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Metal matrix composites (MMCs) exhibit superior characteristics such as low weight, high stiffness, and high mechanical and physical properties. Inheriting such an outstanding combination of specifications, they are nowadays considered as the promising materials in the aerospace and biomedical industries. However, the presence of high abrasive reinforcing particles in MMCs leads to severe manufacturing issues. Due to the tool-particle interactions which occur during the machining of MMCs, high tool wear and poor surface finish are induced and those elements are considered as the main drawbacks of cutting MMCs. In this study, dry turning experiments were conducted for two different inserts and coated carbide on a bar of titanium metal matrix composite (Ti-MMC). Semi-finishing machining is operated with cutting parameters based on the tool supplier's recommendations which were not fully optimized. The maximum flank wear length (VBBmax) was selected as the tool wear criteria.

Within the aerospace industry there is a growing interest in evaluating and reducing the environmental impacts of products and related risks to business. Consequently, requests from governments, customers, manufacturers, and other interested stakeholders, for environmental information about aerospace products are becoming widespread. Presently, requests are inconsistent and this limits the ability of the aerospace industry to meet the informational needs of various stakeholders and reduce the environmental impacts of their products in a cost-effective manner. Energy consumption is a significant business cost, risk, and a simple proxy value for overall environmental impact. This paper presents the initial research carried out by an academic and industry consortium to develop standardised methods for calculating and reporting the embodied manufacturing energy content of aerospace products.

Lessons learned from analysis of in-service icing incidents are described. The airfoil and wing design factors that define an aircraft's natural stall characteristics are explored, including the aerodynamic effects of contamination. Special attention is given to contamination in the form of “roughness” along wing leading edges typical of frost. In addition, the key aerodynamic effects of ground proximity and sideslip/crosswind during the take-off rotation are described. An empirical method, that can be used to predict a wing's sensitivity to wing leading edge roughness, is demonstrated. The paper explores the in-service differences of aircraft that incorporate “hard”, “supercritical” and “slatted” wings. The paper attempts to explain why the statistical evidence appears to favor the slatted wing for winter operations.

In 1991, shortly after acquiring Learjet, Bombardier consolidated all flight testing of new aircraft at the Wichita, Kansas facility. Since then, nine new aircraft were certified, and the Flight Test Center grew from 20 dedicated flight test personnel, to nearly 500 dedicated flight test personnel. The Canadian based company in conjunction with several international risk sharing partners, has created a highly dynamic flight test environment, tasking the Flight Test Center with the challenge of bringing a new product to market each year. This rapid growth was centered on supporting three aircraft product lines; Learjet, Canadair, and DeHavilland. New hangars, telemetry, and ground support facilities were built to accommodate the increased flight test demands. The Bombardier Flight Test Center, otherwise known as BFTC, conducts flight test operations on a seven day per week schedule, and in 1999, flew over 5000 flight test hours in development and certification testing.

The Learjet 85 is a business jet with an unpowered manual elevator control and is designed for a maximum dive Mach number of 0.89. During the early design, it was found that the stick force required for a 1.5g pull-up from a dive would exceed the limit set by FAA regulations. A design improvement of the tailplane was initiated, using 2D and 3D Navier-Stokes CFD codes. It was discovered that a small amount of positive camber could reduce the elevator hinge moment for the same tail download at high Mach numbers. This was the result of the stabilizer forebody carrying more of the tail download and the elevator carrying less. Consequently, the elevator hinge-moment during recovery from a high-speed dive was lower than for the original tail. Horizontal tails are conventionally designed with zero or negative camber since a positive camber can have adverse effects on tail stall and drag.

In civil aviation the main driver for Structural Health Monitoring (SHM) is to provide maintenance and ownership benefits. The maintenance benefits are defined in terms of improving maintenance planning, increasing inspection intervals and reducing inspection cost. The ownership benefits can be measured in residual value and life extension. In this paper different aspects of SHM implementation are discussed for fatigue monitoring and fatigue damage sensing with a consideration of minimizing challenges for SHM implementation. First, the current Fatigue Monitoring implementation scenarios for the most representative agile military aircraft are reviewed. In the following some aircraft utilization results obtained from analyzing different airlines are presented. The obtained results show a better possibility of categorizing fleet of an airline in comparison with agile military aircraft.

The objective of this document is to present the methodology used to verify the structural integrity of a redesigned composite part. While shifting the manufacturing process of a composite part from pre-impregnated to a liquid resin injection process, the Composites Development team at Bombardier Aerospace had to redesign the component to a new set of design allowables. The Integrated Product Development Team (IPDT) was able to quickly provide a turnkey solution that assessed three aspects of airframe engineering: Design, Materials & Processes (M&P) and Stress. The focus of this paper will be the stress substantiation process led by the Stress Engineers. It will also bring up the synergies with M&P that are unique to the IPDT approach. The stress substantiation process required three distinct checks be confirmed.

The need for efficient manufacturing approaches has emerged with the increasing usage of composites for structural components in commercial aviation. Resin Transfer Molding (RTM), a process where a fiber preform is injected with resin into a closed tool, can achieve high fiber content required for structural components as well as improved dimensional accuracy since all surfaces are controlled by a tool surface. Moreover, RTM is well suited for parts that can be standardized throughout the aircraft, such as a fuselage frames and stringers. The objective of this investigation is to develop a preforming approach for a C-Shaped Fuselage frame. Two approaches are proposed: tri-axial braiding and hand lay-up of Non-Crimp Fabrics. The fiber architecture of the basic materials as well as the complete preforms is explained. The necessary preforming operations are detailed. The quality control measurement of fiber orientation and thickness are presented.

Leading edge roughness is known to influence the aerodynamic performance of wings and airfoil sections. Aerodynamic tests show that these effects vary with the type and texture of the applied roughness. The quantification of the relationship between different types of roughness is not very clear. This makes the comparison of results from different tests difficult. An attempt has been made to find a relationship between randomly distributed roughness using cylinders of different heights and densities, roughness using ballotini, and equivalent sand grain roughness. A CFD method based on the Cebeci-Chang roughness model was used to generate correlations with experimental data. It is found that the variation of the size and density of individual roughness elements can be represented using one roughness parameter, Rp, which is equivalent to the sand grain roughness parameter used in the Cebeci-Chang model.

During the course of an aircraft program, cost and weight savings are two major areas demanding constant improvements. An Integrated Product Development Team (IPDT) was set to the task of proposing potential improvements to an aircraft under development. From a list of potential parts, the IPDT selected one which was considered as the most suitable to leverage a co-curing process. In the aircraft manufacturing industry, any major modification to a part design should follow the program's means of compliance to certification. Furthermore, to demonstrate the new design's safety, sizing methodology and all supplementary testing must fit in the certification strategy. The IPDT approach was used to ensure the maturity of both process and part. Indeed, a mature turnkey solution can be implemented quickly on the shop floor. This IPDT approach is detailed in another SAE 2013 technical paper entitled: “A Novel Approach for Technology Development: A Success Story” [3].

Traceability has always been considered a useful but costly activity and different methods have been applied to reduce this cost. The current paper constitutes an attempt to improve these methods by introducing an optimal traceability process to be used in the context of RTCA DO-297 “Integrated Modular Avionics (IMA) Development Guidance and Certification Considerations”. The paper starts by comparing the definitions of traceability from DO-297 and the related development guidelines (i.e. ARP4754A, DO-254 and DO-178B). The paper continues by classifying the traceability methods recommended by the guidelines and introducing a performance criterion for optimal traceability based on category theory. This criterion addresses the possibility of information loss present in the current traceability methods. The paper proposes an optimal traceability process (i.e. that guarantees that information is not lost) and exemplifies it. The paper ends by recommending further enhancements.

In order to guarantee systems immunity, lightning induced electromagnetic energy has to be lower than the system's susceptibility threshold. This can be achieved, if the aircraft structure provides a good protection against lightning current as well as against its electromagnetic induced field. Moreover such a structure is also required to constitute a ground plane that guarantees very low common mode impedance between all grounded systems in order to keep them at the same electrical potential. The interaction of lightning with aircraft structure, and the coupling of induced energy with harnesses and systems inside the airframe, is a complex phenomenon, mainly for composite aircraft. Composite structures are either not conductive at all (e.g., fiberglass) or are significantly less conductive than metals (e.g., carbon fiber).

With the high design/performance requirements in modern aircrafts, the need for a flexible airframe structural modeling strategy during the different phases of the airframe development process becomes a paramount. Hybrid structural modeling is a technique that is used for aircraft structural representation in which several Finite Element Modeling concepts are employed to model different parts of the airframe. Among others, the Direct Matrix Input at a Grid-Point (DMIG) approach has shown superiority in developing high fidelity, yet, simplified Finite Element Models (FEM's). While the deformation approach is a common choice for loads recovery in structures represented by stick models, using structural models simulated by the DMIG representation requires the adoption of a different approach for loads recovery applications, namely, the momentum approach.

Integrated modular avionics (IMA) architectures host multiple federated avionics applications on a single platform and provide benefits in terms of size, weight, and power, which, however, leads to increased complexity, especially during the development process. To cope efficiently with the high level of complexity, a novel, structured development methodology is required. This paper presents a model-based systems engineering (MBSE) development approach for the so-called “distributed integrated modular architecture” (DIMA). The proposed methodology adapts the open-source Capella tool, based on the Architecture Analysis & Design Integrated Approach (ARCADIA) methodology, to implement a complete design cycle, starting with requirements captured from the aircraft level to streamline the development, culminating in the integration of an avionics application into an ARINC 653 platform.

A landing gear design automation tool has been developed and integrated in the conceptual multi-disciplinary optimization (MDO) environment at Bombardier Aerospace (BA). The tool allows an optimization to consider the landing gear integration at each design iteration. It uses design rules followed at BA to determine positions and ground contact points for the nose and main landing gears, while performing all necessary checks such as tip over, tail strike, and wing-tip strike angles. Subject to maximum loads from a set of predefined cases, the landing gear structure is sized and the tires and rims are selected from an embedded database. Once the landing gear is defined, a full kinematic analysis is performed to optimize the pivot axis and stowage of the gear in the fuselage. The tool was validated with actual data from several aircraft showing minimal errors in landing gear positioning and sizing (± 3%).

The Safety Management System requires a structured Risk Management Process to be effective. In the technical fields where numerous potentially catastrophic risks exist, processes and procedures need to account not only for the hardware random failures but also of human errors. The technology has progressed to the point where the predominant safety risks are not so much the machine failures but that of the human interaction. Accidents are rarely the result of a single cause but of a number of latent contributing factors that when combined result in the accident. In the Aerospace industry, the operational risk to the fleet is assessed by the manufacturer and the operator independently and is used in safety and/or regulatory decision-making.

The safe operation of technical systems is a mandatory basic requirement for the entire industry. However, there are specific industries where the safety of operation is critical and is considered as a required characteristic. These types of industries include the aerospace, military, civil aviation, nuclear power, as well as chemical and automotive industries. Safety is everyone's responsibility but engineering plays the most important role in the course of achieving a safe product operation. There are two specific phases of the product life cycle where the safety characteristics should be addressed by engineering activities: the design and development and operation phases. Modern engineering education is oriented to provide future engineers with a sufficient background to be able to Conceive-Design-Implement-Operate.

This paper discusses the correlation of IVHM (Integrated Vehicle Health Management) as an emerging aerospace discipline and the Big Data paradigm widely discussed in the Information Technology industry. The 4-V model is discussed to qualify a Big Data problem in terms of the volume, variety, velocity and veracity of the data involved. Big Data management allows, for example, correlations to be found to “spot business trends, determine quality of research, prevent diseases, combat crime, and determine real-time roadway traffic conditions”. Examining these two fields side by side is necessary and desirable because innovation is very likely to occur when and where different but correlated domains interface. This paper compares the most significant technical components required for Big Data Analytics and IVHM to work.

During the NASA/FAA Tailplane Icing Program, pilot evaluations of aircraft flying qualities were conducted with various ice shapes attached to the horizontal tailplane of the NASA Twin Otter Icing Research Aircraft. Initially, only NASA pilots conducted these evaluations, assessing the differences in longitudinal flight characteristics between the baseline or clean aircraft, and the aircraft configured with an Ice Contaminated Tailplane (ICT). Longitudinal tests included Constant Airspeed Flap Transitions, Constant Airspeed Thrust Transitions, zero-G Pushovers, Repeat Elevator Doublets, and, Simulated Approach and Go-Around tasks. Later in the program, guest pilots from government and industry were invited to fly the NASAT win Otter configured with a single full-span artificial ice shape attached to the leading edge of the horizontal tailplane.

Many uncertainties in an in-flight ice shape prediction are related to convection heat transfer coefficient, which in turn depends on the flow, turbulence and laminar/turbulent transition models. The height of ice roughness element used to calculate the Equivalent Sand Grain Roughness height (ESGR) is a very important input of the turbulence model as it strongly influences the shape of the accreted ice. Unfortunately, for in-flight icing, the ESGR is unknown and generally calculated using semi-empirical models or empirical correlations based on a particular ice shape prediction code. Each ice shape prediction code is unique due to the models and correlations used and the numerical implementation. Ice roughness correlations do not have the same effect in each ice shape prediction code. A new approach to calculate the ESGR correlation taking into consideration the particularities of the ice shape prediction code is developed, calibrated and validated.