An innovative method to optimize the maintenance policies in an aircraft: General framework and case study

Maintenance policies applied to aircrafts are governed by a mix of airworthiness authorities’ regulations and choices of suppliers and users. This allows airlines to use different strategies to minimize the total costs of maintenance. In this paper, a new approach that integrates the failure and reparation processes, such as modelling, optimization algorithms, and simulation methods, is proposed to define the best maintenance strategies for complex systems.A case study of an airline carrier is presented. In particular, several critical components for the A320 aircraft family are considered. The impact of the spare parts inventory management is discussed. Different preventive maintenance policies are tested and simulated. With the new policies, the average availability of the aircraft is satisfactory and the total annual cost is reduced to a value of approximately 20% in comparison with the previous policies adopted by the company.     

A fuzzy assessment method to airport waste management: A case study of Congonhas Airport,Brazil

This study presents a fuzzy mathematical model to support and evaluate airport waste management. The model generates a waste management index, composed of three dimensions, and it was applied in a case study of Congonhas Airport, located in Brazil. In addition to the mathematical model, the nonparametric Mann-Kendall test was applied to verify the existence of bias in the obtained results. The results showed that there is a concern on the part of the airport regarding waste management, reflected in the Fuzzy Waste Management Index (FWMI) results. They also indicated that there was an improvement in waste management in 2015 compared to 2014, resulting from increased accounting for recyclables and awareness of the airport community. The developed model proved to be an important tool to support the decision making of airport managers, including aspects related to waste management steps, and there may be adjustments that may be made to include new indicators.     

Real option analysis of aircraft acquisition: A case study

This paper demonstrates that aircraft acquisition by airlines may contain a portfolio of real options (flexible strategies) embedded in the investment's life cycle, and that if airlines rely solely on the static NPV method, they are likely to underestimate the true investment value. Two real options are investigated: i) the “shutdown-restart” option (a carrier may shutdown a plane if revenues are less than costs, but restarts it if revenues are more than costs), and ii) the option to defer aircraft delivery. We quantify the values of these options in a case study of a major U.S. airline. The economic insight could help explain observed capital expenditures of airlines, and serve as a rule of thumb in evaluating capital budgeting decisions. A compound option (consisting of both the shutdown-restart and defer options) is also analyzed.     

Aircraft routing for on-demand air transportation with service upgrade and maintenance events: Compact model and case study

This paper addresses a problem faced by airline companies that offer on-demand flight services. Given a list of flight requests, the company has to assign its aircraft to these requests while minimizing operational costs. The main issue in this planning process involves the positioning of aircraft when they are not available at the airports of customer departure. The cost of this positioning should be as low as possible, as the customers’ expenditures are proportional to the requested flight hours only. We propose a compact optimization model to support decision making in this situation. It takes into account the mandatory aircraft maintenance events and the possibility of flight upgrades according to the their impact on the operational costs. One important and novel feature of this model is that it allows the anticipation or postponement of the beginning of flights and maintenance events within a given tolerance, giving more freedom to the decision making process. This research is motivated by a case study carried out with a fractional management airline company that operates in European and Asian countries. Computational experiments using real-life data collected from the company show that the proposed model can be solved quickly using general-purpose optimization software, including open-source alternatives. The results indicate that the obtained solutions lead to significant reductions in the operational costs and hence can be used in practice for effective decision making.     

A hybrid fuzzy MCDM approach for mitigating airport congestion: A case in Ninoy Aquino International Airport

In this paper, we introduce the application of an integrated fuzzy multi-criteria decision-making (MCDM) model to mitigate airport congestion which affects the on-time performance of airlines, operational reputation of airports, and air travel experience of passengers. In a classical approach, when congestion occurs at the destination airport while the aircraft is en-route, an air traffic flow management action is prompted for implementation. In selecting the most suitable action in the event of airport congestion, the decision must reflect the multiple criteria nature of the problem as well as the uncertainty and vagueness associated with the decision-making process; thus, an integrated fuzzy MCDM is adopted. The applicability of the proposed approach is demonstrated in a case study at Ninoy Aquino International Airport. It is found that stakeholders of the commercial aviation industry favored to apply rerouting, among other actions, as this satisfies aviation safety as the most prioritized criterion.     

A qualitative study of outsourced aeronautical maintenance: The case of Brazilian organizations

The outsourcing of aeronautical maintenance has been criticized for the quality of services offered. According to the literature, airlines have contracted repair stations to perform maintenance activities on their aircraft or parts when attempting to optimize resources (time, facilities, personnel, money). The attempt to reduce costs in maintenance activities and regulatory deficiencies can lead to maintenance management practices that could threaten equipment airworthiness. Therefore, the aim of this research was to evaluate whether outsourced aeronautical maintenance is aligned to common industrial maintenance management practices. To achieve this goal, qualitative exploratory research was conducted on Brazilian repair stations. For data collection, a questionnaire was developed based on seven factors related to aircraft maintenance. The data revealed that a mismatch exists between the best maintenance management practices and expected repair station performance.     

A causal factors analysis of aircraft incidents due to radar limitations: The Norway case study

Provision of seamless, safe and effective surveillance services to airspace users requires high performance surveillance sensor coverage in the whole airspace. Limitations in the surveillance system will lead to an inability to provide the required surveillance services to the users. This may result in aircraft incident and accident occurrences. In this paper a case study is developed for the Norwegian airspace, based on five years of safety reports, to identify causal factors of incidents/accidents due to radar system limitations. This is conducted with a safety data analysis from Avinor – Norway's Air Navigation Service Provider (ANSP) and structured communication with Surveillance/ATM safety experts from Avinor. The case study shows that, 76 out of 124 occurrences within the five years in the Norwegian airspace/airport were related to the surveillance function, and 34 out of the 76 occurrences were due to limitations in the radar systems. The analysis identified that the highest contributing causal factors of the occurrences due to radar system limitations were limited surveillance coverage, followed by the lack of situational awareness for flight crew/controllers and unsynchronised surveillance information between flight crew and controllers.     

Community development using a sustainable tourism strategy: a case study of the Jordan River Valley touristway

This paper presents the results of a 10‐year collaboration among Yarmouk University, the University of Arkansas and the Jordanian government to develop a sustainable tourism strategy against the backdrop of political and economic uncertainty. It reports our efforts to develop a touristway through the Jordan River Valley that integrates the valley's heritage, archeology, and Christian and Islamic religious sites. It also analyses our community development work in Umm Qais, the touristway's northern anchor, and how our plan contributes to Northern Jordan's economic development. We conclude with a discussion of the specific insights gained from our experiences that may serve others addressing similar issues. Copyright © 2007 John Wiley & Sons, Ltd.     

Impacts of COVID-19 on aircraft usage and fuel consumption: A case study on four Chinese international airports

COVID-19 pandemic starting in early 2020 has greatly impacted human and industrial activities. Air transport in China shrank abruptly in February 2020, following a year-long gradual recovery. The airline companies reacted to this unprecedented event by dramatically reducing the flight volume and rearranging the aircraft types. As the first major economy that successfully controls the spread of COVID-19, China can provide a unique opportunity to quantify the medium-long impacts on the air transport industry. To quantify the corresponding changes and to elucidate the effects of COVID-19 in the wake of two major outbreaks centered in Wuhan and Beijing, we analyze twelve flight routes formed by four selected airports, using the Automatic Dependent Surveillance-Broadcast (ADS-B) data in 2019 and 2020. Our results show that the total flight volume in 2020 reduced to 67.8% of 2019 in China. The recovering time of flight volume was about 2–6 months, dependent on the severity. In order to unwind the severe challenge, airlines mainly relied on aircraft B738 and A321 between February and June in 2020 because the fuel consumption per seat of these two aircraft types is the lowest. Besides, fuel consumption and aircraft emissions are calculated according to the Base of Aircraft Data (BADA) and the International Civil Aviation Organization's Engine Emissions Databank (ICAO's EEDB). At the end of 2020, the ratios of daily fuel consumption and aircraft emissions of 2020 to 2019 rebounded to about 0.875, suggesting the domestic commercial flights were nearly fully recovered. Our results may provide practical guidance and meaningful expectation for commercial aircraft management for other countries.     

A combined MCDM model based on DEMATEL and ANP for the selection of airline service quality improvement criteria: A study based on the Taiwanese airline industry

The aim of this study is to select airline service quality improvement criteria for the Taiwanese airline industry. Numerous factors such as low railway prices, the development of high-speed rail, increases in petroleum prices, increases in foreign airline competition, and the recent economic depression have led many airlines in Taiwan to encounter financial difficulties and even closure. Researchers have begun to identify critical service quality improvement criteria with the goal of increasing the competitive advantages of airlines. Most of the selected criteria, however, suffer from a major technical problem: all of the measurement dimensions are independent, leading to inadequate criteria for measuring service quality. Our calculations consider the interrelationships and effects among the evaluation dimensions and criteria to precisely rank and select criteria. The value of this study is that it provides airlines with a direction for measuring and improving their service quality with the goal of developing sustained competitive advantage over the long term.     

A dynamic network efficiency measurement of airports performance considering sustainable development concept: A fuzzy dynamic network-DEA approach

In this paper, sustainability of airports is considered through a multi-perspective, multi-system, and multi-process operation. It is explored how an extension of fuzzy dynamic network performance measurement approach helps to determine the efficiency performance of an airport system. In this way, a three-pronged approach is intended which considers the internal functions of an airport, functions affecting the community and functions related to the passengers simultaneously. This novel combination makes it possible to have a comprehensive evaluation of airports' performance. Besides, fuzzy extension of SBM dynamic network approach makes it possible to deal better with the vagueness of variables during analysis. So, this extension is valuable from both technical and conceptual aspects which in turn provide useful information and insights for the future design of holistic strategies connected with sustainable development of airports where ever they are.     

A qualitative study on the exploration of challenges to the implementation of the Safety Management System in aircraft maintenance organizations in Turkey

Safety management has recently started using a paradigm that ‘sees the world as it is’ rather than ‘prescribing how it should be’. The Safety Management System (SMS), a product of this paradigm shift, has fairly new and different characteristics. These changes are expected to pose a number of challenges to the successful implementation of the SMS. This qualitative research study sets out to explore challenges to the implementation of the SMS in aircraft maintenance organizations in Turkey, with reference to the perceptions of Quality Management Systems (QMSs) and SMS experts working at these maintenance organizations.Qualitative data was collected from thirty participants through an open-ended questionnaire. Both inductive and deductive methods were used for the data analysis. The results suggest that the SMS entails a cultural transformation and is likely to bring about certain challenges because of its new and different characteristics. It is concluded that significant challenges may derive from a poor positive safety culture. Top management support and the practices of the civil aviation authority also have the potential to pose challenges. Other challenges are expected to result from SMS training and the need for the integration of stakeholder SMSs.The research results are expected to improve the success of the SMS and hence safety in aircraft maintenance. The results may also encourage the regulatory authorities to take measures to improve the success of the SMS in the launch of State Safety Programs (SSPs).     

A conceptual evaluation framework for organisational safety culture: An empirical study of Taipei Songshan Airport

This study included three phases. The first phase was to establish an evaluation hierarchy framework for organisational safety culture in accordance with the fuzzy Delphi method (FDM) and including expert perspectives. The second phase involved evaluating weight and rankings in order of importance using a fuzzy analytic hierarchy process. In the third phase, analysis of variance (ANOVA) and the Scheffe multiple comparison test were used to compare the different evaluation constructs and criteria of the airport's various internal safety management units. The study results demonstrated that Taipei Songshan Airport's general management units believed that ‘Safety Supervision’, ‘Safety-oriented Working Environment’ and ‘System of Incentives and Penalties’ should be considered implementation priorities to improve overall performance in the airport organisational safety culture. In addition, the ANOVA results revealed significant differences among the airport's management units with respect not only to the personal dimension, including ‘Safety Values’, ‘Safety Evaluation Standards’ and ‘Safety Management Updates’, but also to the situational dimension, such as ‘Safety Communication and Commitment’ and ‘Injury Rate’.     

Sustainable airline strategy using portfolio theory: A case study of remote islands in Japan

The thin and fluctuated market generally characterizing air transport to remote islands involves greater business risks for airlines. But air transport often plays an important role in the life and economy of such islands. This paper applies portfolio theory to explore how it can reduce business risks to air transport in this context. The concept of Tourism β is introduced to represent the risk associated with each island market relative to overall tourist demand in the region looking as at 31 airports on remote islands in Japan. The results showed that a well-diversified portfolio of multiple remote islands could reduce the score commercial risks for carriers.     

A study on travelers' transport mode choice behavior using the mixed logit model: A case study of the Seoul-Jeju route

This study is to analyze passengers' choice of the mode of transportation when air transportation is in competition with high speed rail (HSR). The Seoul-Jeju route analyzed as an empirical case study, in which the construction of an undersea tunnel to connect Seoul and Jeju city by HSR has been considered. The study also included two new variables, ‘safety of transportation’ and ‘availability of duty free shopping’ in addition to traditional transport choice variables such as travel time, travel costs and frequency of service to reflect special characteristics of the market. As data gathering tools, SP techniques and mixed logit model, for analytical methodology, were utilized. The authors found that the goodness of fit of the models was improved with new variables. The models also showed that the characteristics of business passengers and leisure passengers in choosing the mode of transportation were different. Business passengers were apt to choose a safety secured mode of transportation regardless of fare while leisure passengers preferred to use duty free shops more than business passengers.     

Exploring characteristics of passengers using traditional and low-cost airlines: A case study of Belgrade Airport

Low cost carriers entered the Serbian air travel market after Serbia joined the European Common Aviation Area (ECAA) in 2006, prompting the development of healthy competition among airlines and resulting in significant traffic increase at Belgrade Airport. The aim of this paper is to examine the characteristics of passengers traveling on low-cost carriers (LCC) in comparison with those traveling on traditional airlines by using cluster analysis, and to provide practical implications to airport management in tailoring their strategies to meet growing demand. A comprehensive passenger survey was recently conducted at Belgrade Airport on the routes where competition between traditional and LCC carrier exists. The results reveal that emigrants, primarily encouraged by favorable fares, constitute a substantial portion of LCC passengers. Affordable service offered by LCC has also been a positive stimulus for emigrants, who purchase tickets for their friends and relatives to visit them in their host countries. On the other hand, passengers using traditional airlines could be generally classified into two segments, those who fly on business and those who fly for leisure purposes, and each had specific needs when choosing their airline.     

A study on passengers' airport choice behavior using hybrid choice model: A case study of Seoul metropolitan area,South Korea

Improving explanatory power is significantly important to understand variables that affect attitudes and perceptions in the decision process. This paper estimates not only tangible attributes but also intangible perceptions and attitudes using a hybrid-choice model to study air passengers' flight choice behavior. The empirical study was conducted for the choice behavior of air passengers at Seoul Metropolitan Area, South Korea. The analysis uses a two-level Nested Logit model in order to examine which factors have more effect on passengers’ choice of airport and airline simultaneously by using airport and airline choice attributes. The study also estimated the parameters in the equations relating the latent variable by using Structural Equation Model (SEM). The results indicate that the models with latent variables have improved Goodness-of-Fit when compared to classical discrete choice models and effectively capture psychological factors that affect choice behavior of passengers.     

A fully fuzzy network DEA-Range Adjusted Measure model for evaluating airlines efficiency: A case of Iran

Due to the competition among companies, evaluating the performance is one of the most important issues for managers. Data Envelopment Analysis (DEA) - Range Adjusted Measure model (RAM) is one of the non-radial models to evaluate the performance of companies. This paper presents a fully fuzzy network DEA-RAM model for evaluating airlines and extends the network DEA-RAM model in the fully fuzzy framework. First, a network structure is designed for airlines and then, a DEA-RAM model is presented for calculating efficiency scores. To handle uncertainty in data, fully fuzzy approach is considered and finally, a multi-objective network model is proposed to calculate airlines’ efficiencies. To solve the proposed fully fuzzy DEA-RAM model, the lexicographic approach is used and the efficiency scores are reported as interval numbers. To illustrate the capability of the proposed fully fuzzy DEA-RAM model, the actual data of 14 Iranian airlines are gathered and the interval efficiencies of airlines are evaluated.     

A case study in the evaluation of geotourism potential through geographic information systems: application in a geology-rich island tourism hotspot

The significant growth in geotourism across all continents over the past two decades has created a strong demand for more creative, robust and systematic approaches to assessing the geotourism potential of natural areas, for identifying suitable sites of geological interest and providing comprehensive frameworks for management. We investigate a range of spatial data-sets using remote sensing analysis tools as well as geographic information systems (GIS) to complement field-derived data and allow for comprehensive analysis of combined data-sets. Such an approach allowed the creation of a spatial geological data base which can be assessed against access and management criteria, including environmental factors and risks. We used the relatively data-rich example of Rottnest Island in the south-west region of Western Australia to demonstrate the opportunities for future geotourism project development.     

Methodology for assessing dependencies between factors influencing airline pilot performance reliability: A case of taxiing tasks

Pilot performance reliability is critical to civil air transportation safety. Internal and external factors influencing pilot performance reliability are important elements to estimate human error probability. However, dependencies between these factors, including state dependencies and effect dependencies, are always ignored or only partially considered in most human reliability analysis (HRA) method. This paper attempts to develop a methodology incorporating both state and effect dependencies between contributory factors into HRA for airline pilot tasks based on fuzzy logic and the Cognitive Reliability and Error Analysis Method (CREAM). Anchor points were determined for each common performance condition (CPC) state levels through airline pilot elicitation process and then corresponding state and effect fuzzy sets were constructed for each CPC. The CPC dependency fuzzy inference rules were constructed and transformed with reference to the CPC dependency assessing rule in CREAM. And a cognitive failure probability (CFP) calculation method based on the final CPC effect fuzzy sets and the extended CREAM was proposed. To illustrate the use of the proposed methodology, a case study about commercial airline pilot taxiing task was given. The results demonstrate the validity of the proposed methodology and its capability of representing the ambiguity and fuzziness of expert judgement.