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This paper presents a novel scheme for the start-up of prime movers in starter/generator systems, such as main engine and auxiliary power units (APUs) in aerospace applications. The paper discusses this novel technique in detail for providing single-phase excitation techniques to a start exciter in a starter/generator system to increase the torque per ampere and lower the excitation voltage requirement. Simulation results are provided comparing this novel scheme with a traditional method.

This paper focuses on advances in active power converter topologies for power quality solutions for More Electric Aircraft (MEA). Advancements in power electronics encompass many technologies including power semiconductors, microprocessors or digital signal processors (DSPs), and component packaging. Hence, active power electronic solutions are becoming more attractive from the perspective of weight, volume, performance and cost. A particular contribution that leads to these advancements is the feasibility of implementing the robust control topologies using faster processors. In this paper various active topologies are reviewed, but a particular emphasis is given to a novel control topology for an active filtering technique where an overall reduction of current harmonics of an aircraft power distribution system can be achieved at the system level rather than at the Line Replaceable Unit (LRU) level.

Aviation propulsion development continues to rely upon fossil fuels for the vast majority of commercial and military applications. Until these fuels are depleted or abandoned, burning them will continue to jeopardize air quality and provoke increased regulation. With those challenges in mind, research and development of more efficient and electric propulsion systems will expand. Fuel-cell technology is but one example that addresses such emission and resource challenges, and others, including negligible acoustic emissions and the potential to leverage current infrastructure models. For now, these technologies are consigned to smaller aircraft applications, but are expected to mature toward use in larger aircraft. Additionally, measures such as electric/conventional hybrid configurations will ultimately increase efficiencies and knowledge of electric systems while minimizing industrial costs.

The comparison between a proposed aircraft cabin and cargo heater control system and conventional control schemes is presented together with the key performance figures of the systems. An active AC/DC converter comprising a Phase-Locked Loop (PLL) is proposed to control the energy supplied by the AC Variable Frequency (VF) source to the heater loads instead of controlling the energy by means of a Pulse-Width Modulated (PWM) AC power flow. The proposed system eliminates problems associated with interharmonics generated in the AC VF PWM case - a material advantage. It draws a close to sinusoidal current from the VF source, features a near unity power factor, and operates within the VF range due to the use of PLL.

An emerging emphasis for the design and development of vehicle condition-based maintenance (CBM) systems amplifies its use for conducting vehicle maintenance based on evidence of need. This paper presents a systems engineering approach to creating an integrated vehicle health management (IVHM) architecture which places emphasis on the system's ultimate use to meet the operational needs of the vehicle and fleet maintainer, to collect data, conduct analysis, and support the decision-making processes for the sustainment and operations of the vehicle and assets being monitored. The demand for a CBM system generally assumes that the asset being monitored is complex or that the operational use of the system demands complexity, timely response or that system failure has catastrophic results. Ground vehicles are such complex systems, which are the emphasis of this paper. Developing the system architecture of such complex systems demands a systematic approach.

A passive gas removal device, i.e. gas trap is used in the Internal Thermal Control System (ITCS) of the International Space Station (ISS) to remove non-condensable gases to prevent the cavitation or air locking of the pump and malfunction of the pressure and flow sensors. Since the non-condensable gases are always ingested into the ITCS during the routine maintenance and/or replacement of components in the ITCS, it is necessary to have an efficient and reliable gas trap in the liquid coolant loop of the ITCS. To increase tolerance to particulate and microbial growth fouling, extend the operational life, reduce the cost and on-orbit maintenance, and decrease crew workload, an alternative gas trap composed of only one type of membrane is developed. This paper describes the efforts involved in this development, which include the design concept of the alternative gas trap, performance modeling, and the preliminary performance test of the alternative gas trap in the relevant environment.

The aerospace ecosystem is a complex system of systems comprising of many stakeholders in exchanging technical, design, development, certification, operational, and maintenance data across the different lifecycle stages of an aircraft from concept, engineering, manufacturing, operations, and maintenance to its disposal. Many standards have been developed to standardize and improve the effectiveness, efficiency, and security of the data transfer processes in the aerospace ecosystem. There are still challenges in data transfer due to the lack of standards in certain areas and lack of awareness and implementation of some standards. G-31 standards committee of SAE International has conducted a study on the available digital data standards in aircraft asset life cycle to understand the current and future landscapes of the needed digital data standards and identify gaps. This technical paper presents the study conducted by the G-31 technical committee.

Industry standards are key enablers in helping businesses around the meet regulatory requirements, keep costs down, gain market access, and instill consumer confidence. SAE International, a standards development organization (SDO) critical to the transportation industry, works in partnership with industry to develop and distribute standards important in automotive and aerospace product development, product performance, and quality management. Historically, industry standards were formatted with the intention of being distributed in print. This changed with the evolution of new electronic formats, and now most standards are available in PDF or EPUB. While progressive at the time, these formats are now proving inadequate due their optimization for readability by the human eye versus consumption by electronic endpoints.

This paper examines why large aircraft engines are started the way they are today, and why that may all change in the not too distant future. Electric starting of aircraft engines and Auxiliary Power Units (APU) has been limited to 28 VDC battery systems, with starting power typically under 10 kW. Above this power level the very high battery currents, and resulting voltage drops, make the approach less and less practical. Large engines for commercial transports may require more than 100 kW to start so low voltage battery starting will not be an option.

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.

During participation on EU FP7 HAIC project, Honeywell has developed methodology to detect High Altitude Ice Crystals with the Honeywell IntuVue® RDR-4000 X-band Weather Radar. The algorithm utilizes 3D weather buffer of RDR-4000 weather radar and is based on machine learning. The modified RDR-4000 Weather Radar was successfully flight tested during 2016 HAIC Validation Campaign; the technology was granted Technology Readiness Level 6 by HAIC consortium. After the end of HAIC project, the method was also evaluated with respect to newly set preliminary industry standard performance requirements1. This paper discuses technology design rationale, high level technology architecture, technology performance, and challenges associated with performance evaluation.

This paper reviews the characteristics of a power line network as data communication medium and studies the challenges encountered when communicating over power wiring. This technology review has been done as part of feasibility study for using aircraft power-lines for data communication. Power-Line Communication is a term which describes the use of existing electrical lines to provide the medium for a high speed communications network. Power Line Communications is achieved by superimposing the voice or data signals onto the line carrier signal using an appropriate communication technology. Power Line Communications represent a potential simplicity for communications among different devices, because it does not need additional wires for connecting devices network together. Power line cables have been used as a communication medium for many years. However, because power line cables are not designed for communication, they pose major challenges for a modem designer.

Listen in as Dr. Ravi Rajamani discusses his new book, the history of electric flight, and electric propulsion. Learn more at books.sae.org/t-135.

Many avionics and aircraft equipment manufacturers use DO-160 [Ref. 1] Section 22 to test their equipment for indirect effects of lightning without understanding why they are testing to specific values. Many aircraft manufacturers struggle with determining the level of indirect lightning that will be acceptable for their vehicle and what level of requirements they need to pass down to the avionics and aircraft equipment manufacturers. Organizations like SAE and RTCA, Inc. work to collect data on lightning and spend countless hours assimilating the information and developing documents to help engineers use the information. They struggle with knowing what data is pertinent and how it will be received and used by the engineering community.

The purpose of the Los Alamos High-Energy Neutron Testing Handbook is to provide user information and guidelines for testing Integrated Circuits (IC) and electronic systems at the Irradiation of Chips and Electronics (ICE) Houses at the Los Alamos Neutron Science Center (LANSCE) at Los Alamos National Laboratory (LANL). Microelectronic technology is constantly advancing to higher density, faster devices and lower voltages. These factors may increase device susceptibility to radiation effects. The high-energy neutron source at LANSCE/LANL provides the capability for accelerated neutron testing of semiconductor devices and electronic systems and to simulate effects in various neutron environments.

The RTCA SC-230 committee began working on minimum operational performance standards (MOPS) for ice crystal detection using weather radar in 2018. The resulting MOPS document will be released in 2023. This paper presents the rationale, summarizes key requirements, and discusses means of validation for an ice crystal detection function incorporated in an airborne weather radar system.

Laser Based Powder Bed Fusion, a specific application of additive manufacturing, has shown promise to replace traditionally fabricated components, including castings and wrought products (and multiple-piece assemblies thereof). In this process, powder is applied, layer by layer, to a build plate, and each layer is fused by a laser to the layers below. Depending on the component, it appears that only 3-5% of the powder charged into the powder bed fusion machine is fused. Honeywell’s initial part qualification efforts have prohibited the reuse of powder. Any unfused powder that exits the dispenser (i.e., surrounds the build or is captured in the overflow) is considered used. In order for the process to be broadly applicable in an economical manner, a methodology should be developed to render the balance of the powder (up to 97% of the initial charge weight) as re-usable.

Blockchain as a technology has been successfully deployed in the financial industry. As the technology continues to mature, there are opportunities to use this to solve operational challenges in Aerospace. One of the common use cases is replacing paper records as a proof of compliance with a blockchain enabled distributed ledger. Commonly available open source blockchain frameworks have security ingrained in the components. However, replacing paper records with a blockchain based distributed ledger will require investigation of potential risks involved in the end to end usage of this technology for records management. The objective of this paper is to elucidate potential risks in an aviation record management workflow environment enabled by blockchain and suggest requirements to mitigate the risks.

There is a growing need for high voltage direct current (HVDC) power distribution systems in aircraft which provide low-loss distribution with low weight. Challenges associated with HVDC distribution systems include improving reliability and reducing the size and weight of key components such as electric load control units (ELCUs), or remote power controllers (RPCs) for load control and feeder protection, and primary bus switching contactors. The traditional electromechanical current interrupting devices suffer from poor reliability due to arcs generated during repeated closing and opening operations, and are generally slow in isolating a fault with potentially high let-through energy, which directly impacts system safety.

“Spotlight on Design: Insight” features an in-depth look at the latest technology breakthroughs impacting mobility. Viewers are virtually taken to labs and research centers to learn how design engineers are enhancing product performance/reliability, reducing cost, improving quality, safety or environmental impact, and achieving regulatory compliance. As global concerns about the negative consequences of greenhouse gases on the environment increase, regulatory agencies around the world are taking serious steps to address the issue of tailpipe emissions In the episode “Fuel Efficiency: Fuel Economy Testing” (12:05), engineers at the EPA’s National Vehicle and Fuel Emissions Laboratory demonstrate how different vehicles are tested for emissions, and AVL’s technical team shows how accurate tailpipe emissions can be measured and reported.