Search Results

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.

This talk will present an overview of the newly published DO-326/ED-202 "Airworthiness Security Process Specification". Presenter Daniel P. Johnson, Honeywell

This paper discusses the problem of designing electric machines (EM) for advanced electric generators (AEG) used in aerospace more electric architecture (MEA) that would be applicable to aircraft, spacecraft, and military ground vehicles. The AEG's are analyzed using aspects of Six Sigma theory that relate to critical-to-quality (CTQ) subjects. Using this approach, weight, volume, reliability, efficiency, and cost (CTQs) are addressed to develop a balance among them, resulting in an optimized power generation system. The influence of the machine power conditioners and system considerations are also discussed. As a part of the machine evaluation process, speeds, bearings, complexities, rotor mechanical and thermal limitations, torque pulsations, currents, and power densities are also considered. A methodology for electric machine selection is demonstrated. Examples of high-speed, high-performance machine applications are shown.

Efficient development and testing of brake systems requires further substitution of expensive and time consuming vehicle testing by appropriate dynamometer testing. Some of the current simulation methods do not reflect the needs of engineering and the progress made in the development of test equipment. The lack of suitable procedures may cause unexpected delays in the realization of projects. Road load simulations for lifetime prediction on brake dynamometers have a long history, however never got a real break-through in Europe - possibly because the prediction quality and efficiency did not satisfy. This paper concentrates first on the analysis of the vehicle data recorded in Mojacar (Spain) which is a sign-off test for wear and noise for brands of Ford Motor Company for European market. Specific attention is given to different types of driving resistances and road profiles and to consideration of different methods for numerical description and comparison of road load data.

Commercial transport aircraft have adopted TCP/IP based onboard networking technology to integrate information interchange. This change along with the addition of a TCP/IP based air-ground data link will permit the aircraft network to establish links with ground networks and be integrated into the airline enterprise network. There are many challenging considerations when connecting a remote network to an enterprise network. These challenges are multiplied when that remote network is constantly in motion, both physically and in terms of its link to the ground network. An important consideration in any enterprise network is the element of security. AEEC has published ARINC Report 811: Commercial Aircraft Information Security Concepts of Operation and Process Framework [1] as a guide for the airlines as they consider how to deal with this new challenge.

Current Environmental Control and Life Support Systems (ECLSS), particularly on large systems, have a tendency to include several heterogeneous processing elements. This approach is also the default in the commercial aircraft industry. However, Honeywell has been extremely successful in the past decade in using an integrated modular approach to command and data handling for aircraft avionics. This approach, dubbed “Fifth Generation Avionics” by the Air Force's Wright Laboratory, has resulted in significant reductions in the size, weight, power, and acquisition costs of the data handling subsystem. Logistics, modification, and upgrade costs also decreased considerably. While commonality is maximized in the integrated modular architecture, each application continues to be independent with internal designs completely under the control of the application developer.

The bleed air contamination monitor was developed at Honeywell to ensure that our products provide the highest quality bleed air to aircraft environmental control systems. The bleed air contamination monitor is currently for ground based applications only. It is being developed into an on board system for future applications. Current Aircraft Cabin Air Quality measurement techniques are very labor intensive and require days or even weeks of laboratory analysis to provide results. This is unacceptable from a manufacturing and service perspective. Development of a real time analyzer began in the early 1990s and has progressed to a point where a product is ready for introduction that not only provides real time information regarding engine air contamination, but is also easy for operators to use with a minimum amount of training.

A detailed study was conducted on nitrification using a bench top bioprocessor system proposed for water recycling of a urine-soap wastewater expected to be generated by crewmembers on International Space Station (ISS) or similar long-term space missions. The bioprocessor system consisted of two packed bed biofilm reactors; one anoxic reactor used for denitrification and one aerobic reactor used for nitrification. lnfluent wastewater was a mixture of dilute NASA whole body soap (2,300 mg/L) and urea (500 mg/L as organic nitrogen). During two months of steady-state operation, average chemical oxygen demand (COD) removal was greater than 95%, and average total nitrogen removal was 70%. We observed that high levels of nitrite consistently accumulated in the aerobic (nitrifying) reactor effluent, indicating incomplete nitrification as the typical end product of the reaction would be nitrate.

The Indirect Boundary Element Analysis is employed for developing a computational pass-by noise simulation capability. An inverse analysis algorithm is developed in order to generate the definition of the main noise sources in the numerical model. The individual source models are combined for developing a system model for pass-by noise simulation. The developed numerical techniques are validated through comparison between numerical results and test data for component level and system level analyses. Specifically, the source definition capability is validated by comparing the actual and the computationally reconstructed acoustic field for an engine intake manifold. The overall pass-by noise simulation capability is validated by computing the maximum overall sound pressure level for a vehicle under two separate driving conditions.

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.

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.