M I T I n t e r n a t i o n a l C e n t e r f o r A i r T r a n s p o r t a t i o n Impact of Operating Context on the Use of Structure in Air Traffic Controller Cognitive Processes Hayley J. Davison, Jonathan M. Histon, Margret Dora Ragnarsdottir, Laura M. Major & R. John Hansman Massachusetts Institute of Technology 5 th FAA/Eurocontrol ATM R & D Seminar June, 2003

Motivation  Structure has been identified in the en route environment as a mechanism of cognitive simplification  Appropriate application of structure could result in a safe increase in the capacity of the air traffic control system, and should be considered in:  Airspace re-design  Design of ATC decision aids  Design of future ATC procedures  This study investigates whether structure-based abstractions hold across other ATC environments

Methodology  Site Visits  TRACONs: Boston, New York, Manchester (NH)  En Route Centers: Boston, New York, Cleveland, Montreal  Oceanic operations: New York, Reykjavik  Air Traffic Data  ETMS enhanced data-stream  ASR-9 data for Boston airspace  Voice Command Analyses  Boston TRACON final approach frequency  Atlanta Center’s Logen sector frequency

Proposed Air Traffic Controller Cognitive Model Adapted from Endsley 1994, Pawlak 1996, & Reynolds, et al., 2002

Previously Identified Structure- Based Abstractions  Standard Flows  Aircraft classified into standard and non-standard classes based on relationship to established flow patterns.  Groupings  Common, shared property, used to define and control groups of aircraft E.g. non-interacting flight levels  Critical Points  Intersection and merge points between flows  Reduce problem from 4D to 1D “time-of-arrival” Histon, et al., 2001

TRACON

TRACON: Example of Standard Flows  TRACON standard flows emerge from facility SOP’s

TRACON: Impact of Standard Flows  Comprehension/Projection: determine future lateral/vertical position based on membership in standard flow  Planning/Evaluation: use the standard flow as a template for flight paths satisfying airspace & traffic flow constraints; standard flows are non-interacting  Monitoring: easily perceive if aircraft is deviating from expected lateral path; different strategies for aircraft not in standard flow COGNITIVE SPACE OF THE AIR TRAFFIC CONTROLLER SITUATION AWARENESS LEVEL 1 Perception LEVEL 2 Comprehension LEVEL 3 Projection DECISION PROCESSES Monitoring Evaluating Planning PERFORMANCE OF ACTIONS Implementing “CURRENT PLAN” WORKING MENTAL MODEL STRUCTURE-BASED ABSTRACTION AIR TRAFFIC SITUATION

TRACON: Examples of Groupings  Altitude & airspeed groupings used in the TRACON

TRACON: Impact of Groupings  Comprehension/Planning: expect certain traffic flows to have certain altitudes & airspeeds  Evaluating: separate flows by altitude to ease load of ensuring separation  Projection: use constant airspeeds correlate distance & time linearly so that projection is simplified COGNITIVE SPACE OF THE AIR TRAFFIC CONTROLLER SITUATION AWARENESS LEVEL 1 Perception LEVEL 2 Comprehension LEVEL 3 Projection DECISION PROCESSES Monitoring Evaluating Planning PERFORMANCE OF ACTIONS Implementing “CURRENT PLAN” WORKING MENTAL MODEL STRUCTURE-BASED ABSTRACTION AIR TRAFFIC SITUATION

TRACON: Examples of Critical Points  Critical points in TRACON:  Ingress points into sector  Egress points out of sector  Merging points in traffic flows  Holding points

TRACON: Impact of Critical Points COGNITIVE SPACE OF THE AIR TRAFFIC CONTROLLER SITUATION AWARENESS LEVEL 1 Perception LEVEL 2 Comprehension LEVEL 3 Projection DECISION PROCESSES Monitoring Evaluating Planning PERFORMANCE OF ACTIONS Implementing “CURRENT PLAN” WORKING MENTAL MODEL STRUCTURE-BASED ABSTRACTION AIR TRAFFIC SITUATION  Perception/Projection: focuses point to which projections made to the recognized critical points in a sector  Monitoring: monitors critical points in sector more frequently because the critical points are the most likely locations of conflict  Planning: plan to meet constraints by the point the aircraft reaches the critical point

En Route Results

Distinct Types of En-route Sectors  Cruise sectors  High or “super-high” altitude sectors  Most aircraft at constant altitude  Transition sectors  Interface between en-route sectors and the terminal airspace  Similar operational conditions as en-route sectors Radar update rates, limitations on available airspace  Tasks are similar to TRACON airspace Majority of aircraft in vertical transition Greater use of vectoring Logen Sector 90% Transitional aircraft 10% Cruise aircraft Utica Sector 40% Transitional aircraft 60% Cruise aircraft

En Route (Cruise) Examples Standard Flows: Preferred Routings & Jet Routes Groupings: by altitude Critical Points: Ingress points Egress points Merge points

En Route (Transitional) Examples Jets Props Standard Flows: SIDs & STARs Groupings: Aircraft type (jet vs. prop) Critical Points: Lateral/Vertical merge point “gates”

Oceanic Results

Oceanic ATC environment

Oceanic: Example of Standard Flows

Reported Workload Impact of Standard Flows  Reykjavik controllers reported that they are cognitively able to handle more traffic as structure increases

Oceanic: Impact of Standard Flows  Comprehension/Projection: determine future lateral/vertical position based on membership in standard flow  Planning/Evaluation: use the standard flow as a template for flight paths satisfying airspace & traffic flow constraints; standard flows are non-interacting COGNITIVE SPACE OF THE AIR TRAFFIC CONTROLLER SITUATION AWARENESS LEVEL 1 Perception LEVEL 2 Comprehension LEVEL 3 Projection DECISION PROCESSES Monitoring Evaluating Planning PERFORMANCE OF ACTIONS Implementing “CURRENT PLAN” WORKING MENTAL MODEL STRUCTURE-BASED ABSTRACTION AIR TRAFFIC SITUATION

Oceanic: Examples of Groupings  Flight strips are grouped by flight direction, time, & altitude groupings reflecting grouping strategy of controllers

Oceanic: Impact of Groupings  Evaluating: separates aircraft into non-interacting altitude groupings and time groupings, which simplifies the evaluation problem into a sequencing problem COGNITIVE SPACE OF THE AIR TRAFFIC CONTROLLER SITUATION AWARENESS LEVEL 1 Perception LEVEL 2 Comprehension LEVEL 3 Projection DECISION PROCESSES Monitoring Evaluating Planning PERFORMANCE OF ACTIONS Implementing “CURRENT PLAN” WORKING MENTAL MODEL STRUCTURE-BASED ABSTRACTION AIR TRAFFIC SITUATION

Oceanic: Examples of Critical Points  Critical points:  Ingress points onto tracks  Egress points from tracks  Position report points

Oceanic: Impact of Critical Points  Perception/Projection: focuses point to which projections made to the recognized critical points in a sector  Monitoring: monitors critical points in sector more frequently because the critical points are the most likely locations of conflict  Planning: plan to meet constraints by the point the aircraft reaches the critical point COGNITIVE SPACE OF THE AIR TRAFFIC CONTROLLER SITUATION AWARENESS LEVEL 1 Perception LEVEL 2 Comprehension LEVEL 3 Projection DECISION PROCESSES Monitoring Evaluating Planning PERFORMANCE OF ACTIONS Implementing “CURRENT PLAN” WORKING MENTAL MODEL STRUCTURE-BASED ABSTRACTION AIR TRAFFIC SITUATION

Projection Discussion  Projection identified as key ATC cognitive task benefiting from application of structural abstractions  Two fundamentally different types of projection identified in ATC: spatial-based projection & time-based projection  Influenced by surveillance available & procedural restrictions  May be aided by decision support tools (e.g., NASA’s TMA) NASA’s TMA

Projection Discussion Minutes in Trail Surveillance Separation Restrictions Decision Support Miles in Trail Spatial-based projection Time-based projection Mixed projection required Miles in Trail Minutes in Trail NASA’s TMA

Projection Discussion  Future surveillance advances & procedural modifications may change the type of projection required and/or change structure present in the traffic  Individualized decelerating approach procedures are being considered in TRACON  Time-based metering has been discovered to be more efficient than spatial-based restrictions in the En Route environment  Oceanic information support may transition from a procedural form of support (flight strip) to a spatial form of support (situation display)  Further investigation will be conducted into what aspects of structure provide the greatest benefits to the projection task

Conclusions  Evidence of 3 key abstractions found in all 3 ATC environments, details of how abstractions apply differ  Projection identified as key ATC cognitive task benefiting from application of structural abstractions  Consideration should be given to making future surveillance & procedures cognitively manageable while taking advantage of existing structure-based abstractions

Discussion Questions  Other structure-based abstractions?  Can the identified abstractions aid cognition in other ways?