Applying Human Error Framework To Explore Prevention Strategies For Wrong Surface Events

Wrong surface events are a serious and ongoing risk to aviation safety in the United States National Airspace System. A wrong surface event occurs when an aircraft lands, departs or attempts to land or depart from a surface other than the intended landing or takeoff, also including aircraft landing at the wrong airport. This research examined the contextual factors that contributed to human error ultimately leading to wrong surface events, assessed the efficacy of technology that can be used to prevent, and aviation professional’s awareness of wrong surface events in order to determine prevention strategies that can reduce occurrences in the NAS. Four NTSB reports were reviewed to identify context that influences a pilot’s actions in wrong surface events. Next, flight deck and air traffic control tower based technologies were examined for their ability to detect and alert the conditions in the four event reports. Finally, eleven aviation professionals were interviewed to assess their awareness and knowledge of risks, strategies, historical events, and terminology related to wrong surface events. The results identified numerous recurring contextual factors in wrong surface events. While technology intended to prevent wrong surface events is improving, numerous shortfalls were identified that inhibit the system’s ability to effectively prevent such occurrences. Additionally, results showed an overall lack of awareness among pilots and a pilot training department of wrong surface events and their associated risks, suggesting that efforts to prevent wrong surface events through training are ineffective. The results give opportunities for human error mitigation strategies to be employed to reduce occurrences of wrong surface events

The Capital Jury Project: Rationale, Design, and Preview of Early Findings

Symposium: The Capital Jury Projec

Investigation of the Paschen Curve for Various Electrode Geometries in IEC Fusion Devices through Monte Carlo Simulations

The creation of plasma is key for achieving fusion in Inertial Electrostatic Confinement (IEC) fusion devices, and the conditions for such electrical breakdown are modelled by Paschen's law, which predicts the breakdown voltage of a system as a function of the product of pressure and gap distance (pd) between electrodes. However, the Paschen curve only models parallel plate configurations of electrodes and is rarely explored in the more complex electrode geometries often seen in IEC fusion devices, including Farnsworth-Hirsch fusors. To bridge this gap, we study the Paschen curve for various electrode configurations by use of Monte Carlo (MC) simulations in Mathematica and Java. We compute alpha - the rate of ionizations per unit length - in constant E-field systems to explore differences between predicted alpha values from the scientific literature and those from our MC simulations. We explore a Markov chain model for 1D alphas which outperforms the literature alpha prediction in modelling our 1D MC-derived alphas and more closely matches parallel plate MC breakdown results at the minimum. 3D simulations and breakdown plots are created for concentric sphere and sphere-in-cylinder geometries. We observe a widened breakdown curve for concentric spheres and sphere-in-cylinder geometries and note the reduced growth of breakdown voltage at small pd values for the sphere-in-cylinder case. These findings help explain the data collected from our own experimental fusor setup and suggest further work in the simulation of more complex electrode configurations and the incorporation of experimental data to verify results.Comment: 7 pages, 13 figures, authors listed alphabetically with equal contributio

Effects of Heat and Moisture Exchangers Designed to Allow Aerosol Delivery on Airflow Resistance and Aerosol Deposition

Introduction: Several problems arise when HMEs are used while giving aerosolized medication including increased airway resistance (Raw) or the need to open the ventilator circuit. Recently, heat and moisture exchangers designed to allow aerosol delivery (HME-AD) have been developed to solve this problem, but no tests have been performed to confirm their effectiveness. The purpose of this study is to evaluate the effect of HME-ADs on aerosol deposition and Raw. Methods: An in-vitro lung model consisting of an 8.0 mm ID endotracheal tube (ETT) connected to a standard ventilator circuit and ventilator was connected to a rubber test lung via cascade humidifier set to deliver 37˚C and 100% relative humidity. The ventilator settings were as follows: Vt 450 ml, RR 20/min, PIF 50 L/min, PEEP 5 cm H2O, and I:E ratio 1:2. HME-ADs used in this study include Circuvent HME/HCH bypass (Smiths-Medical, Keene, NH), Gibeck Humid-Flo HME (Hudson RCI, Arlington Heights, IL), and Airlife BHME (Carefusion, San Diego, CA). As a control, albuterol sulfate (2.5 mg/3mL) was delivered with a vibrating mesh nebulizer (Aeroneb Solo, Aerogen Inc) placed at the wye without any HME-AD in the circuit. Then, the aerosol and HME configurations of each HME-AD were tested by measuring pre-post Raw and aerosol deposition at the end of each run. Each condition was repeated in triplicate (n=3). Aerosol deposition between the aerosol and HME configurations of each HME-AD was compared with a series of student t-tests. Then, differences both in aerosol deposition and in airway resistance among the HME-ADs were analyzed using one-way analysis of variance (ANOVA). Significance was determined as p\u3c0.05. Results: Raw increased after each albuterol treatment with every HME-AD. In the aerosol configuration, the Circuvent and Humid-Flo delivered significantly less aerosol compared to the control (p=.004 and p=.002, respectively), while there was no significant difference on aerosol delivery between the Airlife and the control (p=.084). The Airlife gave the highest aerosol deposition which was not significantly different than control (p=.084). When aerosol delivery between the HME and aerosol configurations in each HME-AD was compared, aerosol deposition with the Humid-Flo was not significantly different (p=.078) but both the Airlife and the Circuvent showed a statistically significant reduction in aerosol deposition with the HME configuration (p=.002 and p=.005). Conclusions: Aerosol delivery and Raw with each HME-AD differ in simulated mechanically ventilated patients. Further studies are needed to determine the effectiveness of these devices over time and with different aerosol generating devices