Flight Performance Determination of Gliders

Die Ermittlung der Flugleistung von Segelflugzeugen anhand kontinuierlich aufgezeichneter Flugmessdaten im Vergleichsflug eröffnet die Möglichkeit, die individuelle Bewegung sowie das induzierte Windfeld beider Flugzeuge zu berücksichtigen. Das Ziel dieser Arbeit ist die Entwicklung, Umsetzung und Validierung einer auf moderner Flugmesstechnik basierenden sensorischen Messmethode mit derzeit höchstmöglicher Genauigkeit. Hierzu wurde ein geeignetes flugmechanisches Modell entwickelt und die Bestimmung des induzierten Windfelds mit verschiedenen Verfahren untersucht. Für die Erfassung der Messdaten wurden Flugmessanlagen aufgebaut, die hinsichtlich Baugröße, Gewicht und Leistungsaufnahme auf den Einsatz in Segelflugzeugen zugeschnitten sind. Für die hochgenaue Messung des Statikdrucks wurde hier eine mittelwertreduzierte Signalumsetzung für die Bestimmung der Vertikalgeschwindigkeit konzipiert und eingesetzt. Anhand verschiedener Untersuchungen konnte bei der Bestimmung der Vertikalgeschwindigkeit ein verbleibender Fehler von 0,01 m/s nachgewiesen werden. Weiterhin wurde eine Flugstrategie entworfen und erprobt, mit der eine wesentliche Reduktion des finanziellen und zeitlichen Aufwands bei der Ermittlung der Flugleistung gegenüber der etablierten fotogrammetrischen Messmethode erreicht wird. Es kann davon ausgegangen werden, dass bei konsequenter Anwendung und stetiger Weiterentwicklung der sensorischen Messmethode wesentliche innovative Impulse für den Segelflugzeugbau gegeben werden können.The flight performance determination of gliders with continuously recorded flight data by using the comparison flight procedure enables the description of the individual movement as well as the wake wind field of the both aircraft. The objective of this investigation is the development, the realization and the validation of a sensory method based on modern flight data systems. For the employment of this method a suitable flight mechanical model was developed and several procedures for the determination of the wake wind field were examined. Due to the very limited space, payload and energy special flight data recorders were assembled for the operation onboard the gliders. A mean value reduced data conversion for the very precise measurement of the static pressure and the calculation of the vertical speed was designed and used. With several tests a remaining error of 0,01 m/s for the determination of the vertical speed could be proved. Furthermore a significant reduction of cost in finances and in time could be realized in comparison with the established fotogrametric method by using a new flight strategy. With the consequent use and continuous development of the sensory method innovative results for the evolution of gliders can be given

Nutzung präskriptiver Instandhaltungsansätze in der Luftfahrt zur vorausschauenden Materialbedarfsplanung

Durch kontinuierliche Bemühungen der Digitalisierung und Ansätze der dauerhaften Systemüberwachung ist es in der Luftfahrt zunehmend möglich, aufkommende Schadensfälle vor ihrem Eintreten zu erkennen und Instandhaltungsereignisse entsprechend bedarfsgerecht zu planen, so dass notwendige Material- und Ressourceneinsätze möglichst minimal gehalten werden können. Da die dazugehörigen Zustandsüberwachungssysteme jedoch häufig noch in frühen Phasen ihrer technologischen Reife stehen, sind diese Prognosen mit gewissen Unsicherheiten behaftet. Es ist daher erforderlich, die Performance solcher Ausfallprognosen in Relation mit dem zu erwartenden Nutzen in der Instandhaltung und Ersatzteilversorgung zu betrachten (bspw. Wie ändert sich der Ersatzteilbedarf reparaturfähiger Komponenten bei Nutzung einer prognose-basierten Instandhaltung im Vergleich zu einer rein korrektiven Instandhaltung, falls das Überwachungssystem eine durchschnittliche Fehlalarmrate von 10% besitzt?). Im Rahmen dieses Vortrag wird das generelle Konzept der präskriptiven Instandhaltung kurz angerissen, um anschließend die modellierungstheoretischen Ansätze der diskreten Ereignissimulation zur verbesserten Ersatzteilversorgung vorzustellen. Das Ziel ist schlussendlich, Anwendern und Systemingenieuren eine Hilfestellung an die Hand zu geben, anhand dessen zum einen die Auswirkungen einer geänderten Instandhaltungsstrategie auf die beteiligten Stakeholder abgeschätzt und zudem auch Mindest-Performance-Kriterien an eine entsprechende Zustandsüberwachungstechnologie definiert werden können

Using Discrete-Event Simulation for a Holistic Aircraft Life Cycle Assessment

With growing environmental awareness and the resulting pressure on aviation, ecological impact assessments are becoming increasingly important. Life cycle assessment has been widely used in the literature as a tool to assess the environmental impact of aircraft. However, due to the complexity of the method itself and the long lifespans of aircraft, most studies so far have made strong simplifications, especially concerning the operational phase. Using a combined discrete-event simulation framework, this paper aims to ecologically assess the individual life cycle phases of an aircraft. The method will be demonstrated in a case study of an A320 and subsequently compared with findings from the literature. Despite the significant environmental impact of flight operations, which covers almost 99.8% of the entire life cycle of the aircraft, a detailed consideration of all life cycle phases is essential to serve as a reference for the ecological assessment of novel aircraft concepts. The presented assessment method thus enables a holistic analysis at an early stage of the design process and supports the decision-making for new technologies and operational changes

A Comparison of Temporally Dynamic Life Cycle Assessment Methods for Ecological Evaluation in Aviation

Most Life Cycle Assessments (LCAs) in aviation are static and do not adequately reflect the long life cycles of aircraft and associated temporal impacts of emissions. However, these temporal aspects will become more important in the future, as the concept of freedom in the climate crisis is now joined by a revolutionary factor, which states that the timing of certain emissions and their consequences will play an increasingly important role in the assessment of aircraft. There are various dynamisation methods that can extend classical LCAs. A literature review including a list of benefits and limitations should provide information on which dynamic methods are particularly suitable for aviation. Especially in the aviation sector, the dynamic life cycle inventory offers great potential for mapping and evaluating the operational life of an aircraft in more detail. A thorough examination, for example with the help of a discrete-event simulation, can therefore offer the possibility of significantly improving the accuracy and quality of the LCA results and thus generate more extensive insights into the ecological impact of aircraft

A New Concept for Permanent Geometric Reference Points made from RFID tags for Composite Aircraft Components

This work presents a new concept for permanent markers consisting of RFID tags built into aircraft components made from fibre reinforced plastics. The novelty of this concept lies in the antenna design, which represents a geometric point that can be accessed using commonly employed non-destructive testing (NDT) methods, specifically suited for thermovision. These geometric points provide a reliable frame of reference for accurate data localization throughout the entire life cycle of the components. Initial results obtained with an antenna design incorporated into a glass-reinforced epoxy laminate quantify the anticipated localization accuracy achieved through our concept. We utilize a geometrically calibrated, off-the-shelf bolometer and standard lock-in thermography in our approach

Aircraft Go-Arounds Associated to Vessel Traffic: Hamburg Finkenwerder Case Study

An aircraft go-around is a costly yet safety critical procedure. While there are many reasons to decide that a go-around is necessary, at Hamburg Finkenwerder airport (EDHI) there is a rather peculiar one: vessel traffic crossing the approach path. As both vessels and aircraft transmit their position at regular intervals through the Automatic Identification System (AIS) and Automatic Dependent Surveillance Broadcast (ADS-B) protocols it is possible to identify vessels that can cause problems to the aircraft’s approach. In this work we identified a 10 time higher than average go-around incidence at Finkenwerder airport and were able to find evidence of its relation to large passing vessels. As vessel traffic has a mostly stable course and speed, we found it is possible to predict the passing vessels well ahead of time in order to determine the best approach and reduce the number of go-arounds, allowing to save both fuel and emissions

Digitalization of Repair Processes in Aviation: Process Mapping, Modelling and Analysis for Composite Structures

Maintenance processes in aviation are of significant importance in order to ensure the operational readiness comprising the availability and reliability of aircraft. The increasing operation of composite-intensive aircraft including Airbus A350 or Boeing 787 as well as the growing usage of composites in secondary structures like stabilizers and winglets motivate research in modification and optimization of repair processes for composite structures in aviation. At the moment, the repair of composite structures is characterized by manual task execution, documentation in paper format and the focus on individual steps. In the future, the process should be digitally supported, documented in paperless format and the focus should be on the interactions and interfaces of the individual process steps in order to optimize the repair process. This is the first important step towards data storage and provision for more automated task execution and decision support systems. This then may serve as a basis for a visionary repair planning and process execution which is highly automated with perfectly aligned and interacting sub-processes with its documentation taking place completely in the digital world. In this paper, the literature and industrial solutions for digital support systems and process modelling approaches for both the aviation sector as well as other industries are reviewed and compared with respect to their digitalization level. The state-of-the-art repair process of aviation composite structures is mapped using the example of sharklets together with an industrial partner. This model is realized using the event-driven process chain (EPC) notation in the simulation software ARIS. The overall process in the repair shop is described hierarchically and relevant documents, information and data are identified. The different process steps are analyzed and potentials for a modified process execution are shown

[Poster] Identifying Maintenance, Repair and Overhaul Events based on ADS-B Data

Maintenance, Repair and Overhaul (MRO) plays a big role in aviation schedules and operational costs. In this work service difficulty reports are combined with aircraft ADS-B data to identify MRO activity based on an aircraft's layover information. The ``Inspection/Maintenance'' stage of operation and date of service difficulty reports allow to label layovers from ADS-B with the presence of MRO activity. Using a support vector machine this work classifies layovers based on their duration and time of day, achieving an 86% overall accuracy and 78% balanced accuracy. These results reflect the difficulty of working with this sparse and incomplete dataset, however, they allow us to study MRO schedules. The combination of these data sources offers new opportunities to find relations between aircraft trajectory information and MRO, which will be further investigated in future work