Refine Your Search

Topic

Author

Search Results

Technical Paper

ONICE2D and DROP3D SLD Capability Assessment

2011-06-13
2011-38-0088
In 1994, an ATR-72 crashed at Roselawn, Indiana, USA. It has been speculated that accident was due to Supercooled Large Droplet (SLD) icing. This accident led to a modification of the regulation rules with the definition of the Appendix O which includes freezing drizzle and freezing rain icing conditions. The associated NPRM (Notice of Proposed Rule Making) has been distributed to industry for comments on 29th June 2010 and could be applicable by beginning 2012. In order to comply with this new rule, the simulation tools, as Acceptable Means of Compliance, have to be improved and validated for these conditions. The paper presents the work performed within Airbus to review, improve and assess simulation tools capability to accurately predict physical phenomena related to SLD. It focuses in particular on splashing and bouncing phenomena which have been highlighted as the first order effects.
Technical Paper

On-line Estimation of Longitudinal Flight Parameters

2011-10-18
2011-01-2769
The introduction of Fly-By-Wire (FBW) and the increasing level of automation contribute to improve the safety of civil aircraft significantly. These technological steps permit the development of advanced capabilities for detecting, protecting and optimizing A/C guidance and control. Accordingly, this higher complexity requires extending the availability of aircraft states, some flight parameters becoming key parameters to ensure a good behaviour of the flight control systems. Consequently, the monitoring and consolidation of these signals appear as major issues to achieve the expected autonomy. Two different alternatives occur to get this result. The usual solution consists in introducing many functionally redundant elements (sensors) to enlarge the way the key parameters are measured. This solution corresponds to the classical hardware redundancy, but penalizes the overall system performance in terms of weight, power consumption, space requirements, and extra maintenance needs.
Technical Paper

Innovation Readiness: Past and Current Drivers in Aeronautical Engineering

2011-10-18
2011-01-2501
This paper proposes a rearview on aeronautical innovation, addresses some 2000-2010 new products, and suggests elements of future vision, serving passengers aspirations. Over 100 years, aeronautics brilliantly domesticated flight: feasibility, safety, efficiency, international travel, traffic volume and noise, allowing airlines to run a business, really connecting real people. Despite some maturations, new developments should extend the notion of passenger service. So far, turbofans became silent and widebodies opened ‘air-bus’ travel for widespread business, tourism or education. Today airports symbolize cities and vitalize regional economies. 2000-2010 saw the full double-decker, the new eco-friendly freighter and electronic ticketing. In technology, new winglets and neo classical engines soon will save short-range blockfuel. In systems and maintenance, integrated modular avionics and onboard data systems give new flexibility, incl by data links to ground.
Technical Paper

Evaluation of Small Scale Icing Tunnel Test Results

2007-09-24
2007-01-3328
A test has been performed using a scaled aircraft wing section in an icing tunnel facility. The model had an electro-thermal ice protection system installed. The tests performed considered both anti-icing and de-icing modes of operation. The results have been assessed using numerical codes and the effect of model scaling has been considered. The non-scaled skin thickness of the model was found to modify the predicted behaviour of a full-scale installation, predominantly due to lateral conduction effects. The extent of this has been assessed and recommendations are made as to the performance that may be expected at full-scale.
Technical Paper

Minimizing Impact on Climate in Aircraft Design

2007-09-17
2007-01-3807
A two-level approach for the consideration of climate change in the aircraft design process is proposed. Depending on the availability of suitable atmospheric metrics, the methodology has been put into practice only recently. The assessment of technology and design changes is enabled with regard to the impact of aircraft on climate. First example applications show that the methodology is not yet ready for full industrial application, but that it can give useful hints for the orientation of aircraft concepts for the future aviation system.
Technical Paper

Uncertainty of the Ice Particles Median Mass Diameters Retrieved from the HAIC-HIWC Dataset: A Study of the Influence of the Mass Retrieval Method

2019-06-10
2019-01-1983
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.
Technical Paper

Extension of a 2D Algorithm for Catch Efficiency Calculation to Three Dimensions

2019-06-10
2019-01-2013
Accurate calculation of the catch efficiency β is of paramount importance for any ice accretion calculation since β is the most important factor in determining the mass of ice accretion. A new scheme has been proposed recently in [1] for accurately calculating β on a discretized two-dimensional geometry based on the results of a Lagrangian droplet trajectory integrator (start and impact conditions). This paper proposes an extension to the algorithm in Ref. [1], which is applicable to three-dimensional surfaces with arbitrary surface discretization. The 3D algorithm maintains the positive attributes of the original 2D algorithm, namely mass conservation of the impinging water, capability to deal with overlapping impingement regions and with crossing trajectories, computational efficiency of the algorithm, and low number of trajectories required to reach good accuracy in catch efficiency.
Technical Paper

Ranking of Thick Ice Shapes Based on Numerical Simulation for Certification

2019-06-10
2019-01-1944
The objective of this paper is to present a numerical method to rank thick ice shapes for aircraft by comparing the ice accretion effects for different icing scenarios in order to determine the more critical ice shape. This ranking allows limiting the demonstration of the aerodynamic characteristics of the aircraft in iced condition during certification to a reduced number of ice shapes. The usage of this numerical method gives more flexibility to the determination of the critical ice shapes, as it is not dependent of the availability of physical test vehicles and/or facilities. The simulation strategy is built on the Lattice Boltzmann Method (LBM) and is validated based on a representative test case, both in terms of aircraft geometry and ice shapes. Validation against existing experimental results shows the method exhibits an adequate level of reliability for the ranking of thick ice shapes.
Technical Paper

Application of EASA Part 21 Requirement Regarding Change to Aircraft Type Design by Airbus

2013-09-17
2013-01-2124
Airbus business and Extended Enterprise require more and more involvement of design and built suppliers, tier 1 but also across the complete supply chain i.e. tier 2-n. These suppliers are not working only for Aerospace industry and may have different cultures. The pressure on cost and overall efficiency is high and everybody has to cope with obsolescence and new regulation (e.g. REACH (Registration, Evaluation and Authorization and Restriction of Chemicals)). So it became very important for Airbus to clarify the criteria under which a change can be done without Airbus review, and criteria under which a change can be done without Airworthiness authority review.
Technical Paper

Aeronautical Fuel Cell System Application and Associated Standardization Work

2006-11-07
2006-01-3093
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.
Journal Article

OBIGGS for Fuel System Water Management - Proof of Concept

2011-10-18
2011-01-2793
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.
Journal Article

A Model-based Solution to Robust and Early Detection of Control Surface Runaways

2011-10-18
2011-01-2803
This paper discusses the design of a model-based fault detection scheme for robust and early detection of runaways in aircraft control surfaces servo-loop. The proposed scheme can be embedded within the structure of in-service monitoring systems as a part of the Flight Control Computer (FCC) software. The final goal is to contribute to improve the performance detection of unanticipated runaway faulty profiles having very different dynamic behaviors, while retaining a perfect robustness. The paper discusses also the tradeoffs between adequacy of the technique and its implementation level, industrial validation process with Engineering support tools, as well as the tuning aspects. The proposed methodology is based on a combined data-driven and system-based approach using a dedicated Kalman filtering. The technique provides an effective method ensuring robustness and good performance (well-defined real-time characteristics and well-defined error rates).
Technical Paper

Applying a Concept for Robot-Human Cooperation to Aerospace Equipping Processes

2011-10-18
2011-01-2655
Significant effort has been applied to the introduction of automation for the structural assembly of aircraft. However, the equipping of the aircraft with internal services such as hydraulics, fuel, bleed-air and electrics and the attachment of movables such as ailerons and flaps remains almost exclusively manual and little research has been directed towards it. The problem is that the process requires lengthy assembly methods and there are many complex tasks which require high levels of dexterity and judgement from human operators. The parts used are prone to tolerance stack-ups, the tolerance for mating parts is extremely tight (sub-millimetre) and access is very poor. All of these make the application of conventional automation almost impossible. A possible solution is flexible metrology assisted collaborative assembly. This aims to optimise the assembly processes by using a robot to position the parts whilst an operator performs the fixing process.
Technical Paper

A New Approach Based on Statistical Modeling of Electrical Consumption for Electrical Generator Demand Estimation

2011-10-18
2011-01-2669
With the last generation of large aircraft, the electrical needs have increased to reach a power close to 1MW. A power increase directly impacts one of the prominent criterions in aircraft design process: weight. Therefore, designers face the challenge to reduce generation while the power demand is increasing. The proposed paper details a methodology based on statistical approach to estimate the electrical consumption of an electrical network. Moreover, the modeling proposed in this paper allows taking into account peaks defined by their power and duration. Based on in-service measurements on commercial aircraft flights, this study proposes two methods to estimate electrical consumption of an electrical network. The first method is described. Based on modeling thanks to an efficient clustering, a Monte Carlo simulation is performed on all the loads to estimate the electrical power on the network with relevant results.
Technical Paper

Rivetless Nutplate Developments for Aerospace Applications

2011-10-18
2011-01-2756
Within this paper, the AIRBUS approach on the development of rivetless nutplates as an alternative to riveted anchor nuts is described. Within the frame of a wider analysis, it was identified that currently used riveted anchor nut elements does have disadvantages with negative impact on an optimized cost-efficient and lead-time driven design and manufacturing environment. Rivetless nutplate systems provide some features that are potentially capable to mitigate some of the identified disadvantages of riveted elements. The paper covers the key requirements and objectives that were put in place in order to identify the most beneficial solution(s). It furthermore contains detailed information on the rivetless nutplate systems selected by AIRBUS and the justification for the selection that was made.
Technical Paper

Virtual Testing for High Lift Systems

2011-10-18
2011-01-2754
Improving the verification and certification process of the high lift system by introduction of virtual testing is one of the approaches to counter the challenges related to testing of future aircraft, in terms of performing more tests of more complex systems in less time. The quality of the applied modelling methods itself and the guarantee of a completely traceable simulation lifecycle management along the aircraft development are essential. The presentation shows how existing processes for the management of all test related data have to be extended to cover the specifics of using multi body simulation models for virtual tests related to high lift failure cases. Based on a demonstrator, MSC Software GmbH and Airbus developed and are still refining the SimManager based “High Lift System Virtual Test Portal”. This portal has to fulfil on the one side global requirements like data management, data traceability and workflow management.
Technical Paper

Flight Test Identification Methods for Loads Models and Applications

2011-10-18
2011-01-2763
The Loads discipline contributes to the aircraft structural design by delivering shear, moment and torque (SMT, loads) all across the airframe resulting from application of aircraft airworthiness requirements as laid down in the CS 25/FAR 25 regulations and in some domestic ones. Loads computation considers the maneuver and gust conditions prescribed therein as well as other special design conditions. It is based on very detailed modeling, accounting for aerodynamics in all configurations, mass properties, flexibility of the airframe, flight control laws and retarded laws, hydraulic actuation, and specification of flight control system failure conditions. The resulting shear loads are processed and refined (e.g. nodal loads) and taken into account by the stress department for structural design.
Technical Paper

Eco-efficient Materials for Aircraft Application

2011-10-18
2011-01-2742
Due to the importance of fulfilling the actual and upcoming environmental legislation, it is an Airbus main target to develop eco-efficient materials. Under consideration of the economical effects, these processes will be implemented into the production line. This paper gives an overview of Airbus and its partners research work, the results obtained within the frame of the European funded, integrated technology demonstrator (ITD) ECO Design for Airframe. This ITD is part of the joint technology initiative Clean Sky. Developments with different grade of maturity from “upstream” as the investigation of materials from renewable recourses up to materials now in use in production as low volatile organic compounds cleaner are under investigation. As a basis for future eco-efficient developments an approach for a quantitative life cycle assessment will be demonstrated.
Technical Paper

Considerations on an Integral Flight Physics Model with Application to Loads Analysis

2011-10-18
2011-01-2767
Increasing technical dependencies between the engineering disciplines driving the overall design of an aircraft and improving optimization techniques that make use of these interactions blur the lines between distinct disciplines and create demand for a harmonized flight physics model. In this paper we present considerations on a general framework that allows the representation of the equations and data from various domains in an object-oriented and scalable structure. Emphasis is put on the loads aspect with the distinct fields of gust loads, maneuver loads and ground loads analysis, which are essential for structural design. A fully generic, grid based data structure is presented, which is suitable for models of different granularity and applicability. All data is represented in this general form independent of its origin and may be transformed in between the different representations using splines. Coordinate transformations are handled automatically.
Technical Paper

Software Complex for Riveting Process Simulation

2011-10-18
2011-01-2772
The presented paper describes the software complex developed in St. Petersburg Polytechnical University for AIRBUS aimed at simulation of aircraft assembly process. Previous version of this complex was described in [1].
X