At first glance it seems absurd that busy people doing important jobs should want their computers to interrupt them. Interruptions are disruptive and people need to concentrate to make good decisions. However, successful job performance also frequently depends on people's abilities to (a) constantly monitor their dynamically changing information environments, (b) collaborate and communicate with other people in the system, and (c) supervise background autonomous services. These critical abilities can require people to simultaneously query a large set of information sources, continuously monitor for important events, and respond to and communicate with other human operators.

This study investigates an aspect of multiple-task management, interruption management, in an opexational context. Fourteen commercial airline pilots each perfimned 16 approaches in a simulated commercial flightdeck. Air traffic control (A'I'C) clea~ances intempted subjects as they perfomaed three procedum during these approaches. Common ATC interruptions w~f e found to be significantly disruptive to ongoing procedure pezfortnance on the flightdeck by producing significantly more procedm performance errors and i n c r d flightpath management activity. These results ~rmborate, for the flightdeck, that which is true in labomtory qwriments, and which is evidenced in aviation accidentlincideut reports. INTRODUCTIONHuman operators increasingly act as managers of multiple tasks in complex and dynamic environments. One aspect of multiple-task management (MTM) is the handling of interruptions, or interruption management. Research in attention management (ag., Broadbent, 1958; Schneider & Detweiler, 1988) and human mor (e.g., Reason, 1992) indicate that humans do not handle interruptions easily, or, often, very well. Previous research invMigating interruption mmagement takes four approaches: (1) development of a thewretical framework for MTM, including interruption management (2) laboratory studies aimed at u -@ mechanisms of intemptions (3) hudmachine i n t e b evaluations using interruption-recovery as an evaiuation metric and (4) identification of intemptions as a causal factor in accident/incident analyses and field investigations.Adams, Tenney, & Pew (1995) describe problems associated with developing situation awareness in MTM environments. One problem associated with situation awareness is to accurately develop and retain a task queue in memory. Consistent with theories of limited working memory capacity, t h m authors suggest that interruptions may cause other tasks' representations to be deleted from the queue, and the tasks not performed. An interruption i s not merely an additional task competing for a limited resource, it also redefines h t wbich is resident in active memory. Knowledge structures asswiated w i t h the interrupting task impose on those already resident at the time of intenuption.Based on these two facets of the MTM problem, Adams, Tenney , & Pew (1995) develop a framework for the management of multiple tasks based on Neisser's (1976) expanded model of the perceptual cycle. Neisser's model includes an qlicitflnrs memory bin and an implicit focus memory bin. Explicit focus describes a limitedcapacity storage, and corresponds to working memory. implicit focus relates t o the knowledge stnactum that are related to those tasks represented in explicit focus. This framewok provides the foundation for spcuiation on when interruptions might be handled most easily. Specifically, that interruptions related to the items in explicit focus should be easily integrated with ongoing activities, and, intemptions tangent to the immediate explicit focus should be relatively easily assimilated due to common repre...

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This study compares how well general aviation (GA) pilots detect convective weather in flight with different weather information sources. A flight test was conducted in which GA pilot test subjects were given different in-flight weather information cues and flown toward convective weather of moderate or greater intensity. The test subjects were not actually flying the aircraft, but were given pilot tasks representative of the workload and position awareness requirements of the en route portion of a cross country GA flight. On each flight, one test subject received weather cues typical of a flight in visual meteorological conditions (VMC), another received cues typical of flight in instrument meteorological conditions (IMC), and a third received cues typical of flight in IMC but augmented with a graphical weather information system (GWIS). The GWIS provided the subject with near real time data-linked weather products, including a weather radar mosaic superimposed on a moving map with a symbol depicting the aircraft's present position and direction of track. At several points during each flight, the test subjects completed short questionnaires which included items addressing their weather situation awareness and flight decisions. In particular, test subjects were asked to identify the location of the nearest convective cells. After the point of nearest approach to convective weather, the test subjects were asked to draw the location of convective weather on an aeronautical chart, along with the aircraft's present position. This paper reports preliminary results on how accurately test subjects provided with these different weather sources could identify the nearest cell of moderate or greater intensity along their route of flight. Additional flight tests are currently being conducted to complete the data set.

Weather is a significant factor in General Aviation (GA) accidents and fatality rates. Graphical Weather Information Systems (GWISs) for the flight deck are appropriate technologies for mitigating the difficulties GA pilots have with current aviation weather information sources. This paper describes usability evaluations of a prototype GWIS by 12 GA pilots after using the system in flights towards convective weather. We provide design guidance for GWISs and discuss further research required to support weather situation awareness and in-flight decision making for GA pilots.

Previous research on civil aircraft inspection and maintenance, (e.g., Shepherd, 1990) has shown the potential for human factors interventions. However, for specific interventions to be tested and detailed models to be developed a system for rapid, off-line experimentation is required. Two computer-simulated inspection tasks are described, one for non-destructive inspection and the other for visual inspection. Both systems have been used for experiments, the brief results of which are presented. Future extensions to the programs, and other experiments under way, are discussed.

This paper describes the recently developed point of departure design for a long duration, reusable Mars Transit Habitat, which was established during a 2016 NASA habitat design refinement activity supporting the definition of NASA's Evolvable Mars Campaign. As part of its development of sustainable human Mars mission concepts achievable in the 2030s, the Evolvable Mars Campaign has identified desired durations and mass/dimensional limits for long duration Mars habitat designs to enable the currently assumed solar electric and chemical transportation architectures. The Advanced Exploration Systems Mars Transit Habitat Refinement Activity brought together habitat subsystem design expertise from across NASA to develop an increased fidelity, consensus design for a transit habitat within these constraints. The resulting design and data (including a mass equipment list) contained in this paper are intended to help teams across the agency and potential commercial, academic, or international partners understand: 1) the current architecture/habitat guidelines and assumptions, 2) performance targets of such a habitat (particularly in mass, volume, and power), 3) the driving technology/capability developments and architectural solutions which are necessary for achieving these targets, and 4) mass reduction opportunities and research/design needs to inform the development of future research and proposals. Data presented includes: an overview of the habitat refinement activity including motivation and process when informative; full documentation of the baseline design guidelines and assumptions; detailed mass and volume breakdowns; a moderately detailed concept of operations; a preliminary interior layout design with rationale; a list of the required capabilities necessary to enable the desired mass; and identification of any worthwhile trades/analyses which could inform future habitat design efforts. As a whole, the data in the paper show that a transit habitat meeting the 43 metric tons launch mass/trans-Mars injection burn limits specified by the Evolvable Mars Campaign is achievable near the desired timeframe with moderate strategic investments including maintainable life support systems, repurposable structures and packaging, and lightweight exercise modalities. It also identifies operational and technological options to reduce this mass to less than 41 metric tons including staging of launch structure/packaging and alternate structural materials.

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