Search Results

Measurements in snow conditions performed in the past were rarely initiated and best suited for pure and extremely detailed quantification of microphysical properties of a series of microphysical parameters, needed for accretion modelling. Within the European ICE GENESIS project, a considerable effort of natural snow measurements has been made during winter 2020/21. Instrumental means, both in-situ and remote sensing were deployed on the ATR-42 aircraft, as well as on the ground (ground station at ‘Les Eplatures’ airport in the Swiss Jura Mountains with ATR-42 overflights). Snow clouds and precipitation in the atmospheric column were sampled with the aircraft, whereas ground based and airborne radar systems allowed extending the observations of snow properties beyond the flight level chosen for the in situ measurements.

In response to the ice crystal icing hazard identified twenty years ago, aviation industry, regulation authorities, and research centers joined forces into the HAIC-HIWC international collaboration launched in 2012. Two flight campaigns were conducted in the high ice water content areas of tropical mesoscale convective systems in order to characterize this environment conducive to ice crystal icing. Statistics on cloud microphysical properties, such as Ice Water Content (IWC) or Mass Median Diameter (MMD), derived from the dataset of in situ measurements are now being used to support icing certification rulemaking and anti-icing systems design (engine and air data probe) activities. This technical paper focuses on methodological aspects of the derivation of MMD. MMD are estimated from PSD and IWC using a multistep process in which the mass retrieval method is a critical step.

The PLANET System was used for real-time satellite data transmission during the HAIC-HIWC Darwin field campaign (January to March 2014). The basic system was initially providing aircraft tracking, chat, weather text messages (METAR, TAF, etc.), and aeronautical information (NOTAMs) in a standalone application. In the framework of the HAIC project, many improvements were made in order to fulfill requirements of the onboard and ground science teams for the field campaign. The aim of this paper is to present the main improvements of the system that were implemented for the Darwin field campaign. New features of the system are related to the hardware component, the communication protocol, weather and tracking display, geomarkers on the map, and image processing and compression before onboard transfer.

The Environmental Control System is a relevant element of any conventional or More Electric Aircraft (MEA). It is either the key consumer of pneumatic power or draws a substantial load from the electric power system. The objective of this paper is to present a tool for the design of Environmental Control Systems and to apply it to an unconventional system. The approach is based on a recently proposed methodology, which is improved with respect to flexibility and ease-of-use. Furthermore, modeling and simulation of vapor compression cycles is discussed, which are candidate technological solutions for More Electric Aircraft concepts. A steady-state moving boundary method is presented to model heat exchangers for such applications. Finally, the resulting design environment is applied to optimization of an unconventional ECS architecture and exemplary results are presented.

Fuel on-board dehydration during flight technologies has been modeled and experimentally studied on a laboratory testing setup in normal specific gas flow rates range of 0.0002-0.0010 sec-₁. Natural air evolution, ullage blowing and fuel sparging with dry inert gas have been studied. It has been shown that natural air evolution during aircraft climb provides a significant, substantial, but insufficient dehydration of fuel up to 20% relative. Ullage blowing during cruise leads to a constant, but a slow dehydration of fuel with sufficient column height concentration gradient. Dry inert gas sparging held after the end of the natural air evolution or simultaneously with natural air evolution provides rapid fuel dehydration to the maximum possible values. It potentially may eliminate water release and deposition in fuel to -50°C. It has been found that for proper dehydration, necessary and sufficient volume of dry inert gas to volume of fuel ratio is about 1.

Water is a contaminant that can lead to fuel system icing, microbial contamination, corrosion and fuel quantity gauging problems and therefore an efficient water management system is required in order to maximise the performance of an aircraft's fuel system. This paper describes a time-transient aircraft fuel tank model with water contamination, due to the principal mechanisms of dissolution, suspension, condensation and transportation. The tank model presented is a component of the NEPTUNE fuel system model which was developed for Airbus using the A380 as an example aircraft. A description of the physics of water contaminated fuel is given and of how this has been incorporated into a mathematical model of an aircraft fuel tank. A modular approach is demonstrated which enables interconnecting fuel tanks to be configured in larger systems in a flexible and easily understood manner.

Air traffic has been steadily increasing for the last years. Moreover, fuel availability at a reasonable cost seems more and more uncertain. Climate change implies that greenhouse gases emissions should be reduced. In this context, the search for new alternative fuels for aircraft seems to be a promising solution. Nevertheless, aeronautic represents a very specific transportation mode, due to its usage (short range, middle range, long range with the same fuel, worldwide distribution of the fuel…) and its compulsory security constraints. In the first part of the European project ALFA-BIRD (Alternative Fuels and Biofuels for Aircraft development - FP7), a selection of the best candidates to become the fuels for the future of aircraft has been done. The selection process was very complex, due to multiple criteria (physical properties, economical issued, environmental issues…).

In the past decades hydraulic systems have dominated actuation tasks in aerospace applications. Even today hydraulic actuation remains in first line for primary flight controls as well as for heavy consumers such as landing gear or auxiliary applications in the perimeter of military functions. Also in future, hydraulic systems and its consumers are candidates to fulfil operational and functional requirements and provide respective improvements to ensure product competitiveness. Thus, this paper deals with potential improvements on hydraulic system level such as, fluid monitoring and light weight applications linked to impacts on aircraft level or interfacing systems.

Water is always present in jet fuel, usually in a mixture of forms. At very low temperatures this phenomenon can lead to the formation of ice crystals within the aircraft fuel system, which can then stay in suspension within the entire volume of fuel. Pumps within the fuel system transfer fuel around the system. Pumps such as boost pumps that are typically used in fuel systems are protected by a weave type filter mesh at the inlet. Ice accretion on the surface of this mesh has operational implications as it can cause non optimal fuel flow. In this investigation, two fundamental tools are being used: 1) a high fidelity MATLAB model of a mesh strainer, pick-up line and pump, and 2) a test rig of the modelled system. The model is being used to investigate fuel system performance when exposed to fuel containing water/ice contaminants at cold temperatures.

Airbus is a leading aircraft manufacturer with the position as technology driver and a distinct customer orientation, broad commercial know-how and high production efficiencies. It is constantly working on further and new development of its products from ecological and economical points of view. Fuel Cell Systems (FCS) on board of an aircraft provide a good opportunity to address both aspects. Based on existing and upcoming research results it is necessary to find trend-setting measures for the industrial implementation and application of this technology. Past and current research efforts have shown good prospects for the industrial implementation and application of the fuel cell technology. Being an efficient source of primarily electric power the fuel cell would be most beneficial when used in conjunction with electrical systems.