The Development of Cockpit Display and Alerting Concepts for Interval Management (IM) in a Near-Term Environment

The National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC) Interval Management (IM) research team has conducted a wide spectrum of work in the recent past, ranging from development and testing of the concept, procedures, and algorithm. This document focuses on the research and evaluation of the IM pilot interfaces, cockpit displays, indications, and alerting concepts for conducting IM spacing operations. The research team incorporated knowledge of human factors research, industry standards for cockpit design, and cockpit design philosophies to develop innovative displays for conducting these spacing operations. The research team also conducted a series of human-in-the-loop (HITL) experiments with commercial pilots and air traffic controllers, in as realistic a high-density arrival operation environment as could be simulated, to evaluate the spacing guidance display features and interface requirements needed to conduct spacing operations

Experiment Description and Results for Arrival Operations Using Interval Management with Spacing to Parallel Dependent Runways (IMSPiDR)

The predicted increase in the number of commercial aircraft operations creates a need for improved operational efficiency. Two areas believed to offer increases in aircraft efficiency are optimized profile descents and dependent parallel runway operations. Using Flight deck Interval Management (FIM) software and procedures during these operations, flight crews can achieve by the runway threshold an interval assigned by air traffic control (ATC) behind the preceding aircraft that maximizes runway throughput while minimizing additional fuel consumption and pilot workload. This document describes an experiment where 24 pilots flew arrivals into the Dallas Fort-Worth terminal environment using one of three simulators at NASA?s Langley Research Center. Results indicate that pilots delivered their aircraft to the runway threshold within +/- 3.5 seconds of their assigned time interval, and reported low workload levels. In general, pilots found the FIM concept, procedures, speeds, and interface acceptable. Analysis of the time error and FIM speed changes as a function of arrival stream position suggest the spacing algorithm generates stable behavior while in the presence of continuous (wind) or impulse (offset) error. Concerns reported included multiple speed changes within a short time period, and an airspeed increase followed shortly by an airspeed decrease

High fibrinogen gamma ' levels in patient plasma increase clot formation a arterial and venous shear

Fibrinogen gamma' accounts for 3% to 40% of plasma fibrinogen. Earlier studies indicated that fibrinogen gamma' forms altered fibrin dots under static conditions, whereas clinically, altered plasma levels are associated with arterial and venous thrombosis. However, the effects of static vs flow conditions on the role of gamma' throughout the pathophysiological range is unknown. This study explores the effects of gamma' levels on clot formation and structure in static and flow conditions. Coagulation of plasma samples with low (n - 41; 3%), normal (n - 45; 10%), or high (n - 33; 30%) levels were compared with that of purified fibrinogen mixtures with increasing ratios of gamma' (3%, 10%, 30%). Clots were analyzed by confocal microscopy, permeation, turbidity, and lysis techniques. In a novel 2-step flow-perfusion model, fibrinogen-deficient plasma repleted with increasing ratios of gamma' (3%, 10%, 30%) or plasmas with low (n = 5, 3%) or high (n = S, 30%) gamma' were flowed over preformed platelet aggregates at arterial (500 s(-1)) and venous (150 s(-1)) shear rates. Increasing gamma' percentages within the pathophysiological range (3%-30%) did not result in any change in dotformation rates; however, it led to significantly higher clot density, thinner fibers, and slower lysis in static conditions. Under flow at arterial shear, high gamma' (30%) led to faster (+44.1%-75.3%) and increased (+104%-123%) fibrin deposition, with clots exhibiting a larger volume (-253%-655%) and height (+130%-146%). These trends were magnified at venous shear. Overall, our findings demonstrate the significant impact of pathophysiological fibrinogen gamma' levels on clot structure and provide new flow-dependent mechanisms to explain how gamma' increases thrombosis risk

Reversing direct factor Xa or thrombin inhibitors: Factor V addition to prothrombin complex concentrate is beneficial in vitro

BACKGROUND: Prothrombin complex concentrate (PCC) is a human plasma‐derived mixture of partially purified vitamin K‐dependent coagulation factors (VKCF). Current therapeutic indication is treatment and perioperative prophylaxis of bleeding in acquired VKCF deficiency. Off‐label uses include treatment of direct factor Xa‐ or thrombin inhibitor‐associated bleeds, treatment of trauma‐induced coagulopathy, and hemorrhagic complications in patients with liver disease. OBJECTIVE: Considering PCC as a general prohemostatic drug, we argued that its clinical efficacy can benefit from supplementation with coagulation factors that are absent in the current PCC formulation. In this study, we focused on factor V. METHODS: We mimicked a coagulopathy in vitro by spiking whole blood or derived plasma with the direct oral anticoagulants (DOAC) rivaroxaban or dabigatran. We studied DOAC reversal by PCC and factor V concentrate (FVC) using a thrombin generation assay, thromboelastography, fibrin generation clot lysis test, and microfluidic thrombus formation under flow. RESULTS: In DOAC‐treated plasma, PCC increased the amount of thrombin generated. The addition of FVC alone or in combination with PCC caused a partial correction of the thrombin generation lag time and clotting time. In DOAC‐treated whole blood, the combination of PCC and FVC synergistically improved clotting time under static conditions, whereas complete correction of fibrin formation was observed under flow. Clot strength and clot resistance toward tissue plasminogen activator‐induced lysis were both increased with PCC and further enhanced by additional FVC. CONCLUSION: Our in vitro study demonstrates a beneficial effect of the combined use of PCC and FVC in DOAC reversal