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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.

This paper presents a generic Redundancy Management (RM) requirements definition process that is applicable to a complex system RM requirements development. In the aerospace industry, the ‘Aerospace Recommended Practices’ (ARP) 4754 and 4761 are typically used processes to ensure given safety and availability goals for complex systems. The process proposed in this paper is based on these standard guidelines and enhances them to provide a standardized process for the development of RM requirements with interactions between the system requirements development and the preliminary system safety assessment processes. The output of this process will help to achieve the following objectives: The system RM/failure monitoring requirements are defined commensurate with the system safety and availability requirements; the system is fault-tolerant to the degree necessary to meet the system safety and availability requirements; the system is robust and the system architecture is optimized.

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.

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.

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.

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.