Aircraft Usage Research Articles

Sustainable Horizons: Exploring Attitudes and Beliefs on Electric Aircraft Usage in General Aviation

This research was conducted to better understand the perceptions surrounding electrically powered aircraft in the general aviation (GA) sector. The study employed survey methodologies to collect responses from ( N = 780) participants, with an emphasis on data from collegiate aviation students as well as a broad subset of the GA community. The study focused on factors such as generational differences, gender, the impact of flight training, and prior exposure to electric or hybrid cars, and how these factors influence the aviation industry’s sustainable transformation. The results indicate a significant and positive correlation between attitudes toward electric aircraft and prior exposure to or ownership of electric or hybrid cars. Generational differences, gender-based variations, and the impact of flight training on willingness to pay for electric aircraft utilization also had significant relationships with attitudes toward electric aircraft. The findings provide valuable insights for industry stakeholders and policymakers in promoting sustainable aviation practices, and complements prior research into the feasibility of electric flight.

Evaluating the Influence of the International Civil Aviation Organization on Aircraft Accident Rates and Fatalities: A Seven-Decade Historical Data Analysis

The advent of air travel, originally proposed by the Wright brothers, has led to a significant surge in aircraft usage for human transportation. In its nascent stages, this mode of transport was linked with a high frequency of accidents and consequent fatalities, placing it in the high-risk category. To counter these risks, the International Civil Aviation Organization (ICAO) was established in 1947 as a collaborative effort among numerous countries with the primary goal of enhancing aviation safety regulations. This study analyzed archival data from the Bureau of Aircraft Accidents Archives (B3A), covering a span of 72 years from 1918, the year of the first commercial airplane crash, until 2020. The objective was to understand the ICAO's impact on altering accident rates, fatalities, and underlying causes. Analytical methodologies encompassed both descriptive statistics—examining data distribution, central tendencies, and category frequencies—and exploratory data analysis (EDA) to identify variable relationships and outlier identification. The results indicated that ICAO's interventions have led to a notable decline in accident rates, with an annual average reduction of 70.9%, and a corresponding decrease in incidents attributed to technical factors. However, an unexpected trend was the increase in fatalities despite the drop in accident numbers, attributable to the introduction of larger aircraft designs carrying more passengers per flight. The findings underscore the ICAO's successful efforts in reducing aircraft accidents, but also suggest a need for further exploration into factors contributing to the rise in fatalities.

Numerical model to predict wear of dynamically loaded plain bearings

Wear resistance of dynamic system components is a major challenge in aeronautics. According the usage of the aircraft, off-centred dynamic loads can appear on shafts when rotating bodies are unbalanced. In literature, most of the wear studies applied to plain bearing consider static loads centred in the contact area. This article presents a study on the wear of a plain bearing submitted to off-centred dynamic loads in order to look for a better mastering of service life of plain bearing for their usage in severe aeronautic conditions. Boussinesq's equations were used to compute the pressure distribution and Archard's law was used to calculate the wear. The wear coefficients of the running-in and stable wear stages were defined experimentally. The evolution over time of the maximum wear depth and the size of the contact zone were validated with experimental results. The perspective of this work is to feed digital twins of dynamic systems in order to predict wear according aircraft usage.

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.

Visual Slope Inspection using Unmanned Aerial Vehicle (UAV)

Nowadays the natural slope cuts for the purpose of the construction of public transport is ubiquitous in Malaysia. These cuts cause the changes of the natural slope structure thus make the slope structure become unstable and causes to rubble. In order to avoid the slope’s failure, the monitoring work on slope should be carried out by the responsible party to ensure that the slopes are in good condition and the advance warning can be issued before the occurrence of the rubble. Conventional method of slope monitoring is extremely high risk. Usually, maintenance personnel will climb up to the top of the slope to take pictures for the purpose of monitoring reports [1]. Slope monitoring activities are also limited as climbing steep slope structures require a lot of energy and takes quite a while. Therefore, this research aims to explore the ability of the micro UAV aircraft usage in order to monitor the slope condition. The aim of study is to monitor the high risk slope using UAV. To achieve the aim, the following objectives are formulated by produce orthomosaic image, Digital Terrain Model (DTM) and Digital Surface Model (DSM) using pix4d mapper software, analysis the image of drainage system taken by UAV and developed contour of the slopes and analyse watershed of the slope using global mapper software. In this paper, the drainage on the slope becomes the focus since its plays an important role as it reduces the existence of groundwater and to transport the rainwater pours on slope surface. The study was conducted at two places where first at Kuala Pilah Federal Route 361 and second at Jalan Bangi Selangor State Route B17. The processes involved were planning and preparation before flight, data retrieval using UAV aircraft, image processing using Pix4dmapper software and assessment of the slope using Global Mapper software. Subsequently, the slope condition can be determine based on the monitoring of the slope drainage. Through this study, the condition of slope surface can be seen by images taken from UAV such as cracking on slope structure and excessive vegetation growth in slope drainage. Besides that, the slope inclination, height and water flows on surface can be known. Therefore, the usage of UAV aircraft for slope monitoring and inspection was successfully and the aims of this paper was achieved since the device shows a very good tendency and the ability to monitor the slope condition.

THE APPLICATION OF INFORMATION TECHNOLOGIES DURING MAINTENANCE TO ENSURE THE RELIABILITY OF THE OPERATION OF AVIATION EQUIPMENT

During the operation of aviation equipment, is carried out a set of works concerning the support and renewal of its serviceability and efficient condition, if necessary and possible. These tasks are solved with the help of information systems during aviation equipment maintenance. If necessary and possible, during the aviation equipment operation, is carried out a work package concerning the support and renewal, of its operative and serviceable condition. These tasks are solved with the help of IT solutions during the aviation equipment maintenance. Aircraft maintenance is an important component of the aviation system which ensures the functioning of aviation throughout the world. Insofar as the air traffic performance grows, and the tough requirements for maintaining the schedule of commercial flights necessitate the need to increase the intensity of aircraft usage. Also is continued the toughening of requirements for the timeliness of maintenance.

Quantitative fractography of fatigue and an illustrative case study

Abstract Quantitative fractography (QF) may be used for measuring service- and test-induced fatigue crack growth (FCG) in metallic components and structures. The QF compares progression and striation markings on fatigue fracture surfaces with known occurrences in the components' load histories. This paper concisely surveys fatigue-related QF, followed by a case study for a crack in a component from a maritime patrol aircraft. The case study illustrates how a FCG versus time history can be estimated. This was achieved using (i) knowledge of when the crack was detected, (ii) a reconstruction of the aircraft usage history from counting accelerometer (g-meter) data, (iii) an exponential FCG model of how cracking could have progressed, and (iv) QF of progression markings. Comparison of the reconstructed usage data and the QF information showed that the model provided a useful correlation.

Intelligent Diagnostics for Aircraft Hydraulic Equipment

In aviation industry, unscheduled maintenance costs may vary in a large range depending on several factors, such as specific aircraft system, operational environment and aircraft usage and maintenance policy. These costs will become more noteworthy in the next decade, due to the positive growing of worldwide fleet and the introduction of more technologically advanced aircraft. The new implemented technologies will bring new challenges in the Maintenance, Repair and Overhaul (MRO) companies, both because of the rising number of new technologies and high volume of well-established devices, such as Electro-Hydraulic Servo Actuators for primary flight control. Failures in aircraft hydraulic systems deeply influence the overall failure rate and so the relative maintenance costs. For this reason, overhaul procedures for these components still represents a profitable market share for all MRO stakeholders. Innovative solutions able to facilitate maintenance operations can lead to large cost savings. This paper proposes new methodologies and features of the Intelligent Diagnostic system which is being developed in partnership with Lufthansa Technik (LHT). The implementation of this innovative procedure is built on a set of failure detection algorithms, based on Machine Learning techniques. This development requires first to bring together the results from different parallel research activities: Identification of critical components from historical data; Designing and testing automatic and adaptable procedure for first faults detection; High-fidelity mathematical modeling of considered test units, for deeper physics analysis of possible failures; Implementation of Machine Learning reasoner, able to process experimental and simulated data.

Maintenance Optimization of Aircraft in Operating Environment using Automatic Identification Techniques

Objectives: To reduce maintenance downtime in operational cycle by integrating automatic identification techniques in the existing aircraft maintenance and utilization environment of a frontline squadron is discussed in this paper. Methods/Statistical Analysis: Along with explaining the routine calendar and hourly based aircraft maintenance philosophies of a frontline aircraft usage of an application software to undertake real-time status monitoring of aircraft maintenance and repair in a frontline squadron is discussed in brief. The effective utilization of the optical barcode functions, barcode generation and their unique application in personnel identification and maintenance enhancement in a frontline squadron is discussed in detail. Findings: The probable reasons for increase in aircraft downtime of military aircraft during defect rectifications and routine inspections and the facility enhancement envisaged in a frontline squadron due to integration of the maintenance monitoring application in the existing aircraft maintenance and utilization environment is explained in the paper. The reduction in aircraft down time in the operational cycle of a frontline military aircraft is the direct indicator of increase the operational efficiency. Application/Improvements: The implementation of an maintenance monitoring application using optical identification technique and the resultant enhancement in the operation efficiency due to aircraft downtime reduction is explained in detail.

Minimizing Fatigue Damage in Aircraft Structures

Aircraft structural health monitoring (SHM) refers to a process in which sensors assess the current (and predict the future) state of a structure in terms of its aging and deterioration to assure users or operators of its safety and performance. In addition to preventing failures, SHM extends aircraft life cycles. Consequently, adopting SHM is strongly motivated not only by flight safety but also by economic considerations. This article focuses on the optimization of aircraft usage as a new aspect of SHM and discusses a knowledge discovery approach based on dynamic time warping and genetic programming. In addition, it points out some of the challenges faced in applying artificial intelligence to aircraft SHM. This novel work reveals that AI provides a means to gain valuable knowledge for decision making on cost-efficient future usage of an aircraft fleet.

Remaining life assessment methodology for aged aircraft fleet

World experience in last few decades has shown that aircraft usage varies from aircraft to aircraft, mission to mission and user to user. This paper describes the procedure to predict the remaining life of an in service aircraft based on the data from onboard flight data recorders. The proposed method uses 'rain flow cycle counting' and 'Palmgren-Miners' techniques to correlate flight parameters with usage frequency for structural life prediction and computes the impact of the actual loads resulting in 'strength degradation' and 'expected remaining life'. It identifies the most stressed areas along with fatigue life cycles thus estimating the remaining life cycles. The data acquired through the successful application of proposed methodology is also assistive in determining the maintenance cycle and its revision, which is a major cost driver during operations. The results attained through computations directly correspond to the severity of usage.

Remaining life assessment methodology for aged aircraft fleet

World experience in last few decades has shown that aircraft usage varies from aircraft to aircraft, mission to mission and user to user. This paper describes the procedure to predict the remaining life of an in service aircraft based on the data from onboard flight data recorders. The proposed method uses 'rain flow cycle counting' and 'Palmgren-Miners' techniques to correlate flight parameters with usage frequency for structural life prediction and computes the impact of the actual loads resulting in 'strength degradation' and 'expected remaining life'. It identifies the most stressed areas along with fatigue life cycles thus estimating the remaining life cycles. The data acquired through the successful application of proposed methodology is also assistive in determining the maintenance cycle and its revision, which is a major cost driver during operations. The results attained through computations directly correspond to the severity of usage.

Investigation of the seizing mechanism of aviation hydraulic drive spool–and–sleeves

The paper is devoted to the study of the process of seizure of spool-and-sleeve pairs of aviation hydraulic drives under the influence of contamination particles contained in working fluids of aircraft hydraulic systems. The mechanism of the particles action on the hydraulic drive is discussed. The process of seizure development is analysed in detail. Two techniques based on the analysis of the results are proposed that make it possible to estimate the state of the spool-and-sleeve. The first one is based on direct measurement of the gap in the spool-and-sleeve of the hydraulic drive during repair. To implement the technique it is necessary to analytically determine the minimal allowed size of the gap that would provide stable functioning of the unit over the whole pressure range of the hydraulic system. The second technique is less labour-intensive (but also less precise) in comparison to the first one and is based on the measurement of the hydraulic drive macroparameter the variation of which depends on the change of the gap size in the spool-and-sleeve during maintenance. It is necessary to determine the dependence of the macroparameter chosen on the size of the spool-and-sleeve gap. Implementation of the described techniques will improve economic efficiency of aircraft usage by reducing the costs and the idle time in repair.

Operational Assessment of Heavy Air Tankers

Flight data collected by various P2V and P3A air tankers in actual operation over several seasons have been used to construct statistical information on aircraft usage and maneuver load spectra in this role. The data used for this report consist of 5316 flight files, collected during the 2008 and 2009 fire seasons. Flights have been divided into multiple phases, separating the segments when retardant is dropped from others. Basic flight parameters such as airspeed, altitude, flight duration and distance, bank, and pitch angles are shown in statistical form. Vertical accelerations are used to construct diagrams for comparison with the manufacturers’ data. Airframe cycle times are shown to be approximately 45 min. Several coincident flight events are shown and compared with operational limits when available. The altitudes, the normal accelerations, and the airspeeds have not revealed any operation outside of the established boundaries. Relatively large dive and roll angles were prominently present during all but the drop phases. Nonetheless, they are shown to remain within the limits stated by the manufacturer or imposed by the Federal Aviation Administration type certificate data sheets. Cumulative occurrences of maneuver loads have been examined and compared with data from other sources when available. It is shown that the cumulative occurrences of maneuver load factor varies by flight phase, with the largest values associated with the drop and exit phases. For the overall flight, maneuver loads were shown to occur at lower frequencies than those stated in Military specification MIL-A-8866C(AS).

Probabilistic Strain Energy Life Assessment Model

Under the “safe-life” methodology used by the United States Navy the service life of aircraft fleet are determined by monitoring the aircraft's usage and estimating the respective fatigue damage. The calculated fatigue life expenditure representing cumulative damage is then used to determine if it is possible for an aircraft or a fleet of aircrafts to reach the point of crack initiation and whether or not it should be retired. This research focuses on the development and initial application of a probabilistic strain-energy model to augment the empirical-based fatigue life expended approach. Experimental fatigue data obtained in this research is used to determine the relation between the number of cycles-to-failure and the cumulative total strain energy. A Bayesian framework for regression, including consideration of the model error is used to develop a probabilistic model of life that includes parameter uncertainties due to the limitation and scatter observed in the experimental data.

Flight-by-flight fatigue crack growth life assessment

Conventionally, fatigue crack growth in aircraft structures under flight spectrum loading is often analysed and predicted based on crack growth rates obtained from constant-amplitude crack growth testing with cycle-by-cycle life prediction methods or models. Because the mechanism of fatigue crack growth under spectrum loading is yet to be fully understood, no matter how closely the models are able to account for the load interaction effects, the predictions generally have to be subjected to the validation by fatigue crack growth tests using either representative specimens or real structures under the representative flight spectrum. In view of this fact, it is not difficult to deduce that the predictions should be much more reliable if the predictions are made directly based on the flight spectrum crack growth data. Therefore, a new approach to fatigue crack growth life assessment has been proposed in this paper based on the analysis of flight-by-flight fatigue crack growth data measured by quantitative fractography for several common aircraft structural materials under various fighter aircraft flight spectra. Quantitative fractography was successfully used for titanium coupons to generate crack growth curves under flight spectrum loading. The crack growths were also shown to be exponential. As a demonstration, the flight-by-flight approach was used to determine fatigue crack growth lives of aircraft aft fuselage frames under a fighter aircraft usage.

Modelling of air pollution on a military airfield

The paper presents a numerical study of exhaust emission and pollutant dispersion of carbon monoxide on a military airfield. Investigations have been carried out for typical conditions of aircraft usage in the Polish Air Force Academy in Dęblin. Two different types of aircraft have been taken into account. One of them is an MI-2 helicopter, the second is a TS-11 plane. Both are used in military pilot education in Poland. Exhaust emission of CO from those aircrafts has been obtained in an experiment carried out on an engine test stand. CO concentrations have been calculated for different meteorological conditions (averaged from 5 years observations) and selected conditions of aircraft use. The finite volume method has been used to discretise the equation describing the process of pollutant dispersion. In addition, the two-cycle decomposition method has been employed to solve the set of ordinary differential equations of the first order obtained after discretisation of the advection–diffusion equation. A meteorological pre-processor, based on relationships resulting from the Monin–Obukhov theory, is used to define eddy diffusivity and the profile of air speed in the lower layer of the atmosphere. In the paper, the computer model and calculated average concentration of CO in the Dęblin airfield during typical flights are presented. The goal of the computational analysis is to predict CO pollution level in the workplace of aircraft service personnel.

Bombardier Flexjet Significantly Improves Its Fractional Aircraft Ownership Operations

The fractional aircraft market is the fastest growing segment of the business aircraft industry. A fractional aircraft operation is complex—essentially an unscheduled airline in a constantly changing environment. Bombardier Flexjet implemented a comprehensive three-module optimization system to simultaneously maximize its use of aircraft, crews, and facilities. AD OPT Technologies designed the modules, using the GENCOL optimizer developed at GERAD, which employs a column-generation approach to decompose large-scale mixed-integer nonlinear programming problems. Since inception, the project has generated savings in excess of $54 million with projected additional savings of $27 million annually, primarily by lowering crew levels (20 percent), aircraft inventory (40 percent), and supplemental charter aircraft usage (five percent) while increasing aircraft utilization (10 percent). The quality of customer service has remained consistently high, with significant reduction in supply.

Indirect approaches to individual aircraft structural monitoring

At present, aircraft structural integrity is maintained by equally applying to an entire fleet knowledge obtained during the design phase and/or from a fleet sample and by introducing conservative assumptions, load surveys, costly inspections and maintenance procedures to safeguard airworthiness. Several investigations have highlighted the significant variations in individual aircraft usage and have indicated the inadequacy of applying “conservative” assumptions and updating the assumptions by monitoring a fleet sample. They have, in addition, suggested the importance of individual aircraft tracking (IAT). IAT can be achieved by fitting each aircraft with strain gauges to monitor critical component loads directly, but maintaining a large number of strain gauges entails high operational costs. Affordable IAT can be achieved by analysing recorded flight parameters to indicate usage, loads and fatigue indirectly. This paper reviews the key investigations into indirect IAT structural monitoring methods.

Use and Impact of Automated Aircraft Data in a Global 4DVAR Data Assimilation System

Abstract The use of automated aircraft data [Aircraft Meteorological Data Relay (AMDAR) and Aircraft Communication Addressing and Reporting System (ACARS)] has recently been extended in ECMWF's operational 4DVAR data assimilation system. Herein, a modified data selection procedure is reported on that allows the use of more aircraft profiling data during the aircraft's ascending and descending phase, and more of the most frequent reports at cruise level. It is shown that the accuracy of analyzed jet streams is improved through these changes, as verified against independent (non–real time) aircraft data that had not been used in the experiments. The modifications are shown to have a clear positive impact on the short- and medium-range forecast performance. The revised aircraft usage was implemented operationally in January 2002. The impact in 4DVAR of profiles from American and European automated aircraft in ascending and descending phase has been tested in a data denial impact study, for January and July 2001. This particular impact study was run partly on the request of the WMO/Commission for Basic Systems (CBS) Expert Team on data requirements and the redesign of the global observing system. Their interest is in testing whether a modern data assimilation system (such as 4DVAR) obtains substantial benefit from the aircraft profiles, which sample very irregularly in space and time, given that America and Europe are relatively well covered by radiosondes and wind profilers. The results show a substantial positive impact of the profiling aircraft data on analysis and forecast accuracy. The short-range forecast performance is improved over North America, the North Atlantic, and Europe. In the medium range a clear positive impact is found in the North Atlantic, the European, and Arctic areas in the winter period, and beyond day 6 in the summer period. These results are statistically significant and support the ongoing WMO initiative for further expansion of the AMDAR/ACARS coverage. The results also illustrate the effectiveness of 4DVAR with respect to observations that are irregularly distributed in space and time.