Simulation of power quality issues in more electric aircraft actuator supplies

To examine the detailed operation of the power distribution network in a future more electric aircraft that employs electric actuation systems, a Micro-Cap SPICE simulation is developed for one of the essential buses. Particular attention is paid to model accurately the most important effects that influence system power quality. Representative system and flight data are used to illustrate the operation of the simulation and to assess the power quality conditions within the network as the flight control surfaces are deployed. The results illustrate the importance of correct cable sizing to ensure stable operation of actuators during transient conditions.

The Information-analytical System for Diagnostics of Aircraft Navigation Units

The operation of technical processes requires increasingly advanced supervision and fault diagnostics to improve reliability and safety. This paper gives an introduction to the field of fault detection and diagnostics and has short methods classification. Growth of complexity and functional importance of inertial navigation systems leads to high losses at the equipment refusals. The paper is devoted to the INS diagnostics system development, allowing identifying the cause of malfunction. The practical realization of this system concerns a software package, performing a set of multidimensional information analysis. The project consists of three parts: subsystem for analyzing, subsystem for data collection and universal interface for open architecture realization. For a diagnostics improving in small analyzing samples new approaches based on pattern recognition algorithms voting and taking into account correlations between target and input parameters will be applied. The system now is at the development stage.

Review of the application of flexible, measurement-assisted assembly technology in aircraft manufacturing

Aircraft assembly is the most important part of aircraft manufacturing. A large number of assembly fixtures must be used to ensure the assembly accuracy in the aircraft assembly process. Traditional fixed assembly fixture could not satisfy the change of the aircraft types, so the digital flexible assembly fixture was developed and was gradually applied in the aircraft assembly. Digital flexible assembly technology has also become one of the research directions in the field of aircraft manufacturing. The aircraft flexible assembly can be divided into three assembly stages that include component-level flexible assembly, large component-level flexible assembly, and large components alignment and joining. This article introduces the architecture of flexible assembly systems and the principles of three types of flexible assembly fixtures. The key technologies of the digital flexible assembly are also discussed. The digital metrology system provides the basis for the accurate digital flexible assembly. Aircraft flexible assembly systems mainly use laser tracking metrology systems and indoor Global Positioning System metrology systems. With the development of flexible assembly technology, the digital flexible assembly system will be widely used in current aircraft manufacturing.

Manufacturing and assembly automation by integrated metrology systems for aircraft wing fabrication

Discrepancies of materials, tools, and factory environments, as well as human intervention, make variation an integral part of the manufacturing process of any component. In particular, the assembly of large volume, aerospace parts is an area where significant levels of form and dimensional variation are encountered. Corrective actions can usually be taken to reduce the defects, when the sources and levels of variation are known. For the unknown dimensional and form variations, a tolerancing strategy is typically put in place in order to minimize the effects of production inconsistencies related to geometric dimensions. This generates a challenging problem for the automation of the corresponding manufacturing and assembly processes. Metrology is becoming a major contributor to being able to predict, in real time, the automated assembly problems related to the dimensional variation of parts and assemblies. This is done by continuously measuring dimensions and coordinate points, focusing on the product's key characteristics. In this paper, a number of metrology focused activities for large-volume aerospace products, including their implementation and application in the automation of manufacturing and assembly processes, are reviewed. This is done by using a case study approach within the assembly of large-volume aircraft wing structures.

High performance liquid-level sensor based on mPOFBG for aircraft applications

A high performance liquid-level sensor based on microstructured polymer optical fiber Bragg grating (mPOFBG) array sensors is reported in detail. The sensor sensitivity is found to be 98pm/cm of liquid, enhanced by more than a factor of 9 compared to a reported silica fiber-based sensor.

Aircraft Marketing in an Era of Deregulation

The deregulation of commercial aviation has had far-reaching effects on all aspects of business. In the Spring 1984 issue, the author explored some of the changes in the domestic airline industry. This article discusses the effects of deregulation on another group - those who manufacture commercial aircraft.

Rilievo fotogrammetrico da drone per la generazione di modelli termici di porzioni di territorio

In questo elaborato viene sperimentato un iter processuale che consenta di utilizzare i sensori termici affiancati a fotocamere digitale in ambito fotogrammetrico al fine di ottenere prodotto dal quale sono estrapolabili informazioni geometriche e termiche dell’oggetto di studio. Il rilievo fotogrammetrico è stato svolto mediante l’utilizzo di un drone con equipaggiamento multisensoriale, termico e digitale, su una porzione di territorio soggetto ad anomalie termiche nei pressi di Medolla (MO). Per l’analisi termica e geometrica sono stati posizionati sul campo 5 target termici di cui ne sono state misurate le coordinate per la georeferenziazione delle nuvole dense di punti e la temperatura. In particolare sono state eseguite due riprese aeree dalle quali sono stati estratti i frame necessari per i processi di restituzione fotogrammetrica. Le immagini sono state sottoposte ad una fase di trattamento che ha prodotto immagini rettificate prive di delle distorsioni impresse dall’obbiettivo. Per la creazione degli elaborati vettoriali e raster a colori e termici sono stati impiegati inizialmente software di fotogrammetria digitale in grado di fornire scene tridimensionali georeferenziate dell’oggetto. Sono state sviluppate sia in un ambiente open-source, sia sfruttando programmi commerciali. Le nuvole dense sono state successivamente trattate su una piattaforma gratuita ad interfaccia grafica. In questo modo è stato possibile effettuare dei confronti tra i diversi prodotti e valutare le potenzialità dei software stessi. Viene mostrato come creare un modello tridimensionale, contenente sia informazioni geometriche che informazioni termiche, partendo dalla nuvola termica e da quella a colori. Entrambe georeferenziate utilizzando gli stessi punti fotogrammetrici d’appoggio. Infine i prodotti ottenuti sono stati analizzati in un ambiente GIS realizzando sovrapposizioni grafiche, confronti numerici, interpolazioni, sezioni e profili.

Aircraft mechanic working on a propeller

General note: Title and date provided by Bettye Lane.

Investigating the Tradespace between Increased Automation and Optimal Manning on Aircraft Carrier Decks

With increasing prevalence and capabilities of autonomous systems as part of complex heterogeneous manned-unmanned environments (HMUEs), an important consideration is the impact of the introduction of automation on the optimal assignment of human personnel. The US Navy has implemented optimal staffing techniques before in the 1990's and 2000's with a "minimal staffing" approach. The results were poor, leading to the degradation of Naval preparedness. Clearly, another approach to determining optimal staffing is necessary. To this end, the goal of this research is to develop human performance models for use in determining optimal manning of HMUEs. The human performance models are developed using an agent-based simulation of the aircraft carrier flight deck, a representative safety-critical HMUE. The Personnel Multi-Agent Safety and Control Simulation (PMASCS) simulates and analyzes the effects of introducing generalized maintenance crew skill sets and accelerated failure repair times on the overall performance and safety of the carrier flight deck. A behavioral model of four operator types (ordnance officers, chocks and chains, fueling officers, plane captains, and maintenance operators) is presented here along with an aircraft failure model. The main focus of this work is on the maintenance operators and aircraft failure modeling, since they have a direct impact on total launch time, a primary metric for carrier deck performance. With PMASCS I explore the effects of two variables on total launch time of 22 aircraft: 1) skill level of maintenance operators and 2) aircraft failure repair times while on the catapult (referred to as Phase 4 repair times). It is found that neither introducing a generic skill set to maintenance crews nor introducing a technology to accelerate Phase 4 aircraft repair times improves the average total launch time of 22 aircraft. An optimal manning level of 3 maintenance crews is found under all conditions, the point at which any additional maintenance crews does not reduce the total launch time. An additional discussion is included about how these results change if the operations are relieved of the bottleneck of installing the holdback bar at launch time.

Requirements, Issues, and Challenges for Sense and Avoid in Unmanned Aircraft Systems

The sense and avoid capability is one of the greatest challenges that has to be addressed to safely integrate unmanned aircraft systems into civil and nonsegregated airspace. This paper gives a review of existing regulations, recommended practices, and standards in sense and avoid for unmanned aircraft systems. Gaps and issues are identified, as are the different factors that are likely to affect actual sense and avoid requirements. It is found that the operational environment (flight altitude, meteorological conditions, and class of airspace) plays an important role when determining the type of flying hazards that the unmanned aircraft system might encounter. In addition, the automation level and the data-link architecture of the unmanned aircraft system are key factors that will definitely determine the sense and avoid system requirements. Tactical unmanned aircraft, performing similar missions to general aviation, are found to be the most challenging systems from an sense and avoid point of view, and further research and development efforts are still needed before their seamless integration into nonsegregated airspace

Departure and approach procedures for unmanned aircraft systems in a visual-flight-rule environment

This paper assesses the departure and approach operations of unmanned aircraft systems in one of the most challenging scenarios: flying under visual flight rules. Inspired by some existing procedures for (manned) general aviation, some automatic and predefined procedures for unmanned aircraft systems are proposed. Hence, standardized paths to specific waypoints close to the airport are defined for departure operations, just before starting the navigation phase. Conversely, and for the approach maneuvers, a first integration into a holding pattern near the landing runway (ideally, above it) is foreseen, followed by a standard visual-flight-rule airfield traffic pattern. This paper discuses the advantages of these operations, which aim to minimize possible conflicts with other existing aircraft while reducing the pilot-in-command workload. Finally, some preliminary simulations are shown in which these procedures have been successfully tested with simulated surrounding traffic.