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Nowadays, optimization of manufacturing and assembly operations requires taking into account the inherent processes variations. Geometric and dimensional metrology of mechanical parts is very crucial for the aerospace industry and contributes greatly to its. In a free-state condition, non-rigid parts (or compliant parts) may have a significant different shape than their nominal geometry (CAD model) due to gravity loads and residual stress. Typically, the quality control of such parts requires a special approach where expensive and specialized fixtures are needed to constrain dedicated and follow the component during the inspection. Inspecting these parts without jig will have significant economic impacts for aerospace industries, reducing delays and the cost of product quality inspection. The Iterative Displacement Inspection (IDI) algorithm has been developed to deal with this problem.

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.

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.

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.

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].

Non Destructive Inspection (NDI) of large Out of Autoclave Cure primary monolithic and sandwich Composite structures is challenging due to high requirement for flaw detection and characterization among porosity, delamination, disbond, foreign material, crushed core, dry fiber. Large scale NDI inspection with semi-automated and automated system is presented for flaw detection/characterization and porosity assessment methodology is described with results for high porosity level assessment in monolithic and sandwich structures.

Manufacturing operations introduce unreliability into hardware that is not ordinarily accounted for by reliability design engineering efforts. Inspections and test procedures normally interwoven into fabrication processes are imperfect, and allow defects to escape which later result in field failures. Therefore, if the reliability that is designed and developed into an equipment/system is to be achieved, efforts must be applied during production to insure that reliability is built into the hardware. There are various ways to improve the reliability of a product. These include: Simplification Stress reduction/strength enhancement Design Improvement Using higher quality components Environmental Stress Screening before shipment Process Improvements, etc. This paper concentrates on ‘Manufacturing Process Improvement’ effort through the use of design of experiments, (DOE). Hence, improved levels of reliability can be achieved.

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 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.