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This paper presents the current state of a three-layer surface icing model for ice crystal icing risk assessment in aircraft engines, being developed jointly by Ansys and Honeywell to account for possible heat transfer from inside an engine into the flow path where ice accretion occurs. The bottom layer of the proposed model represents a thin metal sheet as a substrate surface to conductively transfer heat from an engine-internal reservoir to the ice layer. The middle layer is accretion ice with a porous structure able to hold a certain amount of liquid water. A shallow water film layer on the top receives impinged ice crystals. A mass and energy balance calculation for the film determines ice accretion rate. Water wicking and recovery is introduced to transfer liquid water between film layer and porous ice accretion layer.

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.

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.

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.

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.

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.

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.

Health Ready Components are essential to unlocking the potential of Integrated Vehicle Health Management (IVHM) as it relates to real-time diagnosis and prognosis in order to achieve lower maintenance costs, greater asset availability, reliability and safety. IVHM results in reduced maintenance costs by providing more accurate fault isolation and repair guidance. IVHM results in greater asset availability, reliability and safety by recommending preventative maintenance and by identifying anomalous behavior indicative of degraded functionality prior to detection of the fault by other detection mechanisms. The cost, complexity and effectiveness of the IVHM system design, deployment and support depend, to a great extent, on the degree to which components and subsystems provide the run-time data needed by IVHM and the design time semantic data to allow IVHM to interpret those messages.

Honeywell has developed a unique turbofan engine for application to the super mid-size business aviation market, the HTF7000. This paper will describe the design of this engine including aeromechanical design of its components. The unique design features of this engine will be described along with the technology growth path to keep the engine current. This paper will also describe several features which have been developed for this engine in response to new regulatory requirements. Some aspects of the engine to aircraft integration will also be described.

The term Integrated Vehicle Health Management (IVHM) describes a set of capabilities that enable sustainable and safe operation of components and subsystems within aerospace platforms. However, very little guidance exists for the systems engineering aspects of design with IVHM in mind. It is probably because of this that designers have to use knowledge picked up exclusively by experience rather than by established process. This motivated a group of leading IVHM practitioners within the aerospace industry under the aegis of SAE's HM-1 technical committee to author a document that hopes to give working engineers and program managers clear guidance on all the elements of IVHM that they need to consider before designing a system. This proposed recommended practice (ARP6883 [1]) will describe all the steps of requirements generation and management as it applies to IVHM systems, and demonstrate these with a “real-world” example related to designing a landing gear system.

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 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.

Modeling and analysis of a reduced order tracking 3-phase Phase-Locked Loop (PLL) based on a combined control principle (error + disturbance) to improve PLL locking performance is presented in this work. The principle is in synthesizing a feedforward control that is added to a Stationary/Floating Frame Transformation PLL or Synchronous (Delta Q) Frame Transformation PLL. The feedforward comprises a frequency-to-voltage converter based on a phase/frequency estimation using an algebraic summation while implementing an inverse feedforward control principle relative to the part of the feedback loop seen after the summing junction. The reduced order tracking PLL is shown to desensitize the system relative to the conventional part PI controller tuning parameters and is operated to lock on either linear or nonlinear load current waveform and for arbitrary frequency/phase profile while maintaining stability by minimizing system dynamics.

This paper discusses recent improvements made by Honeywell's Condition-Based Maintenance (CBM) Center of Excellence (COE) to Mechanical Health Management (MHM) algorithms. The Honeywell approach fuses Condition Indicators (CIs) from vibration monitoring and oil debris monitoring. This paper focuses on using MHM algorithms for monitoring gas turbine engines. First an overview is given that explains the general MHM approach, and then specific examples of how the algorithms are being refined are presented. One of the improvements discussed involves how to detect a fault earlier in the fault progression, while continuing to avoid false alarms. The second improvement discussed is how to make end of life thresholds more robust: rather than relying solely on the cumulative mass of oil debris, the end of life indication is supplemented with indicators that consider the rate of debris generation.

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.

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.

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.

This work deals with modeling and analysis of a 3-phase Phase-Locked Loop (PLL) based on an algebraic-summation scheme rather than the Stationary/Floating frame transformation PLL or synchronous (Delta Q) frame transformation PLL, and operated to lock on either linear or nonlinear load current waveform, and in the presence of a loss of phase or unbalanced 3-phase load. The PLL scheme is described and performance results are presented, demonstrating its ability to estimate phase and frequency of the input signal in aerospace applications in which a Unity Vector production and a Frequency-to-Voltage conversion is performed.

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.

Thermal management requirements for aerospace applications continue to grow while weight and volume allotments remain constant or shrink. Compact, high performance and lightweight heat transfer equipment is needed to meet these high heat flux removal requirements. Several innovative heat transfer enhancement techniques are being considered for development of thermal management components that will meet these challenging demands. Honeywell, under an AFRL funded program, is developing two new heat exchanger technologies; microchannel and advanced heat transfer surfaces to improve thermal management systems for a fuel-to-air heat exchanger. Heat transfer systems in military aircraft are increasingly using fuel as a heat sink. Heat transport loops containing several fuel-to-liquid heat exchangers are used to cool electronics, engine oil, hydraulic oil, and elements of the thermal management system.