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Unmanned Aircraft Systems (UAS) have been growing over the past few years and will continue to grow at a faster pace in future. UAS faces many challenges in certification, airspace management, operations, supply chain, and maintenance. Blockchain, defined as a distributed ledger technology for the enterprise that features immutability, traceability, automation, data privacy, and security, can help address some of these challenges. However, blockchain also has certain challenges and is still evolving. Hence it is essential to study on how blockchain can help UAS. G-31 technical committee of SAE International responsible for electronic transactions for aerospace has published AIR 7356 [1] entitled Opportunities, Challenges and Requirements for use of Blockchain in Unmanned Aircraft Systems Operating below 400ft above ground level for Commercial Use. This paper is a teaser for AIR 7356 [1] document.

Currently, the Aviation industry uses traditional methods of communication, coordination, & human interaction to give disposition to resolve any kind of nonconformance occurrences which occur during manufacturing or operation of commercial or defense products. This involves increased in-person interaction and additional travel, especially to address the nonconformance issues arising at supplier plants or airports around the globe. During Covid and post-Covid environments, human interactions for the transfer of detailed information at different & distant manufacturing plant locations has been difficult, since support engineering teams (Example: Liaison, Product Review, Quality, Supplier Quality, and Manufacturing Engineering, and/or Service Engineering) have been working remotely.

For new aircraft production, initial production typically reveals difficulty in achieving some assembly level tolerances which in turn lead to non-conformances at integration. With initial design, tooling, build plans, automation, and contracts with suppliers and partners being complete, the need arises to resolve these integration issues quickly and with minimum impact to production and cost targets. While root cause corrective action (RCCA) is a very well know process, this paper will examine some of the unique requirements and innovative solutions when addressing variation on large assemblies manufactured at various suppliers. Specifically, this paper will first review a completed airplane project (Project A) to improve fuselage circumferential and seat track joins and continue to the discussion on another application (Project B) on another aircraft type but having similar challenges.

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 System Architecture Virtual Integration (SAVI) program is a collaboration of industry, government, and academic organizations within the Aerospace Vehicle System Institute (AVSI) with the goal of structuring a new integration process that relies on a “single-truth” architectural framework. The SAVI approach of “Integrate, then Build” provides a modern distributed development environment which arrests the propagation of requirements errors through the development life cycle. It does so by capturing design assumptions and shared properties of the system design in an authoritative, annotated architectural model. This reference model provides a common, analyzable framework for confirming that system requirements remain complete, consistent, and correct at all levels of system decomposition. Core concepts of SAVI include extensive use of model-based system engineering tools and use of a “single-truth” reference architectural model.

The trend of moving towards model-based design and analysis of new and upgraded aircraft platforms requires integrated component and subsystem models. To support integrated system trades and design studies, these models must satisfy modeling and performance guidelines regarding interfaces, implementation, verification, and validation. As part of the Air Force Research Laboratory's (AFRL) Integrated Vehicle and Energy Technology (INVENT) Program, standardized modeling and performance guidelines have been established and documented in the Modeling Requirement and Implementation Plan (MRIP). Although these guidelines address interfaces and suggested implementation approaches, system integration challenges remain with respect to computational stability and predicted performance over the entire operating region for a given component. This paper discusses standardized model evaluation tools aimed to address these challenges at a component/subsystem level prior to system integration.

This paper will describe the Efficient Assembly Integration and Test (EAIT) system level project operated as a partnership among Boeing business units, universities, and suppliers. The focus is on the successful implementation and sharing of technology solutions to develop a model based, multi-product pulsed line factory of the future. The EAIT philosophy presented in this paper focuses on a collaborative environment that is tightly woven with the Lean Initiatives at Boeing's satellite development center. The prototype is comprised of a platform that includes a wireless instrumentation system, rapid bonding materials and virtual test of guidance hardware there are examples of collaborative development in collaboration with suppliers. Wireless tools and information systems are also being developed across the Boeing Company. Virtual reality development will include university partners in the US and India.

International Space Station (ISS) Payload Engineering Integration (PEI) organization adopted the advanced computation and simulation technology to develop integrated electrical system models based on the test data of various sub-units. This system model was used end-to-end to mitigate system risk for the integrated Space Shuttle Pre-launch and Landing configurations. The Space Shuttle carries the Multi-Purpose Logistics Module (MPLM), a pressurize transportation carrier, and the Laboratory Freezer for ISS, a freezer rack for storage and transport of science experiments from/to the ISS, is carried inside the MPLM. An end-to-end electrical system model for Space Shuttle Pre-Launch and Landing configurations, including the MPLM and Freezer, provided vital information for integrated electrical testing and to assess Mission success. The Pre-Launch and Landing configurations have different power supplies and cables to provide the power for the MPLM and the Freezer.

The International Space Station (ISS) Payload Engineering Integration (PEI) organization has developed the critical capabilities in dynamic circuit modeling and simulation to analyze electrical system anomalies during testing and operation. This presentation provides an example of the processes, tools and analytical techniques applied to the improvement of science experiments over-voltage clamp circuit design which is widely used by ISS science experiments. The voltage clamp circuit of Science Rack exhibits parasitic oscillations when a voltage spike couples to the Field-Effect Transistor (FET) in the clamp circuit. The oscillation can cause partial or full conduction of the shunt FET in the circuit and may result in the destruction of the FET. In addition, the voltage clamp circuit is not designed to detect the high current through the FET, and this condition can result in damage to surrounding devices. These abnormal operations were analyzed by dynamic circuit simulation and tests.

The rising cost of fuel prices, in part due to the perception of diminishing supplies of common fuelstocks, as well as worldwide attention to reducing emissions has pushed the need to explore the use of many alternative fuels. The aviation industry has been under recent scrutiny due to its contribution of greenhouse gas emissions (GHG). Current contribution of GHG by airplanes is relatively small, 2% of the total GHG emissions, but world air traffic is anticipated to continue to grow and may have a corresponding increase in emissions. Both commercial and government aviation sectors have efforts to seek ways to lower fuel consumption through efficiency and reduce emissions. Development of a suitable alternative fuel that can be seamlessly used in place of conventional jet fuel is desirable. A strategy to enable this goal is to be fuel flexible; utilizing an array of fuels from bio-diesel to current jet fuel.

The patented (US 7,277,811 B1) Position Bar provides precise measurement, machining and drilling data for large Engineering and Tooling structure. The Position Bar also supports end item verification seamlessly in the same machining control code. Position Bar measurements are fast, accurate, and repeatable. The true centerline of the machine tool's spindle bearings are being measured to within .002 in a 20 foot cubic volume (20×20×20). True “I”, “J”, & “K” machine tool spindle positions are also precisely measured. Any Gantry or Post Mill Tool can be converted to a Coordinate Measurement Machine (CMM) with this laser tracker controlled Position Bar. Determinant Assembly (D.A.) holes, for fuselage and wing structures are drilled and then measured to within .006 in X, Y, & Z, over a 40 foot distance. Average laser tracker measurement time, per hole, is 2 seconds.

A procedure for calculating the engine inlet diffuser section liquid water content and mass fractions of liquid water content associated with the water droplet size distribution for wind milling engine ice accretion analysis is presented. Critical fuel reserve calculation for extended twin-engine operation requires the determination of drag increase due to ice accretion on inoperative wind milling engine fan blade and guide vane.

Increased emphasis on standardizing processes and controlling variability in production operations includes validating perishable tools used in daily operations. Even though dealing with reputable manufacturers, many factors including communication, custom specifications and personnel turnover can lead to the perpetuation of mistakes if errors are not discovered and corrective action implemented. However, inspection is costly and inspection costs far outweigh many item costs unless considering product defects. A beneficial balance may be obtained by employing statistical sampling techniques similar to ISO 2859 [1] to verify the quality of incoming tools.

The development of new commercial airliners is a very risky proposition. To get it right, airframe manufacturers must balance new technologies and manufacturing methods with global participation and business considerations. The 787 is Boeing's popular new wide body aircraft incorporating state of the art composites design and manufacturing methods. But new technology alone is not enough. A new logistics system was needed to integrate global partners in order to fully benefit from new technologies. The Boeing 747-400 Dreamlifter is a special purpose 747-400 modified to transport Boeing 787 airplane components through various stages of manufacturing.

The Boeing Company (Renton Division) had a requirement for a 30,000 RPM spindle to provide improved surface finish when milling 2034 ice box rivets in hydraulic wing riveters. Electroimpact supplied an electrical spindle which fit into the same cylinder block as the hydraulic spindle. This was reported in SAE Paper #2000-01-3017. Boeing Renton has also now put Electroimpact 20,000 RPM electric drilling spindles into five wing riveting machines so now both spindles in the machine are Electroimpact electric spindles. The electric drill spindle features an HSK 40C holder. Both spindles are powered by the same spindle drive which is alternately connected to the drill and then the shave spindle.

The ISS U. S. ECLSS contains replaceable component designs to facilitate maintenance. A replaceable component is referred to as an Orbital Replacement Unit (ORU). Total U. S. ECLSS maintenance events that have occurred over the five years (2001-2005) of operations are summarized. A more detailed description is provided for the ECLSS Remove and Replace (R&R) maintenance activities that have occurred during the last two years and the associated logistics that supported these activities. Maintenance activities have replaced failed or degraded ORU's by Corrective Maintenance (CM) and replaced spent expendable ORU's by Preventative Maintenance (PM). Corrective maintenance is performed only when necessary and often on relatively short notice. Preventative maintenance is planned in advance and is normally performed at a specified ORU service time. The paper also describes activities and successful efforts to increase the expendable ORU service life.

A flex hose assembly containing aqueous coolant from the International Space Station (ISS) Internal Active Thermal Control System (IATCS) consisting of a 2 foot section of Teflon hose and quick disconnects (QDs) and a Special Performance Checkout Unit (SPCU) heat exchanger containing separate channels of IATCS coolant and iodinated water used to cool spacesuits and Extravehicular Mobility Units (EMUs) were returned for destructive analyses on Shuttle return to flight mission STS-114. The original aqueous IATCS coolant used in Node 1, the Laboratory Module, and the Airlock consisted of water, borate (pH buffer), phosphate (corrosion control), and silver sulfate (microbiological control) at a pH of 9.5 ± 0.5.

The IATCS coolant has experienced a number of anomalies in the time since the US Lab was first activated on Flight 5A in February 2001. These have included: 1) a decrease in coolant pH, 2) increases in inorganic carbon, 3) a reduction in phosphate concentration, 4) an increase in dissolved nickel and precipitation of nickel salts, and 5) increases in microbial concentration. These anomalies represent some risk to the system, have been implicated in some hardware failures and are suspect in others. The ISS program has conducted extensive investigations of the causes and effects of these anomalies and has developed a comprehensive program to remediate the coolant chemistry of the on-orbit system as well as provide a robust and compatible coolant solution for the hardware yet to be delivered.

The characteristics of the friction materials used in aircraft brakes are extremely important to the performance and safe operation of transport airplanes. These characteristics can change during exposure to environmental effects in the duty cycle, which can lead to problems, such as abnormally low friction, or brake induced vibration. Water vapor in the atmosphere produces a direct lubricant effect on carbon. Observed transition temperatures within the range of 140°C to 200°C, associated with increases in friction and wear of carbon brake materials, are attributed to water vapor desorption. Friction and wear transitions in the range of 500°C to 900°C may be associated with oxygen desorption.

Proper design of the air ventilation system is critical to maintaining a healthy environment for the ISS crew. In this study, a computational fluid dynamic model was used to model the air circulation in Node 1 to identify the locations where there are low air velocities under nominal operating conditions and several reduced ventilation flow conditions. The reduced ventilation flow conditions analyzed were loss of cabin air fan, loss of inter-module ventilation from Node 1 to the US Lab, and loss of inter-module ventilation from the airlock to Node 1. For nominal operation of the ventilation system, about 5% of the node had air velocity of between 1 and 5 ft/min and 14% of the node had air velocity of between 5 and 10 ft/min. Loss of the cabin air fan and loss of Lab inter-module ventilation did not have a significant impact on the percentage of the node that would have low air circulation.