An investigation of fatigue issues on different flight operations

The influence of various kinds of flight operations on pilot fatigue remains a chronic problem which has a bearing on flight safety. In this study we sampled flight crews from six airlines in Taiwan, asking them to report on their perceptions of both physical and mental fatigue, before and after flight duty. The data were then analyzed with paired t-test and ANOVA. Our research results confirm findings obtained in other studies, namely, that perceived fatigue levels increase after flight duty, with that of oceanic crews being greater than that of crews serving either regional or short-haul operations. A majority of the pilots surveyed reported feeling fatigued or even nodding-off during long-distance flights, and consequently were in favor of a program of scheduled cockpit napping. While these findings are preliminary, they offer valuable information to aviation regulators and airlines regarding the assigning of consecutively scheduled flights to the same aircrews.     

Identifying flight fatigue factors: An econometric modeling approach

The paper looks at responses of crewmembers of six Taiwan air carriers who were asked to report their levels of fatigue before takeoff and after landing. Ordinal probit models are employed to estimate three fatigue models for different flight operations and serve as vehicles to investigate flight fatigue factors and identify their relative significance. The top three factors for long haul flights are found to be sleep quality at home, sleep quality on aircraft and “nod-off “experiences; for regional flights, age, extra non-flying tasks on the ground, and experiences of fatigue during flight operations are important; and for domestic flights poor cockpit environment, age, and experiences of fatigue during flight operations are relevant.     

Air express network design based on express path choices – Chinese case study

Due to the shortage of cargo aircraft, Chinese express companies have to provide transportation services with a hybrid method that consists of “rented bellies and self-owned cargo aircraft”. Because the bellies are rented from air passenger companies and because the cargo aircraft are owned by the express companies, it is important for the express companies to use their cargo aircraft as effectively as possible. This paper constructs a bi-level model to optimize the flight transportation network of an express company. The upper model designs the network and allocates the transportation capacity with the objective of minimizing the total transportation cost, and the lower model calculates the link flows in user equilibrium. Data from ShunFeng (SF) Express Company (China) are used to conduct the case study. Using the model outputs, the flows on links and at nodes are analyzed to illustrate the transportation and transshipment situations.     

A matheuristic approach to the air-cargo recovery problem under demand disruption

Air cargo transport is subject to unpredictable changes in expected demand, necessitating adjustments to itinerary planning to recover from such disruptions. We study a flight rescheduling problem to react to cargo demand disruptions in the short run. To increase flexibility, we consider two different cargo assignment policies. We propose a matheuristic approach to solve the problem that provides high-quality solutions in a short computational time, based on column generation in which each subproblem is solved using an ad-hoc heuristic. The approach is tested on demand disruption instances containing up to 75 air cargo orders with different penalty levels. The results show that the proposed method improves profit by 54% over the solution generated by a commercial MIP solver within a 1-h time limit, and by 15% over the solution with the routes fixed as in the original flight planning that only allows cargo to be re-routed. We also show that there exist incremental benefits in the range of 3–5% by allowing cargo for a given order to be transported by various aircraft.     

Effects of cargo types and load efficiency on airline cargo revenues

Numerous factors affect air cargo revenue management. Air cargo companies base their cargo charges on whichever is the greater of gross weight or volumetric weight. We developed a cargo consolidation model based on air cargo characteristics, and investigated the effect of cargo density, the Density Ratio of Heavy cargo to Light cargo (DRHL), and the percentage of small cargo on the chargeable weights and revenues of airlines. The empirical results show that a higher DRHL indicates greater chargeable weight, and that as the DRHL climbs to a certain level, the extent of chargeable cargo weights tends to stabilize gradually. The closer the cargo density approaches the most suitable loading density for a flight, the greater the chargeable weight is. A higher proportion of small cargo loaded on an aircraft means higher airline revenue. Our results can effectively combine types of air cargo to increase loading rates and revenues for airlines.     

Safety perceptions of training pilots based on training institution and experience

This study examines training pilot survey data in order to determine how students’ years of education and the institutions that they attend affect their perceptions of the risk factors in aviation as assessed using the SHELL model (software, hardware, environment, and liveware). The results reveal that student pilots lack confidence with respect to their knowledge during flights; moreover, they fail to recognize the importance of maintaining relationships among supporting staff such as air traffic controllers, mechanics, and others involved in the flight process. The findings suggest that to meet an increased demand for pilots, newly approved training centers are needed, centers which will foster awareness of interaction between human factors and other aspect of aviation safety; to support this, there should be more standardization of curricula.     

A longitudinal study on the alteration of consumer perceptions and the use of pilot medication

In 2010, the United States’ Federal Aviation Administration (FAA) approved the use of four antidepressant medications that could be prescribed to pilots on active flight duty, provided the pilot adhered to detailed policies and protocols. These medications were praised by many in the aviation community who were concerned with pilots underreporting mental health issues or engaging in self-medication. The purpose of this study was to complete a follow-up to a study, initially conducted prior to a 2015 Germanwings accident where a European commercial airliner crashed in an alleged case of pilot suicide. In the previous study, consumers were asked their willingness to fly when their pilot was taking various medications (fluoxetine, loratadine, ibuprofen or clonidine); and the findings suggest that the fluoxetine condition produces the lowest willingness to fly scores. The current study was replicated longitudinally in the weeks following the Germanwings accident. The findings of the current study reveal a significant drop in willingness to fly scores for the fluoxetine condition immediately after the accident; however, there is no significant change to the other medications. After 12-weeks, the fluoxetine condition returns to its pre-accident levels.     

Risk analysis of the EASA minimum fuel requirements considering the ACARE-defined safety target

We present the results of flight simulator experiments (60 runs) with randomly selected airline pilots under realistic operational conditions and discuss them in light of current fuel regulations and potential fuel starvation. The experiments were conducted to assess flight crew performance in handling complex technical malfunctions including decision-making in fourth-generation jet aircraft. Our analysis shows that the current fuel requirements of the European Aviation Safety Agency (EASA) are not sufficient to guarantee the safety target of the Advisory Council for Aviation Research and Innovation in Europe (ACARE), which is less than one accident in 10 million flights. To comply with this safety target, we recommend increasing the Final Reserve Fuel from 30 min to 45 min for jet aircraft. The minimum dispatched fuel upon landing should be at least 1 h.     

Offsite passenger service facilities: A viable option for airport access?

Offsite passenger service facilities transfer passengers from a common location to an airport and may provide additional services such as baggage handling and passenger check-in. Although they are conceptually promising, there is a lack of modern methods specifically tailored to forecast their demand. This paper reports on the development of two sequential models that forecast demand for an offsite facility. Models were calibrated based on data collected at six airports in California, Maryland, Massachusetts, and Virginia. The results showed that likely candidates for an offsite facility are airports that are not easily accessible, and departing air passengers with early morning flight departure times and high variability in ground travel times to the airport. A case study demonstrates the application of the models to Virginia’s Richmond International Airport.     

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.     

An analysis of the greenhouse gas emissions profile of airlines flying the Australian international market

International commercial flights (with the exception of flights between countries in European Union including Iceland, Norway and Liechtenstein) are currently not subject to greenhouse gas emission reduction regulation. To formulate effective and efficiency policy to manage greenhouse gas emissions from air transport, policy makers need to determine the emissions profiles of all airlines currently flying into their country or region. In this paper, we use 2012 data on airlines' aircraft characteristics, passenger load and cargo load (obtained from statistics reported by Australian Government Bureau of Infrastructure, Transport and Regional Economics) to estimate the volume and carbon efficiency on each international route flying to and from Australia. This is the first study to use actual passenger and cargo load data to determine the greenhouse gas (specifically CO₂) efficiency of airlines operating in the Australian international aviation market. Airlines' CO₂ emission profile is dependent on many factors including but not limited to the aircraft used, payload, route taken, weather conditions. Our results reveal that the airlines’ CO₂ emission profile is not only dependent on the aircraft used and the number of passengers but also the amount of cargo on each flight.     

The cost of abatement options to reduce carbon emissions from Australian international flights

In 2012, a total of 13.1 million tonnes of carbon dioxide were emitted by 14 airlines while transporting 72 per cent of international passengers into and out of Australia in 2012. With passenger and cargo traffic growing at between five to six per cent annually from 2013 to 2033, acquiring more fuel efficient aircraft to both renew the existing fleet and to service growth has the greatest potential in reducing emissions over the next 20 years. Our analysis shows that implementing carbon dioxide emissions abatement options such as installing light weight seats, iPad electronic flight bags, winglets, washing aircraft engines and reducing the number of engines used during taxiing, all offer net financial savings when considered over 20 years. Acquiring new fuel efficient aircraft has the biggest impact on emissions reduction. Low interest loans and longer loan repayment periods may incentivise airlines to acquire more fuel efficient aircraft to service traffic growth but other complimentary incentives and penalties are required to influence airlines to replace their current fleet with more fuel efficient aircraft.     

Aircraft routing under different business processes

Given a set of scheduled flights that must be operated by the same aircraft type, the aircraft routing problem consists of building anonymous aircraft routes that respect maintenance requirements and cover each flight exactly once. This paper looks at the nature of the problem and introduces a classification according to three business processes that are used to assign the anonymous routes to the specific aircraft tail numbers. Furthermore, we compare the aircraft routing problem variants resulting from these three processes with regard to their adaptability to different contexts, the difficulty of solving them, the cost of the computed solutions, and the robustness of these solutions.     

The effect of management practices on aircraft incidents

Many models have been put forward in order to examine the human factors in aircraft accidents and incidents. Human Factors Analysis and Classification System (HFACS) which is the most widely used in literature is one of these models. HFACS is based on Reason's Swiss Cheese Model. The biggest disadvantage of the Reason's model is its post-accident applicability. Mostly HFACS aviation applications are usually based on accident data. This is a reagent (result-focused) approach. In this study, however, HFACS which is an improved version of Reason's model, was applied to aircraft incidents that did not result in an accident. This is a proactive approach. Thus, with this approach, the biggest disadvantage of Reason's model is turned into an advantage. In addition, a realistic application of this approach has been demonstrated in this study, focusing on aircraft incidents that took place between 2000 and 2018. The year 2000 forms a milestone in the manufacture of more technically advanced aircraft models which significantly reduced occurrence of technical errors in aircrafts, hence the choice of 2000 as base year. A total of 328 aircraft incident reports from the National Transportation Safety Board (NTSB) database were studied and among these reports cockpit crew related incidents were analyzed using HFACS. As a result of the analyzes, the root causes of incidents have been identified. In addition, unlike traditional HFACS analysis, the relationship between errors occurred at management levels of HFACS and the unsafe acts of the cockpit crew in aircraft incidents was statistically revealed.     

Hassles of cabin crew: An exploratory study

The purpose of this study was to explore the hassles of cabin crew. Based on content analysis, this study extracted four themes of hassles: job hassles, peer interaction hassles, passenger service hassles, and personal hassles. Job hassles come from the gap between work standards and practical operations, inadequate service capacities of aircraft facility, irregular work schedules, and emergencies. Peer interaction hassles include uneven work assignments among cabin crew, poor work cohesion among cabin crew, and poor work cohesion between cockpit crew and cabin crew. Passenger service hassles come from verbal and physical violence toward the cabin crew, sexual harassment toward the cabin crew, theft situations on night flights, and passengers concealing infectious diseases. Personal hassles include work-family conflicts and physical health problems. The findings of this study provided a further understanding on hassle experiences on cabin crew.     

Fleet composition of commercial jet aircraft 1952–2005: Developments in uniformity and scale

The fleet composition of an airline is important in determining its costs and operational performance. This composition can be measured using numerical values. An index for measuring fleet uniformity is available, and a structured way of measuring fleet scale is introduced here. The history of all jet aircraft operated by commercial passenger or cargo airlines world-wide is analyzed both in general terms and using these measures. The analysis shows that uniformity in airline fleets has been steadily decreasing, while their scale has been steadily increasing.     

The geography of freighter aircraft operations in the Pacific Basin

The expansion of scheduled freighter aircraft operations is a prominent feature of the contemporary international airline industry. By 2000, more than 1600 freighter aircraft were in use worldwide, with much of that capacity deployed on routes in the Pacific Basin. This paper evaluates the factors that shape the geography of scheduled freighter aircraft operations with particular attention given to the place of individual Asian cities within that geography. The paper also examines the separate spatial strategies exhibited by the scheduled freighter operations of two important categories of cargo airlines: the express carriers like FedEx and the combination carriers like Lufthansa.     

The factors influencing entry level airline pilot retention: An empirical study of Ryanair

Pilot retention has been a significant concern for airlines that find it difficult to recruit and maintain pilots who are classified as high skilled employees. The aim of this research is to determine the factors that influence pilot retention and investigate if these factors differ based on gender, age and level of commercial flying experience of pilots. A mixed methods approach was used. Quantitative information was collected via an online survey sent to 394 Ryanair pilots. Nine in-depth expert interviews were conducted. The pilots ranked, in order of importance, a number of retention-influencing factors spanning seven areas, identified with the help of interviewees and secondary research. The results of the survey indicate that the most important retention influencing factors are being based at home, working a fixed roster pattern for a financially stable airline, being paid a competitive salary and having job security. This research provides qualitative evidence that airlines can use to develop or update their financial and non-financial benefits packages and where necessary, amend work practices and maximise pilot motivation to stay.     

Risk profiling of airline pilots: Experience,temperamental traits and aggression

It has been assumed that the greater the number of flying hours, the better the pilot is at solving problems. The studies suggest, however, that this issue is more complex. What is important is not only a pilot’s experience but also their personality traits such as temperament, aggression, and risk-taking tendencies, which all influence how the pilot reacts under stress. After examining 112 pilots of passenger planes, we found that individuals characterized by a high need for stimulation seek situations, consciously or not, of excessive or unnecessary risk to achieve the right level of stimulation. In terms of their psychological characteristics, the study also revealed that some pilots are less predisposed to be airline pilots.     

What factors predict the type of person who is willing to fly in an autonomous commercial airplane?

There has been much discussion and research lately highlighting autonomous commercial flight, with most of the focus on engineering design and legal issues. Some prior research has shown that many people are generally not willing to fly in fully autonomous aircraft; however, there is a significant proportion of society that is willing to use these types of airplanes. It is critical for the aviation industry to be able to identify these individuals as they will likely be the early adopters. The current study was designed with the purpose of determining what factors predict the type of person who would be willing to fly in fully autonomous commercial airplanes. We provided a hypothetical scenario to 1042 potential passengers from the United States and asked them to rate their willingness to fly in that situation. We also collected demographic data, along with ratings of various scales to determine what predictors were significant in a regression model. In Stage 1, we built the model from a dataset of 522 participants and determined that the significant factors were familiarity with autonomous flight, fun factor, general wariness of new technology, happiness, fear, age, and educational level. This model accounted for 85.9% of the variance in the data. In Stage 2, we tested the model with 520 participants and found excellent model fit. We discuss the practical and theoretical implications of these findings.