Aircraft Fleet Research Articles

Airborne Remote Sensing for Environmental and Disaster Management Applications

Abstract. As a national research institution, the German Aerospace Center (DLR) has the largest fleet of research aircraft in Europe and uses optical imaging systems to provide a valuable research basis for a wide range of applications in the fields of environment and climate, as well as global disaster management. Airborne remote sensing provides an independent database and is essential for developing and validating methods for satellite-based systems. This article gives a brief insight into the current research topics of DLR’s Earth Observation Center (EOC) with a focus on airborne remote sensing with regard to methane source analysis, water remote sensing, forestry, urban energy management and current disaster management missions, and shows how airborne remote sensing can contribute to the understanding and management of climate change.

Optimizing Inspection Intervals Through Risk Evaluation in Aircraft Structures

Abstract As aircraft fleets age, maintaining operational readiness at an affordable cost becomes increasingly challenging. This is largely due to the rise in Preventive Maintenance Task Requirements (PMTRs) outlined in the Aircraft Maintenance Program (AMP). While aging aircraft may require more frequent inspections, leveraging data from prior inspections enables the optimization of inspection intervals based on risk, ensuring cost efficiency by minimizing unnecessary downtime, while maintaining the required safety level. The primary objective of the AMP is to ensure the airworthiness and operational readiness of an aircraft system throughout their service life. To achieve this, it is essential to establish an acceptable level of risk as a basis for determining optimal PMTR recurrence. The SMART|DT tool, developed with FAA funding, provides a robust framework for conducting risk assessments of aircraft structures using Probabilistic Damage Tolerance Analysis (PDTA), which effectively assesses and manages the risk of structural failure. During the sustainment phase of the Swiss Air Force F/A 18 fleet, data-driven analyses within SMART|DT, and other tailored statistical tools, were performed to evaluate the risks associated with various PMTR intervals. This paper will explain the methodology applied to both Safe-Life and Damage-Tolerance structures, with real-world applications to demonstrate how inspection intervals can be optimized. By doing so, PMTR recurrence can be fine-tuned to enhance aircraft readiness and program affordability while maintaining an acceptable level of safety.

DETERMINANTS OF GARUDA AIRFARE REVENUE BEFORE AND AFTER THE COVID-19 PANDEMIC

The main revenue of service companies engaged in the aviation industry comes from the sale of passenger tickets, and PT Garuda Indonesia Tbk is no exception. However, there was a drastic decline when the covid-19 pandemic hit which limited the mobility of people. This study is directed at comparing pre- and post-pandemic conditions, which will then lead to an analysis of domestic flight ticket revenue factors. A quantitative approach is used to dissect the problem with paired sample t-test and exploratory factor analysis (EFA). The initial test uses secondary data in the form of pre- and post-pandemic airplane ticket revenues for each of the 15 periods (months). Meanwhile, the second test used primary data collected through distributing questionnaires to 60 respondents who use economy aircraft type B737-800NG on domestic routes. The results showed a significant difference in pre and post-pandemic airplane ticket revenues. After an in-depth study, of the six proposed determinant variables, two of them can be considered as determinants, namely maintenance as factor 1 and price as factor 2. The remaining four variables, namely punctuality, audio video services, aircraft cleanliness and seat comfort, are categorized in factor 1. These findings support the importance of airline marketing strategies, especially setting competitive ticket prices and excellent service to its users. The more affordable the price offered plus the better the service. The practical implications for management are (1) operational efficiency such as aircraft fleet optimization or digitization and automation of business processes, (2) product and service segmentation by offering tiered services and ticket bundling, (3) utilization of technology by opening application-based services and loyalty programs, (4) strategic partnerships, especially hotels, restaurants and land transportation, and (5) focus on customer satisfaction.

TAGUCHI METHOD-BASED MAN-HOUR OPTIMIZATION FOR BOEING 777 A-CHECK INTERVAL

Aircraft maintenance is critical for safety and operational efficiency. For the Boeing 777, A-checks are conducted every 1000 flight hours (FH), resulting in five checks per aircraft annually, with significant downtime and labor costs. This study proposes a Taguchi method-based man-hour optimization model extending the A-check interval to 1500 FH and reducing the number of annual checks while maintaining safety and regulatory compliance. The analysis carried out in this study revealed significant benefits of this interval extension. Annual downtime for the 12-aircraft fleet decreased from 60 to 40 days, allowing 20 additional operational days and generating $1 million in extra revenue. Labor costs were also reduced, with annual man-hours dropping from 1586 to 1153 per aircraft, saving 5196 hours fleet-wide. This optimization translates to $416.000 in labor cost savings annually, with a total financial benefit of $1416 million. Redistributing tasks between A- and L-checks further enhanced efficiency. Tasks such as lubrication and minor inspections were consolidated, and comprehensive cabin cleaning at 1500 FH was supplemented with intermediate cleaning at 500 FH to maintain passenger experience. These adjustments balanced the workload without affecting turnaround time or safety. This optimization demonstrates the potential for significant cost savings and operational improvements in aviation maintenance. Extending the A-check interval increased fleet availability, reduced labor requirements, and ensured compliance with regulatory standards. The findings highlight the importance of strategic maintenance planning and the potential for similar optimizations across other aircraft types and fleets.

Entrepreneurship and Future Perspectives in BRICS- Operational Improvements and Sustainable Air Transport Development in the Global South

There is a clear inequality between air transport systems development in Global North countries from the Global South ones. It is possible to observe this inequality when analyzing each region's route network and the total number of flights. This article aims to analyze how the adherence to The Carbon Offset Scheme for International Aviation (CORSIA) which comprises a market-based measure to stabilize emissions from 2020 onwards by international civil aviation can restrict growth and impact air transport expansion in developing countries, focusing on the BRICS countries. Considering a bibliographical review, the article highlights how ICAO developed measures to reduce CO2 emissions, including operational, technical, and alternative fuel measures, consisting of CORSIA in a complementary market measure. Additionally, based on the methodology developed by ICAO, the estimated reduction in CO2 emissions from implementing operational measures in Brazil was calculated using the annual number of arrivals and departures at airports. Operational measures are more in line with developing countries' United Nations' sustainable development goals, which have a broader sustainable development view of society. They are the best short-term option since Technological measures have a high implementation cost, and their incorporation into aircraft fleets takes a long time using SAF strongly depends on reducing associated production costs and developing a supply chain that allows its production to scale. As BRICS countries implement operational measures in their air transport systems, there is an increasing gain in efficiency and a reduction in CO2 emissions. Market measures such as CORSIA can restrict the expansion of air transport infrastructure in developing countries, consequently impacting their economic growth.

Long-term monitoring of barometric altitude measurement performance using the example of a research aircraft

Abstract The barometric flight altitude is the decisive variable for the vertical separation of aircraft in the airspace. At present, no aircraft operator is able to independently monitor the proper function of barometric altimetry in flight. In this paper, a method is presented for long-term monitoring of barometric altimetry system performance only by means of flight data and model output data from a numerical weather prediction model. This method enables aircraft operators to independently monitor barometric altimetry system performance of their aircraft fleet. Aberrant aircraft can be identified earlier and can be taken out of service for inspection measures more predictable, or inspected as part of already planned maintenance measures. Already existing flight data from DLR’s research aircraft Airbus A320-232 ATRA from 2014 to 2020 were used to determine the long-term behavior of the barometric altitude measurement performance using this method. During two of the flights under consideration, the aircraft was equipped with a trailing cone system, which is currently considered the most accurate way for measuring ambient pressure airborne. Hence, these flights were used as a reference. The summary of the implementation, evaluation, and main results is presented in this paper, starting with a brief introduction to numerical weather prediction models and their model output data. Details on the air data system and position measurement of the research aircraft are addressed as well as prerequisites regarding selection of parameters. Both reference and distance flights are described during which the analyzed flight data were gathered. Data pre-processing and evaluation are explained comprehensively. Finally, obtained results and findings are assessed and discussed with regard to the applicability of the method and future research work. In summary, application of the presented method to a research aircraft has shown good agreement compared to an established method such as the trailing cone system.

Arranjo Institucional Histórico: a Cooperação Aeronáutica Brasil/Suécia na Década de 2010

The Defense scenario has always provided models of international cooperation, in which political-diplomatic practices are associated with varied technological demands. The FX-2 program, to achieve a fighter aircraft fleet for the Brazilian Air Force (FAB), led to studies and completion by the Swedish Gripen NG. In this field, the work presented explores the Brazil-Sweden associative model, from the perspective of social, political and economic components, mainly. The introduction to the article reveals the purpose, while a brief contextualization follows, and then theoretical references used. The methodology explains the descriptive and bibliographic nature of the production, culminating in the findings and their discussion. In this context, the social, cultural, political and economic scenarios of Swedish society are verified, in a historical review, promoting bilateral understanding and continuity within the scope of cooperation in aeronautics. Finally, a conclusion to the article takes place.

Managing Operational Efficiency and Reducing Aircraft Downtime by Optimization of Aircraft On-Ground (AOG) Processes for Air Operator

This research aims to identify patterns and root causes of aircraft downtimes by comparing various forecasting models used in the aviation industry to prevent AOG events effectively. At its heart, this study explores innovative forecasting models using time series analysis, time series modeling and binary classification to predict spare part usage, reduce downtime, and tackle the complexities of managing inventory for diverse aircraft fleets. By analyzing both data and insights shared by aviation industry experts, the research offers a practical roadmap for enhancing supply chain efficiency and reducing Mean Time Between Failures (MTBF). The thesis emphasizes how real-time data integration and hybrid forecasting approaches can transform operations, helping airlines keep spare parts available when and where they are needed most. It also shows how precise forecasting is not just about saving costs, it is about boosting customer satisfaction and staying competitive in an ever-demanding industry. In addition to data-driven insights, this research provides actionable recommendations, such as embracing predictive maintenance strategies and streamlining logistics. These steps aim to ensure smoother operations, fewer disruptions, and more reliable service for passengers and operators alike.

Possibilities of using a mixture of Kazakhstan oils as a raw material for the production of jet kerosenes

In the context of constant renewal of the aircraft fleet of airlines in the Republic of Kazakhstan by equipping it with modern aircraft such as Boeing, Airbus, etc., the problem of developing a technology for producing aviation fuels made from local oil raw materials is urgent. In order to provide the Shymkent Oil Refinery with raw materials, it is necessary to conduct targeted and extensive scientific research to determine the physical and chemical characteristics of oils and oil mixtures, their individual distillate fractions. This paper presents the results of a study of oils, a mixture of oils and straight-run fractions obtained from them, which are potential raw materials for the production of aviation fuels for gas turbine engines, and indicates the directions and methods for obtaining commercial grades of aviation kerosene. The directions and methods for obtaining commercial grades of aviation kerosene TS-1, RT and Jet A-1 from straight-run kerosene fractions are determined. Hydrodewaxed kerosene fraction with the possibility of involving straight-run kerosene fraction from atmospheric distillation of oil can be used as the main component of Jet A-1 fuel produced by the Shymkent Oil Refinery. Considering the need for stable and continuous production of aviation kerosene at refineries of the Republic of Kazakhstan, regardless of the quality of the processed oil, it is advisable to produce Jet A-1 fuel using technology using hydrogenation processes and the introduction of lubricating and antioxidant additives.

Optimal Flight and Maintenance Planning of a Military Aircraft Fleet through to Life-of-Type

Optimal Flight and Maintenance Planning of a Military Aircraft Fleet through to Life-of-Type

Performance Scaling of Modular Hybrid Propulsion System for Flight Vehicles

A modular hybrid propulsion system (MHPS) concept for which the electrical components are interchangeable on a mission-to-mission basis is proposed as an enabler for aircraft performance flexibility. Modular hybrid aircraft takeoff, climb, cruise, and payload performances are characterized to be functionally dependent on hybridization and modularity ratios. Scaling relationships in terms of nondimensional groups that reflect system design and operating parameters yield the following findings: For a parallel hybrid configuration, increasing hybridization improves takeoff and payload performances when electric motor specific power is greater than carbon fuel engine specific power. For all hybrid configurations, increasing hybridization decreases cruise time and range if the product of the ratios of electric motor to carbon fuel engine efficiency and battery to fuel specific energy is less than 1. With current and near-future technology, hybridization is found to be primarily beneficial for aircraft utilizing reciprocating engine(s) as the main power plant. Minimum battery specific energy and power values are found to be dependent on either the energy required for climb or the power required to drive the electric motor at peak power output; an optimum battery size would be one that meets both requirements with equality. Modularity would enable a single airframe to accomplish a wide variety of missions, potentially resulting in a reduction in aircraft fleet size. The scaling relationships provide useful guidelines for the selection and sizing of MHPS components to meet mission requirements.

Fit & Fly

A pioneering project to decarbonize its fleet of aircraft is taking a Canadian training company into the world of electric aviation

Landing scheduling for carrier aircraft fleet considering bolting probability and aerial refueling

Landing scheduling for carrier aircraft fleet considering bolting probability and aerial refueling

Planning maintenance tasks in airline operating companies: A mathematical programming model applied to a case study

This paper explores a mixed-integer linear programming (MILP) approach to plan the maintenance tasks in an airline. The MILP model finds feasible maintenance plans, by minimizing the costs associated with maintenance activities and costs associated with unavailability. A constructive matheuristic approach is put forward, by solving the maintenance planning problem sequentially. The model and the matheuristic is then applied to a case study from the main Portuguese airline company. The results suggest that the proposed matheuristic approach for maintenance planning in practice, as explored in the case study, finds feasible solutions in a much lower computational time. Moreover, a sensitivity analysis is conducted to assess the impact of hangar’s capacity and other input parameters in the maintenance plan. Our approach provides an effective way to support decision-making in maintenance planning for a fleet of aircraft, while complying with several operational, technical, and labour constraints.

A bi-level heuristic maintenance scheduling framework for an aircraft fleet under uncertain mission scenarios

A bi-level heuristic maintenance scheduling framework for an aircraft fleet under uncertain mission scenarios

СТРАТЕГИЧЕСКАЯ РОЛЬ МАЛОЙ АВИАЦИИ В ТРАНСПОРТНО-ЛОГИСТИЧЕСКОЙ СИСТЕМЕ СЕВЕРНОГО РЕГИОНА (НА ПРИМЕРЕ АРХАНГЕЛЬСКОЙ ОБЛАСТИ И НЕНЕЦКОГО АВТОНОМНОГО ОКРУГА)

The socio-economic development of the northern territories of Russia directly depends on the state of regional transport and logistics systems. It is important to note that small aircraft plays a special strategic role in the connectivity of the northern territories in conditions of limited transport accessibility and the absence of other year-round transport links. Using the example of such northern regions of Russia as the Arkhangelsk oblast and the Nenets autonomous okrug, the author gives a description of the work of air enterprises on local airlines, including the route network, the state of the fleet of ships, examines the financial indicators of regional air detachments, analyzes the dynamics of passenger traffic. According to the results of the SWOT analysis of the development of small aircraft in the Arkhangelsk oblast and the Nenets autonomous okrug, it was found that its weaknesses are: high costs of organizing transportation; lack of qualified personnel; limited possibility of updating the aircraft fleet due to sanctions restrictions; postponement of the production and commissioning of new domestic passenger aircraft. The problems of excessive requirements for air transportation and operation of landing sites, rising prices for fuels and lubricants and components, which leads to an increase in the costs of regional budgets, remain common for the northern regions. For the development of small aviation in the northern regions of Russia, the article proposes such solutions as: reducing the excise duty on aviation fuel for air enterprises engaged in socially significant transportation; approving charter flights within the territory of the subject at unregulated tariffs and other routes to generate additional income within the framework of an approved transport order.

Modern Development of Transport Infrastructure in Kyrgyzstan

The article is devoted to the analysis of the modern development of transport infrastructure in Kyrgyzstan. The work considers the key trends and directions of state policy in this area. The study shows that Kyrgyzstan has a stable positive dynamic in the development of various types of passenger and freight transportation. There is an increase in the volume of automobile, rail, air, and other transport services. Particular attention is paid to the implementation of large-scale infrastructure projects for the reconstruction and modernization of key highways connecting Kyrgyzstan with neighboring countries. This contributes to improving the quality and availability of transport communications, as well as the country's integration into regional and global logistics chains. In the aviation industry, measures are being taken to expand the route network of the national air carrier, improve the quality of airport services, and renew the aircraft fleet. Comprehensive measures in the field of transport infrastructure carried out in Kyrgyzstan are aimed at increasing the efficiency, competitiveness, and environmental friendliness of the national transport system, which plays a key role in ensuring economic growth and sustainable development of the country.

РОЗРОБКА ТА ВИРОБНИЦТВО ЛЕГКИХ ЛІТАЛЬНИХ АПАРАТІВ СІЛЬСЬКОГОСПОДАРСЬКОГО ПРИЗНАЧЕННЯ

Issues of protecting plants from diseases and pests are becoming more and more urgent. Climate change causes an increase in the activity of weedy plants and insects harmful to agriculture. Because of this, the chemical treatment of fields by aviation in modern agriculture should serve the purpose of preserving the future harvest in both a qualitative and quantitative sense. An important role in this is played by the biological method of plant protection, which is quite effective and environmentally friendly. It is based on the use of living organisms, their waste products and biologically active substances that regulate the development and reproduction of harmful plant organisms. Scientists have developed technologies for the breeding of such zoophages to protect plants from plant pests: Trichogramma, predatory mite Phytoseiulus, encarzia, Aphidimyza gallica, etc., as well as the production of microbiological preparations to protect plants from diseases and pests, the high efficiency of their use has been proven. Aircraft (planes, helicopters, ultralight aircraft) that are registered in the State Register of Civil Aviation Aircraft of Ukraine and have a certificate for the right to perform aerochemical work are allowed to carry out aerial work on the application of pesticides during agrochemical activities on agricultural and forest crops. The requirements for the characteristics of the aircraft, directive requirements for the technology of production, operation and maintenance of airworthiness were formulated. The evaluation of the manufacturability of the considered products (agricultural LA) cannot be evaluated without taking into account the operational manufacturability, which largely determines the costs when performing work in the field. Along with the requirements for the manufacturability of the aircraft design, the so-called operational requirements are of great importance. These requirements determine the suitability of the structure and equipment for its maintenance and repair during the operation of the aircraft, taking into account the high quality of work, the least consumption of time, labor and materials. Satisfying operational requirements ensures reliability, durability of the aircraft, high labor productivity during maintenance, reduction of operational costs and efficiency of use of the aircraft fleet. The appearance of the trichogram required the development of special means for its introduction. An attempt to use existing means showed their unsuitability due to their low functional efficiency and high cost of work. The task was solved by increasing the manufacturability of agricultural aircraft during their production and operation. This made it possible to organize its serial production and operation in many farms of the country.

Informing the Delineation of Input Uncertainty Space in Exploratory Modelling Using a Heuristic Approach

ABSTRACTExploratory modelling is an emerging approach which can address the challenge of model‐based decision making in dealing with input model uncertainties. Exploratory modelling samples from an input uncertainty space and generates extensive computational experiments to analyse possible model behaviours in an output solution space. The way that the input uncertainty space is delineated influences the results of exploratory modelling and its computational cost. In this article, we show the statistical significance of the implication of the size of an input uncertainty space on the resulted output solution space. We also propose a heuristic approach which informs the delineation of input uncertainties by screening the relevant model behaviour in the solution space. An illustrative example of an aircraft fleet management system is used to demonstrate the implementation of our approach in practice. We conclude that the delineation of input uncertainty space can be a way to control simulations in exploratory modelling and to enhance the efficiency of the exploration process and the confidence of the final results.

A contribution to mitigate NOx and H2O emissions for a hydrogen-powered hypersonic vehicle

Abstract Hypersonic transport fueled with liquid hydrogen (LH2-HST) is currently considered as long-term future technology of civil aviation to fly with speeds greater than Mach 5 at stratospheric altitudes of 25–38 km. In this paper, we present a comprehensive methodology to assess the emission mitigation potential (via NOx and H2O) of future LH2-HST through operational measures, considering realistic constraints such as the sonic boom carpet as well as tolerable g-forces acting on the passengers while flying with hypersonic speeds. Both NOx- and H2O-optimal 4D-trajectories are identified by a brute-force algorithm that varies the initial cruise altitude from 30 to 36 km. As case study, the Mach 8 passenger aircraft STRATOFLY-MR3, which was conceptually developed in the framework of the H2020 STRATOFLY project, is operated on a single route from Brussels (BRU) to Sydney (MYA). The findings are highlighted as relative changes regarding MR3's design flight altitude set at 32 km, respectively, 105 000 ft. As scientific contribution, 3D emission inventories are calculated and made publicly available for a world fleet of MR3 aircraft operated along the BRU-MYA route on both NOx- and H2O-optimal mission profiles in the year 2075.