect the taxi-out time and build an estimation model that takes the most important ones into account. An analysis conducted at Boston Logan International Airport identified the runway configuration, the airline/terminal, the downstream restrictions and the takeoff queue size as the main causal factors that affect the taxi-out time. Of these factors the takeoff queue size was the most important one, where the queue size that an aircraft experienced was measured as the number of takeoffs that took place between its pushback time and its takeoff time. Consequently, a queuing model was built to estimate the taxi-out time at Logan Airport based on queue size estimation. For each aircraft, the queuing model assumes knowledge of the number of departure aircraft present on the airport surface at its pushback time and estimates its takeoff queue size by predicting the amount of passing that it may experience on the airport surface during its taxi out. The prediction performance of the queuing model was compared at Logan Airport with a running average model, which represents the baseline used currently in the Enhanced Traffic Management System (ETMS). The running average model uses a fourteen-day average as the estimate of the taxi-out time. The queuing model improved the mean absolute error in the taxi-out time estimation by approximately twenty percent and the accuracy rate by approximately ten percent, over the fourteen-day running average model.

The Relationship between Working Conditions and Commercial Pilot Fatigue Development

Fatigue is an important factor in aviation accidents, and effective fatigue management requires understanding the relationship between working conditions and fatigue. Two studies were conducted to clarify the relationship between working conditions and fatigue. In the first study, 59 airline pilots completed a workload questionnaire and the Profile of Mood States (POMS) in the morning and at the completion of their final flight of the day. In the second study, 133 pilots completed a revised questionnaire and the POMS. In both samples, fatigue increased and vigor levels decreased. Regression of fatigue increase upon working conditions indicated that the number of takeoffs and landings during the day were related to fatigue development. Correlation of incident level with both weather and airport difficulty suggest that incident level is a function of weather conditions and airport difficulty. These results argue that fatigue management should be founded upon the demands of working conditions, not merely the simplistic assessment of hours of work.

Effects of permethrin at different temperatures on pyrethroid-resistant and susceptible strains of Anopheles.

The influence of temperature (16, 22, 28, 37 degrees C) on effects of permethrin was investigated for susceptible and pyrethroid-resistant strains of the mosquitoes Anopheles gambiae and An. stephensi (Diptera: Culicidae). Young unfed female adult mosquitoes were exposed to 0.25% permethrin test papers or to polyester netting treated with permethrin 500mg a.i./m2. The time to 50% knockdown (KT50) declined as temperature increased, i.e. there was a positive temperature coefficient of this effect of the pyrethroid. Resistance ratios (comparing KT50 values) between resistant and susceptible An. stephensi ranged between 2.5 and 4.4 at the different temperatures. Comparative tests of pyrethroid tolerance of different strains would be valid over the 22-28 degrees C range but, when using a discriminating dose to detect resistance, more precise temperature control is desirable. Mortality 24h after exposure to 0.25% permethrin of both susceptible and resistant strains of An. stephensi showed a negative correlation with temperature between 16 and 22 degrees C and a positive correlation at higher temperatures. In An. gambiae, however, the correlation was positive over the whole range. Irritancy of permethrin-treated netting to Anopheles females (measured as time lapse until first flight take-off, and the number of take-offs during 7.5 min exposure) was positively correlated with temperature in all four strains and was much greater for the susceptible than the resistant strains.

Comment on the Editorial: What Was Measured?!

vs traveling in an automobile. That is primarily because the per-mile-based risk of flying can vary by a factor of 100 or more, depending upon the length of the trip. If all other things are equal, a long flight segment is obviously less safe than a short flight segment. (Flight segment orflight cycle describes the interval from a takeoff to the next landing. Aflight, in commercial-airline parlance, can be one or more flight segments.) But the difference in safety between a short and a long flight segment is quite small, because relatively little safety risk is contributed by the cruise portion. Furthermore, the situation can be confounded if all other things are not equal - eg, longer flight segments might tend to use airplanes with more sophisticated safety-related systems, or they might tend to be flown by more experienced (and therefore possibly more competent) pilots. But if a single statistic is chosen by someone knowledgeable about airplane safety to reflect an accident rate, it is almost invariably based on the number of flight cycles (which is the same as the number of takeoffs) - either of passengers or airplanes. It is not based on either passenger miles or airplane miles of exposure.

Responses of female New World screwworm flies, Cochliomyia hominivorax, to swormlure-4 in the laboratory.

The behaviour of 4-day-old virgin female New World screwworm flies Cochliomyia hominivorax Coquerel was investigated in a wind tunnel using video. Addition of the screwworm attractant swormlure-4 to the airstream resulted in an increase in the number of take-offs and in the duration of flight. In the presence of swormlure-4 the flight speed decreased and the rate of turning increased. Take-off was significantly orientated upwind during the period when swormlure-4 was added to the airstream, and significantly orientated downwind in the period after the addition of swormlure-4. The possible means by which this species finds a point source of odour in the field are discussed and compared with the mechanisms used by other flies.

Responses of the stable fly, Stomoxys calcitrans (L.) (Diptera: Muscidae), to carbon dioxide and host odours. I. Activation

AbstractLaboratory experiments were carried out to investigate the effect of carbon dioxide and breath odours on the flight activity of Stomoxys calcitrans (L.). The flies responded to an increase in carbon dioxide concentration by an increase in flight activity (measured as the number of flights or the number of take-offs). The extent of this response was dependent on the period of starvation before exposure and the level of the increase in the carbon dioxide concentration. Flies rapidly habituated or adapted to new levels of carbon dioxide. Expired human breath elicited a greater increase in flight activity than would be predicted from its carbon dioxide content, and it was shown that the increased activity was caused by breath odours acting synergistically with an increase in the carbon dioxide concentration.

Airport Installation

A set of analytical expressions and a computerised simulation model has been designed by the National Bureau of Standards so that airport planners and designers can analyse the capacity and performance of present airport configurations and predict the performance of new configurations, equipment and operating rules. The analytic formulae express runway capacity for simple airport configurations in terms of average landing and takeoff times, the mix of different kinds of aircraft, and other factors. For a wider variety of airport configurations, the computerised simulation model can be used to estimate throughput (number of takeoffs and landings in a given time interval) and delay (the extra time needed to complete a takeoff or landing beyond that required when there is no other traffic).