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Die besprühte alte Piper Aztec (PA23) hat eine geringere Umweltwirkung – 14,5 kg (äquivaltente) CO2 pro 100 km pro Sitzplatz – als ein neues Passagierflugzeug (z.B. A320neo): 18,9 kg äquivalente CO2 pro 100 km pro Sitzplatz. Das liegt daran, dass die Aztec tiefer fliegt. Ein Business Jet (z.B. Learjet 70/75) hat andere Zahlen: 64,7 kg äquivalente CO2 pro 100 km pro Sitzplatz.

Der "Arbeitskreis klimaneutrale Luftfahrt" beim Bundesministerium für Wirtschaft und Klimaschutz (BMWK) diskutiert auch zum Thema der Forschungsförderung. Der teilnehmende Staatssekretär aus dem BMDV setzt sich für solarbetriebene Flugzeuge ein. Doch die fliegen mit weniger als 100 km/h recht langsam und sind als Passagierflugzeug untauglich. Die Förderung von Forschungs- und Entwicklungsvorhaben im Rahmen des sechsten nationalen zivilen Luftfahrtforschungsprogramms – Dritter Programmaufruf (LuFo VI-3) – vom 25. April 2022 soll der klimaneutralen Luftfahrt deutlich mehr Schwung verleihen. So die Zielvorgabe aus dem grünen BMWK. Doch das BMWK wurde möglicherweise falsch beraten. Viele Ansätze sind gar nicht zielführend. Begriffe wie "emissionsfrei" und "klimaneutral" werden nicht definiert und werden daher auch nicht konsistent gebraucht. Das "Zero Emission Aircraft" kann es nicht geben. Es ist die werbewirksame Wortschöpfung eines Flugzeugherstellers. Im Call werden konkrete Technologien benannt, doch die korrekte Terminologie und Flugphysik bleibt auf der Strecke. Dabei geht es um Flugzeugkonfigurationen, Laminarströmung, Flügel hoher Streckung sowie um Böenlast- und Manöverlastminderung. Das BMWK nimmt sich der Kondensstreifen an, aber die Zielvorgabe ist nicht klar definiert. Gerade bei der Aviation Induced Cloudiness (AIC) könnte man sofort handeln, jedoch ist im LuFo-Aufruf eine Tendenz erkennbar, der Industrieposition nachzugeben und Handeln aufzuschieben. Das BMWK meint, dass Urban Air Mobility (UAM) den Personentransport sukzessiv bis 2035 revolutionieren wird und dass es besser wäre, Verkehrsflugzeuge ohne Piloten fliegen zu lassen. So etwas sollte nicht als feste Tatsache hingestellt werden, sondern besser erst diskutiert werden. Auch der Klima- und Transformationsfonds (KTF) fördert u.a. die Luftfahrt. Gefördert werden Erzeugungsanlagen für strombasierte Kraftstoffe, Antriebstechnologien und Bodenstromanlagen an Flughäfen. Das sind grundsätzlich richtige und wichtige Themen. Im Detail muss genau untersucht werden, was die Industrie gefördert haben möchte. Nicht alle Vorschläge werden halten, was versprochen wird. Im Unterschied dazu wären einfache Verbesserungen in der Luftfahrt möglich, die noch nicht einmal etwas kosten müssen. Der Kraftstoffverbrauch von Flugzeugen muss einheitlich definiert werden. Flugzeughersteller sind anzuweisen den Kraftstoffverbrauch ihrer Flugzeuge anzugeben. Jedes Flugzeug eines Herstellers (Flugzeugmuster, Triebwerkstyp, Standardkabinenlayout) oder einer Fluggesellschaft (gewähltes Kabinenlayout) sollte sein vergleichendes "Ecolabel for Aircraft" in Stil des EU-Energielabels erhalten. Damit wird ein systematischer Vergleich von Passagierflugzeugen ermöglicht. Flugzeugentwürfe sollten auf nachvollziehbaren Rechnungen und/oder Messungen basieren und in einem einheitlichen Layout aussagekräftig kommuniziert werden. Wenig hilfreich sind im Gegensatz dazu lediglich künstlerisch ausgestaltete Flugzeugbilder (artist's impressions oder concept planes). Greenwashing sollte öffentlich geächtet werden. Vorbild ist die Advertising Standards Authority (ASA) aus UK., Internes Fachgespräch "Luftfahrtforschungsprogramm, Klima- und Transformationsfonds", Online, Bundestag, 13.12.2022, 12:30 – 14:00

Truth decay and compromised ethical behavior can be observed when looking back into the history of the aviation industry. The author has presented since 2012 about related questionable views and behavior. In this presentation he compiles the "best" of his slides into one lecture that tries to give an overview of the problem at hand. Commercial aviation provides one of the strongest examples of Jevons Paradox, nevertheless the aviation industry keeps praising efficiency gains as the way to safe fuel and emissions on a global scale. Questionable goal setting with respect to aviation emissions started as early as 2000. Inside the aircraft another problem exists: contaminated aircraft cabin air. Here, the aviation industry rather fights claims of victims in court instead of working on a technical solution. The idea of massive use of air taxies is as old as 1899, but has still not come. Eventually it will most probably be a polluting means of transportation for the super-rich. Battery electric aviation has a clear range limit. Proposals that deny this fact are green washing. Grid-connected electric mobility operates successfully on tracks e.g. as high-speed trains. Claims for a large number of propellers may have been made without looking at certification rules and geometry. The year 2020 came. Those waiting to see a difference in aviation (massive CO2-compensation by the industry) to fulfill at last aviation's goal setting promise of Carbon Neutral Growth (CNG) saw – nothing. However, the Corona pandemic came after two month into the year 2020. Most aircraft rested on the ground. Subsequently, passengers saw more legends than truth about cabin ventilation. The legends were distributed by the aviation industry in an effort to retain at least a minimum of revenues. IATA turned out to be the biggest liar among all. Airbus chief engineer Jean-Brice Dumont was given the new title "guru" and explained cabin ventilation on Facebook. Emirates presented two highly protected technicians mounting a new and clean HEPA filter on an A380. Still in the same year the next legend was presented by Airbus: Aircraft burning hydrogen in jet engines would produce "zero emissions". In contrast to science, this would mean no NOx and no contrails. After the pandemic, industry could not wait to see air traffic reaching again 2019 levels and old growth figures. It was still not understood that instead a reduction in air traffic would be necessary to reach proclaimed goals. It was also not understood that regenerative energy would need to be used first to substitute coal power plants and that massive aviation regenerative electricity demands for LH2 and SAF had no chance to be addressed by society. Aviation would need to produce its green energy itself. Time scales slipped or turned out to have been lies in the first place. 2021 was the year to look back at the "money burning" A380 project. This reminded us that Airbus lied already 20 years ago when demanding a runway extension in Hamburg-Finkenwerder for the A380. The extension was not necessary, but was built (from public money) anyway and against much protest from local population and their precise engineering/aviation arguments. Aviation ethics can be summed up under: "G^4", which stands for "Continuous Growth to increase Gain to satisfy shareholders expectations can lead to Greed and to an ever more ruthless industry behavior accumulating Guilt in the end." Some aviation organizations seem not to be willing to abide by the law, even if enforced and with consequences leading to the end of company existence. Boeing gambled with saving a second angel-of-attack sensor on the B737 MAX, resulting in two crashes and 346 people dying. Airbus paid 3.6 Billion Euro penalty due to bribery. The aviation industry is far from abidance by the law and even further away from taking up the code of a respectable / honorable businessman. The list of unethical issues in the aviation industry is long., SARC Friday Club

Die Berechnungen zur Verlängerung der Start- und Landebahn in Hamburg-Finkenwerder für den A380 führten in den Jahren 2002 bis 2006 zu Unverständnis und Unzufriedenheit der Anwohner des anliegenden Dorfes Neuenfelde. Organisiert in einer Bürgervertretung stellten sie die Notwendigkeit für die Verlängerung infrage. Airbus hatte bei der Gesellschaft für Luftverkehrsforschung (GfL) ein Gutachten in Auftrag gegeben. Besonders unverständlich war die von Airbus geforderte Landemasse von 410 t (66 % MTOM, 96% MLM), die zudem auf einer um 30 t zu hohen Startmasse basierte. Für 410 t ergab sich nach Airbus-Daten eine erforderliche Landestrecke von 1990 m. Auch damit wäre die damalige verfügbare Landestrecke (auf der Bahn 23) von 2684 m - 478 m = 2206 m ausreichend gewesen und die Bahnverlängerung damit unnötig.

Every aircraft produces wake turbulence during flight. The strength of wake turbulence depends on various factors, for example aircraft mass, wingspan, speed or wing geometry. However, FAA, EUROCONTROL and ICAO consider only aircraft mass and wingspan for categorization of aircraft wake turbulence. In this approach, other variables related to flight mechanics and aircraft design are used to calculate induced power. Based on these calculations, new aircraft wake turbulence categories are presented and compared to FAA, EUROCONTROL and ICAO categories.

Nur 14 Jahre nach der Erstauslieferung wird die Produktion des größten Passagierflugzeuges der Welt eingestellt. Mit der letzten Auslieferung am 16.12.2021 an Emirates hob der letzte neu produzierte A380 vom Airbus Werksgelände in Hamburg-Finkenwerder ab. Eine kurze Zusammenfassung über die geschichtliche Entwicklung des Projekts A380 und dessen Auswirkung auf die Stakeholder.

Ob auf der Straße, der Schiene oder in der Luft, am Department Fahrzeugtechnik und Flugzeugbau faszinieren uns Fahrzeuge, Flugzeuge und die in diesen integrierten mechatronischen Systeme. Das Ziel der Ausbildung am Department ist die Befähigung zur selbstständigen Anwendung von wissenschaftlichen und praxisnahen Methoden aus dem Bereich der Entwicklung und Konstruktion von Straßen-, Schienen- und Luftfahrzeugen aller Art.

In Flugzeugen wird die Maskenpflicht nicht wie ursprünglich geplant verschärft, sondern zum Oktober 2022 abgeschafft. In der Bahn soll sie bestehen bleiben. Die Argumente, die dazu geführt haben, sind wissenschaftlich nicht nachzuvollziehen.

Collection of Memoranda from AERO. A memorandum is a note with something memorable, in short a memo. It can be a short technical description or an opinion piece. The word is of Latin origin: memorandum literally means "that which is to be remembered". The plural is memoranda.

Kein anderes Verkehrsmittel erzeugt pro Person und Zeit eine so hohe Klimawirkung wie ein Passagierflugzeug. Alle diskutierten Lösungen (Wasserstoff, synthetischer Kraftstoff) haben ihre Probleme. Eine wirkungsvolle Senkung der Emissionen der Luftfahrt kann nur durch eine Reduktion des Luftverkehrs erfolgen. Wenn keine Verbote ausgesprochen werden sollen und können, sollte zumindest das Vielfliegen nicht weiter gefördert werden. Vielfliegerprogramme mögen für die Fluggesellschaften Kundenbindung bringen, sind aber in Zeiten des Klimawandels nicht mehr zeitgemäß und gehören auf den Prüfstand. Im Extremfall führen sie zu suchtartigem Verhalten, wenn „Mile Runners“ sich mit ihrem Vielfliegerstatus aufwerten wollen., https://www.dglr.de/informieren/magazin

Purpose – The presentation summarizes the state-of-the-art in aircraft end-of-life strategies. Methodology – A literature review is the basic research method utilized. A visit to a dismantling site complemented the findings. Journeys and the Internet show examples of special reuse approaches giving aircraft and components a second life. Findings – In the past aircraft went to "boneyards" at their end-of-live where they were simply left on their own. This should be avoided in the future. Instead aircraft are initially parked and stored. If no further operation is possible, aircraft are dismantled. Components and material is recycled as far as possible. The rest is disposed. Research has been done on the topic by Airbus, Boeing, other industrial companies, and academic institutions. The aircraft recycling industry starts to build up now by the launch of several recycling plants. The aircraft recycling market will slowly mature with associations like the Aircraft Fleet Recycling Association (AFRA) and with the publication of guidance material for best practices. The significant higher percentage of composites in modern aircraft types is a challenge for aircraft recycling. Special reuse approaches are only a niche market and not able to cope with the number of aircraft that need to be decommissioned each year. Value – The presentation gives a year 2022 overview on the state-of-the-art of aircraft end-of-life handling with many pictures., Hamburg Aerospace Lecture Series --- Collection of Presentations --- http://www.AeroLectures.de

Die Förderung von Forschungs- und Entwicklungsvorhaben im Rahmen des sechsten nationalen zivilen Luftfahrtforschungsprogramms – Dritter Programmaufruf (LuFo VI-3) – vom 25. April 2022 soll der klimaneutralen Luftfahrt deutlich mehr Schwung verleihen. So die Zielvorgabe aus dem neuerdings grünen Bundesministerium für Wirtschaft und Klimaschutz (BMWK). Doch das BMWK wurde möglicherweise falsch beraten. Viele Ansätze sind gar nicht zielführend. Begriffe wie "emissionsfrei" und "klimaneutral" werden nicht definiert und werden daher auch nicht konsistent gebraucht. Das "Zero Emission Aircraft" kann es nicht geben. Im Call werden konkrete Technologien benannt, doch die korrekte Terminologie und Flugphysik bleibt auf der Strecke. Dabei geht es um Flugzeugkonfigurationen, Laminarströmung, Flügel hoher Streckung sowie um Böenlast- und Manöverlastminderung. Das BMWK nimmt sich der Kondensstreifen an, aber die Zielvorgabe ist nicht klar definiert. Gerade bei der Aviation Induced Cloudiness (AIC) könnte man sofort handeln, jedoch ist im LuFo-Aufruf eine Tendenz erkennbar, der Industrieposition nachzugeben und Handeln aufzuschieben. Das BMWK meint, dass Urban Air Mobility (UAM) den Personentransport sukzessiv bis 2035 revolutionieren wird und dass es besser wäre Verkehrsflugzeuge ohne Piloten fliegen zu lassen. So etwas sollte nicht als feste Tatsache hingestellt werden, sondern besser erst diskutiert werden.

Zweck – Darstellung der Hintergründe und der konkreten Möglichkeiten zur Minimierung der Umweltwirkung bei einer Dienstreise mit dem Flugzeug. Methodik – Zusammenfassung eigener Forschungsergebnisse und weiterer Informationen. Ergebnisse – Die Umweltwirkung durch die zivile Luftfahrt ist erheblich und extrem ungleich verteilt. Sie wird fast vollständig verursacht von wohlhabenden Bevölkerungsschichten in reichen Staaten. Hier sind insbesondere die Vielflieger zu nennen. Urban Air Mobility ist für die Eliten, bietet keine Vorteile für die Umwelt und ändert nichts an den Staus in der Stadt. Kurzstrecken sollten mit der Bahn zurückgelegt werden. Für Mittelstrecken zwischen Megacities bieten Hochgeschwindigkeitszüge viele Vorteile. Wir haben in der Luftfahrt weniger ein CO2-Problem als mehr ein Problem der Erderwärmung durch Wolkenbildung aufgrund von Kondensstreifen (Aviation-Induced Cloudiness, AIC). Das größte Umweltthema ist aber wohl das der Trinkwasserversorgung, die jedoch mit der Erderwärmung und der Abnahme der fossilen Energieressourcen verbunden ist. Das Trinkwasserproblem wird daher durch die Luftfahrt verstärkt. Die Wahl des Verkehrsmittels kann man bereits nach den physikalischen Grundprinzipien vornehmen. Das System Rad-Schiene hat hier einen klaren Vorteil. Der Kraftstoffverbrauch von Flugzeugen ist nicht normiert. Eine Berechnungsformel wird vorgeschlagen und dargestellt, mit welchen einfachen öffentlichen Angaben der Kraftstoffverbrauch von Flugzeugen abgeschätzt werden kann. Die Umweltwirkung ist von der Flugstrecke abhängig und von der Flughöhe. Durch niedrigeres Fliegen könnte die Umweltwirkung stark verringert werden. Vorgestellt werden die Parameter, mit denen jeder Flugreisende seine Umweltwirkung verringern kann. Verschiedene Bewertungstools für eine Flugreise stehen zur Verfügung. Das "Ecolabel for Aircraft" bewertet ein Flugzeug. Eine Flugreise sollte, so weit möglich, als Direktflug gewählt werden. Verschiedene Buchungstools stehen im Internet zur Verfügung, die auch den CO2-Ausstoß angeben. Wenn ein Flug nicht vermieden werden kann, dann können die nach der Optimierung verbliebenen äquivalenten CO2 kompensiert werden. Soziale Bedeutung – Kenntnisse über die Umweltwirkung der Luftfahrt können helfen, eine Flugreise zu optimieren oder auf einen anderen Verkehrsträger zu verlagern, unabhängig von den (Werbe-)Aussagen einzelner Anbieter., "Mittagsgespräch" im Bundesministerium für wirtschaftliche Zusammenarbeit und Entwicklung (BMZ), Online, 17.03.2022, 12:00 – 13:00

Purpose: This paper discusses potential contamination of the air in passenger aircraft cabins. It gives an overview of cabin air contamination basics. It further names possible contamination sources and possible routes of contamination. Methodology: Evidence follows from a review of material found on the Internet and from the documentation of a visit to an aircraft recycling site. Parts were retrieved at the site and investigated later with more time. Findings: Jet engine seals leak oil in small quantities. Metallic nanoparticles are found in the oil and have been detected in human fatty tissue of aviation workers. It has been observed that the potable water on board can also be contaminated. Oil traces have been found in bleed ducts, air conditioning components, and in air conditioning ducts. Deicing fluid and hydraulic fluid can find their way into the air conditioning system via the APU air intake. Fuel and oil also leak down onto the airport surfaces. These fluids can be ingested by the engine from the ground and can enter the air conditioning system from there. Entropy is the law of nature that states that disorder always increases. This is the reason, why it is impossible to confine engine oil and hydraulic fluids to their (predominantly) closed aircraft systems. This is why engine oil with metal nanoparticles hydraulic fluids, and deicing fluids eventually can go everywhere and finally into the human body. Research Limitations: No measurements have been made. Practical Implications: Awareness and prevention of contaminated cabin air can protect passengers and crew. Social Implications: The exposure of contaminated cabin air provides a basis for a general discussion and shows that people should be alerted and need to act. New technologies need to be implemented such as a bleed free architecture. Originality: This paper shows many original images of contaminated parts and air ducts between engine compressor and cabin air outlet. Own observations are combined with similar observations found in literature and online. The collected evidence is visualized in a diagram showing the routes of possible aircraft cabin air (and water) contamination.

Following the successful initial Special Issue on "Aircraft Design (SI-1/2017)" and the relaunch with "Aircraft Design (SI-2/2020)", this is already the third SI in sequence named "Aircraft Design (SI 3/2021)". Activities in the past showed that aircraft design may be a field too small to justify its own (subscription-based) journal. A continuous open access special issue may fill the gap. As such, the Special Issue "Aircraft Design" can be a home for all those working in the field who regret the absence of an aircraft design journal. SI-3/2021 contains six papers (original research articles) about 1.) Oil Fumes in the Cabin and Flight Safety, 2.) Closed-Loop Flying Qualities Requirements, 3.) Preliminary Design of a Medium Range Box Wing Aircraft, 4.) Influence of Novel Airframe Technologies on the Feasibility of Fully-Electric Regional Aviation, 5.) Design and Optimization of a Large Turboprop Aircraft, 6.) Sources of Onboard Fumes and Smoke.

The aim of the current paper is to present a flutter analysis of a 3-D Box-Wing Aircraft (BWA) configuration. The box wing structure is considered as consisting of two wings (front and rear wings) connected with a winglet. Plunge and pitch motions are considered for each wing and the winglet is modeled by a longitudinal spring. In order to exert the effect of the wing-joint interactions (bending and torsion coupling), two ends of the spring are located on the gravity centers of the wings tip sections. Wagner unsteady model is used to simulate the aerodynamic force and moment on the wing. The governing equations are extracted via Hamilton���s variational principle. To transform the resulting partial integro-differential governing equations into a set of ordinary differential equations, the assumed modes method is utilized. In order to confirm the aerodynamic model, the flutter results of a clean wing are compared and validated with the previously published results. Also, for the validation, the 3-D box wing aircraft configuration flutter results are compared with MSC NASTRAN software and good agreement is observed. The effects of design parameters such as the winglet tension stiffness, the wing sweep and dihedral angles, and the aircraft altitude on the flutter velocity and frequency are investigated. The results reveal that physical and geometrical properties of the front and rear wings and also the winglet design have a significant influence on BWA aeroelastic stability boundary., Preprint of an article published in International Journal of Structural Stability and Dynamics, vol. 22, no. 02, pp. 2250016-1 ��� 2250016-24. https://doi.org/10.1142/S021945542250016X. �� 2021, World Scientific Publishing Company, https://www.worldscientific.com/worldscinet/ijssd, https://www.worldscientific.com/page/authors/author-rights

We consider that use of SAF is mainly a question of its availability and price. For engineers, it is a matter of sourcing primary energy involved in producing SAF- not to forget that SAF is only sustainable, if the CO2 is really taken out of the atmosphere in fuel production, which is intended to be put back into the atmosphere during flight. LH2 requires new (or modified) aircraft that are less efficient than conventional aircraft. Calculations show about 40% more fuel consumption (by energy) for LH2. This adds to the demand of LH2 for sourcing more primary energy. Batteries for electric flights suffer from their weight (as we already know). In addition, there are interesting aircraft design questions arising from issues such as: higher number of propellers and propeller integration into the airframe. It is explained, why hybrid electric or turbo electric solutions have clear disadvantages. There are also the non-CO2 effects. Here we shall consider flying lower with LH2 and also kerosene/SAF aircraft., RAeS Conference: Alternative Propulsion Systems – the Challenges and Opportunities for Aircraft Design

Zweck ��� Dieser Vortrag untersucht die sozialen Auswirkungen von Flugzeugen oder Flugzeugprojekten mit einem Lebenszyklusansatz am Beispiel des Programms Airbus A380. Methodik ��� Soziale Auswirkungen werden analysiert, indem eine Social Life Cycle Assessment (S-LCA) basierend auf den "Guidelines for Social Life Cycle Assessment for Products" des Umweltprogramms der Vereinten Nationen (UNEP) und der Society of Environmental Toxicology and Chemistry (SETAC) durchgef��hrt wird. Stakeholder und Unterkategorien werden ausgew��hlt und Daten werden mit qualitativen Interviews und Webrecherchen gesammelt. Eine Folgenabsch��tzung wird mit der Subcategory Assessment Method (SAM) durchgef��hrt. Die Ergebnisse werden interpretiert und verallgemeinert. Ergebnisse ��� W��hrend seiner Lebensdauer hat ein Flugzeug oder Flugzeugprogramm Auswirkungen auf verschiedene Interessensgruppen. Die Lebenszyklusphase "Rohstoffgewinnung" k��nnte zu Menschenrechtsverletzungen f��hren, aber auch lokale Gemeinschaften in der N��he der wichtigsten Produktionsst��tten sind mit sozialen Auswirkungen konfrontiert, sowohl positiv als auch negativ. Die wirtschaftliche Bedeutung des Luftfahrtsektors beeinflusst die Gesellschaft, politische Entscheidungstr��ger, lokale Gemeinschaften und Arbeitnehmer. All dies zeigte sich auch im A380-Programm. Grenzen der Anwendbarkeit ��� Die Datenverf��gbarkeit schr��nkte die Untersuchung teilweise ein. Das Projekt deckt nicht alle Lebenszyklusphasen und Interessensgruppen ab. Stattdessen liegt der Fokus auf ausgew��hlten Phasen und Gruppen. Bedeutung in der Praxis ��� Die Studie kann Entscheidungstr��gern in der Luftfahrt helfen, ein Produkt bereitzustellen, das das Wohlergehen seiner Interessensgruppen verbessert. Soziale Bedeutung ��� Die Durchf��hrung einer S-LCA in der Luftfahrt r��ckt die sozialen Implikationen des Flugzeugprogramms in den Fokus und bietet eine Grundlage f��r eine allgemeine Diskussion ��ber seine soziale Nachhaltigkeit. Originalit��t ��� Dies scheint die erste Arbeit zum Thema S-LCA eines Flugzeugs oder Flugzeugprogramms zu sein., Hamburg Aerospace Lecture Series --- Collection of Presentations --- http://www.AeroLectures.de

Purpose – Reach awareness about the strategy of the aviation industry (manufacturers, airlines, organizations) when faced with restrictions from government. Internal emissions (corona virus) and external emissions (CO2, NOX, AIC) are the threats today. Approach – Industry published information during the corona pandemic as well as related to aviation and climate change is collected from the Internet and set against scientific evidence. Findings – Internal emissions: HEPA filters in aircraft do not produce cabin air "as clean as in a hospital operating theater". External emissions: The goal "zero emission" is proclaimed, but it becomes evident already now that measures are not sufficient and dates will not be met to come even close to set goals. Sustainable aviation fuel (SAF) is very energy intensive. Non-CO2 effects from aircraft burning hydrogen in jet engines must not be ignored. SAF will only make aircraft climate neutral when about 3 times more CO2 is captured with Direct Air Capture (DAC) then emitted. This is necessary to account for the non-CO2 effects. Research limitations – The presentation is based on examples. Practical implications – The public gets ill informed. Therefore, it is important so set the record straight. In addition, the strategy used by the aviation industry is exposed. Social implications – The discussion opens up the topic beyond aviation expert circles. Originality – Not much comparable information is given by other authors., German Aerospace Congress 2021 (DLRK 2021), Online, 01 September 2021--- https://publikationen.dglr.de/?tx_dglrpublications_pi1[document_id]=550292

Passenger aircraft occasionally encounter a Cabin Air Contamination Event (CACE). When these events make themselves know with a distinct smell they are called Smell Events. When they are evident even by smoke (and smell), they are called Fume Events. The objectionable classical cabin air contamination from "bleed", "engine oil", "hydraulic fluid", and "deicing" accounts together for roughly 1/3 of the events. Oil has left traces on its way from the engine to the cabin interior: In bleed air ducts, air conditioning ducts, in recirculation filters, on cabin surfaces (wall panels, seats ...). Hydro carbon concentrations in the cabin can be calculated and agree with measurements. SAE has highlighted the risk of obtaining contaminated air from the engine compressor. It may preclude its use for transport aircraft, regardless of other good reasons. Nevertheless, aviation organizations like IATA claim that "Cabin air is as clean as a hospital operating theatre". Cabin air ventilation in passenger aircraft is done with outside air. At cruise altitude, ambient pressure is below cabin pressure. Hence, the outside air needs to be compressed before it is delivered into the cabin. The most economic system principle simply uses the air that is compressed in the engine compressor anyway and taps some of it off as "bleed air". The engine shaft is supported by lubricated bearings. They are sealed against the air in the compressor usually with labyrinth seals. Unfortunately, the jet engine seals leak oil by design in small quantities. The oil leaking into the compressor contains toxic additives. Furthermore, the oil includes toxic metal nanoparticles – normal debris from the engine. An alternative source for the compressed air is the Auxiliary Power Unit (APU). Like the aircraft's jet engine, it is a gas turbine, built much in the same way when it comes to bearings and seals. For this reason, also compressed air from the APU is potentially contaminated in much the same way. Compressed air from the engine is also used to pressurize the potable water. It has been observed that the potable water on board can also be contaminated. Fan air and bleed air ducts at the interface between engine and wing carry outside compressed air. The inside of the ducts shows differences. The brown stain in the bleed air duct appears to be engine oil residue. In comparison, the fan air duct is clean. This shows that oil leaves the compressor bearings. Ducting further downstream shows a black dry cover. The reason for the change in color seems to result from the different air temperatures: 400 °C at engine outlet and 200 °C further downstream behind the precooler. The water extractor is a part of the air conditioning pack. The inlet of the water extractor is covered with black oily residue, because the temperature is even lower at this point. The air conditioning air distribution ducts in the cabin are black inside from contaminated bleed air. New ducts are clean. Air duct are even clean inside at the end of the aircraft's life, in areas where they are used such that no bleed air flows through them. Flow limiters have been found in ducts of the air conditioning system that are clogged from engine oil. Also riser ducts feeding the cabin air outlets are black inside from engine oil residue. Cleaning on top of the overhead bins brings to light dirt that is clearly more than dust. The black residue known from the ducts settles also on the bin surface. Deicing fluid and hydraulic fluid can find their way into the air conditioning system via the APU air intake. A fence and a deflector around the air intake cannot fully prevent contaminants from entering the APU. Traces of contamination tend to be visible on the lower part of the fuselage. Contaminants are carried by the air flow in flight, from the landing gear bay to the APU inlet. Hydraulic systems are never leak free. A hydraulic seal drain system tries to collect hydraulic fluid leaving the system with partial success. It is impossible to catch all leaking hydraulic fluid. If the containers of the seal drain system are not emptied they spill over. In old aircraft, surfaces in the landing gear bay are covered with a layer of hydraulic fluid. Dirt accumulates on the sticky surface. The hydraulic fluid is not confined to the inside of hydraulic bays, but continues its journey on the lower side of the fuselage towards the APU. Deicing fluid if applied in the winter to the aircraft and can leak from the tail into the APU inlet. Fuel and oil also leak down onto the airport surfaces. These fluids can be ingested by the engine from the ground and can enter the air conditioning system from there. Entropy is the law of nature that states that disorder always increases. This is the reason, why it is impossible to confine engine oil and hydraulic fluids to their (predominantly) closed aircraft systems. This is why engine oil with metal nanoparticles hydraulic fluids, and deicing fluids eventually go everywhere and finally into the human body. Filtration can help to avoid cabin air contamination. HEPA filters are in use with most passenger aircraft that work with recirculated air. Only HEPA carbon filters can also filter some of the Volatile Organic Compounds (VOCs). They are available for only some aircraft types and only lead to about 40% reduction of the concentration of VOCs in the cabin. Necessary would be to filter the incoming air from the engine compressor. Filter manufacturer Pall has worked on such a total air filtration option for the Airbus A320 for several years, but is so far not able to offer the new system. For this reason, we are left with a situation, where engines are longer and longer on the wing without the chance to replace engines seals that get worn out more the longer the engine is operated. This leads to an increasing number of CACEs. Airbus duct cleaning maintenance procedures after a CACE are ineffective. Aircraft released back into service over night after an (oil based) CACE are not cleaned as instructed by Airbus, because ducts cannot be removed from behind the panels in this short time, the inside of ducts is not accessible, and most of the deposit are firmly attached to the surface and cannot be removed. This leaves the passengers in a situation for which the degree of contamination is unknown but real. Strictly, the amount of oil in the cabin cannot be determined from the oil consumption of the engine. For legal benefit of the aviation industry, sensors are missing on board and deprive passengers and crew from data that could be used in court., Hearing of Prof. Dr. Scholz on the operation of air conditioning in aircraft cabins and the associated air quality. The hearing was on July 8th, 2021, from 9h30 to 11h30, by video conferencing.

Purpose– Reach awareness that the aviation industry (manufacturers, airlines, organizations) is lying about cabin ventilation on board of passenger aircraft. Approach – Industry information published during the corona pandemic is collected from the Internet and set against scientific evidence. --- Findings – HEPA filters in aircraft do not produce cabin air "as clean as [in] a hospital operating theatre". Viruses and other substances like CO2 are generated in the cabin and need to be washed out. Their concentration follows from their source strength and the ventilation air flow rate. Aircraft cabin air is not "fully renewed in 2 to 3 minutes". It takes several such air changes to reach 1% of the initial concentration. The air change rate is not even relevant for the concentration of e.g. viruses or CO2 in the cabin. The "air flow in the cabin" is not "only flow from top to bottom". The air is mixed within several rows and beyond. --- Research limitations – Neither the industry campaign nor the literature on (aircraft cabin) ventilation is fully explored. Only examples are given to illustrate how the aviation industry deceived politics and the public for their economic advantage. --- Practical implications – Learning from the past to be prepared for similar manipulation in the future. Importance to question any given information – also this one. --- Social implications – The discussion opens up the topic beyond aviation expert circles. --- Originality – Not much comparable information is given by other authors., Hamburg Aerospace Lecture Series --- Collection of Presentations --- http://www.AeroLectures.de

In order to produce thrust, the air needs to be accelerated by the propulsor (the propeller or the jet engine). The more the air gets accelerated from flight speed v = v_1 to exit speed v_4 (i.e. the higher v_4/v_1), the lower the efficiency. However, without accelerating the air, no power or thrust is produced. The efficiency depends on the non-dimensional thrust, called thrust loading, c_S, which is a function of aircraft speed. Disc loading k_P is calculated from power, P air density, rho and propeller disc area, A_S. k_P is independent of speed and as such a good characteristic parameter of a propeller. Together, this makes the propulsive efficiency a function of disc loading, k_P and flight speed, v. Further losses come from angular momentum. The efficiency calculated considering angular momentum in addition dependents on the ratio of forward speed, v and tip speed u (v/u). A constant speed propeller can run at a favorable speed for the piston or turboprop engine at a limited Mach number of the blade tips. At higher speeds, v and also v/u increases and hence required engine torque. This increases the angular momentum and reduces the efficiency. At low speeds, the ratio v_4/v_1 gets unfavorably high and the efficiency is low. At zero speed v_4/v_1 goes to infinity and the efficiency to zero. For an example calculation, optimum efficiencies were obtained at v/u between 3 and 5 depending on disc loading. Not considered is the limited lift-to-drag ratio (L/D) of the propeller blades and losses at blade tip (which could be accounted for by a performance factor between 0.85 and 0.9).

From a fundamental consideration of the efficiency (eta = P_out / P_in) it already follows that the power-specific fuel consumption, PSFC or c_P of an aircraft engine should be approximately constant, while c = c_P * V applies to the thrust-specific fuel consumption, TSFC or c in a first approach. Obviously, fuel is consumed already at static thrust (V=0). For this reason the thrust-specific fuel consumption needs an extended approach c = c_a + c_b * V. Breguet's range equation can certainly be described with a constant thrust-specific fuel consumption c, if c is determined for the cruise speed in question. However, this leads to an error if you want to use it to calculate an optimal flight speed in a flight performance calculation. It is recommended (for a first simple consideration) to write Breguet's range equation for jets with a constant power-specific fuel consumption c_P. This then leads to an optimal cruising speed for maximum range at minimum drag (md) V_md instead of 1.316 * V_md as it is determined with the "classic" derivation. For more detailed considerations, the "Herrmann model" should replace the simple equation c = c_a + c_b * V.

Purpose of this review is to understand how to find values for three input parameters for the calculation of the oil concentration in aircraft cabins. These are the number of bearings of the jet engine and the number of them upstream of the bleed air ports as well as the oil consumption per hour. ---Methodology is an Internet review of related facts. ---Findings: Jet engine schematics are available online and can be interpreted to find the number of bearings.Values for the CFM56 engine are 5 bearings with 3 of them upstream of the bleed port. Oil consumption should be assumed to be 0.3 L/h for the CFM56 engine.Rates for selected other engines are also given. ---Research limitations are due to the fact that detailed company data is not available and own measurements can not be made on passenger jets.

Ventilation on board of an aircraft is governed by the ventilation equation. In the steady state case, a concentration of any substance depends only on the source strength and the effective air flow rate for ventilation. Not all air for ventilation is effective and helps to lower concentration. Some air leaves the cabin without mixing and rinsing. This is expressed by the ventilation efficiency. The dynamics follows an exponential function and is expressed by a time constant that depends on the air change rate and the ventilation efficiency. The (theoretical) air change rate is the air flow rate divided by the volume of the room. With full mixing (i.e. ventilation efficiency of 1), the concentration is reduced to 36.8% after one air change.

Purpose: This conference paper discusses potential contamination of the air in passenger aircraft cabins. It gives an overview of cabin air contamination basics. It further names possible contamination sources and possible routes of contamination. Methodology: Evidence follows from a review of material found on the Internet and from the documentation of a visit to an aircraft recycling site. Parts were retrieved at the site and investigated later with more time. Findings: Jet engine seals leak oil in small quantities. Metallic nanoparticles are found in the oil and have been detected in human fatty tissue of aviation workers. It has been observed that the potable water on board can also be contaminated. Oil traces have been found in bleed ducts, air conditioning components, and in air conditioning ducts. Deicing fluid and hydraulic fluid can find their way into the air conditioning system via the APU air intake. Fuel and oil also leak down onto the airport surfaces. These fluids can be ingested by the engine from the ground and can enter the air conditioning system from there. Entropy is the law of nature that states that disorder always increases. This is the reason, why it is impossible to confine engine oil and hydraulic fluids to their (predominantly) closed aircraft systems. This is why engine oil with metal nanoparticles hydraulic fluids, and deicing fluids eventually can go everywhere and finally into the human body. Research Limitations: No measurements have been made. Practical Implications: Awareness and prevention of contaminated cabin air can protect passengers and crew. Social Implications: The exposure of contaminated cabin air provides a basis for a general discussion and shows that people should be alerted and need to act. New technologies need to be implemented such as a bleed free architecture. Originality: This paper shows probably more images with parts upstream of the engine compressor contaminated by leaking engine oil than any previous publication., This is a publication from the International Aircraft Cabin Air Conference 2021 (Online, 15-18 March 2021)

Cabin air ventilation in passenger aircraft is done with outside air. At cruise altitude, ambient pressure is below cabin pressure. Hence, the outside air needs to be compressed before it is delivered into the cabin. The most economic system principle simply uses the air that is compressed in the engine compressor and taps some of it off as "bleed air". The engine shaft is supported by lubricated bearings. They are sealed against the air in the compressor usually with labyrinth seals. Unfortunately, the jet engine seals leak oil by design in small quantities. The oil leaking into the compressor contains toxic additives. Furthermore, the oil includes toxic metal nanoparticles ��� normal debris from the engine. An alternative source for the compressed air is the Auxiliary Power Unit (APU). Like the aircraft's jet engine, it is a gas turbine, built much in the same way when it comes to bearings and seals. For this reason, also compressed air from the APU is potentially contaminated in much the same way. Compressed air from the engine is also used to pressurize the potable water. It has been observed that the potable water on board can also be contaminated. Fan air and bleed air ducts at the interface between engine and wing carry outside compressed air. The inside of the ducts shows differences. The brown stain in the bleed air duct appears to be engine oil residue. In comparison, the fan air duct is clean. This shows that oil leaves the compressor bearings. Ducting further downstream shows a black dry cover. The reason for the change in color seems to result from the different air temperatures: 400 ��C at engine outlet and 200 ��C further downstream behind the precooler. The water extractor is a part of the air conditioning pack. The inlet of the water extractor is covered with black oily residue, because the temperature is even lower at this point. The air conditioning air distribution ducts in the cabin are black inside from contaminated bleed air. New ducts are clean. Air duct are even clean inside at the end of the aircraft's life, in areas where they are used such that no bleed air flows through them. Flow limiters have been found in ducts of the air conditioning system that are clogged from engine oil. Also riser ducts feeding the cabin air outlets are black inside from engine oil residue. Cleaning on top of the overhead bins brings to light dirt that is clearly more than dust. The black residue known from the ducts settles also on the bin surface. Deicing fluid and hydraulic fluid can find their way into the air conditioning system via the APU air intake. A fence and a deflector around the air intake cannot fully prevent contaminants from entering the APU. Traces of contamination tend to be visible on the lower part of the fuselage. Contaminants are carried by the air flow in flight, from the landing gear bay to the APU inlet. Hydraulic systems are never leak free. A hydraulic seal drain system tries to collect hydraulic fluid leaving the system with partial success. It is impossible to catch all leaking hydraulic fluid. If the containers of the seal drain system are not emptied they spill over. In old aircraft, surfaces in the landing gear bay are covered with a layer of hydraulic fluid. Dirt accumulates on the sticky surface. The hydraulic fluid is not confined to the inside of hydraulic bays, but continues its journey on the lower side of the fuselage towards the APU. Deicing fluid if applied in the winter to the aircraft and can leak from the tail into the APU inlet. Fuel and oil also leak down onto the airport surfaces. These fluids can be ingested by the engine from the ground and can enter the air conditioning system from there. Entropy is the law of nature that states that disorder always increases. This is the reason, why it is impossible to confine engine oil and hydraulic fluids to their (predominantly) closed aircraft systems. This is why engine oil with metal nanoparticles, hydraulic fluids, and deicing fluids eventually go everywhere and finally into the human body., This is a presentation from the International Aircraft Cabin Air Conference 2021 (Online, 15-18 March 2021)