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Demand on the reliability of Electric Generators for Aerospace applications is assuming more importance everyday with the advent of “Fly-by-Wire” and “More-Electric-Aircraft” concepts. With today's high-powered avionics and sophisticated control systems, airline operators expect better performance and would no longer accept weak links in the system that need frequent maintenance. One of the weakest points in an electric generator is its reliance on rolling element bearings, which are subject to unpredictable and frequent failures. Huge redundancy and frequent maintenance ensure uninterrupted supply of electricity in an aircraft.

It’s a common practice to use different kinds tools to aid in the development and verification of modern safety critical avionics systems. These tools play a key role in avionics engineering and used in all project phases: requirements development, software design, source code development, integration, configuration management, and verification. Tools assist to analyze and improve system safety by automation of some of the activities which if performed manually and are therefore prone to human error. However, incorrect functioning of a tool can have negative impact on the safety and performance of the Safety Critical system. Hence, tools are proposed to be qualified whenever any of the design assurance process(es) described in RTCA/DO-178C or RTCA/DO-254 are eliminated, reduced, or automated using the tool unless the output of the tool is verified manually. Qualification of the tool gives confidence in the tool functionality.

Aircraft accidents caused by explosion of the vapor within the fuel tanks have been the subject of many recent articles. Methods of either suppressing the combustion or preventing the ignition have been considered. Indeed, solutions such as liquid nitrogen, halon, and reticulated foam have been installed on production aircraft. However, these have proved to be expensive to operate or are being phased out. By working together, the authors have developed the capability to provide fully integrated On-Board Inert Gas Generating Systems (OBIGGS) based on novel hollow fiber membrane technology. An overview of the advantages of such an approach is presented together with an outline of the system design method. The importance of considering the effect of differing flight profiles, and the inter-reactions of the OBIGGS, with the Fuel System, Engine Bleed Air Management, and Environmental Control Systems in the design process are emphasized.

Atmospheric Neutron Single Event Effects (SEE) are widely known to cause failures in all electronic hardware, and cause proportionately more failures in avionics equipment due to the use altitude. In digital systems it is easy to show how SEE can contribute several orders of magnitude more faults than random (hard) failures. Unfortunately, current avionics Safety assessment methods do not require consideration of faults from SEE. AVSI SEE Task Group (Aerospace Vehicle Systems Institute Committee #72, on Mitigating Radiation Effects in Avionics) is currently coordinating development of an atmospheric Neutron Single Event Effects (SEE) Analysis method. This analysis method is a work in progress, in close collaboration with SAE S-18 and WG-63 Committees (Airplane Safety Assessment Committee). The intent is to include this method as part of current revisions to ARP4761 (Guidelines and Methods for Conducting the Safety Assessment Process on Civil Airborne Systems and Equipment).

The operating environment of aircraft causes accumulation and build-up of contamination on both the narrowest passages of the ECS (Environmental Control System) i.e: the heat exchangers. Accumulated contamination may lead to reduction of performance over time, and in some case to failures causing AOG (Aircraft on Ground), customer dissatisfaction and elevated repair costs. Airframers/airlines eschew fixed maintenance cleaning intervals because of the high cost of removing and cleaning these devices preferring instead to rely on on-condition maintenance. In addition, on-wing cleaning is t impractical because of installation constrains. Hence, it is desirable to have a contamination monitoring that could alert the maintenance crew in advance to prepare and minimize disruption when contamination levels exceed acceptable thresholds. Two methods are proposed to achieve this task, The effectiveness of these methods are demonstrated using analytical and computational tools.

Increased nickel concentrations in the IATCS coolant prompted a study of the corrosion rates of nickel-brazed heat exchangers in the system. The testing has shown that corrosion is occurring in a silicon-rich intermetallic phase in the braze filler of coldplates and heat exchangers as the result of a decrease in the coolant pH brought about by cabin carbon dioxide permeation through polymeric flexhoses. Similar corrosion is occurring in the EMU de-ionized water loop. Certain heat exchangers and coldplates have more silicon-rich phase because of their manufacturing method, and those units produce more nickel corrosion product. Silver biocide additions did not induce pitting corrosion at silver precipitate sites.

The Biological Wastewater Processor Experiment Definition team is performing the preparatory ground research required to define and design a mature space flight experiment. One of the major outcomes from this work will be a unit-gravity prototype design of the infrastructure required to support scientific investigations related to microgravity wastewater bioprocessing. It is envisioned that this infrastructure will accommodate the testing of multiple bioprocessor design concepts in parallel as supplied by NASA, small business innovative research (SBIR), academia, and industry. In addition, a systematic design process to identify how and what to include in the space flight experiment was used.

The issues of active vs. passive means of power quality improvement in aerospace applications are addressed. The concept of nonlinear load, i.e., the relationship between the current harmonics and system power factor has been reviewed. Both passive and active means of harmonic minimization are discussed, including resonance issues associated with passive networks and presenting an active rectifier switched in a Space Vector (SV) Pulse Width Modulation (PWM) manner. The analysis of power quality in aerospace applications is presented, together with the industry governing standards. Results of case studies are given, using Saber hierarchical tools for the system analysis. Both simulation and experimental results are provided, demonstrating power quality improvements in several aerospace applications.

In this work we have proposed an interesting clamping solution of V-band which has an important industrial impact by reducing the cost and assembly process as well compare to the traditional V-band. The design what we are focusing for is applied for all size of turbochargers which helps to connect the hot components such as manifold and turbine housing. The cost for V-band is mainly from T-bolt. It is made from special stainless steel which represents 50% of the total cost. In this work it is proposed a new V-band joint by changing bolt clamping status from tension to compression. From tension to compression we change the bolt material from high cost steel to low cost steel. The new total cost is reduced by 40%. The prototype is made and performed in static tests including anti-rotating torque test and salt spray test. The new joint meets the design requirements at static condition. Further work will focus on the dynamic qualification and at high temperature as well.

The implementation of the Future Air Navigation System (FANS) will be evolutionary rather than revolutionary. Different generations of airplane models, each operating in a variety of operating environments will dictate more than a single growth path. How these markets will evolve is a function of our collective ability to assign benefits to specific equipage, to forge new business relationships and to address the market as a global one. Realization of the full benefits of FANS will depend on leadership: who and when.