Altitude Restrictions Research Articles

Drag augmentation for collision avoidance in LEO

Space debris proliferation in Low Earth Orbit (LEO) has heightened the urgency for effective Collision Avoidance Manoeuvres (CAMs). This work presents a pioneering framework aimed at devising a novel collision avoidance manoeuvre design for drag-augmentation small platforms. The framework facilitates the alteration of drag acceleration by adjusting the satellite’s ballistic coefficient through cross-sectional area changes. This approach generates controlled deviations in the nominal trajectory, offering a feasible solution for collision avoidance without necessitating thrusters or fuel consumption.The paper introduces an analytical method for propagating drag augmentation manoeuvres and applies it for collision avoidance studies purposes. The formulation followed to implement this manoeuvre within a numerical propagator is presented, as well as the optimisation process developed for the application of drag augmentation manoeuvres in collision avoidance scenarios. Real-world applications showcase the suitability of these approaches, confirming the use of drag augmentation manoeuvres to avoid collisions in LEO. Additionally, the requirements and boundaries of the strategy, including altitude restrictions and satellite-specific properties, are discussed.

항공학적검토를 통한 고도제한 완화의 경제적 효과 분석: 울산광역시 중구 지역을 중심으로

연구목적 본 연구는 울산공항 인근 울산광역시 중구 지역 11곳에 대해 고도제한 완화로 인한 재건축·재개발 사업효과를 바탕으로, 이에 근거한 경제적 효과를 분석하고자 한다. 연구방법 분석 방법으로 주택수를 근거로 이에 연계한 자산가치, 지방세수, 인구유입 효과로 나누어 각각 분석하였다. 결과 분석 결과 세부 항목 모두에서 긍정적 효과가 나타남을 확인하였다. 결론 본 연구를 통해 항공학적검토에 따른 고도제한 완화는 해당 지역 재건축·재개발에 의한 주택수 증가 효과를 넘어 자산가치, 지방재정, 인구 등 다양한 분야에서 선순환적인 긍정적 효과를 발생시킬 수 있음을 확인하였다.

SUAS Remote Sensing to Evaluate Geothermal Seep Interactions with the Yellowstone River, Montana, USA

Small unmanned aerial systems (sUAS) are becoming increasingly popular due to their affordability and logistical ease for repeated surveys. While sUAS-based remote sensing has many applications in water resource management, their applicability and limitations in fluvial settings is not well defined. This study uses a combined thermal-optic sUAS to monitor the seasonal geothermal influence of a 1-km-long reach of the Yellowstone River, paired with in-situ streambed temperature profiles to evaluate geothermal seep interactions with Yellowstone River in Montana, USA. Accurate river water surface elevation along the shoreline was estimated using structure from motion (SfM) photogrammetry digital surface models (DSMs); however, water surface elevations were unreliable in the main river channel. Water temperature in thermal infrared (TIR) orthomosaics was accurate in temperature ranges of tens of degrees (>≈30 °C), but not as accurate in temperature ranges of several degrees (>≈15 °C) as compared to in-situ water temperature measurements. This allowed for identification of geothermal features but limited the ability to identify small-scale temperature changes due to river features, such as pools and riffles. The study concludes that rivers with an average width greater than or equal to 123% of the ground area covered by a TIR image will be difficult to study using structure from motion photogrammetry, given Federal Aviation Administration (FAA) altitude restrictions and sensor field of view. This study demonstrates the potential of combined thermal-optic sUAS systems to collect data over large river systems, and when combined with in-situ measurements, can further increase the sUAS utility in identifying river characteristics.

Feasibility study on applying continuous descent operations in congested airspace with speed control functionality: Fixed flight-path angle descent

Continuous descent operations (CDO) are an efficient descent operation for passenger/cargo aircraft and implemented at various airports worldwide. However, it is difficult for air traffic controller (ATCo) to predict the CDO trajectory and control the CDO aircraft, therefore limiting the applicable window only during the low traffic periods. To maximize potential benefits by introducing the CDO, it is required to implement the CDO into congested airspace and time window. This study introduces an augmentation to CDO application in the congested airspace, called fixed flight-path angle (Fixed-FPA) descent. The fixed-FPA descent was originally proposed and investigated only for small passenger jet aircraft; thereafter the fixed-FPA descent was introduced to large passenger jet aircraft. This proposed procedure consists of several altitude restrictions along the arrival route. By following the altitude restrictions, the aircraft flies with a specified flight-path angle. Additionally, specifying the flight-path angle facilitates the prediction of the CDO trajectory by ATCo. Moreover, by setting a shallower flight-path angle compared with the conventional CDO, the fixed-FPA descent is capable of speed control. The preceding studies conducted only the preliminary feasibility study of the fixed-FPA descent on large jet aircraft. In this study, a series of full-flight simulator experiments and Monte Carlo simulations were conducted to assess the operational feasibility and demonstrate the capabilities of fixed-FPA descent. Experimental results demonstrated that the fixed-FPA descent meets the requirements for integrating the CDO into congested airspace, such that the vertical path of the CDO can be predicted by the ATCo, and the speed of the CDO aircraft is controllable. Additionally, the simulation results revealed that the fixed-FPA descent has better fuel efficiency than the conventional when the descending aircraft is required to delay its arrival time.

Patients With Traumatic Brain Injury Transported by Critical Care Air Transport Teams: The Influence of Altitude and Oxygenation during Transport.

Traumatic brain injuries (TBIs) are life-threatening, and air transport of patients with TBI requires additional considerations. To mitigate the risks of complications associated with altitude, some patients fly with a cabin altitude restriction (CAR) to limit the altitude at which an aircraft's cabin is maintained. The goal of this study was to examine the effects of CARs on patients with TBI transported out of theater via Critical Care Air Transport Teams. We conducted a retrospective chart review of patients with moderate-to-severe TBI evacuated out of combat theater to Landstuhl Regional Medical Center via Critical Care Air Transport Teams. We collected demographics, flight and injury information, procedures, oxygenation, and outcomes (discharge disposition and hospital/ICU/ventilator days). We categorized patients as having a CAR if they had a documented CAR or maximum cabin altitude of 5,000feet or lower in their Critical Care Air Transport Teams record. We calculated descriptive statistics and constructed regression models to evaluate the association between CAR and clinical outcomes. We reviewed the charts of 435 patients, 31% of which had a documented CAR. Nineteen percent of the sample had a PaO2 lower than 80mm Hg, and 3% of patients experienced a SpO2 lower than 93% while in flight. When comparing preflight and in-flight events, we found that the percentage of patients who had a SpO2 of 93% or lower increased for the No CAR group, whereas the CAR group did not experience a significant change. However, flying without a CAR was not associated with discharge disposition, mortality, or hospital/ICU/ventilator days. Further, having a CAR was not associated with these outcomes after adjusting for additional flights, injury severity, injury type, or preflight head surgery. Patients with TBI who flew with a CAR did not differ in clinical outcomes from those without a CAR.

An Empirical Exploration of Resilience in Human-Autonomy Teams Operating Remotely Piloted Aircraft Systems

Project overview Team resilience is an interactive and dynamic process that develops over time while a team maintains performance. This study aims to empirically investigate systems-level resilience in a Remotely Piloted Aircraft (RPA) System simulated task environment by examining team interaction during novel events. The approach used in the current study to measure systems-level resilience was developed by Hoffman & Hancock (2017). In their conceptual study, resilience was considered a key feature of success in emerging complex sociotechnical systems; in our case, that is applied to Human-Autonomy Teams (HATs). Hoffman and Hancock conceptualized a resilience measure dynamically by means of several components, such as the time it took the system to recognize and characterize anomalies, and the time taken to specify and achieve new goals. In their framework, there were two main sub-events which expressed resilience via time-based measures, and upon which we designed ours in this study: (1) time taken to design a new process and (2) time required to implement it (Hoffman & Hancock, 2017). Design In this current research, there were three heterogeneous team members who used a text-based system to communicate and successfully photograph target waypoints: (1) navigator – provided information regarding a flight plan with speed and altitude restrictions of each waypoint; (2) pilot – controlled the RPA by adjusting its altitude and airspeed through negotiating with the photographer in order to take a good photo of the target waypoints; and (3) photographer – screened camera settings and sent feedback to the other team members regarding the status of target’s photograph. This study followed the Wizard of Oz paradigm wherein the navigator and photographer were seated together in one room and were told that the pilot was a synthetic agent. In actuality, the pilot was a well-trained experimenter who was working from a separate room. This ‘synthetic’ pilot used restricted vocabulary to simulate that of a computer. The main manipulations in this study consisted of three degraded conditions: (1) automation failure - role-level display failures while processing specific targets, (2) autonomy failure - autonomous agent behaved abnormally while processing specific targets (i.e., it provided misinformation to other team members or demonstrated incorrect actions), and (3) malicious cyber-attacks - the hijacking of the synthetic agent, which led to the synthetic agent providing false, detrimental information to the team about the RPA destination. Because the malicious cyber-attack only occurred once (during the final mission), we will focus on the automation and autonomy failures for this study. Each failure was imposed at a selected target waypoint and the teams had to find a solution in a limited amount of time. The time limit for each failure was related to the difficulty of the failure. Each failure was introduced at a pre-selected target waypoint for each team. Method In this experiment, there were 22 teams, with only two participants randomly assigned to the navigator and photographer roles for each team, because the pilot was a highly-trained experimenter. The current task was comprised of ten 40-minute missions in which teams needed to take as many “good” photos as possible of ground targets while avoiding alarms and rule violations. For this study, using the RPAS paradigm, we calculated two team resilience scores (1) time taken to design a new process and (2) time required to implement it (Hoffman & Hancock, 2017). For the calculations, we used the message sent time (in seconds) for each role to express resilience in terms of the proportion of total task time (2400 seconds). As an outcome measure, we used target processing efficiency as a coordination and time-based performance score, which was based on how quickly teams were able to take a good photo of each target. Results and discussion We found that teams were more resilient during automation failures and progressed toward targets more successfully than during autonomy failures. We see three possible explanations for this: (1) automation failures were more explicit than autonomy failures, since at least one team member interacted with other teammates; (2) autonomy failures took more time for human teammates to identify the failure, because the autonomous agent’s abnormal behavior was not as straight forward; and 3) human teammates overtrusted to the autonomous agent and lack confidence in themselves and let the failure go on. Acknowledgements This research is supported by ONR Award N000141712382 (Program Managers: Marc Steinberg, Micah Clark). We also acknowledge the assistance of Steven M. Shope of Sandia Research Corporation, who integrated the synthetic agent and the testbed.

Team Coordination of Team Situation Awareness in Human-Autonomy Teaming

Project Overview Team Situation Awareness (TSA), which is a part of team cognition, is a critical factor that influences team effectiveness. It can be defined as getting the right information from the right person within the right amount of time, in order to overcome an unexpected event (Gorman, Cooke, Pederson, Connor, & DeJoode, 2005). TSA is developed and maintained through team interactions, allowing for the measurement of TSA based on team interaction (Cooke & Gorman, 2009). In the current study, a specific measure, Coordinated Awareness of Situation by Teams (CAST) is used (Cooke & Gorman, 2009). CAST evaluates the effectiveness and efficiency of team interaction under “roadblock” scenarios (Gorman, Cooke, & Winner, 2006). These roadblocks represent novel situations in the task and require effective team communication and coordination. Team members must assess the situation according to their own specialized role and/or resources and coordinate with other team members to overcome each separate roadblock. In this task, effective communication refers to team anticipation. That is, each team member needs to anticipate each other’s needs by pushing information rather than pulling information during the task (Demir, McNeese, & Cooke, 2017). In this study, we examined how pushing and pulling information, and CAST were associated with Team Situation Awareness (TSA) in both Human-Autonomy (HAT) and all-human teams in simulated Remotely Piloted Aircraft System (RPAS) task environment. In this research, we integrated the synthetic agent to the Cognitive Engineering Research on Team Tasks Remotely Piloted Aircraft Systems - Synthetic Task Environment (CERTT-RPAS-STE) which was designed to be both a flexible research platform and a realistic task environment with a view to researching team performance and interaction-based measures of team cognition. In the simulated CERTT testbed, there are three heterogeneous teammates who need to take good photos of each target waypoint by communicating via text-chat: (1) the navigator who creates a dynamic flight plan and provides information about the waypoints, the RPA’s airspeed, and altitude restrictions to the pilot; (2) the pilot, who controls the RPA’s heading, altitude, and airspeed, and negotiates with the photographer in order to take a good photo; and (3) the photographer, who monitors sensor equipment in order to take photographs of target waypoints and sends feedback to the other team members about the quality of the photo. This project aimed to understand how team behaviors and team performance differed between HATs and all-human teams in RPAS operations: (1) the synthetic condition—the pilot role was given to the synthetic teammate, which was an ACT-R based cognitive model (which had a limited interaction ability, see Ball et al., 2010; Demir et al., 2015); (2) the control condition—the pilot was a randomly selected human participant, just like the other two participants; and (3) the experimenter condition—one of the experimenters served as an expert pilot. Experimenter condition utilized a Wizard of Oz paradigm in which a trained experimenter (located in a separate room) used a script to imitate a synthetic teammate and communicated with participants in limited communication behaviors but pushing and pulling information in a timely manner (robust coordination). Method There were 30 teams (10 for each condition): control teams consisted of three participants randomly assigned to each role; synthetic and experimenter teams included two participants randomly assigned to the navigator and photographer roles. The experiment took place over five 40-minute missions, and the goal was to take as many “good” photos of ground targets as possible while avoiding alarms and rule violations. During each mission, teams were presented with “roadblocks” by the introduction of a new, ad hoc target waypoint. We collected several measures, but we focused on: the proportion of roadblocks overcome per mission as an outcome measure of TSA; the CAST which is a coordination sequence of team interaction across the team members (i.e. which team members share with team members their experience during the roadblock); and verbal behaviors such as pushing and pulling information. Results and discussion In this team task, effective teamwork involves anticipating the needs of teammates, which in turn means pushing information before it is requested. However, in addition to anticipation, effective coordination is also needed during roadblocks. HATs demonstrated significantly lower levels of CAST than all-human teams. These results indicate that HATs’ lack of anticipation and coordination resulted in poorer TSA performance. These findings help HATs to grow its coordination and communication methodologies. Finally, future studies might examine the relationships highlighted in this study via nonlinear measures in terms of team stability and flexibility based on their communication and coordination patterns during the novel events. HAT is here to stay but improvements to human-machine interactions must continue if we are to improve team effectiveness.

131 Patients With Traumatic Brain Injury Transported by Critical Care Air Transport Teams: The Influence of Altitude and Oxygenation During Transport

Moderate and severe traumatic brain injuries (TBI) are life-threatening, necessitating prompt evaluation and intervention. The safe air transport of patients with TBI to a higher level of care requires additional considerations. Patients with TBI are susceptible to complications related to altitude, including hypobaria and hypoxia. To mitigate this risk, some patients are transported with a cabin altitude restriction (CAR), which limits the altitude at which an aircraft’s cabin is maintained. The goal of this study was to examine the effects of altitude and oxygenation on patients with TBI transported via critical care air transport teams (CCATT) from a Role III medical treatment facility (MTF) to Landstuhl Regional Medical Center (LRMC). We conducted a retrospective chart review of patients with moderate to severe TBI evacuated out of combat theater via CCATT. Data abstractors collected data on demographics, flight information (including CAR), injury type, injury severity, pre-flight procedures, in-flight oxygenation, in-flight complications, and outcomes (mortality, hospital days, ICU days, and ventilator days). We calculated descriptive statistics and conducted Cox proportional hazards regression analyses to evaluate the association between CAR and clinical outcomes. We reviewed the CCATT charts of 435 patients with TBI transported via CCATT from a Role III MTF to LRMC. Eighty-one patients (19%) had a recorded CAR. About 19% of the sample had a PaO2 lower than 80 mmHg and 5% of patients experienced an in-flight SpO2 of 93% or lower. Flying without a CAR was not significantly associated with increased mortality or more hospital days, ICU days, or ventilator days. Further, having a CAR was not significantly associated with hospital days, ICU days, or ventilator days after adjusting for additional flights, injury severity, and injury type. Patients with moderate or severe TBI who were flown with a recorded CAR did not significantly differ from those who flew without a CAR in mortality rates, hospital days, ICU days, or ventilator days. Funding support: Air Force Medical Service (AFMS) Disclaimer: The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the Department of the Air Force, Department of the Army, Department of Defense, or US Government.

Гравитационные маневры при осуществлении марсианской пилотируемой экспедиции с электроракетной двигательной установкой

The paper focuses on the analysis of energy-ballistic efficiency of gravity-assist maneuvers in the implementation of the Martian manned expedition in the period 2049–2050. The purpose of this analysis was to identify the opportunities for improving the energy-ballistic performance indicators of the Martian manned expedition through gravity-assist maneuvers around the Earth and Venus. The methodical approach to calculating the main energy-ballistic indicators of the Martian manned expedition is based on dividing the flight trajectory into sections. To determine the main characteristics of these sections, the statement corresponding to the restricted two-body problem was used. The heliocentric trajectory sections were optimized using the Pontryagin maximum principle. The families of solutions with a gravity-assist maneuver near Venus were obtained, differing in the direction of the flyby of Venus and the height of the flight orbit pericenter. The research shows the existence of extremals close in characteristics, which are with the fly-by orbit pericenter altitude restriction and without it. A comparison was made in terms of the duration of the expedition and the initial mass with solutions without a gravity-assist maneuver.

TF/TA Optimal Flight Trajectory Planning Using a Novel Regenerative Flattener Mapping Method

In this paper, a new methodology has been proposed to enhance the conformal mapping applications in the process of optimum trajectory planning in Terrain Following (TF) and Terrain Avoidance (TA) Flights. The new approach uses the conformal mapping concept as a flattener tool to transform the constrained trajectory-planning problem with flight altitude restrictions due to the presence of obstacles into a regenerated problem with no obstacle and minimal height constraints. In this regard, the Schwarz–Christoffel theorem has been utilized to incorporate the height constraints into the aircraft dynamic equations of motion. The regenerated optimal control problem then is solved employing a numerical method namely the direct Legendre-Gauss-Radau pseudospectral algorithm. A composite performance index of flight time, terrain masking, and aerodynamic control effort is optimized. Furthermore, to obtain realistic trajectories, the aircraft maximum climb and descent rates are imposed as inequality constraints in the solution algorithm. Several case studies for two-dimensional flight scenarios show the applicability of this approach in TF/TA trajectory-planning. Extensive simulations confirm the efficiency of the proposed approach and verify the feasibility of solutions satisfying all of the constraints underlying the problem

Tactical Conflict Detection with Altitude Restrictions in Terminal Airspace

Automated conflict detection in terminal airspace is a challenging problem, in part because key information regarding flight intent is not available. Unlike en route controllers, terminal controllers currently do not enter altitude clearances when they issue them by voice, so the altitude at which a flight will level off is unavailable to the conflict detection automation. This uncertainty increases the likelihood of false alerts. Requiring terminal controllers to enter all altitude clearances may be met with resistance due to workload concerns. This Paper studies a new method in which a ground-based trajectory predictor predicts altitude leveloffs a priori, based on altitude restrictions on published runway descent profiles and at waypoints on nominal interior routes and area navigation departure procedures. The full benefit of the flight-intent information of all altitude clearances is shown to be achievable when controllers only make entry of altitude clearances not attributable to altitude restrictions, which leads to an insignificant workload increase; an unacceptable level of workload increase may result if all altitude clearances are entered during busy hours. In addition, the integration of altitude restriction improves on alert lead time by 16% on average based on operational error cases.

Team Situation Awareness in Human-Autonomy Teaming: A Systems Level Approach

Project overview. The current study focuses on analyzing team flexibility by measuring entropy (where higher values correspond to system reorganization and lower values correspond to more stable system organization) across all-human teams and Human-Autonomy Teams (HAT). We analyzed teams in the context of a fully-fledged synthetic agent that acts as a pilot for a three-agent Remotely Piloted Aircraft System (RPAS) ground crew. The synthetic agent must be able to communicate and coordinate with human teammates in a constructive and timely manner to be effective. This study involved three heterogeneous team members who had to take photographs of target waypoints and communicate via a text-based communication system. The three team members’ roles were: 1) navigator provides information about flight plan with speed and altitude restrictions at each waypoint; 2) pilot adjusts altitude and airspeed to control the Remotely Piloted Aircraft (RPA), and negotiates with the photographer about the current altitude and airspeed to take good photos for the targets; and 3) photographer screens camera settings, and sends feedback to other team members regarding the target photograph status. The three conditions differed based on the manipulation of the pilot role: 1) Synthetic – the pilot was the synthetic agent, 2) Control – the pilot was a randomly assigned participant, and 3) Experimenter – the pilot was a well-trained experimenter who focused on sending and receiving information in a timely manner. The goal of this study is to examine how overall RPAS flexibility across HATs and all-human teams are associated with Team Situation Awareness (TSA). Method. There were 30 teams (10-teams per condition): control teams consisted of three participants randomly assigned to each role; synthetic and experimenter teams included two participants randomly assigned to the navigator and photographer roles. The experiment took place over five 40-minute missions, and the goal was to take as many “good” photos of ground targets as possible while avoiding alarms and rule violations. We obtained several measures, including mission and target level team performance scores, team process measures (situation awareness, process ratings, communication and coordination), and other measures (teamwork knowledge, workload, and demographics). We first estimated amount of system reorganization of the RPAS via an information entropy measure, i.e., the number of arrangements the system occupied over a given period of time (Shannon & Weaver, 1975). Based on information entropy, we defined four layers to represent the RPAS (Gorman, Demir, Cooke, & Grimm, In Review): 1) communications - the chat-based communication among team members; 2) vehicle - the RPA itself, e.g., speed, altitude; 3) control - interface between the RPA and the user; and system - the overall activity of the sub-layers. Then, we looked at the relationship between layers and TSA, which was based on successfully overcoming and completing ad hoc embedded target waypoints. Results and conclusion. Overall, the experimenter teams adapted to more roadblocks than the synthetic teams, who were equivalent to control teams (Demir, McNeese, & Cooke, 2016). The findings indicate that: 1) synthetic teams demonstrated rigid systems level activity, which consisted of less reorganization of communication, control and vehicle layers as conditions changed, which also resulted in less adaptation to roadblocks; 2) control teams demonstrated less communication reorganization, but more control and vehicle reorganization, which also resulted in less adaptation to roadblocks; and 3) experimenter teams demonstrated more reorganization across communication, control and vehicle layers, which resulted in better adaptation to roadblocks. Thus, the ability of a system to reorganize across human and technical layers as situations change is needed to adapt to novel conditions of team performance in a dynamic task

Clinical Impact of Cabin Altitude Restriction Following Aeromedical Evacuation.

Combat medical care relies on aeromedical evacuation (AE). Vital to AE is the validating flight surgeon (VFS) who warrants a patient is "fit to fly." To do this, the VFS considers clinical characteristics and inflight physiological stressors, often prescribing specific interventions such as a cabin altitude restriction (CAR). Unfortunately, limited information is available regarding the clinical consequences of a CAR. Consequently, a dual case-control study (CAR patients versus non-CAR patients and non-CAR patients flown with a CAR versus non-CAR patients) was executed. Data on 1,114 patients were obtained from TRANSCOM Regulating and Command and Control Evacuation System and Landstuhl Regional Medical Center trauma database (January 2007 to February 2008). Demographic and clinical factors essentially showed no difference between groups; however, CAR patients appeared more severely injured than non-CAR patients. Despite being sicker, CAR patients had similar clinical outcomes when compared with non-CAR patients. In contrast, despite an equivocal severity picture, the non-CAR patients flown with a CAR had superior clinical outcomes when compared with non-CAR patients. It appeared that the CAR prescription normalized severely injured to moderately injured and brought moderately injured into a less morbid state. These results suggest that CAR should be seriously considered when evacuating seriously ill/injured patients.

Team Coordination Dynamics in Human-Autonomy Teaming

Project overview. The current study focuses on the nature of team coordination dynamics within all-human teams and Human-Autonomy Teams (HAT) in the context of the development of a fully-fledged synthetic agent that is a computational cognitive model for a three-agent Unmanned Aircraft System (UAS) ground crew. In this study, the relationship between team coordination dynamics and team performance within the HAT and all-human teams is considered. To serve as a teammate, the synthetic agent must be able to communicate and coordinate with its human teammates in a constructive and timely manner (Demir, McNeese, & Cooke, 2016). In this current research, there were three heterogeneous team members who communicated via a text-based communication system to photograph target waypoints. Each team member had a different role: (1) navigator – provides information regarding a flight plan with speed and altitude restrictions of each waypoint; (2) pilot – controls the UAS by adjusting its altitude and airspeed by negotiating with the photographer to take a good photo for the target waypoints; and (3) photographer – screens camera settings, and sends feedback to the other team members regarding the status of target’s photograph. At each target waypoint, this coordination sequence among the team members, called Information-Negotiation-Feedback (INF), is captured by a Kappa Score (Gorman, Amazeen, & Cooke, 2010) that describes the sequence and timing of the information coordination. Three conditions were created that manipulated the pilot role: (1) Synthetic – pilot was the synthetic agent, (2) Control – pilot was a randomly assigned participant, and (3) Experimenter – pilot was an experimenter who was highly experienced with the task and focused on pushing and pulling the information in a timely manner. Method. In this experiment, there were 30 teams (ten teams for each condition): control teams were composed of three participants randomly assigned to each role; synthetic and experimenter teams were composed of only two participants randomly assigned to the navigator and photographer roles. The experiment consisted of five missions (each 40 minutes) in which teams needed to take as many “good” photos as possible of ground targets while avoiding alarms and rule violations. Several measures were obtained from this research, including team performance scores (mission and target level), team process measures (situation awareness, process ratings, communication and coordination), and other measures (teamwork knowledge, workload, and demographics). The research reported here identifies how differences in team coordination, captured by Kappa, relate to performance of all human teams and HAT teams. In this paper, we focus on: (1) target level team performance scores calculated based on the time spent inside a target waypoint to get a good photo; and (2) two team coordination dynamics measures: stability and team communication determinism. Stability was inversely related to the largest Lyapunov Exponent which was estimated by Kappa, that is, the INF coordination sequence. Team communication determinism was estimated from communication data using Joint Recurrence Quantification Analysis (Marwan, Carmen, Thiel, & Kurths, 2007) and served as an index of flexible behavior. Results and discussion. In general, findings indicate that (1) synthetic teams were most stable, followed by experimenter teams, who were moderately stable, and control teams, who were least stable; and (2) extreme stability and instability corresponded to lower levels of performance; experimenter teams performed best, followed by control teams and, then synthetic teams. Thus, synthetic agents could be made more effective if interventions were developed to enhance the flexibility and adaptive nature of HATs (Demir, 2017).

A Retrospective Cohort Analysis of Battle Injury Versus Disease, Non-Battle Injury-Two Validating Flight Surgeons' Experience.

Today, military combat medical care is the best it has ever been. Regulated U.S. Air Force aeromedical evacuation (AE) is one important reason. The Theater Validating Flight Surgeon (TVFS) validates that a patient is ready for flight. Two TVFSs' experiences, successively deployed in 2007, are the focus of this study. A unique operational worksheet used to manage the AE queue was used for approximately 5 months. A descriptive analysis of the worksheet's 1,389 patients found the majority male (94%), median age 30 years, and mostly Army enlisted soldiers (63%). U.S. civilians made up 9%. Battle Injury (55%) surpassed Disease, Non-Battle Injury (45%); most frequently seen were extremity injuries (73%) and cardiac illness (31%), respectively. Common to both Battle Injury and Disease, Nonbattle Injury were several TVFS prescriptions including no "remain overnights" (79%), head of bed elevation (78%), cabin altitude restriction (57%), no stops (44%), Critical Care Air Transport Team (27%), and supplemental oxygen (22%). This study is a first look at the TVFS experience and it offers up an initial accounting of the TVFS clinical and prescriptive practices. It is also a jumping point for future TVFS investigations using the available AE databases.

The Synthetic Teammate as a Team Player in Command-and-Control Teams

Project overview. The current project is part of a larger effort that focuses on Human-Automation Teaming (HAT) interaction in the context of the development, integration, and validation of a computational cognitive model that acts as a full-fledged synthetic teammate for a three-agent Unmanned Aircraft System (UAS) ground control crew. Our most recent effort looked at team process and team performance within the HAT. In order to be considered a team player, the synthetic teammate must be able to communicate and coordinate with its human teammates and do so in a subtle manner (Demir et al., 2016). In this task, there were three different and interdependent team members: 1) Air Vehicle Operator (AVO) – controls the UAS’s heading, altitude, and airspeed; 2) Data Exploitation, Mission Planning, and Communications (DEMPC) – provides a dynamic flight plan as well as speed and altitude restrictions; and 3) Payload Operator (PLO) – monitors sensor equipment, negotiates with the AVO, and takes photographs of target waypoints. The communication within a three-agent UAS team occurred over a text-based communications system. In this research, there were three conditions which are differentiated by the AVO role: 1) the Synthetic - the synthetic teammate was assigned the AVO role; 2) the Control - the AVO was an inexperienced human participant; 3) the Experimenter - the AVO was one of the experimenters who was experienced with the task. The experimenter AVO asked questions of other team members to ensure timely and adaptive passing of information at target waypoints. In this current study, the coordination among the team members occurs at each target waypoint and requires a specific sequence of information passing for an optimum team performance (Cooke, Gorman, Duran, & Taylor, 2007): the information is provided by the DEMPC about the upcoming target waypoint to the AVO. After that, the PLO and the AVO negotiate regarding an appropriate altitude and airspeed for the target waypoints about required camera settings. Finally, the PLO sends feedback to other team members about the status of the target photo. Method. Activities during this period included conducting an experiment to: 1) evaluate the synthetic teammate’s performance, and the HAT team performance in comparison to all human teams, 2) understand how team process differs between all human and human-synthetic teams and how this impacts performance, and 3) compare the human-synthetic teams and all human control teams to a team with a pilot that is experienced in pushing and pulling information across the team. For this experiment, participants were randomly assigned for the duration of the experiment. Within each of the five missions, teams were told to obtain as many “good” photos as possible while avoiding alarms and rule violations in less than 40 minutes. The overall focus of this paper is: team process that is comprised of eight verbal behaviors associated with team effectiveness; team performance that is a combination of mission variables, including the rate of successful target photographs, time spent in alarm and warning states (for each individual), and the critical waypoint acquisition rate; and target processing efficiency took into account the time spent inside a target waypoint to get a good photo. Results and discussion. In general, findings indicate that synthetic AVOs perform more poorly than control AVOs in terms of team performance. Synthetic teams perform as well at the mission level as control teams. However, in terms of target processing efficiency, synthetic teams perform poorer than control teams. In terms of team process, synthetic teams demonstrate interaction patterns corresponding to more pulling of information than pushing with little change over time. In summary, these results indicate that there is a strong potential for using synthetic team member as a teammate in real world tasks and for training.

Complication Rates in Altitude Restricted Patients Following Aeromedical Evacuation.

Military aeromedical evacuation, especially that associated with the present Middle East conflict, is seeing increasing research. This ecological study initiates research into the validating flight surgeon by looking at cabin altitude restriction (CAR), arguably the validating flight surgeon's prescription with the highest patient-mission impact, and its association with postflight complications. CAR rates from January 2006 through February 2008 were determined from the U.S. Transportation Command Regulating and Command and Control Evacuation System database. Postflight complication rates-the rate of patients with postflight complications (PFC) and the postflight complications per 100 patients (PFC-100)-from January 2007 through June 2008 were calculated from the Landstuhl Regional Medical Center trauma database. CAR and complication rates were examined before, during, and after the authors' deployment. In addition, the relationship between CAR and postflight complication rates was investigated; as the rates were nonlinear, a Spearman correlation was performed. CAR rates during the authors' deployments were significantly up compared to the authors' predecessors or successors; their predecessors and successors did not differ statistically. Likewise, the PFC rate during the authors' deployments was significantly lower than that of the before or after time frames. Furthermore, a statistically significant inverse relationship between CAR and PFC rates (Spearman rho = -0.587) as well as CAR and PFC-100 rates (Spearman rho = -0.568) was demonstrated. CAR rate was inversely correlated to PFC and PFC-100 rates. This finding suggests that aggressive prescribing of CARs may have a salutary effect on postflight complication rates and bears further investigation.

Causes and risk factors for fatal accidents in non-commercial twin engine piston general aviation aircraft

Accidents in twin-engine aircraft carry a higher risk of fatality compared with single engine aircraft and constitute 9% of all general aviation accidents. The different flight profile (higher airspeed, service ceiling, increased fuel load, and aircraft yaw in engine failure) may make comparable studies on single-engine aircraft accident causes less relevant. The objective of this study was to identify the accident causes for non-commercial operations in twin engine aircraft.A NTSB accident database query for accidents in twin piston engine airplanes of 4–8 seat capacity with a maximum certified weight of 3000–8000lbs. operating under 14CFR Part 91 for the period spanning 2002 and 2012 returned 376 accidents. Accident causes and contributing factors were as per the NTSB final report categories. Total annual flight hour data for the twin engine piston aircraft fleet were obtained from the FAA. Statistical analyses employed Chi Square, Fisher’s Exact and logistic regression analysis.Neither the combined fatal/non-fatal accident nor the fatal accident rate declined over the period spanning 2002–2012. Under visual weather conditions, the largest number, n=27, (27%) of fatal accidents was attributed to malfunction with a failure to follow single engine procedures representing the most common contributing factor. In degraded visibility, poor instrument approach procedures resulted in the greatest proportion of fatal crashes. Encountering thunderstorms was the most lethal of all accident causes with all occupants sustaining fatal injuries. At night, a failure to maintain obstacle/terrain clearance was the most common accident cause leading to 36% of fatal crashes. The results of logistic regression showed that operations at night (OR 3.7), off airport landings (OR 14.8) and post-impact fire (OR 7.2) all carried an excess risk of a fatal flight.This study indicates training areas that should receive increased emphasis for twin-engine training/recency. First, increased training should be provided on single engine procedures in the event of an engine failure. Second, more focus should be placed on instrument approaches and recovery from unusual aircraft attitude where visibility is degraded. Third, pilots should be made aware of appropriate speed selection for inadvertent flights in convective weather. Finally, emphasizing the importance of conducting night operations under instrument flight rules with its altitude restrictions should lead to a diminished proportion of accidents attributed to failure to maintain obstacle/terrain clearance.

Strategies for Choosing Descent Flight-Path Angles for Small Jets

A standard descent procedure with a fixed flight-path angle is proposed to improve trajectory predictability for arriving small jets in the transition airspace into congested terminal area. Three candidate strategies for selecting fuel-efficient and flyable descent flight-path angles are proposed. The three strategies vary in operational complexity and fuel-burn merits. To mitigate variation of wind among flights, the two simpler strategies are adapted to airport, directions of arrival, and time. Three major U.S. airports with different degrees of wind variation and disparate arrival traffic flows are analyzed. Results show that, when compared to the simple airport–static adaptation, the finest adaptation of the simpler strategies recover up to 50–75% of the extra fuel burn relative to the minimum-fuel strategy. Wind variation, descent altitude restrictions, arrival directions, and fleet composition all affect the fuel efficiency of the simple strategies. Tradeoffs between fuel burn and planned speed-brake usage in the choice of the flight-path angle are discussed. Fuel efficiency of simple strategies for the entire national airspace in the United States is estimated. Considerations and implications for air navigation service providers are discussed.

Criteria of applicability of a gas-dynamic approximation of a continuous medium to describing the dispersion of combustion products of rocket propellants

Two criteria for the applicability of a gas-dynamic approximation of continuous medium to describing the dispersion of combustion products of rocket propellants at high altitudes are formulated. Related numerical estimates are given for different launch vehicles and one upper stage with fairly extended boost phases. The use of a continuous medium approximation is shown to have a clear altitude restriction.