The requirement for low-level navigation flight conducted between 200 and 500 feet above ground level is something unique to the military helicopter pilot. Each novice helicopter pilot is introduced to this skill early and in a limited number of flights or flight hours. A low situational awareness (SA)is historically noted among the novice pilots during their first few flights within this flight regime. To that end, this thesis continues with the work conducted earlier to develop a trainer that places the pilot in an immersive and familiar cockpit environment for training through the use of chromakeyed technology as employed in the Virtual Environment Helicopter System (VEHELO). The pilot will then be able to learn and exercise required piloting tasks and multi-place aircraft communications as authentically and as meticulously as in actual flight. The focus of this thesis is to continue validation of the ChrAVE/VEHELO system. This will be accomplished by comparison of data obtained from data collected by pilots flying the ChrAVE and flying the actual aircraft during initial navigational training flights. Additionally this thesis will attempt to show that the latest version of the system has a previously unrecognized ability to improve pilot performance. The system is capable of teaching novice pilots the important skill of Crew Resource Management (CRM) and the appropriate communication skills. The original Chromakey Augmented Virtual Environment (ChrAVE) helicopter flight simulation system was developed to substantiate the feasibility of having embedded trainers for helicopters. Both the ChrAVE and VEHELO are comprised of commercial off the shelf (COTS) equipment in a mobile wheeled box. To determine the effectiveness of the ChrAVE as an instructional tool, the opinions of pilots and pilot instructors will be collected for analysis. The subject pilots will be tasked with numerous realistic piloting tasks. Empirical data will be collected and evaluated according to the low-level navigation performance thresholds set forth by Marine Medium Helicopter Training Squadron 164 (HMMT- 164) which is the CH-46E Model Manager. / US Marine Corps (USMC) author.

A significant number of aircraft incidents and accidents have been caused, in part, by flightcrew failure to properly manage cockpit activities, such as failure to initiate activities at the appropriate time, misprioritization of activities, or the failure to appropriately monitor activities and terminate them when required. To facilitate the management of the cockpit activities, a computational aid, the Agenda Manager (AM) has been developed for use in simulated cockpit environments in an investigation which was one aspect of a more extensive research project supported by the NASA Ames Research Center. The AM is directed at the management of goals and functions, the actors who perform those functions, and the resources used by these actors. Development of an earlier AM version, the Cockpit Task Management System (CTMS), demonstrated that it could be used to assist flightcrews in the improvement of cockpit activity management under experimental conditions, assuming that the AM determined pilot goals accurately as well as the functions performed to achieve those goals. To overcome AM limitations based on that assumption, a pilot goal communication method (GCM) was developed to facilitate accurate recognition of pilot goals. Embedded within AM, the GCM was used to recognize pilot goals and to declare them to the AM. Two approaches to the recognition of pilots goals were considered: (1) The use of an Automatic Speech Recognition (ASR) system to recognize overtly or explicitly declared pilot goals, and (2) inference of covertly or implicitly declared pilot goals via use of an intent inferencing mechanism. These two methods were integrated into the AM to provide a rich environment for the study of human-machine interactions in the supervisory control of complex dynamic systems. Through simulated flight environment experimentation, the proposed GCM has demonstrated its capability to accurately recognize pilot goals and to handle incorrectly declared goals, and was validated in terms of subjective workload and pilot flight control performance. / Graduation date: 1997

Στα πλαίσια της παρούσας εργασίας θα ασχοληθούμε με παθητικές μεθόδους τρισδιάσατης ανακατασκευής του χώρου και συγκεκριμένα με την επεξεργασία δεδομένων εικόνων που λαμβάνονται από μια φωτογραφική μηχανή. / In this paper we will analyse pathetic methods of 3D reconstruction and especially data proccess of pictures received from a digital camera.

The flightcrew of a modern airliner operates in a multi-tasking environment with several tasks competing for the same attentional resources at the same time. Too many tasks vying for the crew's attention concurrently imposes a heavy workload on the flightcrew. This results in the satisfactory execution of some tasks at the expense of others. Consequently, flightcrews must manage cockpit tasks a process we call Cockpit Task Management (CTM). Funk (1991) defines cockpit task management (CTM) as the process flightcrews use to prioritize cockpit tasks, allocate required resources, initiate and terminate multiple concurrent tasks. Despite improvements in aircraft reliability and advancements in aircraft cockpit automation, "pilot error" is cited as the main reason (over 60% of all aircraft accidents) for planes still falling out of the skies. One of the objectives of this research was to determine the significance of CTM errors in "pilot errors". Having established its significance, the next step was to refine the existing error taxonomy of Chou & Funk (1991). A structured error classification methodology was also developed for classifying CTM errors and validated using 470 Aviation safety Reporting System (ASRS) airline incident reports. This study identified CTM errors as a significant component of "pilot errors" accounting for 231 of the 470 incidents analyzed (49.2%). While Task Initiation errors accounted for the largest of the general error categories (41.5%), it was the Task Prioritization errors (35% of general and specific error categories) that unlocked the door that led to error committals in the other error categories. Task Prioritization errors led to Resource allocation errors which, in turn, resulted in several kinds of errors being committed in the other categories. The findings had implications that were largely training-based. In particular, the importance of pilot education which CTM provides (as opposed to crew training that CRM provides) is emphasized. The incorporation of formal CTM concept into existing CRM training programs was advocated. In addition, a staggered scheduling mechanism in crew training agenda involving CTM, CRM, Line-Oriented-Flight-Training (LOFT) and simulator sessions was suggested. A recommendation was made for a comprehensive Cockpit Task Management System (CTMS) to be installed in the cockpit to help crews to prioritize tasks and remind them of the need to initiate, terminate or reprioritize tasks as necessary. The inclusion of Air Traffic Control personnel in flightcrew training sessions was also recommended. / Graduation date: 1994

No description available.

Thesis (Ph.D. (Physics)) -- University of Limpopo, 2021 / Titanium metal and its alloy components find extensive applications in various industries such as aerospace, medicine and automotive due to its light weight-strength ratio. More importantly, titanium-based components with better surface finishing are required in the titanium manufacturing industries. However, these components suffer from surface roughness and brittleness due to the formation of alpha-case layer. Recently, the etching process has been widely used for metal surface modification, but the etching mechanism and the choice of etchant are not well prescribed. On the other hand, the adsorption of halogen molecules on the metal surface has received much attention due to their technological applications and relevance for material surface processing, corrosion and etching. This is considered as a promising approach towards selecting an effective etchant for the metal surface etching process. In this study, the first-principle approach has been used to study the adsorption behaviour of halogen molecules and ions on Ti (100) and (110) surfaces. Their adsorption mechanism was deduced from the calculated adsorption energy, heats of formation, desorption energy, work function, charge density difference and density of states. In particular, to understand how different etchant can influence the properties of titanium metal surface during etching process. Firstly, the free halogen molecules (HF, HCl, HBr and HI), as well as the clean Ti (100) and (110) surfaces were investigated to deduce the reactivity and surface stability, respectively. It was established that the HF dissociate easily due to its lowest dissociation energy and higher electronegativity, which suggest stronger interaction with the Ti surfaces. The halogen molecules stability trend was found to follow the order of HF>HCl>HBr>HI consistent with the electronegativity strength. Furthermore, it was also found that Ti (110) is the most stable surface displaying the lowest surface energy as compared to Ti (100) surface. v Secondly, the adsorption of halogen molecules on Ti (100) and Ti (110) surfaces was studied to investigate the chemical interaction and their reactivity. The halogens were adsorbed on three possible adsorption sites (Top, Bridge and Hollow) and their reaction is spontaneous. Moreover, the bridge and top sites were found to be the most favourable sites on Ti (100) and Ti (110) surfaces, respectively. Our results showed that all halogen molecules dissociate spontaneously on both Ti surfaces. The findings revealed that the adsorption of halogen molecules on Ti surfaces is energetically favourable suggesting adsorption energy strength order of 𝐸𝑎𝑑𝑠𝐻𝐹>𝐸𝑎𝑑𝑠𝐻𝐶𝑙>𝐸𝑎𝑑𝑠𝐻𝐵𝑟>𝐸𝑎𝑑𝑠𝐻𝐼. This indicates that the adsorption of HF molecule on these surfaces is thermodynamically more stable than HCl, HBr and HI molecules. Also, our results revealed that the adsorption of halogen ions (F-, Cl-, Br- and I-) is more favourable than the adsorption of halogen molecules (HF, HCl, HBr and I) on the bridge site in both Ti surfaces considered. The F ion was found to be the most preferable than Cl, Br, and I ions. In addition, the interaction of halogen ions with Ti surfaces was deduced with regards to electron charge. We found that the amount of electron charge transferred depends on the adsorption energy strength. In particular, it was found that the F atom accepts more electrons than other halogen ions. Moreover, the spherical shape was observed, this suggests that the charge density distribution between Ti atom and halogen exhibit ionic bonding behaviour. We also found that the adsorption of halogen has a stronger effect on the work function of Ti surfaces depending on the halogen ion. The magnitude of the induced work function varies from the halogen ionic order of F>Cl>Br>I. Lastly, in order to describe the dependence of the surface coverage of an adsorbed molecule, F2 and Cl2 molecules were adsorbed on Ti (100) surface at different coverages. We observed the formation of etching products TixFy and TixCly species on the surface. The heats of formation (EHF) and desorption energy of volatile etch products were calculated. Our findings show that the formed volatile molecules (TixFy and TixCly) are energetically favourable (EHF<0), suggesting an vi exothermic process. We also found that the TixFy clusters is more stable with lower heats of formation than the TixCly species. Moreover, the desorption energy of the formed volatile (TiF4) species was found to be lower than TiCl4 indicating that that TiF4 species desorb easily. This demonstrates that F2 is more suitable for surface etching as compared to Cl2. / Council for Scientific and Industrial Research (CSIR) and the Department of Science and Innovation (DSI)

Altitude excursions particular to high speed aircraft are investigated in this thesis. An aerodynamic database of the XB-70 is created and a longitudinal linear model is constructed for a high speed cruise flight condition. An examination of the unpiloted aircraft dynamics revealed that the excursions were not due to a poorly handling aircraft. Thus, it is theorized that the excursions are due to pilot vehicle interactions. A classical control method developed a loop closure scheme suitable for acceptable control of the aircraft. The results showed that a pilot should close an inner loop with negative attitude feedback and an outer loop with positive flight path feedback. A modern control method analysis using an optimal control pilot model confirmed the preceding conclusions. Based on these results, the cockpit pitch attitude display resolution should be less than 1° so that the pilot will be able to perform the loop closures necessary for constant altitude flight. / Master of Science

Forty-eight licensed pilots flew three cross-country flights in which certain aspects of perceptual workload were varied by altering the rate and number of instrument-displayed incipient danger conditions. A moving-base simulation of a single-engine general aviation aircraft was used. The sensitivity of eight mental workload estimation techniques investigated to changes in perceptual workload was within a univariate factorial design. Concurrently, the differential intrusion of the eight techniques on four primary task measures was investigated using multivariate analysis. Of the eight techniques, six displayed statistically-significant sensitivity to load level. These included two opinion rating scales, secondary task measures of time estimation standard deviation and tapping regularity, respiration rate, and a primary task measure of danger condition detection/identification time. No intrusion effect was found. Recommendations for applying the various techniques, based on the relative sensitivity of those showing significance, are discussed. / Ph. D.

Pilots and other aircrew members are often required to perform tasks involving a substantial amount of mediational or cognitive activity. Generally speaking, workload estimation techniques have not been tested to determine their relative sensitivity and intrusion to mediational piloting tasks. An experiment comparing the sensitivity and intrusion of eight workload estimation techniques was conducted using a mediational loading task in a three-degrees-of-freedom moving-base aircraft simulator. The primary task mediational loading required the pilots to solve a variety of navigational problems while maintaining straight-and-level flight. The presented problems were sorted prior to the experiment into low, medium, and high difficulty problems. The eight techniques included opinion measures (modified Cooper-Harper rating scale and multi-descriptor rating scale), spare mental capacity measures (time estimation and tapping regularity), primary task measures (mediational reaction time and control movements per unit time), and physiological measures (pulse rate variability and pupil dilation). A sensitive technique was defined as a technique which indicated statistical differences of scores across the three mediational load levels. An intrusive technique was defined as a technique which significantly changed the primary task measures compared to the primary task measures obtained in a control condition. One opinion measure (modified Cooper-Harper measure (time (mediational rating scale), one estimation), and one spare mental capacity primary task measure reaction time) demonstrated sensitivity. Mediational reaction time demonstrated sensitivity to all levels of load. The other two showed partial sensitivity to load. One spare mental capacity measure (time estimation) demonstrated intrusion on two primary task measures (mediational reaction time and percent error response). / Ph. D.

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2007. / This thesis relates to the successful development of a flight control system to perform a range of aerobatic manoeuvres autonomously. The project is the first to try to extend the flight control capabilities of the Computer and Control group at the University of Stellenbosch. A simplified mathematical aircraft model is developed which encapsulates the important dy- namic characteristics of the airframe. It is demonstrated how computational fluid dynamics software can be used to calculate the stability and control derivatives of a conventional air- frame. A vehicle independent kinematic state estimator is presented and used to obtain the complete aircraft state vector. The estimator makes use of extended Kalman filter theory to combine a series of low quality sensor measurements in an optimal manner. A model predictive control strategy is then used to regulate the aircraft about arbitrary, time variant trajectories. The controller’s architecture is not in any way specific to the aerobatic manoeuvres demonstrated in this project. The avionics and ground station used for the implementation of the estimator and control algorithms are presented. The development of a hardware in the loop simulator is discussed and used to verify the correct implementation of the respective algorithms. Finally, practical results from two days of flight tests are presented.