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Time series of meteorological parameters at ten Greek airports since 1955 indicated the level of climate change in the Eastern Mediterranean area. Using this data, take-off performance was analysed for the DHC-8-400—a typical short range turboprop airliner, and the A320, a typical medium scale turbofan airliner. For airports with longer runways, a steady but unimportant increase in take-off distances was found. For airports with shorter runways, the results indicate a steady reduction in available payload. At the most extreme case, results show that for an Airbus A320, operating from the, relatively short, 1511m runway at Chios Airport, the required reduction in payload would be equivalent to 38 passengers with their luggage, or fuel for 700 nautical miles (1300 km) per flight, for the period between the A320’s entry to service in 1988 and 2017. These results indicate that for airports where aeroplane maximum take-off mass is a performance limited function of runway length, and where minimum temperatures have increased and/or mean headwind components decreased, climate change has already had a marked impact on the economic activity in the airline industry. Similar analyses could be usefully carried out for other runway-length–limited airports, which may often include island airports. It is also noted that previous research has only considered temperature effects, and not wind effects. Wind effects in this study are less significant than temperature, but nonetheless have an effect on both field performance noise and pollution nuisance around airports.

A seal is a component that impedes the flow of fluid through a given system. The word "impede" holds emphasis as there is no such thing as a zero leakage seal. All dynamic seals must leak, even if it is as low as 1 mm^3 per year and referred to as "emission".

Der Vortrag stellt den Flugversuch in den heutigen Kontext der Luftfahrt mit seinen Verknüpfungen zur Zulassung und Entwicklung des Luftfahrzeuges. Welche Anforderungen gibt es? Welche Vorgaben der EASA müssen beachtet werden. Was ist ein Entwicklungsbetrieb? Anhand von Beispielen aus der täglichen Arbeit wird die praktische Umsetzung der Flugversuche dargestellt. Zusammen mit den beteiligten Wissenschaftlern bereitet der Projekt- und Entwicklungsingenieur die Flugversuche vor und übernimmt die Verantwortung für die strukturelle Implementierung der Flugversuchsinstallationen. Für einen sicheren Betrieb des Versuchsträgers bei sich ständig ändernden Versuchseinbauten ist die Konfigurationsdefinition und Konfigurationskontrolle unerlässlich. Das DLR betreibt sowohl Hubschrauber als auch Flächenflugzeuge. Dabei geht/ging es von der für 19 Passagiere ausgelegten Dornier Do 228 über die VFW 614 bis zum Airbus A320-200 als Advanced Technology Research Aircraft (ATRA)., Hamburg Aerospace Lecture Series --- Collection of Presentations --- http://www.AeroLectures.de

Cet article présente les menaces qui pèsent sur la conservation des outils et des machines de l’industrie aéronautique. En effet, cette activité récente et florissante n’a pas encore pris pleinement conscience de sa dimension historique et patrimoniale. Ses acteurs agissent parfois en ordre dispersé pour sauver ce qui peut l’être. Dans cet univers qui a le culte du secret, l’historien universitaire n’est pas toujours le bienvenu, à Toulouse comme à Seattle. Heureusement, il existe des associations dynamiques qui multiplient les initiatives afin d’éviter des pertes irréparables. Mais pour les périodes les plus anciennes, beaucoup de documents et d’objets manquent déjà à l’appel. This paper discusses the threats to the conservation of tools and machinery in the aviation industry. Indeed, this recent and flourishing activity has not yet become fully aware of its historical and heritage dimension. Its actors sometimes act in a scattered order to save what can be saved. In this world which has a cult of secrecy, the university historian is not always welcome, in Toulouse as in Seattle. Fortunately, there are dynamic associations that multiply initiatives in order to avoid irreparable losses. But for the oldest periods, many documents and objects are already missing.

We report on the flight test results of an Airbus 320 during novel advanced required navigation performance (RNP) procedures which contain a fixed radius turn that delivers the aircraft onto a short instrument landing system (ILS) precision final. Moreover, the advanced RNP part contains altitude constraints and/or a coded vertical path angle. The approaches were flown automatically with guidance and autothrust as computed by the flight management system. We investigated the use of the fixed radius in conjunction with vertical path options onto (a) the performance of the speed profile for arrival time optimisation, (b) the vertical path during the RNP part of the procedure and (c) the performance of the autoland capability after a curved transition onto an ILS.For the trials, we designed five instrument approaches to a runway equipped with ILS. A RF curve terminates at the ILS intercept point at heights of 550, 750, 1000, 1500 and 2000 ft above aerodrome level and each approach had four different initial approach fixes which corresponded to a track angle change of 30°, 60°, 90° and 180° during the constant radius turn-to-final. We constructed the procedure such that the altitude constraints at initial, intermediate and final approach fix describe a continuous vertical path with minus 2° inclination, transitioning to the –3° glide path of the ILS and intercepting the glide path from below. In all cases, the land mode of the flight guidance computer became active between 316 and 381ft radar altitude. The vertical path following error depended on the coding of the procedure in the database. With coded vertical path angle and altitude constraints, the vertical path following error was never greater than +57 m (above desired flight path) during the RNP part when flown by the automatic flight guidance system without any pilot intervention.

Structural improvements in aircraft design, seeking to improve energy efficiency, can significantly reduce greenhouse gas emissions (GHG) by reducing reduced fuel consumption. This research reviews improvements with the introduction of a structural component known as "winglet;" these are positioned at the top of the aircraft wing, and increased Airbus Group A320 sales. Data used are taken from air traffic in Spain for the 2010–2014 period with projections being made for 2020. The results show that winglets reduce CO2 equivalent emissions associated with Spain's air transport for the 2015–2020 period between 66.29 and 59.56 Gg. depending on the scenario considered in 2020. Junta de Andalucía proyecto SEJ-132 Fundación Roger Torné, Universidad de Sevilla, Cátedra de Economía de la Energía y del Medio Ambiente 1394/0103 Ministerio de Economía y Competitividad de España ECO2014-56399-R Universidad Autónoma de Chile

International audience; Le 18 décembre 1970 naît le groupement d’intérêt économique (GIE) Airbus Industrie. Fruit d’une collaboration franco-allemande dont s’est retiré l’État britannique, il marque le début d’une aventure industrielle européenne exceptionnelle. L’Espagne rejoint rapidement cette entité qui intègre aussi la firme anglaise Hawker Siddeley spécialisée dans les voilures. Dès l’origine, Toulouse constitue le pôle majeur de recherche et d’assemblage des différents éléments de ce mécano complexe. La ville rose en devient aussi le siège social opérationnel en 2012 et peut donc revendiquer le titre de capitale européenne, voire mondiale, de l’aéronautique. Mais le cheminement vers ce triomphe s’avère long et difficile, né à l’ombre de Concorde, le premier Airbus A300B demeure longtemps méprisé. Plusieurs échecs commerciaux doivent être surmontés pour arriver au remarquable succès de la famille de l’A320 fragilisé par le Covid-19…

Se comenta cómo utilizar la app de Airbus para calcular la distancia de aterrizaje de un A320

Purpose – This presentation takes a critical look at various electric air mobility concepts. With a clear focus on requirements and first principles applied to the technologies in question, it tries to bring inflated expectations down to earth. Economic, ecologic and social (noise) based well accepted evaluation principles are set against wishful thinking. Design/methodology/approach – Aeronautical teaching basics are complemented with own thoughts and explanations. In addition, the results of past research projects are applied to the topic. Findings – Electric air mobility may become useful in some areas of aviation. Small short-range general aviation aircraft may benefit from battery-electric or hybrid-electric propulsion. Urban air mobility in large cities will give time advantages to super-rich people, but mass transportation in cities will require a public urban transport system. Battery-electric passenger aircraft are neither economic nor ecologic. How overall advantages can be obtained from turbo-electric distributed propulsion (without batteries) is not clear. Maybe turbo-hydraulic propulsion has some weight advantages over the electric approach. Research limitations/implications – Research findings are from basic considerations only. A detailed evaluation of system principles on a certain aircraft platform may lead to somewhat different results. Practical implications – The discussion about electric air mobility concepts may get more factual. Investors may find some of the information provided easy to understand and helpful for their decision making. Social implications – How to tackle challenges of resource depletion and environment pollution is a social question. Better knowledge of the problem enables the public to take a firm position in the discussion. Originality/value – Holistic evaluation of electric air mobility has not much been applied yet. This presentation shows how to proceed., Hamburg Aerospace Lecture Series --- Collection of Presentations --- http://www.AeroLectures.de

In 2017 Airbus delivered a record 718 aircraft to its customers. Before its delivery each individual aircraft has to pass a ground and flight test phase to obtain the certificate of airworthiness. This lecture gives an overview of the production flight testing in an industrial environment. It describes the series of tests from the moment the aircraft leaves the final assembly line until its delivery to the customer. Flight test engineer Andreas Balk is part of the production flight test department team at Hamburg Finkenwerder and provides an inside view on his daily work testing A320 family and A380 production aircraft., Hamburg Aerospace Lecture Series --- Collection of Presentations --- http://www.AeroLectures.de

We report on the performance of our Airbus 320 during novel advanced required navigation performance (RNP) procedures which contain a fixed radius turn that delivers the aircraft onto a short ILS precision final above aerodrome level. The approaches were flown automatically with guidance and autothrust as computed by the flight management system. Main areas of interest of the flight trials were the performance of the autoland capability, vertical path following during the RNP part of the procedure as well as maintaining an optimized speed profile during the continuous descent approaches Within the PBN concept exists the possibility to incorporate turns with a precise ground track into departure, en-route, arrival and approach procedures called fixed radius transitions or radius-to-fix. They offer the advantage of repeatable ground tracks during the turn and thus more freedom for the procedure designer when route planning in dense traffic, high terrain or obstacle rich environments. Additionally, ARINC 424 allows to specify altitude constraints at waypoints and vertical path angles for each RNP segment terminating at such a waypoint. Whilst offering these benefits such advanced RNP approach operations are still non-precision procedures and automatic landings cannot be performed after their successful completion. Hence, to enable automatic landings and to extract maximum benefits from RNP operations, they must transition into a precision final approach segment provided by any precision landing system (ILS, GLS, MLS) so that the guidance loops for flare and land modes of the auto flight guidance system can activate. This is often called RNP to xLS (or RNP2xLS). Moreover, the vertical path angle feature is currently largely unused and unexplored, except for the final approach segment of an RNP approach. These new options, when properly exercised, would allow any aircraft to benefit from better fuel efficiency during a continuous descent approach and a potentially reduced obstacle clearance due to the fixed vertical RNP profile and RF tracks. Ground tracks are repeatable and could be used for better noise abatement — besides their main purpose, obstruction clearance along the aircraft's path. In this study we investigated the use of the described ARINC424 coding options onto (a) the performance of the speed profile for arrival time optimization (b) the vertical path during the RNP part of the procedure and (c) the performance of the autoland capability after a curved transition onto an ILS. For the trials, we designed five instrument approaches to runway 26 at Braunschweig-Wolfsburg airport, which is equipped with an Instrument Landing System. A RF curve terminates at the ILS intercept point at heights 550ft, 750ft, 1000ft, 1500ft and 2000ft above aerodrome level and each approach had four different initial approach fixes which corresponded to a track angle change of 30,60,90 and 180 degrees during the constant radius turn-to-final. For each initial approach path coded as advanced RNP segments, we programmed different combinations of vertical path angle and height constraints at waypoints. Moreover, as the thrust computer automatically reduces speed to a value suitable for initial approach, we varied the distance of the initial approach fix of one of the approaches from ranging between 3 to 7NM from the FAF in order to allow the aircraft to decelerate as late as possible. For the trials, we used DLR's own Advanced Technology Research Aircraft (ATRA), an Airbus A320 MSN659 with flight test instrumentation and a Thales FMS2. The approaches were entirely flown using the auto flight guidance in managed mode and with auto-thrust activated. The approach mode was armed either at the FAF or before the initial approach fix. We show supporting evidence that RNP2ILS approaches can be safely flown all the way to an automatic landing using the flight management guidance computer and the auto flight control system. In order to fly the desired path with vertical path angle during the RNP initial and intermediate approach, a separate mode (such as LNAV/VNAV) different from the singular approach mode would need to be implemented in the aircraft. Additionally, airlines and other operators currently apply stabilization criteria following which the aircraft must be established on a straight final with the correct sink rate at 1000ft above aerodrome level in order to continue the approach. For landings in low visibility conditions, more stringent criteria are often applied. An operational implementation of RNP2ILS approaches with a curved final intercept would require a rephrasing of the criteria to include a concept such as RNP established.

An unstructured flow solver has been equipped with transition prediction techniques based on different streamline-based approaches, applying the eN method for the estimation of the points of transi...

Diese Masterarbeit analysiert die Zusammenhänge des Turnarounds beim Flugzeugmuster Airbus A320. Die nötigen Prozesse, um ein Flugzeug nach der Landung für den nächsten Flug vorzubereiten, werden als Turnaround bezeichnet. Durch das Aufführen und Analysieren aller Einzelprozesse werden Engpässe herausgearbeitet. Bestehende Optimierungsansätze wurden recherchiert und dokumentiert, sowie deren Umsetzbarkeit in einem Kurzstreckenflugzeug untersucht und bewertet. Skizzen und Abbildungen dienen dazu eigene Ideen für die Optimierung des Boardings und des Beladens mit Gepäck vorzustellen und zu präzisieren. Abschließend wird ein Ausblick auf mögliche zukünftige Entwicklungen und die immer stärkere Vernetzung von allen Beteiligten für den immer schnelleren Informationsaustausch gegeben.

Übersichtsvortrag zu Aktivitäten der CFD-Transitionsmodellierung am Institut AS in der Abteilung C²A²S²E

In order to further improve aircraft performance, multifunctional control surfaces become more and more important. The integration of multifunctional control surfaces causes a significant increase in the overall system complexity. Novel design methods have to be used by the involved engineers and designers in order to assess system performance, system interdependencies and safety issues in an early stage of the design process. One powerful method that is used to support the development of complex mechatronic systems, is the so called physical modeling approach. Within the scope of this thesis, the physical modeling approach shall be applied on two different aircraft trailing edge configurations.First, the regular Airbus A320 trailing edge system architecture is analyzed regarding involved components and system interdependencies. Key components are then modeled within the MatLab Simscape environment. The component models are assembled step by step, such that a full-scale A320 trailing edge model is generated. The same component models are then used to model a second trailing edge configuration which has been developed in the Low Drag Aircraft in Operation project. Both trailing edge configurations are then subjected to typical failure conditions and the resulting system performance is analyzed.It will be shown that the Low Drag Aircraft in Operation wing configuration has to be supplied by a more powerful hydraulic system then the current A320. Furthermore, important information regarding physical modelling in MatLab Simcape will be given. The component library proposed in this work will be complemented with additional components and might be validated against experimental data by the German Aerospace Center in subsequent work.*****In order to further improve aircraft performance, multifunctional control surfaces become more and more important. The integration of multifunctional control surfaces causes a significant increase in the overall system complexity. Novel de

This thesis shows the performance of DLR’s test aircraft A320-ATRA during flight tests of experimental RNP to ILS approaches to Braunschweig-Wolfsburg airport. The purpose of the flight test campaign was to demonstrate the feasibility of advanced procedures including a fixed radius turn onto ILS precision final segments with lengths between one and five nautical miles for autoland operations. Enabled by precise area navigation systems based on satellite navigation, these procedures allow the inclusion of turns with a predictable ground track into the approach phase, thus allowing the construction of more flexible routes in areas with a high traffic density or difficult terrain. Furthermore, more environment-friendly procedures can be created due to shorter approach tracks and the possibility to circumnavigate areas sensitive to noise. During the flight tests, three main areas of interest were investigated: The autoland performance of the ATRA was evaluated in approaches with varying lengths of the final approach segment in order to identify a minimum required length for the autoland capability of the test aircraft. Beyond that, the vertical path generated by the flight management system was assessed with regard to its compliance with the intended flight path for a successful transition to ILS guidance at the end of the turn before the final approach. Additionally, the lateral path following during the transition to localizer guidance was investigated for possible violations of the RNP corridor. The results of the flight tests show that it is possible to perform an automatic landing during all experimental approaches, regardless of the length of the final approach segment. Lateral navigation is precise enough to support operations with high accuracy requirements such as RNP 0.1, although the activation of the approach mode can cause larger deviations as soon as the aircraft enters the localizer service volume. During the flight tests, it was also found that RNP to ILS approaches should be coded with a flight path angle in the navigation database in order to prevent an early descent to the ILS intercept height. Although procedures coded without a flight path angle were successful as well, an undesirable level segment was included into the approach by the flight management system, reducing or neutralizing the benefits with regard to noise pollution and fuel efficiency. However, in consideration of the findings of this flight test campaign, it is possible to safely fly RNP to ILS approaches while maintaining the advantages inherent to these procedures.

A new concept of a passenger aircraft using hydrogen as fuel is presented. Due to the future depletion of fossil fuels and growth of aviation within the next years, the aeronautical industry must get ready now for a realistic solution. Many projects were conducted for hydrogen-fueled aircraft designs in the past, however all the effort was focused on an expensive totally new aircraft design. In this work, research is based on the Airbus A320 with a requirement for 1510 NM range at 19.3 t maximum payload. Goal is to redesign the aircraft under the premise of minimum change and minimum costs. Hydrogen as the new energy carrier will be stored at cryogenically temperatures. Still it needs more tank volume. This extra volume is best generated with an aircraft stretch leading to an increase of aircraft length. A minimum change option would be to simply use A320 seating in an A321, using the additional space for the new hydrogen fuel tanks. Unfortunately, the additional volume on its own is not sufficient. Therefore, three different hydrogen-fueled versions are developed. 1.) The A321-HSO stretched beyond the length of the A321. 2.) The A321-HWO with A321 fuselage and additional under-wing podded hydrogen fuel tanks. 3.) A321-H19O with A321 fuselage and A319 cabin. All three versions were designed and optimized in OPerA, the in-house conceptual design and optimization program based on a genetic algorithm. Objective function for the optimization are minimum Direct Operating Costs (DOC). Assumed is a price for hydrogen, energy-equivalent to kerosene and estimated for 2030 to be 1.12 USD/kg. All three versions stayed in feasible dimensions. The weight of the aircraft is decreased between 3.4% (A321-H19O) and 0.7% (A321-HSO). Depending on the version considered, the DOC of the aircraft is increased by 20% to 30%. Hydrogen aircraft do not show CO2 emissions, releasing only water vapor, NOx and particles into the air. However, water emitted at altitude can form cirrus clouds. This effect on global warming is presently not fully understood. The result: If fossil fuels get near to depletion and kerosene gets so scarce that the price of hydrogen matches that of kerosene, passenger air transport remains available with hydrogen-fueled minimum change conversions of existing aircraft types., https://dlrk2015.dglr.de

Beim Unfall von Germanwings 9525 waren ingenieurwissenschaftliche Aussagen auch ohne Insiderwissen möglich. Dies insbesondere basierend auf den früh verfügbaren Daten von FlightRadar24 und den öffentlich verfügbaren Daten zur A320 über Flugleistung und Flugzeugsysteme. Die vereinfachte statische Auswertung der Daten von FlightRadar24 anhand der Polare der A320 ermöglichte eine erste Einordnung und Überprüfung der Daten und förderte das Verständnis über den Sinkflug von 4U9525. Es konnte gezeigt werden, dass der Nicklagewinkel des Flugzeugs während des Sinkfluges 5°(nose down) nicht überschritten hat und die Passagiere daher wahrscheinlich zunächst wenig Anlass zur Besorgnis hatten. Die Übereinstimmung der Messwerte von FlightRadar24 und bekannten Charakteristiken einer funktionstüchtigen A320 kann aber in diesem Fall letztlich nur mit Hilfe einer dynamischen Betrachtung gezeigt werden. Eine flugwissenschaftliche Arbeitsweise konnte bei diesem Flugunfall frühzeitig weitere Erkenntnissen aus wenigen bekannten Fakten generieren. Schon vor der Pressekonferenz von Lufthansa-Chef Spohr (26.03.15, 14:56) konnte technisches Versagen des Flugzeugs bereits weitgehend ausgeschlossen werden. Ingenieure sollten sich daher mit ihrem Wissen verstärkt auch in die öffentliche Diskussion einbringen. Öffentlich zugängliche Informationen wie die von FlightRadar24 helfen dabei, die Bewertung eines Flugunfalls zu demokratisieren. Die Allgemeinheit ist damit nicht allein auf die gesteuert bereitgestellten Informationen der Luftfahrtindustrie angewiesen., https://dlrk2015.dglr.de

Task was to find an innovative aircraft design for a new medium range aircraft. The aircraft design methodology is based on equations (in contrast to numeric methods) and formal optimization with a genetic algorithm called differential evolution. Airbus has postponed an all-new A320 to 2025 or even 2030. This allows including also unconventional configurations into the search. Economic requirements are extreme: 25 % to 40 % reduction in fuel consumption, 35 % reduction in Cash Operating Costs. To achieve this, all aircraft design parameters have to be open for discussion. An aircraft called "The Rebel" is prepared to go to extreme parameters: low cruise speed, high wing span and long take-off and landing distance. Without new technologies it achieves 36 % reduced fuel consumption. The "Smart Turboprop" stays in conventional limits with its parameters, but makes use of a braced wing with natural laminar flow. It also achieves 36 % reduced fuel consumption plus a 17 % reduction in Direct Operating Costs (DOC). In addition, several Box Wing Aircraft where designed: Diamond Box Wing and Biplane Box Wing as Wide Body and alternatively as Slender Body. The Biplane Box Wing shows overall advantages due to its conventional tail. The details of Box Wing Aircraft design where mastered, but the Direct Operating Costs of the Box Wing Aircraft turned out to be higher than those of the A320 reference. This leaves the "Smart Turboprop" as the proposed configuration for an Airbus A320 replacement. As a short term measure, it is proposed to offer a horizontal wing tip extension as an option for the A320neo instead of the winglets. An extension with the same length as the winglet height offers far greater drag reduction. Airports will tolerate and accommodate some aircraft with a wing span above the ICAO limit in Class C of 36 m.

Since the dawn of aviation, cargo loading on aircraft has remained virtually constant. A person and a baggage cart together have been the primary method of loading baggage on to aircraft, and this practice has virtually remained unchanged, especially for narrow body aircraft. This study explores the question of whether a loading device, designed for Embraer 190 aircraft, can increase economic efficiency by reducing aircraft turnaround times, increasing aircraft utilization and reducing work hours. In the course of designing a theoretical loading device for an Embraer 190, various literature ranging from elaborate articulating conveyor belts, to the use of LD3-45W containers in Airbus 320 aircraft were analyzed. In the pursuit of understanding ground operations with containers, the study looked at the Boeing 767-300 and the Boeing 777-200LR to analyze the timeliness in which containers can be loaded and unloaded from an aircraft. With the goal of using common narrow body ground support equipment, time trials were done with a Purdue University baggage belt loader to see if loading a container on a conventional belt loader was feasible. To create a theoretical working container design, the LD3-45W boundaries in relation to the Airbus 320 aircraft cargo walls was scaled to match the Embraer 190s. With this scale, a container size could be derived, as well as volume, capacity, tare weight and maximum weight. In determining these various parameters, the amount of baggage that could be placed in 11 loading device containers was determined. With these figures an extensive comparison between loading baggage by hand and loading baggage utilizing containers, was analyzed.

Aquest projecte tracta sobre el desenvolupament d’un software que permeti enllaçar un simulador de vol i una cabina real de DC9, situada al Institut de la Illa dels Banyols al Prat de Llobregat - Barcelona. Mitjançant una llibreria externa al simulador, s’estableix una comunicació entre aquest i el programa en qüestió. Per una banda s’aconsegueix extreure les dades que es necessiten mostrar en la cabina del DC9 i per l’altra es poden generar certes fallades en el simulador a mode de pràctica per als estudiants que utilitzin el software. El programa ha estat desenvolupat mitjançant el llenguatge C# a través de la plataforma Microsoft Visual Studio 2010, versió 10.0.30319.1 RTMRel de ©2010 Microsoft Corporation. Anglès: This project is developing software capable of binding a flight simulator and a real DC9 cabin, located on the Island Institute of Banyols in Prat de Llobregat - Barcelona. Using an external library, it establishes a communication between the simulator and the program. On one hand, it extracts the data needed to show in the cabin of the DC9. On the other hand, certain faults can be generated in the simulator as a practice for students using the software. The program has been developed with C# language, through Microsoft Visual Studio 2010 platform, version 10.0.30319.1 RTMRel of ©2010 Microsoft Corporation.

El desarrollo de este TFC consiste en analizar la influencia de la carga de pago y el combustible en el centrado de una aeronave A320 y su influencia en el consumo. Como objetivo se pretende tambien evaluar la influencia que tiene el descentrado en la inclinación en el timon horizontal que conlleva y si este aspecto repercute de manera significativa en un aumento de la resitencia y consumo.