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2015-09-15
Technical Paper
2015-01-2521
Manimaran Govindarasu, Aditya Ashok
Many critical infrastructures, such as energy and transportation systems, are cyber-enabled physical systems that increasingly rely on smart sensors, communication networks, and control algorithms for their efficient, reliable, and economic operations. Risk modeling is a key component of any comprehensive security solution to protect these infrastructures against cyber attacks. In this paper, we present a quantitative methodology for risk assessment and mitigation for cyber-physical systems and contrast its strengths and weaknesses with respect to qualitative risk assessment methodology that is widely used in industry.
2015-09-15
Technical Paper
2015-01-2520
Thabet Kacem, Jeronymo Carvalho, Duminda Wijesekera, Paulo Costa, Márcio Monteiro, Alexandre Barreto
Since its emergence, Automatic Dependent Surveillance Broadcast (ADS-B) has been considered as a major contribution to air traffic control (ATC) surveillance. However, despite the several benefits that this promising technology has to offer, it suffers from a major security flaw since ADS-B packets are sent in clear text without enforcing any kind of security property. In this paper, we enhance a security framework, which we describe in a previous paper, aiming at detecting and mitigating attacks targeting ADS-B protocol, with a cognitive engine. First, this would facilitate the physical risk assessment of the ADS-B attacks based on the collected data describing the aircraft and its surrounding. Second, it would be beneficial to the ATC controllers who would have a better idea about the best ways to optimize the aircraft taking off and touching down without any disruptions from possible attacks targeting this technology.
2015-09-15
Technical Paper
2015-01-2519
Rosa Maria Rodriguez, Javier Garcia, Pedro Taboso
Boeing Research & Technology Europe (BR&T-Europe), a subsidiary of The Boeing Company, is developing an innovative approach to Communication, Navigation and Surveillance (CNS) in order to enhance both security and efficiency. Our approach will use the broadband internet connection onboard to securely interchange CNS data between aircraft and ground. On board broadband will allow new technological solutions and applications, not possible with current approaches, in a more secure and cost effective way. It also supports permanent surveillance and virtual event data recorder (black box). This concept is based on the dramatic improvement of broadband services on board. With some internet service providers promising up to 50Mbps per aircraft and global coverage, traditional data links (ACARS and ATN) are becoming obsolete. The solution supports the concept of aircraft always connected to ground servers to delocalize and automatize some CNS features.
2015-09-15
Technical Paper
2015-01-2580
David Lednicer
During the 1930s and 1940s, aircraft designers worked on developing novel design features. Some of these features worked and are commonplace today. Other features fell by the wayside and are forgotten. Examples include laminar flow wings, low-drag cooling systems, buried propulsion systems, turbocharging, jet engines, break-away wing tips, pressure cabins and swept wings. This paper will discuss how these features were included in the design of such aircraft as the P-51 Mustang, P-39 Airacobra, Messerschmitt Me 262 and Grumman F8F Bearcat. The development and applications of these features will be examined. Specific technical details of these applications will be included in this examination. For the design features that fell by the wayside, the reasons for this outcome will be discussed. In addition to the discussion of “lessons learned”, there will be discussion of “lessons forgotten”.
2015-09-15
Technical Paper
2015-01-2581
Scott Eberhardt
In 1915 Anthony Fokker, using a 1913 patent of Franz Schneider, designed an interrupter gear for his Eindeckers (monoplanes), after the Germans captured Roland Garros and his bullet-deflector-equipped airplane. The otherwise inferior Eindecker E.III gained dominance in the skies for a period lasting from August 1915 to June 1916, a period known as the “Fokker Scourge.” A lasting consequence of this period was the rapid technological innovations that one sees throughout the war. This paper will focus on four areas where WWI aircraft innovations set the stage for the next quarter century of airplane development. Specifically, it will look at drag reduction, control surface design and handling, airfoil technology and the use of metal in aircraft construction. The discussion of drag reduction will illustrate the innovations of the British on external wire bracing drag, the French on cowl design and the Germans on cantilevered wings and induced drag.
2015-09-15
Technical Paper
2015-01-2592
Joao Pedro Malere, Wlamir Olivares Loesch Vianna
This paper presents a method to determine the root cause of an aircraft component failure by using the fault messages history. The K-nearest neighbors (K-nn) and the Tree-Augmented naive Bayes methods were used in order to classify the failure causes as a function of the fault messages (predictors). The training set contained the fault messages history from a fleet and the causes reported by the maintenance stations. A cross-validation was performed in order to check the loss function value and a comparison between the methods was performed.
2015-09-15
Technical Paper
2015-01-2596
Uli Burger, Ludovic Rochat
Lightweight structures are one key issue for all future mobility concepts. Carbon fibre reinforced plastics (CFRP) play an important role in these disciplines due to their outstanding mechanical performance regarding to their weight. Therefore, CRFP structures have been widely used since decades in aerospace industry resulting in improvements in payload, fuel consumption and range. The Airbus A350, Boeing B787 in civil airplane industry as well as military products like the NH90 transport helicopter are examples of this development towards “all composite”-aircrafts with nearly all structural parts made out of composite materials. A main difference of CFRP-structures towards metallic ones is the behavior regarding damage tolerance and fatigue. For helicopter composite structures this issue is newly defined in §573 of the relevant certification specifications (CS for EU, FAR for US) valid since December 2012.
2015-09-15
Technical Paper
2015-01-2595
Darren Winter, Paul Ashton-Rickardt, Carwyn Ward, Paul Gibbons, Chris Mcmahon, Kevin Potter
This paper reports on a methodology for risk reduction, developed and tested at a new aerospace manufacturing facility that produces high value aero-structures. The facility was formed as part of a ‘Risk Sharing Partnership’ between Airbus and GKN for production of the Airbus A350 ‘Fixed Trailing Edge’. The challenge for GKN was to increase production volume for each successive year of operations, whilst concurrently engineering the product and improving its processes. For schedule adherence, elimination of process failures often manifested at the final stage of assembly (in an integration cell) was critical. The integration cell comprised of bespoke solutions where, on attempting to increase to scheduled rate, failures increased impacting cycle times. Most failure events encountered comprised of sub-failures whose permutations were often unknown i.e. caused through varying interactions between hardware, software and staff.
2015-09-15
Technical Paper
2015-01-2594
Thomas G. Jefferson, Panorios Benardos, Svetan Ratchev
Current assembly systems that deal with large, complex structures present a number of challenges with regard to improving operational performance. Specifically, aerospace assembly systems comprise a vast array of interrelated elements interacting in a myriad of ways, resulting in a deeply complex process that requires a multi-disciplined team of engineers. The current approach to ramp-up production rate involves building additional main assembly fixtures which require large investment and lead times up to 24 months. Within Airbus Operations Ltd there is a requirement to improve the capacity and flexibility of assembly systems, thereby reducing non-recurring costs and time-to-market. Recent trends to improve manufacturing agility advocate Reconfigurable Assembly Systems (RAS) as a viable solution. Yet, adding reconfigurability to assembly systems further increases both the operational and design complexity.
2015-09-15
Technical Paper
2015-01-2612
Laerte de ARAUJO LIMA
Process Failure Mode Effect an Analysis (PFMEA) is a standardized methodology that enables to assess and prevent / mitigate risks linked to a Process. PFMEA technique is widely spread in automotive, which becomes the industrial benchmark in terms of product/process development (i.e. APQP) and industrial resources optimization (i.e. Lean and Six Sigma). In the aerospace supply, chain, beside the fact that a high level of quality standards are apply PFMEA technique is not systematically applied. The aim of this paper is to present the “as is” situation of the PFMEA deployment in the Aerostructures supply chain perimeter, identify the reason of no deployment, understand the constraints, analyze the root cause and propose an effectiveness process, that can increase the level of PFMEA maturity, deployment and effectiveness in the Aerostructures supply chain perimeter.
2015-09-15
Technical Paper
2015-01-2387
Rajagopal Ananthasubramaniam
Abstract DFSS has the objective of addressing the needs of the customer and business simultaneously to drive these needs in to the product or process solution so created. DFSS is relevant to complex system/product synthesis phase, especially in the context of unprecedented system development rather it is process generation in contrast to process improvement. DMADV Define-Measure-Analyse-Design-Verify, is sometimes synonymously referred to as DFSS. Design for Six Sigma (DFSS) is a strategy, a concept, a process and a set of tools. As a strategy to develop new and better products/processes to address the "voice of the customer", as a concept to drive robust engineering (product & process) and validation with focus on "problem prevention" and a process to translate "voice of the customer" to engineering requirements and optimize the relationship between influencing factors and their effects on customers to achieve and sustain high quality levels.
2015-09-15
Technical Paper
2015-01-2386
Thierry Pamphile
As technology for both military and civilian aviation systems mature into a new era, techniques to test and evaluate these systems have become of great interest. To achieve a general understanding as well as save time and cost, the use of computer modeling and simulation for component, subsystem or integrated system testing has become a central part of technology development programs. However, the evolving complexity of the systems being modeled leads to a tremendous increase in the complexity of the developed models. To gain confidence in models there is a need to evaluate the risk in using those models for decision making. Examples of methods used to assess the risk of using a given model in a decision making exercise include statistical model validation and hardware-in-the-loop (HIL). By using HIL we can setup more realistic boundary conditions for the hardware under test, which aids in the validation process. In this paper, we will examine the validation of a drive stand model.
2015-09-15
Technical Paper
2015-01-2388
Tom Clark, Luis Rabelo
For many critical space operation systems, timely recognition of an anomalous condition immediately starts the evaluation process. For complex systems, isolating the fault to a component or subsystem results in corrective action sooner so that undesired consequences may be minimized. These beneficial anomaly detection and fault isolation capabilities are widely recognized and have resulted in the development of innovative techniques for quickly discovering underlying system problems. This paper will address augmenting a legacy system with additional detector/isolator capabilities best suited for that system. A cryogenic liquid hydrogen (LH2) tank pressurization subsystem (from the Kennedy Space Center (KSC) launch pad) is the basis for the model. This system is operated remotely and supports time-critical and high-risk operations making it a good candidate to supplement with this technology. The proposed approach models the existing system using the System Modeling Language (SysML).
2015-09-15
Technical Paper
2015-01-2401
Michael Schmidt, Philipp Nguyen, Kay Plotner, Mirko Hornung
The projected uptick in world passenger traffic challenges the involved stakeholder to optimise the current aviation system and to find new solutions being able to cope with this trend, since especially large hub airports are congested and operate at their capacity limit. Delays due to late arrival of aircraft or unreliable and inefficient ground operation processes would disrupt the airport operations tremendously. Various concepts improving the current turnaround processes have been presented thus far, whereby radical aircraft design changes have little chances for realization. Based on a clustering of aircraft interfaces, such as doors and services panels, for state-of-the-art passenger aircraft, concepts targeting to reduce the required resources and time are presented. By maintaining the established overall aircraft configuration, the concepts promote higher probability to become commercially available for aircraft manufactures and operators.
2015-09-15
Technical Paper
2015-01-2400
Craig Lawson, Irfan Madani, Ravinka Seresinhe
With the rapid growth in passenger transportation through aviation projected to continue into the future, it is incumbent on aerospace engineers to seek ways to reduce the negative impact of airliner operation on the environment. Key metrics to address include noise, fuel consumption, Carbon Dioxide and Nitrous Oxide emissions, and contrail formation. The research presented in this paper generates new aircraft trajectories to reduce these metrics, and compares them with typical scheduled airline operated flights. Results and analysis of test cases on trajectory optimization are presented using an in-house aircraft trajectory optimization framework. The framework is a trajectory optimization software tool created under the European Clean Sky Joint Technology Initiative, Systems for Green Operation Integrated Technology Demonstrator.
2015-09-15
Technical Paper
2015-01-2402
Yucheng Liu
Differential equations play a prominent role in aerospace engineering by modeling aerospace structures, describing important phenomena, and simulating mathematical behavior of aerospace dynamical systems. Presently, aerospace systems have become more complex, space vehicle missions require more hours of simulation time to complete a maneuver, and high-performance missiles require more logical decisions in there phases of flight. Because of these conditions, a computationally efficient algorithm for solving these differential equations is highly demanded to significantly reduce the computing time. This paper presents an efficient method for solving the differential equations by using variational iteration method, which can be implemented into software package to dramatically reduce the computing time for simulating the aerospace systems thereby significantly improving computer’s performance in real-time design and simulation of aircrafts, spacecrafts, and other aerospace vehicles.
2015-09-15
Technical Paper
2015-01-2444
Myron Hecht, Elisabeth Nguyen, Aaron Chuidian, Julia Pinchak, Emily Dimpfl
This paper describes a method for automated generation of Functional Hazard Assessments (FHAs) or Failure Modes and Effects Analyses from SysML models. Such analyses are identified in SAE ARP 4754A (“Guidelines for Development of Civil Aircraft and Systems “) and 4761 (“Guidelines and Methods for Conducting the Safety Assessment Process on Civil Airborne Systems and Equipment”). Ideally, they should be performed iteratively throughout the design process. However, because they are labor intensive and costly, they are generally performed only after the functional or detailed designs have been completed. If they could be integrated into a Model Based Systems Engineering process, significant safety and cost saving benefits could be achieved. The general approach is to create a system model that includes the following: 1. A block definition diagram (BDD) defining all of the system blocks used in the system 2.
2015-09-15
Technical Paper
2015-01-2445
Hartmut Hintze, Ralf God
The increasing functionality associated with the rising complexity of aircraft cabin systems which are used by cabin crew, passengers, maintenance staff and other stakeholders, requires a reconsideration of the methods for the development of aircraft cabin systems. This paper deals with a model-based security engineering approach based on the so called three-V-model [1] as an appropriate process model, which represents the governing system engineering process (SEP) associated with the safety engineering process (SafEP) and the security engineering process (SecEP). All three processes are pursued concurrently and are interacting reciprocally by working within the same system model on each development level. We describe in detail the involved model-based security engineering activities of the SecEP and the integration of the CORAS risk analysis method [2] in a consistent System Modeling Language (SysML) approach.
2015-09-15
Technical Paper
2015-01-2450
Jon Friedman
The foundation of a well-structured development process are the requirements and acceptance criterion to which the engineering teams’ designs must conform. Textual specifications remain the predominant format for capturing systems requirements and acceptance criterion. Systems engineers perform various levels of reviews to determine the completeness and correctness of the requirements. Once implemented, the system engineer will verify the system design against those requirements to determine proper behavior as specified in the acceptance criterion. Despite the fact that this need for good requirements and acceptance criteria is well known, a very large percentage of system defects continue to be traced to defective requirements. This paper describes a technique for improving the quality of the textual requirements by translating the requirements to a machine readable and analyzable language (MATLAB and Simulink) using a parser created with ANTLR.
2015-09-15
Technical Paper
2015-01-2451
Luiz A. Costa
The main purpose of this paper is to propose a basic guideline in the process of designing optimal mechanical or electromechanical actuators. The method presented requires as input data the actuator’s envelope definition, alloted power, and the load profile defined by the expected worse case scenarios of speed and torque as a function of time. As output data the graphical representation of the optimum gear ratio as a function of the lowest desired number of gear links is obtained. By optimum here we refer to the gear ratio points that will imply the lowest possible drive torque, while taking in consideration a lower bound in the number of gear links
2015-09-15
Technical Paper
2015-01-2452
Vicki S. Johnson
The Systems Engineering (SE) “Vee” is generally recognized as one of the primary identifying features of systems engineering processes. While there are many specifications which include SE in their titles and show a version of the “Vee” in their process descriptions, there are other specifications which make no claim to be an SE standard but show a “Vee” describing the processes in the specification. There are also specifications which appear at first glance to be completely unrelated to SE but, perhaps, accidently, describe processes which are very much SE. This wide variety of documents leads to a question of the possibility of identifying the common core which composes SE (the soul of systems engineering)? And how would using that core make for more robust processes which could better meet the needs of systems today and into the future (e.g., Unmanned Aerial Vehicles or Multi-vehicle Space Transport Systems).
2015-09-15
Technical Paper
2015-01-2446
Anwar ul haque, Waqar Asrar
The configuration design phase of a hybrid buoyant aircraft is quite complex due to the augmentation of aerostatic and aerodynamic lift. The first step in assessing the optimal configuration for such aircrafts is to approach the design in a number of different ways with different shapes of hull and diversed empennage arrangements. Concept selection methods like Pugh concept selection charts can assist to rank the population of different concepts of such aircrafts. In the present work, an effort was done to explore the potential usage of Pugh’s method in a comprehensive manner and to establish a basis for choosing a particular design concept. Driving factors of such design concepts were reviewed alongwith the selection of figure of merits, which were further evaluated by taking Megalifter as a reference with which all other configurations under consideration were compared.
2015-09-15
Technical Paper
2015-01-2447
John Low
The development of the Electrical Wire Interconnection System, or EWIS, for today’s advanced aircraft is one of the most complicated engineering activities around. In addition to having to respond to very high rates of change during development, the aircraft are continually evolving in electronic and electrical content along the entire lifecycle. Relatively new mandates such as the CFR Part 25 Subpart H EWIS have put additional demands on aircraft OEMs and their key suppliers, forcing companies to reassess their design practices and methodologies. This paper will investigate how a systems engineering approach to the development of the electrical wiring systems can enable and facilitate a more efficient EWIS methodology.
2015-09-15
Technical Paper
2015-01-2449
Solange Baena, Joseph K-W Lam, Craig Lawson
This paper focuses on the investigation of the nature, process and effects of ice accretion on different feed pump strainers upstream of the aircraft engine feed system. A suitable test rig was designed to circulate Jet A-1 containing water/ice contaminants at cold temperatures through the strainers. Following an extensive literature review, a number of screening tests were performed. These provided a strong base for an exhaustive study of fuel icing in the dynamic environment offered by the test rig. The effects of the rate of fuel cooling on the nature of ice were examined. The effects of temperature in the adhesion and cohesion properties of ice in a dynamic system, and the effects of contaminants in the yield, nature and porosity of ice generated in the fuel are also now better described. As expected, it was observed that the yield of ice generated on the mesh screen increased with the water concentration in the fuel.
2015-09-15
Technical Paper
2015-01-2448
Steve Trythall
Meeting aerospace configuration control mandates involves a host of issues such as data access control, configuration context including effectivity and release management, just to name a few factors. Design tools must assist organizations and individual designers with this myriad of challenges instead of relying on the PLM environment to identify and sort out issues during data release. The recent advancements of the model-based development (MBD) process puts much more emphasis on the actual data instead of simply drawings. This paper explores how many leading aerospace OEMs are adopting new capabilities for the designers during the development process in an effort to mitigate errors related to data inconsistencies.
2015-09-15
Technical Paper
2015-01-2385
Richard C. Millar
At the Naval Postgraduate School, the faculty & students have exploited the flexibility and cost effectiveness of UAS as experimental flight test platforms, but this has recently been impeded by a ruling that these flights must comply with the NAVAIR interim flight clearance (IFC) process and procedures. The research project described and discussed in this presentation & publication was initiated to rapidly come to grips with this problem, identify mitigations and demonstrate a method to satisfy the need of all parties. The initial phase exposed mismatches in NPS design & analysis capability and the requirements of the contrasting developmental modes and resources, but also highlighted the procedural flexibility of the UAS developmental model. The need for a more effective but suitable process for managing small UAS flight test risks was recognized.
2015-09-06
Technical Paper
2015-24-2511
Theodoros Grigoratos, Georgios Fontaras, Giorgio Martini, Cesare Pelleto
Gas operated Heavy Duty Vehicles (HDV) powered by Natural Gas (NG) are seen as a possible option for curbing CO2 emissions, fuel consumption and operating costs of goods transport. Initiatives have been adopted by various organizations worldwide in order to introduce NG fueled HDVs in their fleets. In this study, an advanced newly designed CNG prototype engine, which was developed in the framework of the FP7 research project “CO2 Reduction for long distance transport” (CO2RE), is benchmarked against its parent Euro V compliant CNG engine (reference) in terms of emissions and fuel consumption. The main technological innovation includes a new cylinder head equipped with a Variable Valve Actuation system designed to provide on the intake side a continuous fully flexible variation of the valve lift and timing. The newly developed engine was optimized for urban emission profiles and operation such as garbage collection purposes.
2015-06-29
WIP Standard
J1555
This SAE Recommended Practice applies to all portions of the vehicle, but design efforts should focus on components and systems with the highest contribution to the overall average repair cost (see 3.7). The costs to be minimized include not only insurance premiums, but also out-of-pocket costs incurred by the owner. Damageability, repairability, serviceability and diagnostics are inter-related. Some repairability, serviceability and diagnostics operations may be required for collision or comprehensive loss-related causes only, some operations for non-collision-related causes only (warranty, scheduled maintenance, non-scheduled maintenance, etc.), and some for both causes. The scope of this document deals with only those operations that involve collision and comprehensive insurance loss repairs.
2015-06-24
WIP Standard
ARP6328
This document contains guidance for implementing a counterfeit mitigation program in adherence with AS5553B.
2015-06-21
WIP Standard
AS4877E
This procurement specification covers bolts and screws made from a corrosion and heat resistant, age hardenable nickel base alloy of the type identified under the Unified Numbering System as UNS N07718.
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