Search Results

Many of the certification regulations in 14 CFR Part 25 are by design, broad and as such, can be subject to large differences in the interpretation of what constitutes adequate compliance. Advisory Circulars (AC's) were developed for many of the regulations to assist industry, as well as certification personnel, with what is considered an acceptable, but not the only means, of compliance. However, there are many regulations where no advisory material is available. In these cases, the “acceptable means” of compliance can vary to a greater degree among the various aircraft certification offices. This difficulty is aggravated as new applicants and regulatory personnel enter the certification field. Recent discussions and interpretations on the usage of an avionic unit's mean time between failure or MTBF for its detectable faults as the basic repair rate for undetected or latent faults, is a subject area where no significant advisory material exists.

Since the 1960s, aerospace research and development (R&D) has been on a quest to eliminate oil lubrication systems from gas turbine engines. Beginning with small solar power dynamic “engines” for space applications, U.S. Government and industry have invested millions of dollars to mature this technology for incorporation into modern aircraft propulsion engines. This paper traces the evolution of oil-free rotor support systems that have actually been tested in advanced demonstrators, and the technology that enables this revolutionary engine configuration. However, this technology has yet to be fielded in aerospace products. The key factors of 45 years of Government and industry R&D and a vision to mature oil-free gas turbine engines are presented herein.

The first concept and early experiments of a mechanical counter pressure (MCP) spacesuit were published by Webb in the late 1960's. MCP provides an alternative approach to the conventional full pressure suit that bears some significant advantages, such as increased mobility, dexterity, and tactility. The presented ongoing research provides a thorough investigation of the physiological effect of mechanical counter pressure applied onto the human skin. In this study, we investigated local microcirculatory effects produced with negative and positive ambient pressure on the lower body as a preliminary study for a lower body garment. The data indicates that the positive pressure was less tolerable than negative pressure. Lower body negative and positive pressure cause various responses in skin blood flow due to not only blood shifts but also direct exposure to pressure differentials.

The first concept and early experiments of a Mechanical Counter Pressure (MCP) spacesuit were published by Webb in the late 1960's. MCP provides an alternative approach to the conventional full pressure suit that bears some significant advantages, such as increased mobility, dexterity, and tactility. The presented ongoing research provides a thorough investigation of the physiological effect of mechanical counter pressure applied onto the human skin. In this study, we investigated local microcirculatory effects produced with negative and positive ambient pressure on a bare arm, and with a MCP glove and sleeve. The data indicates that the MCP glove and sleeve effectively counteracted the adverse effects of negative environmental pressure.

The first concept and early experiments of a Mechanical Counter Pressure (MCP) spacesuit were published by Webb in the late 1960’s. MCP provides an alternative approach to the conventional full pressure suit that bears some potential advantages, such as increased mobility, dexterity, and tactility. The presented ongoing research provides a thorough investigation of the physiological effect of mechanical counter pressure applied onto the human skin. Preliminary results are presented from glovebox testing with an existing MCP glove. The data indicates that properly applied mechanical counter pressure greatly reduces the effect of low-pressure exposure, which makes MCP a viable technology for spacesuit gloves.

This paper introduces a novel method for an electric power generation system (EPGS) employing a lead-unity-lag (LUL) permanent-magnet (PM) generator operation for a direct current (DC) power distribution bus. In addition, background information of the prior art for a leading power factor EPGS is discussed. The concept of the new approach is defined and a comparative analysis between the new and old state-of-the-art solutions are documented. The performance features and technical details of the system parameters with respect to power generation system requirements are presented and discussed. Analysis and testing results are included. Finally, the advantages of this system, a conclusion, and recommendations for future work are provided. Test results from a system having elements of this novel approach are included. With this method for an LUL EPGS, the capability of the high-performance electric power generation systems is improved substantially.

The past twenty years have seen tremendous changes in the Avionics display and flight deck lighting due to the application of solid-state LED (light emitting diode) light sources and LCDs (liquid crystal displays). These advances significantly benefit the customer and pilot users when integrated correctly. This paper discusses recommended practices and guidance given in SAE ARP 4103 for modern Avionics flight deck lighting systems to satisfy the end user and obtain certification. SAE ARP 4103 Flight Deck Lighting for Commercial Transport Aircraft has recently been revised to keep up with the Avionics state-of-the-art and add clarification where needed. ARP 4103 contains recommended Avionics flight deck lighting design and performance criteria to ensure prompt and accurate readability and visibility, color identification and discrimination of needed information under all expected ambient lighting and electrical power conditions. For additional details, see the actual ARP 4103.

This paper addresses the implementation of electric taxiing without the use of main engines by using electric propulsion of the landing gears. Substantial progress in this area has been achieved by Honeywell Aerospace and Safran in a joint initiative for developing an electric green taxiing system (eTaxi). Considerable analysis, design, fabrication, and testing have already been completed, which culminated in a demonstration at the Paris Air Show (PAS) in 2013. The eTaxi system has been installed on an A320 airplane that uses the auxiliary power unit (APU) to generate electric power to provide propulsion to two wheels of the main landing gear. The main advantages of such a system are reduction of fuel consumption and audio noise, reduction of CO2 , carbon and nitrous emissions, reduced engine foreign object damage (FOD) exposure and fast-turn time savings by elimination of the ground tractor for pushback operation.

This paper presents a novel method and system for an electric power alternating-current (AC)-to-direct-current (DC) converter employing composite technology. The term composite entails utilization of more than one type of conversion operating in parallel. In addition, background information for the prior art, based on conventional autotransformer rectifier units (ATRUs), and active converters are discussed. The major requirements of AC-to-DC converters from both functional and protection perspectives are provided. The concept of the new approach is defined. Comparative analysis between the new and old methods is documented. The performance features and technical details of the system parameters with respect to AC-to-DC converter system requirements are presented and discussed. Analysis, simulation results, and test data are included. Finally, the advantages of this technology, which nearly doubles power density compared to the state-of-the-art, are summarized and a conclusion included.

Water recovery from wastewater is essential for the success of long-term missions to the Moon and Mars and human crew operations during explorations of these planets. Honeywell International and the team consisting of Thermodistillation Co. ( Kyiv, Ukraine) and NASA JSC Crew and Thermal Systems Division are developing an efficient wastewater processing subsystem that is based on centrifugal vacuum distillation. This subsystem will be tested at the NASA JSC Advanced Water Recovery Systems Development Facility. The Wastewater Processing Cascade Distillation Subsystem (CDS) utilizes an innovative and proven multi-stage thermodynamic process to produce purified water efficiently, and its rotary centrifugal design provides gas/liquid phase separation and liquid transport (pumping) under microgravity conditions.