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    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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    <language>en-us</language>
    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>Adequate mathematical modelling by wide-sense robust control design in a thrust-vectored flight dynamics problem</title>
      <link>https://trid.trb.org/View/1678305</link>
      <description><![CDATA[The conflict between the accuracy and the complexity of the adequate mathematical modelling approximations of physical phenomena is discussed. The need of finding certain types of topological equivalency between nonlinear mathematical models as the keystone to successful study is emphasized. We formulate the control problem when the controlling functions cannot directly act on the phase variables defining a given terminal manifold as a control aim through the right-hand sides of differential equations describing a mathematical model under study. The idea of creating a hierarchical cascade of controlling attractors–mediators is introduced. It is shown how the method of the goal-oriented formation of the local topological structure of one-codimensional foliations as the basis of Poincaré’s-strategy-based backstepping method can be successfully used for designing terminal control. One brings up the problem of developing the tools intended for the creation of the topologically equivalent and quantitative–deviation–tolerable simplifications of the complex original mathematical models suitable for the synthesis of the control laws that are supposed to be applied to the latter ones. The two-dimensional example is analytically investigated to explain the procedure of constructing the cascade of controlling one-codimensional attractor mediators. The essentially nonlinear five-dimensional mathematical model of the longitudinal flight dynamics of a thrust-vectored aircraft in a wing-body coordinate system with two controls, namely, the angular deflections of a movable horizontal stabilizer and a turbojet engine nozzle, is investigated. The core of the designed wide-sense robust and stable in the large-tracking control algorithm is a hierarchical cascade of controlling attractor–mediators consisting of the two one-codimensional manifolds. The results of the computer simulation are presented. The topicality in creating the general theory of nonlinear mathematical modelling, as the tools to construct and manipulate the sets of topologically equivalent models being qualitative–quantitative adequate to corresponding physical phenomena, is pointed up in conclusion.]]></description>
      <pubDate>Tue, 28 Jan 2020 09:46:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/1678305</guid>
    </item>
    <item>
      <title>Modeling of aircraft fuel consumption using machine learning algorithms</title>
      <link>https://trid.trb.org/View/1678304</link>
      <description><![CDATA[With the aid of recording systems such as the flight data recorder, information from aircraft sensors can be transmitted in-situ to airlines or maintenance providers during the flight in form of reports, or stored for subsequent analysis in the postprocessing. This allows the determination of current aircraft performance with regard to fuel consumption or emissions. At present, data in a highly aggregated form (predominantly averages) are used for statistical estimations or physical models. The metrics are calculated on a rolling basis as performance indicators of the aircraft and are then compared with book values from the manuals or with data from the performance monitoring system. However, this procedure represents only a situational, aggregated point evaluation of stable flight conditions. The data aggregation is based on strict validity limits for parameter variations. Furthermore, trigger conditions of the recording logic determine the number and quality of the transmitted reports, such, that only a few data points are available for performance analyses. To improve realistic performance analyses, the time series of all aircraft sensors over the entire flight mission (full-flight data) can be used. In contrast to physical models, this study presents data-based approaches using machine-learning tools from the field of artificial intelligence, to develop fuel flow models based on full-flight data. The proposed methods result in detailed statements for the diagnosis of aircraft fuel consumption. The paper deals with the model development and results of different analyses based on a variety of an airline’s operational flight data records. This study describes the learning methods and shows results for two different data-based models, including neural networks and decision trees. Finally, future applications for the models and an outlook on the authors’ activities will be provided.]]></description>
      <pubDate>Tue, 28 Jan 2020 09:46:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/1678304</guid>
    </item>
    <item>
      <title>Longer-term aircraft fleet modelling: narrative review of tools and measures for mitigating carbon emissions from aircraft fleet</title>
      <link>https://trid.trb.org/View/1678303</link>
      <description><![CDATA[Aviation industry stakeholders such as International Air Transport Association (IATA) agreed on ambitious goals and a basket of measures for mitigating aircraft emissions. Determining the emissions mitigation potentials (EMPs) of these measures requires the use of a set of assumptions or longer-term forecasts in an integrated modelling environment. However, the results of longer-term forecasts are only as reliable as the reliability and consistencies of their assumptions and methods with industry trends, as well as their compatibility with other dominating external developments. In this article, nine approaches to modelling aircraft fleet development were reviewed. Each of the first eight approaches used a unique fleet development model, while the last approach combines two additional models with one of the eight models. Therefore, ten global and regional longer-term aircraft fleet development models were reviewed and compared. The review focus was on their individual methods used for aircraft addition to and disposal from the fleet. Where available, the EMPs of individual measures were compared in order to create an overview of the EMPs of the measures. Furthermore, methods used for fleet development modelling in the studies were compared with the airline industry trends and practices for fleet planning in order to identify opportunities for research. This study is useful to policy-makers in knowing the expected emissions mitigation benefit of proposed environmental policies related to the IATA basket of measures. Aviation stakeholders like aircraft manufacturers and airlines would also have an overview of expected emissions savings of individual and combined measures. Lastly, researchers can also understand state-of-the-art modelling methods and scenario assumptions for the purpose of duplication studies, as well as identify unexplored areas for research.]]></description>
      <pubDate>Tue, 28 Jan 2020 09:46:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/1678303</guid>
    </item>
    <item>
      <title>Performance analysis of a hybrid-electric retrofit of a RUAG Dornier Do 228NG</title>
      <link>https://trid.trb.org/View/1678302</link>
      <description><![CDATA[The research in this paper provides an analysis of the payload-range capabilities of a retrofitted CS-23, 19-passenger class aircraft, specifically the RUAG Do 228NG. The aircraft is retrofitted with a serial-hybrid electric propulsion system having current technology-level components. The analysis in this paper finds the design points of the propulsion system (battery mass and generator size) with regard to specific operational requirements by performing mission simulations with different flight profiles (operating scenarios). With the requirement of pure electric take-off and initial climb, it was found that two operational parameters, the top-of-climb altitude and the generator-activation altitude, are significant drivers for the battery mass. The generator size is mainly driven by the design’s speed. The mission performance results show that operational decisions affect the sizing of a retrofitted serial-hybrid propulsion system. The results suggest that once a system is sized, the airplane cannot easily be operated under different conditions. The calculated payload-range chart shows that the retrofit cannot match the payload-range capabilities of the baseline aircraft, showing a range reduced by 37% at a payload of 50% (1020 kg).]]></description>
      <pubDate>Tue, 28 Jan 2020 09:46:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/1678302</guid>
    </item>
    <item>
      <title>Integration aspects of the collaborative aero-structural design of an unmanned aerial vehicle</title>
      <link>https://trid.trb.org/View/1678299</link>
      <description><![CDATA[Overall aircraft design is a complex multidisciplinary process, which requires knowledge from many different fields such as structures, aerodynamics, systems and propulsion. For unconventional configurations lacking an empirical knowledge base, higher fidelity physics-based methods are required to reliably estimate the feasibility of a given new design concept. Analysis tools and results are provided by highly specialized groups of experts, possibly from different organizations. In the AGILE (aircraft 3rd generation MDO for innovative collaboration of heterogeneous teams of experts) project, new approaches to setting up cross-organizational collaborative aircraft design optimization workflows have been investigated, including the employment of common parametric aircraft configuration schema as a central common data schema and the provision of disciplinary analysis competences as callable services. Following this paradigm, the present paper details a distributed workflow to perform an aero-structural design optimization of an unmanned aerial vehicle (UAV) design. Taking advantage of disciplinary capabilities provided by several partners based in various locations across Europe, an integrated design workflow including a distributed and tightly coupled aero-structural analysis loop has been assembled using the process integration and design optimization system remote component environment developed at the German Aerospace Center. To enable the necessary load and displacement transfer between non-matching disciplinary meshes, a versatile and lightweight algorithm using radial basis functions has furthermore been implemented. The functionality of the workflow is demonstrated by performing the optimization on the baseline configuration of the UAV.]]></description>
      <pubDate>Tue, 28 Jan 2020 09:46:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/1678299</guid>
    </item>
    <item>
      <title>Modeling and control of lift offset coaxial and tiltrotor rotorcraft</title>
      <link>https://trid.trb.org/View/1678298</link>
      <description><![CDATA[The US Department of Defense has established an initiative to develop a family of next-generation vertical lift aircraft that will fly farther, faster, and more efficiently than the current fleet of rotorcraft. To accomplish these goals, advanced rotorcraft configurations beyond the single main rotor/tail rotor design must be considered. Two advanced configurations currently being flight tested are a lift offset coaxial rotorcraft with a pusher propeller and a tiltrotor. The US Army Aviation Development Directorate has developed generic, high-fidelity flight-dynamics models of these two configurations to provide the government with independent control-system design, handling-qualities analysis, and simulation research capabilities for these types of aircraft. This paper describes the modeling approach used and provides model trim data, linearized stability and control derivatives, and eigenvalues as a function of airspeed. In addition, control allocation for both configurations is discussed.]]></description>
      <pubDate>Tue, 28 Jan 2020 09:46:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/1678298</guid>
    </item>
    <item>
      <title>Metric evaluating potentials of condition-monitoring approaches for hybrid electric aircraft propulsion systems</title>
      <link>https://trid.trb.org/View/1678297</link>
      <description><![CDATA[Hybrid electric aircraft propulsion will become a necessity for general and commercial aviation in the near future to enable the achievement of ambitious objectives with respect to a reduction of emissions in air traffic. Furthermore, this technology is crucial to facilitate the introduction of new aircraft concepts such as electric vertical takeoff and landing (eVTOL) for personal air mobility. The advent of electrified propulsion systems for aeronautical applications raises questions concerning the reliability and the possibility of detecting faults of the propulsion chain before they become critical. Evaluating the influence of individual subsystems on reliability is necessary for decision making during condition-monitoring design. To address these questions, a reference hybrid electric propulsion system (HEPS) is defined and analyzed in terms of its possible failure modes and failure probabilities. A condition-monitoring system (CMS), applied to the subsystems of a hybrid electric propulsion system, is assessed with regard to its potential to reduce the probability of a total loss of thrust (TLOT). For the purpose of this assessment, a metric is developed which allows for a quantitative comparison of failure probabilities of the reference system with and without CMS, which offers a more intuitive approach on decision making during the design process. The results of this study showcase for which components of a hybrid electric propulsion system the application of CMS could potentially be beneficial.]]></description>
      <pubDate>Tue, 28 Jan 2020 09:46:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/1678297</guid>
    </item>
    <item>
      <title>Verification of a low fidelity fast simulation framework through RANS simulations</title>
      <link>https://trid.trb.org/View/1678296</link>
      <description><![CDATA[Verification and validation of simulation models are critical steps in engineering. This paper aims at verifying the suitability of reduced order aerodynamic models used in an aeroservoelastic framework designed to analyze the flight dynamics of flexible aircraft, known as the Cranfield Accelerated Aircraft Loads Model. This framework is designed for rapid assessment of aircraft configurations at the conceptual design stage. Therefore, it utilizes or relies on methods that are of relatively low fidelity for high computational speeds, such as modified strip theory coupled with Leishmann–Beddoes unsteady aerodynamic model. Hence, verification against higher order methods is required. Although low fidelity models are widely used for conceptual design and loads assessments, the open literature still lacks a comparison against higher fidelity models. This work focuses on steady-trimmed flight conditions and investigates the effect of aerodynamic wing deformation under such loads on aerodynamic performance. Key limitations of the reduced order models used, namely fuselage and interference effects, are discussed. The reasons for the overall agreement between the two approaches are also outlined.]]></description>
      <pubDate>Tue, 28 Jan 2020 09:46:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/1678296</guid>
    </item>
    <item>
      <title>A multidisciplinary process for integrated rotorcraft design</title>
      <link>https://trid.trb.org/View/1678295</link>
      <description><![CDATA[This paper presents a new integrated design process for rotorcraft developed by German Aerospace Center (DLR). The fundamental features of this process are distributed computation on the servers of the different institutes, analysis tools with increasing physical fidelity along the progress of the design process and a high modularity inside the software framework. A reliable data exchange between the tools is provided by an extended version of DLRs Common Parametric Aircraft Configuration Schema. The tools cover the phases of conceptual and largely preliminary design. The design process is initialized by a statistical concept study, providing the first configuration for the following sizing and optimization task. The methods of the tools applied range from blade element theory over vortex panel theory, to finite element methods for structural sizing. The high modularity allows an easy integration of new abilities into the toolbox. The process and design environment presented here are the results of two DLR internal projects carried out by the Institute of Flight Systems, the Institute of Aerodynamics and Flow Technology and the Institute of Structures and Design.]]></description>
      <pubDate>Tue, 28 Jan 2020 09:46:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/1678295</guid>
    </item>
    <item>
      <title>Progress in the airworthiness technology of civil aero-engine : A study on FAR 33 (airworthiness standards: aircraft engine)</title>
      <link>https://trid.trb.org/View/1678294</link>
      <description><![CDATA[According to the airworthiness technology of civil aero-engine, the historical evolution of airworthiness regulation, FAR 33, is investigated. And the general rules are obtained which include developing form, influencing factors of development, and changing trend. Furthermore, the analysis of airworthiness verification technology will be presented in the four aspects which are use, working environment, structure, and system. Plus, the critical points of airworthiness certification and management are discussed. Based on the analysis above, the opportunity and challenge the airworthiness certification work face in the next period are finally prospected, to provide a reference for the related research in the aviation industry.]]></description>
      <pubDate>Tue, 28 Jan 2020 09:46:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/1678294</guid>
    </item>
    <item>
      <title>The GSD dependency of the eTOD photogrammetric survey</title>
      <link>https://trid.trb.org/View/1678293</link>
      <description><![CDATA[We have been looking for a safe and economical technique for making an Electronic Terrain and Obstacle Data collection (eTOD). We have developed a method and a quality assurance system which covers the complete process from making an aerial survey to data processing. In addition to presenting the method, the article focuses on the dependence of the aerial photogrammetric obstacle survey on spatial resolution. We have found that the most effective way of making an obstacle database is by making a passive aerial remote sensing, which is supported by a high-speed (200–600 km/h) fixed-wing aircraft. The high-speed aerial camera systems with vertical and oblique camera axis are more accurate and more aerial triangulation can be used with them than with classic single camera solutions. The carefully planned flights for fixed-wing platforms provide a stable camera position and the homogeneous shooting network more easily, and obstruct the air transport for less time. In most cases, a terrestrial survey in itself does not allow the creation of the eTOD within a reasonable time frame and with complete safety, because of hard-to-reach areas, subjectivity and slow traversal in the field.]]></description>
      <pubDate>Tue, 28 Jan 2020 09:46:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/1678293</guid>
    </item>
    <item>
      <title>Noise evaluation of battery powered small aircraft</title>
      <link>https://trid.trb.org/View/1678292</link>
      <description><![CDATA[Preliminary assessments of battery powered aircraft designs show potential for noise reduction. However, profound analyses estimating this noise reduction potential using white-sheet preliminary aircraft designs are missing so far. Additionally, an investigation on the sensitivity of crucial aircraft design parameters impacting both aircraft performance and noise emissions could be utilized to derive design recommendations for quieter battery powered aircraft without a considerable performance decrease. Feasible preliminary aircraft designs are derived using the multidisciplinary preliminary aircraft design and optimization tool MICADO. The derived preliminary aircraft designs are subsequently evaluated towards their noise emission. Because the propeller represents the dominant noise source, the noise evaluation is focused on the propeller as only source. The noise is evaluated at an observation point situated beneath the flight path on the ground 2500 m away from the brake-release point. Three different aircraft configurations are assessed employing one, two and four electric engines. Besides electric engines, a piston engine aircraft with one engine is assessed for proper baseline values. The design maximum propeller tip Mach number is varied for each configuration resulting in 22 different preliminary aircraft designs. Results substantiate that single electric engine aircraft compared to an analogous single engine piston aircraft, within the actual technology and in terms of propeller noise, produces a higher noise annoyance. Despite this result, important noise reduction potential for electric aircraft can be achieved. When increasing the number of electric engines from one to four, while reducing the design maximum propeller tip Mach number, a max OASPL reduction of 23.8 dBA can be observed for the given TLARs.]]></description>
      <pubDate>Tue, 28 Jan 2020 09:46:22 GMT</pubDate>
      <guid>https://trid.trb.org/View/1678292</guid>
    </item>
    <item>
      <title>Energy-optimal guidance of a battery-electrically driven airplane</title>
      <link>https://trid.trb.org/View/1678291</link>
      <description><![CDATA[This study introduces an approach to decrease the electric energy consumption by efficient guidance of a battery-electrically propulsed airplane. An appropriate mathematical model containing a detailed energy consumption estimation is presented. With this, an optimal control problem is formulated and solved using the MATLAB Toolbox FALCON.m. Furthermore, steady state efficiency criteria are established for a range optimal climb and a horizontal flight. With the help of steady state grid calculation, values for both efficiency criteria and corresponding guidance parameters are determined. The optimal values of both criteria are correlated with the steady state arcs of the optimal trajectory. For the descend segment, an optimal airspeed is determined and correlated also with the trajectory. As a result, energy optimal steady state guidance parameters can be provided to the pilot for each flight segment. A concept of a cockpit display is introduced that delivers efficient guidance parameters to the pilot.]]></description>
      <pubDate>Tue, 28 Jan 2020 09:46:22 GMT</pubDate>
      <guid>https://trid.trb.org/View/1678291</guid>
    </item>
    <item>
      <title>Validation of decision logic of an autoland system for a UAV using model-based safety-assessment techniques</title>
      <link>https://trid.trb.org/View/1678290</link>
      <description><![CDATA[Software of automatic flight control systems requires thorough verification and validation. Traditionally, this is achieved with elaborate development processes following pertinent industry standards. To reduce the development effort, however, new methods have emerged: a model-based software development process is used at the Institute of Flight System Dynamics of the Technical University of Munich for the design of auto-flight systems with MATLAB/Simulink. Besides, the model-based safety assessment (MBSA) framework ExCuSe has been developed, which implements methods for fault modeling and automatic cut-set extraction using the Simulink Design Verifier. This paper proposes an application of MBSA techniques for the efficient requirements and design validation of decision logic in auto-flight-system software. With ExCuSe, software design models of an investigated decision logic are supplemented by models for off-nominal inputs (e.g., a sensor fault) and for the design requirements. With the analysis, either a formal proof is obtained that the investigated decision logic fulfills the requirements under any circumstances (guaranteed properties), or a counterexample illustrates a requirement violation. The functional principle and applicability of the method are demonstrated by the analysis of decision logic of the autoland system of the SAGITTA Demonstrator UAV. ExCuSe is used to prove that the logic guarantees a timely flare initiation so that a safe touchdown sink rate is achieved despite altitude-measurement inaccuracy and closed-loop flare dynamics uncertainty. As virtually all auto-flight systems feature decision logic, this initial demonstration of the technique opens up many opportunities for further applications in future work.]]></description>
      <pubDate>Tue, 28 Jan 2020 09:46:22 GMT</pubDate>
      <guid>https://trid.trb.org/View/1678290</guid>
    </item>
    <item>
      <title>High-lift design for a forward swept natural laminar flow wing</title>
      <link>https://trid.trb.org/View/1678289</link>
      <description><![CDATA[The scope of the paper is to present the results of a RANS-based aerodynamic high-lift design for a natural laminar flow wing with negative sweep. The chosen high-lift system consists of a Krueger leading edge flap with shielding function and a fixed-vane trailing edge flap. The design was first optimized in two main wing sections and then verified by 3D RANS simulations of a wing-body model. Finally, engines were added to the geometric model to estimate the high-lift performance of the landing configuration. With a maximum lift coefficient of 𝐶L=2.85 for the wing-body model with engine, the target from the preliminary aircraft design was reached. Further potential for improvement was found in the optimization strategy and the shape of the fuselage–wing junction.]]></description>
      <pubDate>Tue, 28 Jan 2020 09:46:22 GMT</pubDate>
      <guid>https://trid.trb.org/View/1678289</guid>
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