Recent studies at NASA Ames Research Center have investigated the development and use of ground-based (air traffic controller) tools to manage and schedule air traffic in future terminal airspace. An exploratory study was undertaken to investigate the impacts that such tools (and concepts) could have on the flight-deck. Ten Boeing 747-400 crews flew eight optimized profile descents in the Los Angeles terminal airspace, while receiving scripted current day and futuristic speed clearances, to

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... rtain their ability to fly schedulematching descents without prior training. Although the study was exploratory in nature, four variables were manipulated: route constraints, winds, speed changes, and clearance phraseology. Despite flying the same scenarios with the same events and timing, there were significant differences in the time it took crews to fly the approaches. This variation is the product of a number of factors but highlights potential difficulties for scheduling tools that would have to accommodate this amount of natural variation in descent times. The focus of this paper is the examination of the crews' aircraft management strategies and outcomes. This includes potentially problematic human-automation interaction issues that may negatively impact arrival times, speed and altitude constraint compliance, and energy management efficiency. I https://ntrs.nasa.gov/search.jsp?R=20140005972 2020-05-09T10:11:58+00:00Z The Air Traffic Management (ATM) Technology Demonstration-1 (ATD1) concept was developed by NASA to safely sustain high runway throughput while also enabling fuel-efficient operations. 2 Research is being undertaken in advanced scheduling capabilities that create schedules at the runway to enable aircraft to fly Optimized Profile Descents (OPDs) along Area Navigation (RNAV) routes. 3 Aircraft on these descents will be cleared to the runway and then will be able to rely on speed to maneuver as they fly into and through the terminal area. This will allow an aircraft to maintain its place in a tightly packed stream by meeting its scheduled time of arrival (STA). The STA is allocated prior to top-of-descent by a ground-based scheduling system. Assuming en route controllers feed the Terminal Radar Approach Control (TRACON) with a reasonable flow, within certain tolerances of the schedule, TRACON controllers would rely primarily on speed adjustments to bring aircraft through the TRACON. 4 ontroller-Managed Spacing (CMS) research in the Airspace Operations Laboratory has conducted a series of real-time human-in-the-loop simulations to investigate specific controller decision support tools (DSTs) for such operations. 5 With relatively straight-forward display enhancements, TRACON controllers were able to manage dense arrival flows that followed OPDs along RNAV routes and met runway schedule times without significant increases in their workload. 6 DSTs also included a speed advisory that was formulated as a speed to fly until a specified downstream waypoint that put the aircraft back on schedule, enabling it to resume published speeds. 7 One advantage of the CMS clearances, developed to convey such intentions, is that it results in a closed four-dimensional trajectory (4DT) that can be programmed into the FMS. One set of assumptions within the ATD1 concept, and for the recent relevant research to date, is that these schedule-based RNAV OPDs will have minimal impact on the flight-deck. This encompasses primarily three subassumptions: firstly, that crews will be able to fly these descents and meet the speed instructions issued to them using existing automation; secondly, that they will be able to do this without significant increases to their workload; and thirdly, that no training is required. This flight-deck simulation study was undertaken to explore these assumptions and to examine the crews' workload level and aircraft management strategies. A secondary driver for this study was to explore the variation in, or range of, speeds that are acceptable to a crew throughout their descent, and to inform DSTs regarding where and what limits should be set within the automation. 8 The advantage of larger speed changes is that DSTs would be able to solve bigger schedule mismatches using speed alone. The disadvantage is that crews would have to manage substantial energy tradeoffs while deviating from the 4DTs computed by their aircraft's FMS for the OPD. To intentionally explore the outer limits of acceptable speed variations, it was determined that twenty percent deviations relative to the published speed profile (or roughly twice the expected control range of the CMS speed advisories), would be used in this study. A workload and task feasibility analysis as part of this study discovered that some crews could manage large variations in speed instructions and effectively manage the aircraft automation to absorb some of the redistributed/increased workload, but not all. 9 This paper contains an analysis of the flight-deck aircraft management strategies that were utilized and how they affected the outcomes. This includes identification of potentially problematic human-automation interaction issues that may negatively impact arrival times, speed and altitude constraint compliance, and energy management efficiency. II. Flight-Deck Study The flight-deck simulation study described in this paper was exploratory and broad, encompassing multiple factors of human-computer interaction, including crew procedures and the use of automation tools. The study consisted of ten Boeing 747-400 crews flying eight OPDs in the Los Angeles terminal airspace. A confederate controller issued scripted voice clearances and addressed queries from the crews. Pseudo pilots controlled traffic in the vicinity for realism. Although the study was exploratory in nature, four variables were manipulated: route constraints, winds, speed changes, and clearance phraseology. A. Simulation Facilities The study was flown in the Boeing 747-400 simulator at the Crew-Vehicle Systems Research Facility at NASA Ames Research Center. 10 This FAA certified Level D simulator has the same cab configuration as a United Airlines flight-deck (747-422 variant). Additional traffic was generated by the Multi Aircraft Control System (MACS), which also generated the ATC displays. 11 B. Participants Twenty commercial airline pilots (from one of four different carriers) participated as ten two-person crews, with each crew consisting of pilots from the same carrier. All participants were actively flying and type-certified on the B747-400. The average total flight time for the participants was 16,288 hours.