Table Of ContentDOCUMENT RESUME
CE 059 900
ED 340 848
Redding, Richard E.; And Others
AUTHOR
Cognitive Task Analysis of En Route Air Traffic
TITLE
Control: Model EXtension and Validation.
Human Technology, Inc., McLean, VA.
INSTITUTION
Jan 92
PUB DATE
352p.; For related documents, see CE 059 898 and CE
NOTE
059 901.
Reports - Research/Technical (143)
PUB TYPE
MF01/PC15 Plus Postage.
EDRS PRICE
*Air Traffic Control; Air Transportation; Aviation
DESCRIPTORS
Education; Cognitive Processes; Concept Formation;
*Coping; Electronic Equipment; *Job Performance; *Job
Skills; Models; *Problem Solving; Radar; Skill
Development; *Stress Management; Task Analysis
*Work Overload
IDENTIFIERS
ABSTRACT
Phase II of a project extended data collection and
analytic procedures to develop a model of expertise and skill
development for en route air traffic control (ATC). New data were
collected by recording the Dynamic Simulator (DYSIM) performance of
five experts with a work overload problem. Expert controllers were
interviewed in depth for mental model elaboration and validation.
Federal Aviation Administration data regarding operational errors
were analyzed. An extended literature review was conducted to
integrate findings with existing literature. An elaborated and
refined mental model and task decomposition were developed. The
structure of the mental model implied both a conceptual framework
used by the controller for organizing ATC knowledge and a strategy
for applying the knowledge in job conduct. The task decomposition
resulted in a listing and validation of 12 tasks. The analysis of
strategy usage showed that experts tended to use fewer strategies, a
greater variety of different strategies, more workload management
strategies, and strategy usage that varied with context. A working
model of interrelationships among key ATC constructs was developed. A
revised listing of critical cues of work overload indicated that
particiiints viewed anxiety and communication errors as being the
most important cues that an overload sit.uation was developing.
Training implications were identified in the areas of instructional
content, sequencing, media delivery, and training environment.
(Appendixes include the following: a list of 57 references, a
glossary of terms and acronyms, a glossary of strategies, a
validation study timeline, strategy listings and validation
interviews, retrospective protocols of DYSIM overload problem
solving, a work overload questionnaire, and an error listing for
DYSIM overload problem solving.)
(YLB)
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Reproductions supplied by EDRS are the best that can be made
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COGNITIVE TASK ANALYSIS OF
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CONTROL:
EN ROUTE AIR TRAFFIC
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MODEL EXTENSION AND VALIDATION
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Developed By:
Richard E. Redding
Joan M. Ryder
Thomas L. Seamster
Janine A. Purcell
John R. Cannon
Human Technology, Inc.
McLean, Virginia
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January 1992
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Abstract
A cognitive task analysis was performed to analyze the key cognitive components of the
en route air traffic controllers' job.
Our goal was to ascertain expert mental models and decision-making strategies, and to
identify important differences in controller knowledge, skills, and mental models as a function
of expertise. By comparing experts, intermediates, and novices, the cognitive analysis provides
traditional, behavioral methods of
a much better understanding of skill progression than would
This understanding can serve as a foundation for improving the training of
task analysis.
professional air traffic controllers, and provides important insights into improved training
methods for other complex, high-performance job environments that require speedy decision-
making and prioritization of competing tasks (such as aircraft flight decks, nuclear power plant
operation, and combat information centers).
This report presents the results from the model extension and validation phase of the task
The first phase of the cognitive task analysis had included the development of an
analysis.
The Phase II
expert mental model of air traffic control and associated tasks and strategies.
findings reported herein extend and validate the model and expert strategies. Phase II analyzed
the critical cues of work overload and operational error data, and the original data were
subjected to further analysis. New work overload data were also collected and analyzed. This
iterative process of data collection led from the analysis of general controller expertise to a
narrower analysis of controller expertise under conditions of heavy workload.
This report also provides an integration of the findings and training recommendations
from Phases I and II of the analysis, resulting in a comprehensive view of controller expertise
and an integrz ted model for training development for the Federal Aviation Administration's new
en route air traffic control curriculum.
This research represents one of the first uses of cognitive task analysis to support the
development of a complete curriculum for the training of a complex, high-performance task.
The results suggest exciting and innovative approaches for air traffic control training, as well
in a time-constrained, multi-tasking
as for training other tasks that must be performed
environment.
VALIDATION
COGNITIVE ANALYSIS REPORT: MODEL EXTENSION AND
TABLE OF CONTENTS
ran
I.
Introduction
1
Purpose
1
General Approach
1
4
II.
Mental Model And Task Decomposition
4
Method
4
Participants
4
Procedures
6
Measures And Data Analysis
9
Results
9
Results: Mental Model
12
1) Sector Management
Mental Model Category:
13
Mental Model Category: 2) Conditions
3) Prerequisite Information
13
Mental Model Category:
14
Mental Model: Levels Within Category Panels
17
Sector Management Category
22
Conditions Category
24
Prerequisite Information Category
27
Results: Task Decomposition
27
Tasks
28
Task Flow
30
Task Goals, Triggers, And Subgoals
47
Task Triggers
59
Perceptual Events
Results:
61
Results: Validation
61
Sector Management Category
Validation:
64
Conditions Category
Validation:
65
Prerequisite Information Category
Validation:
65
Validation: Task Decomposition
66
Summary
70
III.
Expert Strategies Analysis
70
Method
70
Participants
70
Procedures
71
Measures And Data Analysis
76
Results
76
Results Of Expert Strategies Analysis
81
Structured Problems
91
Work Overload Problem
93
Limitations Of The Data
97
Summary
Continued
. . .
Page ii
4
COGNITIVE ANALYSIS REPORT: MODEL EXTENSION AND VALIDATION
TABLE OF CONTENTS
(Continued)
East
100
Relationships Among The Constructs
IV.
100
Relationships Among Key ATC Constructs
100
Mental Model
102
Task Decomposition
107
Perceptual Events
107
Strategies
115
Critical Cues Of Work Overload
Working Model Of Interrelationships Among
115
Key ATC Constructs
Critical Cues Of Work Overload And Cognitive-Perceptual
V.
120
Causes Of Operational Errors
120
Method
120
Critical Cues Of Work Overload
120
Strategy Usage And Error Rates
121
Operational Errors
122
Results
122
Critical Cues Of Work Overload
125
Strategy Usage And Error Rates
129
Air Traffic Control Operational Errors
134
Summary
137
Summary Of Results
VI.
137
Summary Of Phase I And Phase II Results
Summary: Essential Features Of ATC Expertise
169
172
Implications For Training
VII.
172
Introduction
172
How Should Instruction Be Organized?
174
Recommendations For Instructional Content
174
Mental Model
175
Task Decomposition And Perceptual Events
Strategic And Goals
177
178
Decisionmaking
179
Recommendations For Instructional Sequencing
181
Recommendations For Instructional Media
182
Recommendations For Training Environment
185
VIII.
References
Continued
. . .
MMMEINe
Page iii
COGNITIVE ANALYSIS REPORT: MODEL EXTENSION AND VALIDATION
TABLE OF CONTENTS
(Continued)
Fut
Glossary Of Terms And Acronyms
IX.
191
Glossary Of Strategies
199
X.
Appendixes
Mental Model And Task Decomposition Validation Study Timeline
A-1
A.
Strategy Listings For Each Problem And Participant Group
B-1
B.
C-1
Strategy Validation Interviews
C.
Retrospective Protocols Of DYSIM Overload Problem Solving
D-1
D.
Work Overload Questionnaire
E.
E- 1
Error Listing For DYSIM Overload Problem Solving
F-1
F.
Page iv
COGNITIVE ANALYSIS REPORT: MODEL EXTENSION AND VALIDATION
LIST OF FIGURES
Eau
10
Expert Mental Model Of ATC
Figure 1
Characteristics Of Mental Model
Figure 2
Categories And Panels
11
Example Of The Organization Of The Mental Model
16
Figure 3
29
En Route Air Traffic Control Task Flow
Figure 4
Frequency Of Strategy Usage Across Groups
Figure 5
77
For Structured Problem 1
Frequency Of Strategy Usage Across Groups
Figure 6
78
For Structured Problem 2
Frequency Of Strategy Usage Across Groups
Figure 7
79
For Both Structured Problems Combined
Strategy And Comment Frequency For
Figure 8
80
Work Overload Problem
82
Interaction Between Experience And Strategy Usage
Figure 9
82
Interaction Between Problem Type And Strategy Usage
Figure 10
Contents Of Sector Traffic Events Panel In
Figure 11
103
Validation Timeline
104
Contents Of Aircraft Data Panel In Validation Timeline
Figure 12
Contents Of Sector Control Plan Panel In Validation Timeline
105
Figure 13
Contents Of Area And Sector Factors, Weather Factors, And
Figure 14
106
Controller Factors Panels In Validation Timeline
Page v
COGNITIVE ANALYSIS REPORT: MODEL EXTENSION AND VALIDATION
LIST OF TABLES
faze
32
The 12 En Route Air Traffic Control Tasks
Table 1
Relationships Of Task Triggers To Mental Model Components
Table 2
48
And Tasks
60
Perceptual Events
Table 3
73
List Of Strategy Codes And Their Sources
Table 4
75
Sample Production Developed During Phase I
Table 5
Expert Strategy Usage Across Both Structured
Table 6
85
Problems Combined
Intermediate Strategy Usage Across Both Structured
Table 7
87
Problems Combined
Novice Strategy Usage Across Both Structured
Table 8
89
Problems Combined
92
Examples Of Other Workload Management Strategies
Table 9
94
A Preliminary Structure For Controller Strategies
Table 10
Relationships Among The Constructs
Table 11
101
Relationships Of Strategies To Tasks And Task Subgoals
109
Table 12
Sample Working Model Of Interrelationships Among The
Table 13
Mental Model, Tasks, And Strategies
116
Critical Cues Of Work Overload
Table 14
123
124
Representative Aids For Reducing Workload
TaNe 15
Correlations Between Number Of Errors And Strategy Usage
126
Table 16
Correlations Between Number Of Errors And Workload
Table 17
128
Management Strategies
Common Errors In Planning And Decisionmaking
132
Table 18
Page vi
COGNITIVE ANALYSIS REPORT: MODEL EXTENSION AND VALIDATION
LIST OF TABLES
(Continued)
Summary Of Conclusions Based On Results From
Table 19
Each Analysis
138
Summary Of Key Results From The Phase I Data Collection
Table 20
168
Page vii
:I
I. INTRODUCTION
I 0
