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The “holy grail” for prognostics and health management (PHM) professionals in the aviation sector is to have integrated vehicle health management (IVHM) systems incorporated into standard aircraft maintenance policies. Such a change from current aerospace industry practices would lend credibility to this field by validating its claims of reducing repair and maintenance costs and, hence, the overall cost of ownership of the asset. Ultimately, more widespread use of advanced PHM techniques will have a positive impact on safety and, for some cases, might even allow aircraft designers to reduce the weight of components because the uncertainty associated with estimating their predicted useful life can be reduced. We will discuss how standard maintenance procedures are developed, who the various stakeholders are, and – based on this understanding - outline how new PHM systems can gain the required approval to be included in these standard practices.

Frequently, a choice between system concepts must be made on the basis of something other than a detailed evaluation of the design effectiveness of these systems. This paper develops a rudimentary analysis process for use in addressing this problem.

This recommended practice has been developed for use in any EEE system used in the AADHP industries. RPA is especially important to AADHP systems, which are often safety critical applications that must operate for long times in rugged environments. These EEE systems often use EEE components that were originally designed and produced for more benign consumer applications. Although the focus of this recommended practice is on AADHP applications, the process described herein is not limited to AADHP and may be used for EEE systems and components in any industry.

Abstract Fighter pilots must study models of aircraft dynamics before learning complex maneuvers and tactics. Similarly, autonomous fighter aircraft applications may benefit from a model-based learning approach. Instead of using a preexisting physics model of a given aircraft, a machine learning system can learn a predictive model of the aircraft physics from training data. Furthermore, it can model interactions between multiple friendly aircraft, enemy aircraft, and the environment. Such a system can also learn to represent state variables that are not directly observable, as well as dynamics that are not hard coded. Existing model-based methods use a deep neural network that takes observable state information and agent actions as input and provides predictions of future observations as output. The proposed method builds upon this approach by adding a residual feedforward skip connection from some of the inputs to all of the outputs of the deep neural network.

This SAE Aerospace Information Report (AIR) is prepared for stakeholders seeking information about the evolution, integration, and approval of SHM technologies for military aircraft systems. The report provides this information in the form of (a) two military organizations’ perspectives on requirements, and (b) general SHM challenges and industry perspectives. The report only provides information to generate awarness of prespectives for military aircraft and, hence, assists those who are involved in developing SHM systems understanding the broad range of regulations, requirements, and standards published by military organizations that are available in the public domain from the military organizations.

Abstract This article describes the research work taken to compare the effect of air blast and surface-buried mine blast loading on an armored fighting vehicle (AFV) escape hatch, using the coupled Eulerian-Lagrangian (CEL) technique. Two types of escape hatch were considered for the study, namely, the flat plate version and double-side curved-plate version. To evaluate the research methodology used in this investigation, initially, a published experimental work on a circular plate subjected to air blast was chosen and a benchmark simulation was carried out using the CEL technique to establish the simulation procedure. Then the established procedure was utilized for further analysis. It was observed that the variation in the deformation between the published literature and the simulation work was well within the acceptable engineering limits.

A common scenario in engineering design is the availability of several black-box functions that describe an event with different levels of accuracy and evaluation cost. Solely employing the highest fidelity, often the most expensive, black-box function leads to lengthy and costly design cycles. Multi-fidelity modeling improves the efficiency of the design cycle by combining information from a small set of observations of the high-fidelity function and large sets of observations of the low-fidelity, fast-to-evaluate functions. In the context of Bayesian optimization, the most popular multi-fidelity model is the auto-regressive (AR) model, also known as the co-kriging surrogate. The main building block of the AR model is a weighted sum of two Gaussian processes (GPs). Therefore, the AR model is well suited to exploit information generated by sources that present strong linear correlations.

Abstract The use of converging-diverging (C-D) variable area nozzle (VAN) in military aeroengines is now common, as it can give optimal expansion and control over engine back pressure, for a wide range of engine operations. At higher main combustion temperatures (desired for supercruise), an increase in the nozzle expansion ratio is needed for optimum performance. But changes in the nozzle throat and exit areas affect the visibility of engine hot parts as the diverging section of the nozzle is visible for a full range of view angle from the rear aspect. The solid angle subtended by engine hot parts varies with change in visibility, which affects the aircraft infrared (IR) signature from the rear aspect. This study compares the performances of fixed and variable area nozzles (FAN and VAN) in terms of engine thrust and IR signature of the engine exhaust system in the boresight for the same increase in combustion temperature.

This Handbook is intended to accompany or incorporate AS5643, AS5643/1, AS5657, AS5706, and ARD5708. In addition, full understanding of this Handbook also requires knowledge of IEEE-1394-1995, IEEE-1394a, and IEEE-1394b standards. This Handbook contains detailed explanations and architecture analysis on AS5643, bus timing and scheduling considerations, system redundancy design considerations, suggestions on AS5643-based system configurations, cable selection guidance, and lessons learned on failure modes.

The potential for small scale local production of Bio fuel derivatives and their partial blending with aviation turbine fuel in non-civilian bases has been investigated. A feasibility study on technical readiness levels for process viability is presented in the paper. Demand side analysis for various blend mixes and corresponding requirement for production facilities and land area requirements are performed. Sustainable production and blending operations are the basis for selection of key performance indicators for the air base. Guiding framework and readiness evaluation processes are delineated for the base. Qualitative inference is combined with quantitative scoring system within the framework.

Future tactical aircraft will have increased capabilities that will place greater demands on their secondary power systems. Added capabilities such as low observability or internal weapons storage are being planned for without significantly increasing the aircraft's size and weight. The power system must therefore have reduced volume, weight, and complexity, while also being more reliable and maintainable. The auxiliary power unit (APU) is a critical component that must be improved to upgrade the capabilities of the power system. Increasing the APU's power density is one important way for reducing the power system's size and weight. Increased power density, however, will require a power unit operating with higher gas generator temperatures, so this condition will be the major challenge for new APU designs.

Abstract To assist in initializing the conceptual design of hypersonic aircraft, we outline a new, systematic framework based on historical aircraft data and primarily composed of design data and regression models. It is a rapid, low-fidelity analysis to provide a starting point for the conceptual design process by (1) assessing the performance capabilities of four types of high-speed aircraft, (2) providing initial estimates for weights and geometry with uncertainty, and (3) exploring how changes in these affect performance within design spaces. Using this framework, an initial set of reasonable aircraft configurations is obtained based on speed, altitude, and payload requirements, which can serve to accelerate the design process and avoid unforeseen problems later in the design cycle. An example is provided to demonstrate the application of the framework to launch the conceptual design of a new hypersonic aircraft with a given set of mission requirements.

Finite Element Analysis (FEA) is a powerful and well recognized tool used in the analysis of heat transfer problems. However, FEA can only analyze solid bodies and, by necessity thermal analysis with FEA is limited to conductive heat transfer. The other two types of heat transfer: convection and radiation must by approximated by boundary conditions. Modeling all three mechanisms of heat transfer without arbitrary assumption requires a combined use of FEA and Computational Fluid Dynamics (CFD).

Finite Element Analysis (FEA) has been an indispensable tool for design simulation for several decades but this wide spread use has been limited to simple types of analyses. Relatively recently, more advanced analyses have given easy-to-use interfaces enabling design engineers to simulate problems formerly reserved for analysts. FEA Beyond Basics targets the FEA users who wish to explore those advanced analysis capabilities. It will demonstrate how to move past the ubiquitous linear structural analysis and solve structural nonlinear problems characterized by nonlinear material, large displacements, buckling or nonlinear connectors.

Project Oculus is an in-flight deployable mechanical arm/pod system that will accommodate 500 pounds of sensor payload, developed for a C-130 military aircraft. The system is designed for use in counter narco-terrorism and surveillance applications by the Department of Defense and the National Guard [1]. A prototype of the system has been built and is in the testing/analysis phase. The purpose of this study was to analyze the actual stresses and strains in the critical areas found using previous Finite Element (FE) simulations and to ensure that acceptable safety requirements have been met. The system components tested will be redesigned, tested, and reconstructed in the case of unacceptable safety factors or if more reliable methods can be implemented. The system was built to be deployed and retracted in flight, to avoid causing any problems in take off and landing.

The present study examined the degree of spatial awareness obtained using what has been called an Augie Arrow, enabled so that it could be displayed as either a “nearest horizon pointer” (NH) or an “up arrow” (UP) indicator. Another issue investigated concerned the usefulness of analog dials vice digital readouts of airspeed and altitude as an aid to recovery. During simulated flight, twelve subjects were required to recover from six unusual attitudes employing one of four HUD formats: (1) Standard HUD, (2) Augie Arrow, (3) Analog Dials, and (4) Augie Arrow with Analog Dials. Results revealed that the Augie Arrow produced the most rapid recovery time. The Augie Arrow configuration was optimal at the most severe unusual attitudes, especially for the NH mechanization. The Dials only HUD was not particularly helpful in recovery, and the Arrow with Dials HUD was rated as a significant clutter problem.

Currently, for various military activities such as construction of bridges, digging trenches, construction of roads and clearing the area during landslides, separate unit of bulldozer for dozing operation and loader for loading operation is required. But the need is to develop a single unit which could perform both of these operations efficiently and simultaneously. The paper discusses about the development of dozer bucket mechanism as a single unit to perform dozing and loading operation and connected to the amphibious infantry combat vehicle. To develop the dozer bucket mechanism synthesis of mechanism (Linkages and Boom) has carried out and care has taken to fulfill the above stated functional requirement and satisfy the geometrical constraints. The synthesis of mechanism is done with the help of ‘CATIA’ software packages. The force calculation on various joints at the different position of mechanism has evaluated with the help of ’ADAMS’ software.