TRB Special Report 301: Traffic Controller Staffing in the En Route Domain A Review of the Federal Aviation Administration's Task Load Model (2010) / Chapter Skim
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2 Model Overview
2 Model Overview
Pages 18-25
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From page 18... ...
These observations are explored in more depth in the following chapters. MODELING R-SIDE TASKS ONLY Aircraft typically pass through multiple en route sectors during a flight.
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From page 19... ...
task load model was originally developed for the purpose of assessing the maximum number of flights that can safely traverse a sector during a time period. For the reasons explained earlier, a two-controller team can handle more traffic than a single controller because the lead controller can devote all of his or her controlling time to the R-side tasks that accompany all flights.
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From page 20... ...
schedules can vary Exit Traffic operations and by flight type: Flash through Times for subtasks flight-planning data Nonradar arrival – Nonmilitary for other triggered tasks – Propeller Nonradar departure (modeled using GOMS) Separation event data – Military Transition – International Spacing and delay data Separation assurance Subtask scheduling Delay (7 types)
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From page 21... ...
The subtasks are then scheduled across the total period of time it takes to complete the task. For some tasks involving certain types of flights -- military, propeller, and international flights -- the model increases the computed task times by 25 percent to reflect the assumed additional complexity of this traffic.
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From page 22... ...
Total R-side task load is thus estimated by simply summing all of these times spent on tasks to generate 1-minute task loads averaged over 15-minute periods on a rolling basis. CONVERTING R-SIDE TASK LOAD INTO PTT Estimating PTT requires information on when the total R-side and D-side task load fully occupies the controlling time available to the lead controller.
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From page 23... ...
threshold across all en route sectors. In particular, managers and controllers consulted in several of the en route centers expressed concern that using a single threshold neglected the variability in D-side task load that occurs across sectors and centers because of variability in traffic complexity.
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From page 24... ...
• The task load model was originally developed to estimate the through put capacity of en route sectors, believed to be a function of the lead controller's available time to perform R-side tasks. Because two con trollers are needed to maximize throughput in a sector, the model assumes that two controllers are in position at all times, with the lead controller performing all R-side tasks and the associate controller per forming all D-side tasks.
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From page 25... ...
Model task times are generated primarily through GOMS modeling and from informa tion obtained from consultations with subject matter experts. • To model PTT, which is an estimate of whether one or more controllers are required to work the traffic, requires information on total controller task load.
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