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The article presents a comparative characterization of the structural materials (composites and metals) used in modern aviation structures, focusing on the airframe structure of the most modern aircraft (Airbus A-380, Boeing B-787, and JSF F-35). Selected design and operational problems were analysed, with particular emphasis on composites and light metals (aluminium). For this purpose, the Shore’s method was used for the analysis of the obtained strength results and the programming environment (ANSYS, SolidWorks) required to simulate the GLARE 3 2/1-04 composite. The focus was on highlighting the differences in the construction and modelling of these materials resulting from their various structures (isotropy and anisotropy), e.g., by analyzing the mechanics of metal destruction and comparing it with the composite material. In terms of solving the problems of finite element analysis FEM, tests have been carried out on two samples made of an aluminium alloy and a fiberglass composite. The focus was on highlighting the differences in the construction and modelling of these materials resulting from their various structures (isotropy and anisotropy), e.g., by analyzing the mechanics of metal destruction and comparing it with the composite material. On the basis of the obtained results, the preferred variant was selected, in terms of displacements, stresses, and deformations. In the final part of the work, based on the conducted literature analysis and the conducted research (analysis, simulations, and tests), significant observations and final conclusions, reflected in practical applications, were formulated.

This paper describes a life cycle model for the development of electronic equipment for use on board military aircraft in the South African context. The life cycle model presented consolidates the activities of systems engineering, safety and certification, and quality assurance. The life cycle model provides a clear-cut and comprehensive framework for the development process in order to streamline planning and control. Concepts fundamental to the definition of a development process are identified and explained, and a generalised life cycle model is derived. Applications of this life cycle model in the description of development processes for airborne electronic equipment are presented.

This paper presents a new approach based on Multi-Criteria Decision Analysis (MCDA), named PROMETHEE-SAPEVO-M1, through its implementation and feasibility related to the decision-making process regarding the evaluation of helicopters of attack of the Brazilian Navy. The proposed methodology aims to present an integration of ordinal evaluation into the cardinal procedure from the PROMETHEE method, enabling to perform qualitative and quantitative data and generate the criteria weights by pairwise evaluation, transparently. The modeling provides three models of preference analysis, as partial, complete, and outranking by intervals, along with an intra-criterion analysis by veto threshold, enabling the analysis of the performance of an alternative in a specific criterion. As a demonstration of the application, is carried out a case study by the PROMETHEE-SAPEVO-M1 web platform, addressing a strategic analysis of attack helicopters to be acquired by the Brazilian Navy, from the need to be evaluating multiple specifications with different levels of importance within the context problem. The modeling implementation in the case study is made in detail, first performing the alternatives in each criterion and then presenting the results by three different models of preference analysis, along with the intra-criterion analysis and a rank reversal procedure. Moreover, is realized a comparison analysis to the PROMETHEE method, exploring the main features of the PROMETHEE-SAPEVO-M1. Moreover, a section of discussion is presented, exposing some features and main points of the proposal. Therefore, this paper provides a valuable contribution to academia and society since it represents the application of an MCDA method in the state of the art, contributing to the decision-making resolution of the most diverse real problems.

Autopilot failures have caused fatal results for both military and civilian applications, leading to loss of life and property. Major contributing factors are disturbances (e.g., winds), uncertainties (e.g., unmodeled dynamics and parameter variations), and couplings (e.g., a bank maneuver affecting pitch attitude). In this brief, a novel disturbance/uncertainty/coupling estimator structure is introduced for identifying and canceling these effects as a whole. A controller scheme based on the $\mathcal {H}_\infty$ design is implemented with explicit bounds for robust stability and robust performance. Validity of the proposed approach is illustrated under high winds, strong couplings, and large parameter variations. [ABSTRACT FROM AUTHOR]

The evaluation of pilots’ fatigue status is of substantial significance in aviation safety, which faces two major issues. They are how to get the fatigue status feature representation and how to identify the fatigue behavior status of pilots via electroencephalogram (EEG) signals. To solve the first issue, we propose a novel fatigue evaluation index via different window functions to compute the power spectrum of relative rhythms from EEG signals. Wavelet packet transform is used to decompose EEG signals from pilots to form four major rhythms, i.e., $\boldsymbol {\delta }$ wave, $\boldsymbol {\theta }$ wave, $\boldsymbol {\alpha }$ wave, and $\boldsymbol {\beta }$ wave, and the combined representation of their power spectrum curve area is the features of pilots’ mental status. To solve the second issue, we propose a new deep contractive autoencoder (AE) network with a softmax (SM) classifier to detect the multistatuses of mental fatigue workload. The recognition results of our model are also compared with that of other models such as the deep AE network with a SM classifier model. The experimental results show that our deep learning model has superior classification performance, and the recognition accuracy of fatigue mental status is up to 91.67%, which shows that the proposed method performs excellently compared with the state-of-the-art methods. [ABSTRACT FROM AUTHOR]

Sustainable development of civil aviation is associated with the end of the block confrontation between East and West, which is directly related to the reduced use of military aviation. The modern military aircrafts are engaged in international air traffic in strict compliance with the requirements of each member state of the EU and Eurocontrol. Ensuring enough freedom to fly through the airspace of European countries depends on the equipment of the military aircrafts, the available military air traffic management infrastructure, the adopted rules and procedures for flight operations, and the training of the pilot and navigational staff. By providing adequate freedom to use airspace creates prerequisites for successful implementation of tasks in overcoming the consequences of disasters, accidents and catastrophes. With the use of area navigation and implementation of new airspace structures was put into action the concept proposed by Eurocontrol - the Concept of Flexible Use of Airspace (FUA). Combined with facilitating access to the aeronautical information of member states of Eurocontrol, opportunities are being created to conduct research into the use of airspace by military aircrafts. Through comparative study may identify best practices to inspire the creation of conditions for improving the interaction between civil air traffic service units and controlling military units in coordinating the use of airspace by military aircrafts. This study proposes criteria and approaches to assess the possibilities of using the airspace of member states of Eurocontrol by military aircrafts. Based on the results obtained, recommendations can be made to improve the legislation in determining the conditions for use of the national airspace by military aircrafts. The analysis stands conclusion that there are conditions to improve the possibilities of using the airspace of Bulgaria by military aircraft. [ABSTRACT FROM AUTHOR]

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In this letter, we investigate how a rotary-wing unmanned-aerial vehicle (UAV) acts as a wireless base station to provide emergency communication service for a post-disaster area with unknown user distribution. The formulated optimization task is to find out the optimal path starting and ending at the same point to serve as many as possible users under limited battery capacity. We show that this problem can be transformed to an extended multi-armed bandit (MAB) problem, for which we propose two efficient path planning algorithms. Simulation results show that, in terms of the total number of served users, our proposed algorithms outperform the straightforward helical path that scans the entire area by circles with increasing radius. [ABSTRACT FROM AUTHOR]

Metal matrix hybrid composites are usually preferred for high energy aircraft (1-10 MJ) brake pads (HEABP) applications. The report focuses mainly on the evaluation of the wear and braking performance of the composite for the military aircraft applications. In this paper, the design and processing of a typical HEABP composite have been discussed in detail. The airworthiness qualification tests for the HEABP and the brake units are outlined with details. Also, brake testing parameters calculations derived from the typical aircraft data are presented for both the laboratory and full scale dynamometer tests. A case study of Fe-Si3N4- graphite composite pads is presented to exemplify the steps involved in the design, development, and airworthiness certification of HEABPs for the 8 MJ energy military aircraft. From the microstructure and wear surface morphology analysis and the results of brake performance parameters, functional tests and aircraft trials, it is concluded that the Fe-Si3N4- graphite composite has a minimum life of 200 normal energy landings with excellent braking performances.

Military operations may result in noise impacts on surrounding communities and wildlife. A recent transition to more powerful military aircraft and a national consolidation of training operations to Whidbey Island, WA, USA, provided a unique opportunity to measure and assess both in-air and underwater noise associated with military aircraft. In-air noise levels (110 ± 4 dB re 20 µPa rms and 107 ± 5 dBA) exceeded known thresholds of behavioral and physiological impacts for humans, as well as terrestrial birds and mammals. Importantly, we demonstrate that the number and cumulative duration of daily overflights exceed those in a majority of studies that have evaluated impacts of noise from military aircraft worldwide. Using a hydrophone deployed near one runway, we also detected sound signatures of aircraft at a depth of 30 m below the sea surface, with noise levels (134 ± 3 dB re 1 µPa rms) exceeding thresholds known to trigger behavioral changes in fish, seabirds, and marine mammals, including Endangered Southern Resident killer whales. Our study highlights challenges and problems in evaluating the implications of increased noise pollution from military operations, and knowledge gaps that should be prioritized with respect to understanding impacts on people and sensitive wildlife.

Wildlife-aircraft strikes threaten both human and animal safety and result in hundreds of millions of dollars per year in aircraft damage and lost flight hours. Large-bodied birds are especially hazardous to aircraft. However, given high-speed flight at low altitudes, military aircraft may be especially vulnerable to strikes and more susceptible to damage even when encountering small birds. We summarized all wildlife-aircraft strike records from Randolph Air Force Base (San Antonio, Texas) over a 25-year period and compared the number and cost of strikes across avian species and species groups. Because columbids (i.e., pigeons and doves) are among the most frequently struck species by both civilian and military aircraft and because several columbid species have demonstrated marked population increases over the past decade, we also quantified characteristics (i.e., month, time of day, precipitation patterns, phase of flight, altitude) of columbid strikes. White-winged doves (Zenaida asiatica) have undergone a substantial northward range expansion over the past 60 years and are now numerous in San Antonio. Given local interest, we also highlighted characteristics of aircraft strikes involving this species. Though columbids were not the most frequently struck species group during the survey period (1990–2014), they were the most costly. Columbid strikes were more frequent from May to July than during other months and often occurred during morning hours, especially from 08:00–10:00, with a smaller afternoon peak from 15:00–17:00. Columbid strikes occurred during landing more than during other phases of flight, typically at ≤152 m above ground level (AGL), though white-winged doves were more likely to be struck on takeoff than expected. To reduce costs and safety concerns where columbids are prevalent, military flight planners, aircrews, and wildlife managers can reduce air travel, increase vigilance during takeoffs and landings, and implement on-the-ground hazing techniques in morning and late afternoon hours during spring and summer months.