# Advancing Free Flight Through Human Factors

# 

# 

# Workshop Report

# 

# August 1995 

# 

# Advancing Free Flight Through Human Factors Workshop Report

We are pleased to present this report on the technical workshop,
Advancing Free Flight Through Human Factors, jointly sponsored by the
FAA\'s Air Traffic Plans and Requirements Service and the Office of the
Chief Scientific and Technical Advisor for Human Factors. The results of
the workshop represent an important first step in the consideration of
human factors issues in the integration of free flight into the National
Airspace System. While much of the critical work remains to be done,
these results will assist human factors scientists, system designers,
and operational experts in making free flight a reality. Our commitment
is to develop the best possible system by applying the best possible
research and human factors information. We appreciate the interest and
efforts of all the workshop participants representing industry,
academia, and the federal government. Without their help the progress
made would have been impossible.

  ---------------------------- --------- ---------------------------------
  Neil Planzer                           Mark A. Hofmann, Ph.D., CPE

  Program Director, Air                  Chief Scientific and Technical
  Traffic                                Advisor

  Plans and Requirements                 for Human Factors
  Service                                
  ---------------------------- --------- ---------------------------------

***Acknowledgments***

We gratefully acknowledge the extraordinary efforts of the following
individuals for their dedicated work on this project: Glen Hewitt, Karol
Kerns, Karl Grundmann, Larry Cole, Doug Rachford, Lisa Cuebas, Robert
Hilb, Bill Corwin, Richard Cox, Dianne Boone, Russ Benel, Darrell
Meachum, Kelly Harwood, and Tom Toula.

# Table of Contents

Executive Summary

Purpose

Background

Organization of the Report

Description of the Workshop

Working Group Findings

**Traffic Flow Management**

**Domestic En Route and Cruise Transition**

**Oceanic and International**

**Terminal, Final Approach, and Airport Surface**

Conclusions

Recommendations

Appendix A: List of Attendees

Appendix B: Summary of Issues Generated by Working Groups

Appendix C: Workshop Agenda

#  {#section-4 .unnumbered}

# Executive Summary

This report describes the results of the Advancing Free Flight Through
Human Factors technical workshop held on June 20 and 21, 1995. The
purpose of this technical workshop was to begin the process of
identifying and solving human factors issues related to a new aviation
concept called \"free flight.\" The FAA sponsored an RTCA select
committee to define the concept of free flight and to identify the
issues and activities that must be undertaken to advance the concept.
The select committee prescribed free flight as a concept encompassing a
real time air traffic management triad: People, Procedures, and
Technologies. The long range changes envisioned by the RTCA select
committee to move the system toward free flight will involve the human
as the most critical element in the use of new technologies, equipment,
and procedures. There were four human factors related issues that were
among the key issues identified in this select committee. These are:

-   What modeling and analysis effort is necessary to ensure safety?

-   How will the FAA and users coordinate development and accommodate
    evolving technologies and new requirements?

-   What are the human factors considerations?

-   Can the separation assurance function shift between the pilot
    \[and\] controller?

To meet these human factors related challenges, the FAA Chief Scientific
and Technical Advisor for Human Factors (AAR-100) and the Director of
Air Traffic Requirements (ATR-1) invited approximately 70 leading
aviation human factors and operational experts to participate in a
technical workshop. The workshop was envisioned as the first of a series
of initiatives to help guide and manage human factors research and
development (R&D) activities in support of free flight. The primary
purpose of this workshop was to identify and define major human factors
challenges associated with free flight and assess their relative
importance for research and implementation.

The participants were divided into four work groups mirroring the four
domains called out in the RTCA report: Oceanic and International;
Domestic En Route and Cruise Transition; Terminal, Final Approach, and
Airport Surface; and Traffic Flow Management. The four working groups
generated a great deal of information and issues to consider in
developing the free flight concept. The discussions and products of each
working group indicated that many of the issue areas are applicable to
multiple domains. The information can be categorized into 14 different
issue areas. Of these 14 areas, 13 of them were addressed by multiple
groups.

Several general conclusions have been drawn from the findings of the
workshop. It was concluded that a central coordination point is needed
for the important elements of free flight development represented by
"people" (the third leg of the RTCA program). There are now and will be
in the future many other requirements for the coordination and
dissemination of human factors free flight efforts. A planned approach
to this coordination and dissemination is necessary. Also, it was
concluded that a follow-on activity that identifies, analyzes, filters,
and prioritizes the human factors work to be done is needed. Finally, it
was concluded that the workshop results must be transmitted to the RTCA
task force and that joint ATR/AAR-100 participation in any agency
response to the RTCA work is required.

The findings and conclusion of the workshop provide insight into the
challenges associated with human factors and free flight. There were
many specific recommendations made for research efforts, however, the
major general recommendations are:

1.  Designate ATR and AAR-100 as a joint FAA focal point for human
    performance considerations in Free Flight

2.  Charter the FAA focal point with resources and responsibility to:

-   further identify, prioritize, and develop essential human factors
    issues and requirements

-   develop a program to systematically monitor critical human factors
    areas and ensure their resolution

-   ensure that human factors efforts supporting free flight development
    (FAA and industry) are fully coordinated and integrated

1.  Charge the focal point to conduct efforts in support of human
    factors in free flight that:

-   expand the coordination effort initiated by this initial workshop

-   disseminate findings, conclusions, results, and products related to
    future developments in free flight human factors

1.  Establish formal joint ATR/AAR involvement in agency response and
    follow-up to RTCA Free Flight developments by:

-   Formal transmission of this report to RTCA Free Flight Task Force 3

-   Participating in any agency response to the RTCA recommendations

-   Participating in future agency free flight developments

# Advancing Free Flight Through Human Factors

# Report

# Purpose

This report describes the results of the Advancing Free Flight Through
Human Factors technical workshop held on June 20 and 21, 1995. The
purpose of this technical workshop was to begin the process of
identifying and solving human factors issues related to a new aviation
concept called \"free flight.\"

# Background

After the U.S. airline industry was deregulated in 1978, air carriers
began lobbying for more fuel efficient routing and fewer air traffic
control imposed delays. International pressure crystallized in 1991 when
the U.S. adopted the ICAO FANS concept. The pressure to reduce
constraints in the National Airspace System reached a crescendo in 1993
with the Airline Commission Report. Several air carriers and aviation
associations, particularly the Air Transport Association (ATA) called
for a new approach and labeled it \"free flight.\" The Federal Aviation
Administration (FAA) joined with the aviation industry under the
auspices of an RTCA select committee to define "free flight." The
committee defined free flight as:

A safe and efficient flight operating capability under instrument flight
rules (IFR) in which operators have the freedom to select their path and
speed in real time. Air traffic restrictions are only imposed to ensure
separation, to preclude exceeding airport capacity, to prevent
unauthorized flight through special use airspace, and to ensure safety
of flight. Restrictions are limited in extent and duration to correct
the identified problem. Any activity which removes restrictions
represents a move toward free flight.

The select committee also prescribed free flight as a concept
encompassing a real time air traffic management triad: People,
Procedures, and Technologies. The long range changes envisioned by the
RTCA select committee to move the system toward free flight will involve
the human as the most critical element in the use of new technologies,
equipment, and procedures. These changes will, in turn, necessitate a
\"new way of doing business\" for both the FAA and the aviation industry
with organizational, staffing, job design, training, communication, and
other implications. In addition, the RTCA report identifies several
issues which must be dealt with for free flight to be successful. Four
of these issues were identified by the Director of Air Traffic
Requirements (ATR-1) and the Chief Scientific and Technical Advisor for
Human Factors (AAR-100) as critically related to human factors:

-   What are the human factors considerations?

-   What modeling and analysis effort is necessary to ensure safety?

-   How will the FAA and users coordinate development and accommodate
    evolving technologies and new requirements?

-   Can the separation assurance function shift between the pilot
    \[and\] controller?

To help answer these questions and meet the human factors challenge, the
FAA recognized the importance of involving the nation's leading
technical experts early-on in the development of this concept to ensure
that human factors are usefully and systematically considered. To this
end, ATR and AAR jointly sponsored the technical workshop on Advancing
Free Flight Through Human Factors. The participants of this workshop
were a select set of approximately 70 aviation human factors and
operational experts from various government, industry, and academic
organizations. (See Appendix A for complete list of attendees.)

The workshop was envisioned as the first of a series of initiatives to
help guide and manage human factors research and development (R&D)
activities in support of free flight. The primary purpose of this
workshop was to identify major human factors challenges associated with
free flight and assess their relative importance for research and
implementation. In addition, it was the goal to provide input from the
human factors community to the RTCA Task Force 3 effort regarding the
human factors issues generated in the initial RTCA select committee
report.

# Organization of the Report

The remainder of the report is organized into the following four
sections: a description of the workshop, the findings of the working
sessions, conclusions, and recommendations.

# Description of the Workshop

Prior to the workshop, the participants received a read-ahead package of
materials pertaining to free flight. The documents in this package
included the *Report of the RTCA Board of Directors' Select Committee on
Free Flight*, the January-March 1995 edition of *The Journal of Air
Traffic Control,* and a *Human Factors Issues in Free Flight* white
paper by the Mitre Corporation. The purpose of the read-ahead package
was to establish a common understanding of free flight for the workshop
participants.

The workshop participants received presentations describing free flight
concepts, complexities, and challenges from several senior executives
from the FAA and NATCA. In addition, research findings, free flight
functions demonstrations, and presentations of various free flight
scenarios were provided. The participants were divided into four
technical working groups based on the four operational domains described
by the RTCA select committee: Oceanic and International; Domestic En
Route and Cruise Transition; Terminal, Final Approach, and Airport
Surface; and Traffic Flow Management. Each group was co-chaired by both
a human factors and an operational representative. The groups were asked
to define the human factors issues in each of three areas: current
initiatives towards free flight, transition to free flight, and mature
free flight.

The results of each technical working group were presented to the
plenary session of the workshop. The co-chairs of each working group
served as panel members for a discussion of conclusions and
recommendations. This report constitutes the findings of the four work
groups and their conclusions. (Appendix B is a table that presents the
correspondence between working group issues.) The workshop concluded
with closing remarks from senior FAA executives. (See Appendix C for the
workshop agenda.)

# Working Group Findings

## 

## Traffic Flow Management

The free flight concept holds that the design of the present NAS overly
constrains user access and operations. It sets out the fundamental
directive to identify changes in the NAS that remove restrictions,
allowing system users the flexibility to make choices based on business
considerations subject to the constraints necessary to ensure safety. In
TFM, this directive will have particular significance for developing a
functional architecture which describes the roles, responsibilities, and
authority for strategic and tactical decision making with respect to
system restrictions. In turn, the functional architecture will be
influenced by associated requirements for information gathering, use,
sources, and distribution.

Human factors should play an integral part in supporting the integration
of the automated TFM functional components with the humans that will
operate them. The TFM working group defined nine major issues that
should be addressed as part of free flight research and development.

### Information Collection, Dissemination, Display and Use 

Information collection, dissemination, display, and use in TFM was a key
issue for discussion in the TFM working group. It was recognized that in
order to support meaningful participation by users in TFM, more
information sharing and exchange would have to occur at all stages of
the decision making process. The types of information required include
the following: information necessary to set constraints, information on
the constraints, reasons for the constraints, allocation of capacity to
users, choices available within the constraints, information necessary
to evaluate the choices, intentions of users based on the choices, and
feedback on the results of the choice.

### Measures and Metrics

The changing patterns of traffic in the system will necessitate new
definitions of traffic flow problems and in turn, collection of new
information on problem characteristics, locations, and probabilities.
Measurement of system capacity, demand, and capacity utilization will
undergo significant changes in a free flight environment. Metrics are
needed for predictive decision making and TFM performance assessment.
This requires development and display of new classes of metrics to
provide feedback that can reduce uncertainties before decisions are made
and help validate the effectiveness of TFM decisions after they are
made.

### Uncertainty and Predictability

In addition to determining what types of information and metrics would
be needed in a free flight environment, the TFM working group also
discussed issues of information quality and availability. Use of
uncertain information in TFM decisions will require new ways to
represent this uncertainty for display to users and operators. Improved
dissemination of information will be accompanied by greater variability
in accuracy of information. Display coding techniques will be required
to clearly represent attributes such as the age and source of the data.
Automated and manual procedures will be needed to reconcile
inconsistencies in the data and guide users responses.

### Selection, Training, and Education

In the TFM working group, selection, training and education programs
were discussed as a vehicle for implementing new roles for traffic
managers and promoting trust among all of the players involved in the
TFM process. Additional knowledges and skills may be required, and
therefore, the criterion for selecting traffic managers may change.
Training will need to emphasize team work and cooperative decision
making. All participants must be educated concerning their respective
roles, the roles of the other participants, and how these individual
roles fit together. Ensuring a common understanding and awareness of
participants roles and their interrelationships was considered to be a
prerequisite for developing greater consistency and commonality in the
criteria that will be used at the local facility level to establish
resource constraints and parameters.

### Functional Architecture

A basic and overriding concern in the area of TFM and Free Flight was
the development of a functional architecture for TFM which addresses
preflight as well as airborne decisions. Determining an appropriate
functional architecture will involve analyzing the information
requirements dictated by alternative allocations of functions, including
the requirements for distribution of information among the various
players. Human factors can help determine and evaluate the number,
roles, and interactions of TFM elements. Specific contributions focus on
determining human performance metrics and criteria for discriminating
among alternatives, and evaluations of alternatives via analytic
studies, computer simulations, and human-in-the-loop studies. Human
factors input can also help in prioritizing the alternatives according
to their relative performance with respect to the criteria and
presenting these results for discussion by the representatives of the
TFM players. Participant comments and preferences can then be factored
into the priorities to help arrive at a consensus.

### Transition: Phases vs. Levels 

Two classes of transition issues were noted in the TFM working group.
One class of issues concerned the potential complexity introduced by
multiple levels of free flight capability within the NAS. The TFM group
discussed issues associated with human monitoring, awareness, and
responses under multiple levels of free flight capability in the system.
The second class of transition issues discussed by the group concerned
the process of moving from the current system to a future system. In
this area, the group discussed personnel and institutional issues
related to government provision of TFM services. The group also
identified the need for systematic testing and evaluation of
transitional steps based on predefined performance parameters and
criteria.

### Roles, Responsibilities, and Authority

In the context of TFM, the discussions on roles, responsibilities, and
authority centered on maintaining trust and honesty among decision
makers in the face of uncertain information. The challenge in this area
is to establish roles and responsibilities which will allow users and
air traffic service providers to cooperate and employ \"win-win\"
strategies rather than competing with \"win-lose\" strategies. To
support a cooperative environment, the roles and responsibilities of
each party must be defined explicitly and timely feedback must be
provided to reinforce appropriate behaviors and discourage inappropriate
behaviors.

### Airspace Changes

The TFM working group discussed the potential impact of changes in
airspace and traffic patterns on controllers. New TFM metrics that take
into account human workload will be needed to predict manageability and
prevent overload situations. Increased flexibility in routes, flight
altitudes, and altitude transitions will affect the manageability of the
airspace. New procedures with acceptable lead times must be devised for
transitioning an airspace to increase traffic structure when necessary
to maintain manageability.

### 

### Player Acceptance

The TFM working group concluded that effective and coordinated human
performance will be required for the successful implementation of TFM
role changes associated with free flight concepts. A key to effective
performance is that the participants accept and endorse their new roles.
To ensure participant acceptance, the design of the new functional
architecture must consider issues associated with the separation of
decision making authority from the execution of functions. Moreover, the
plan for implementing Free Flight capabilities must consider user
acceptance issues and develop plans to address those issues. Although
the group recognized that substantial participant involvement must be
inherent in the Free Flight design process, it was also acknowledged
that it will be impossible for all potential participants to be
involved. It is therefore necessary to develop a plan for assessing
reactions and concerns of potential participants who have not been
involved and for the use of orientation, training and participant
feedback programs to address the concerns.

## 

## Domestic En Route and Cruise Transition

The En Route work group focused on the six salient issues of information
requirements and display; communication and decision making;
coordination and delineation of responsibility; measuring and managing
workloads; alternative strategies for separation; and human factors
expertise in free flight concept development, requirements
determination, and operational implementation:

### Information and Display

Determination of En Route informational requirements imposes an
evolutionary challenge in the free flight operational concept. With the
removal of standard routes as well as unrestricted horizontal and
vertical limitations, technology and procedures must find appropriate
substitutes for stable flight paths. These informational requirements
will place additional demands upon the aviation community to devise
innovative approaches to display the required information. As new
display technologies and techniques are developed, human performance
considerations must be anticipated and analyzed. Because the En Route
will provide an increasingly dynamic environment as free flight
proliferates, the communication and display of information must be
sensitive to the current and future operational context of the aircraft
and controller workstation situation. This contextual sensitivity of
information and display may provide opportunities for increased
efficiency in pilot and controller tasks, but also poses the potential
for increased complexity in hardware/software/liveware configurations,
decreased situational awareness, and unanticipated human responses.
Resolving the potential complications of the dynamic En Route
environment will necessarily entail significant analysis of information
and display alternatives and human performance simulation. The human
factors work currently underway related to the demonstration and
validation of information requirements (such as that related to data
link, CTAS, CHI alternatives, and cognitive engineering) applies.

### Cognitive Workload Allocation 

The evolution of procedures and the new technologies introduced under
free flight operations reflect only the tip of the iceberg of mental
task load changes for pilots, controllers, and operations personnel.
While there are needs to analyze and accommodate changes in the physical
aspects of the new functions and methods (e.g., work station design,
work space environmental parameters, equipment configurations,
supervisory controls, staffing schedules), the most challenging and
complex change will occur in the cognitive demands imposed by new
procedures, tightly coupled supporting systems, increasingly complex
software configurations, active user collaboration, dynamic air traffic
situations, mixed equipage, increased variety of traffic patterns, and
non-standard scenarios. Both new means to measure and revise threshold
criteria (e.g., sector complexity and workload factors) are required to
assess these impacts on operator workloads. Implementing free flight may
result in revised human cognitive tasks associated with such
considerations as changing memory demands, attention, situational
awareness, fail soft and recovery, and transitions in phases of flight.
New automation tools will impose a variety of sub-cognitive models for
the controller and pilot. To assess how well these tasks and models are
(and need to be) defined, structured, trained, maintained, and fully
understood in routine and emergency conditions will place heavy demands
on the resources of activities and facilities supporting free flight
development and implementation. The most promising solution to this
complex and challenging requirement is a comprehensive plan of
distributed simulation modeling that becomes fully integrated into the
FAA engineering and acquisition community.

### Communication and Decision Making

Free flight in the En Route environment solves many questions and
concerns of the current system architecture and operation, but it
imposes many new ones. One of the areas likely to be significantly
altered by changes in technology, procedures, and training is the area
of air/air and air/ground communications. En Route operations are not
expected to necessitate a unique treatment of this area, but all free
flight communications are likely to see considerable change. Major
emphasis must be placed on identifying the requirements for and
providing the solution to information consistency, information sharing,
information sufficiency, communication dynamics of shifting
responsibility for separation, decision conflicts, decision voids, team
coordination, cooperative team training, and the like. To address this
area requires an effort to define the communication requirements under
alternative En Route scenarios, and the use of exploratory simulation to
communicate allocation schemes. A key part of this effort will involve
evaluating integrated air/air and air/ground datalink with voice
communication and automation.

### Allocation of Responsibility 

The unambiguous delineation of responsibility is one of the most
fundamental principles of safe air travel under any set of procedures
and technology. Under free flight, the allocation of responsibility must
be no less clear. Achieving this clarity will entail a well orchestrated
development process in which procedural and technological improvements
and training for those modifications are well coordinated system-wide.
To ensure uniformity in human and system performance parameters and
common understanding by pilots and controllers will require increased
attention to factors affecting awareness, decision making, and
automation development trade-offs, especially as they affect failure
recovery, active-passive interface with automation, redundancy, and
structured versus non-structured environments. As with some other
modifications to the pilot-controller-operations interactions, extensive
analysis and simulation are necessary to provide data for trade-off
decisions.

### Separation Strategies

As the new technology of free flight provides greater opportunities for
alternative concepts in maintaining separation, new challenges in
designing the human interfaces (air/air and air/ground and
ground/ground) must be addressed. For the future En Route environment to
take full advantage of the opportunities presented by the new
technologies entails exploring innovative methods for performing the
traditional tasks of aircraft separation (for both pilots and
controllers). In addition to capitalizing on improved equipment (e.g.,
faster response times, higher resolution of display, improved location
correction algorithms), new approaches to pilot and controller actions
must be assessed. Developing these new strategies for the controller and
pilot interactions necessitates exploring areas where free flight
procedures can complement the introduction of free flight technology.
This exploratory work includes evaluation of single pilot operations,
self separation alternatives and requirements, mixed equipage and
non-participating complexities, assessments of variations in risk
taking, standardization of pilot and controller response actions,
proficiency evaluations, alternative alert and protection zone
standards, managing different levels of conflict probe, determining
acceptable false alarm rates, flight path and traffic flow
predictability, accuracy of intent information, and many other factors
involving human performance. In future En Route traffic management, an
evaluation of these factors are likely to lead to changes in areas such
as flight planning requirements, aircraft-to-aircraft and
aircraft-controller teaming arrangements, new situational awareness
methods (alerts and displays), and methods for communicating intent.
There is little doubt that initiatives in these areas will play a
critical role in the feasibility and sufficiency of alternative
separation strategies.

### Integrated Structured Human Factors Support

During discussions of the technical issues and challenges, implicit and
explicit references to management related obstacles periodically
surfaced. Considerable concern was expressed about the need for a
systematic and structured approach to integrating human performance
considerations in the extra-agency developments related to free flight
as well as the internal technical implementation of free flight
operational concepts. While the visibility of human factors in the
recent developments of free flight is an encouraging sign, there was
some agreement that the discipline is inadequately represented in the
organizations supporting free flight developments and in the processes
by which the implementation is being conducted. There was general
agreement that expert human factors involvement at every stage of free
flight development was needed in order to identify and resolve the human
interface requirements that will enable a smooth transition. The very
core of this requirement are human-centered, performance-based analyses
(especially in establishing system baselines and trade-off decision
criteria) and human-in-the-loop engineering and simulation. To
strengthen the current approaches in addressing this issue will involve
priority, policy and organizational changes that will affect near, mid,
and long term developments. It was recommended in the session that
internal and external resources be devoted to monitor and manage human
factors efforts as the free flight program evolves, and that increased
human factors and subject matter expertise be employed in the related
FAA Integrated Product Team (IPT) and system architecture development
activities supporting the definition and development of free flight.

## 

## 

## Oceanic and International

The Oceanic group began their session by discussing several typical
oceanic scenarios under the current environment, highlighting the human
component. They then defined the problems and issues with current
oceanic operations that might be improved by free flight. Finally they
described a free flight oceanic environment. The group considered the
oceanic environment to be the most likely place to begin free flight
operations because, given the area and traffic volume, separation
problems are simpler and less frequent. Also the implementation of
satellite communication and navigation for oceanic operations will yield
large payoffs. The group agreed that the transition phase (between en
route and terminal operations or across international boundaries) poses
the greatest number of issues for implementing free flight in the
oceanic environment. The Oceanic group identified 14 issue areas for
human factors in free flight in the oceanic environment organized around
either ground or airborne considerations. These have been collapsed into
11 issue areas.

### 

### Degradation/Failure of Automation

The Oceanic group discussed the need and the process for the automation
to degrade in a manner that allows the controller and pilot to safely
transition back to a system similar to today. Individual automation
components should be able to fail independently of the complete system,
and if this is available, loss of service can be limited. There is also
a concern over skill degradation (for current manual skills) once the
oceanic controllers begin depending on the automated system. Reverting
to a manual system may not be a feasible backup if the controllers no
longer are proficient in these skills.

### Surveillance Requirements

Given that there is no passive surveillance available in the Oceanic
realm today, any change will be a major improvement. How this
information will be provided by the cockpit and displayed to the
controllers, must be explored. The expected decrease in separation
minima could lead to increased congestion in today\'s sectorization
plan. It may become necessary to resectorize the oceanic airspace into
smaller more manageable sectors. This scenario needs to be modeled to
determine the impacts on controllers and automation.

### Identification of Potential Conflict/Cockpit Conflict Probe

A conflict probe / conflict resolution system is envisioned as necessary
for all environments under free flight. The Oceanic group predicted that
this will affect the ocean in the same manner as the other domains for
both controllers and in the cockpit. The matter of display to both sets
of operators must be answered in the beginning of development through
the use of rapid prototyping and simulation. The size and shape of the
protected and alert zones and the distance/time for resolution may
require some adjustment for the oceanic environment. Also, some
standardization of the information and conflict probe/resolution
capabilities and tools in the cockpit is necessary for free flight to be
effective.

### Controller Conceptualization of Flight Paths

The present oceanic airspace and route structure is simple and static.
In free flight the possible route choices may be more variable and
complex. Prototyping and modeling of these possibilities and how
controllers will understand these more complex flight paths is required.
Some study of tools and training is necessary to ensure that the
controllers will still \"have the picture\" so that any intervention
will be well informed and result in the optimization of conflict
resolutions.

### Transition from Free Flight Airspace to Structured or Sovereign ATC Environment

The most unique facet of the ocean operation is envisioned to be the
transition from free flight to structured airspace (i.e. busy terminal
airspace along the domestic coast), or the transition to and from free
flight and international airspace (i.e. between U.S. free flight and
another sovereign country's ATC system). This issue expands to
standardization among airlines from all countries in terms of their
ability to operate within the free flight system. These transitions may
involve advance planning to sequence and separate the aircraft prior to
the structured environment. Therefore the transitions may constrain free
flight in the unstructured airspace. These issues must be resolved
(particularly who is responsible for making the transition occur, the
controller or the pilot). Additionally, the rules for the transition to
international airspace must be negotiated within international groups
(e.g., ICAO).

### 

### Display

As in the other environments, human factors engineering must be an
integral part of the design phase of the oceanic display systems. If the
oceanic systems are different from the domestic systems, this will
require prototyping and modeling beyond that for the domestic systems.
Commonality of user interface between oceanic and domestic systems would
be highly desirable from training and work force utilization
perspectives.

###  

### Identification of Training Requirements

Given the radical paradigm shift required to move to free flight,
considerable changes will be necessary in the training provided to both
controllers and flight crews (perhaps in the AOC also). Prototypes and
models must be examined for changes in the training objectives and
perhaps training systems. Team based training which includes flight
crew, AOC, and controller roles is necessary.

### Roles and Responsibilities of Controller and Pilot in Maintaining Separation

Free flight posits a change in the roles and responsibilities of pilots
and controllers. These roles may be dynamic, changing during a flight
with separation responsibility transferring between the two parties.
Based on the early modeling and prototypes, and continuing throughout
implementation, new procedures need to be developed.

### 

With conflict resolution tools available on the ground (and possibly in
the cockpit) more than one conflict resolution solution is highly
probable. The aircraft operator should be afforded the opportunity to
choose the solution optimal for him/her. This could be accomplished by
turning separation responsibility to the cockpit or, workload
permitting, by negotiation between the controller and operator.
Automation and procedures need to be designed and implemented to enable
this process.

### Mixed Equipage

Different levels of aircraft equipage pose human factors problems in
free flight. Much of free flight presupposes automation and technology
upgrades that allow for the transmission of digital information and the
use of new navigation and communication systems. However, if aircraft
without the latest technology continue to populate the system,
controllers may be required to adjust their procedures and guidance to
the equipage level of the user. This poses cognitive workload and
training issues on the controller side which must be investigated before
free flight is initiated.

### Communication and Intent

Since significant communication improvements are envisioned for the
ocean, the procedures and the means of displaying information must be
determined. These issues need to be modeled and prototyped.

### 

Intent is one of the central issues in free flight. Intent information
is critical for everyone involved in separation. The nature of the
intent information and how it is to be communicated/broadcast must be
modeled as part of the basic human factors design. This information may
include everything from velocity vector to flight plan.

### International Standardization

There are tremendous advantages to having standard flight deck
procedures throughout the world. This commonality should cross oceanic,
domestic cruise, and terminal environments. There are human factors
issues for training, cognitive load, and communication if these
procedures are not standardized. There may be significant time and
effort required for the U.S. to coordinate and negotiate with the rest
of the world to adopt free flight procedures, particularly in the
oceanic environment which is controlled by different countries in
different areas. If the U.S. unilaterally changes oceanic procedures in
the Pacific, there may be an outcry from other nations. If the U.S.
unilaterally implements free flight domestically, the procedures may be
out of sync with those in other parts of the world. Lack of
standardization may lead to duplicative equipment and to human factors
incidents and errors as a result of flight crews confusing procedures
based on geography.

## 

## Terminal, Final Approach, and Airport Surface

The terminal group generated 17 issues related to free flight in the
terminal environment. Three activities preceded the generation of these
issues, which, in turn, helped to constrain and guide issue definition.
These activities were:

-   Defining the terminal environment under the free flight concept

-   Establishing a set of assumptions

-   Drawing from the RTCA Free Flight Report to use the \"operational
    need of free flight\" concept.

The terminal environment under the free flight concept was defined
functionally as well as geographically. The functional terminal
environment is made up of the pilot, controller, airline dispatcher, and
automation which work together to varying degrees to perform the
following functions: sequence aircraft, assign runways, separate
aircraft, maximize airspace and airport capacity, and to merge traffic
flows. The geographic terminal environment includes sector boundaries
and restrictions (e.g., airspeed, altitude, separation). Both the
functional and geographic terminal environments will vary dynamically
depending on aircraft capabilities, traffic complexity, and traffic
density. The group also argued that the definition of the free flight
terminal environment will evolve from a current terminal environment
with a free flight en route environment to a free flight terminal
environment.

The terminal group also established a set of assumptions that serve as
constraints

for guiding issue generation:

-   mixed capability aircraft must be accommodated

-   traffic densities, airspace complexity, runway occupancy time, wake
    avoidance, and lateral separation will constrain the feasibility of
    free flight in the terminal environment

-   runway preference will be an option for the pilot

-   a conflict detection and avoidance automation capability will be
    available on the ground and in the flight deck

-   aircraft separation assurance rests with the ground unless it is
    advantageous to shift responsibility to the air

-   information available to the pilot allows traffic separation to the
    same degree as VFR operations

The RTCA Free Flight Report indicates that the operational need of free
flight is keep protected zones from touching. According to this concept,
alert zones can touch but with some level of intervention by the
controller. The terminal group used this concept as key assumption in
their discussions about free flight in the terminal environment.

Given the definition of the terminal environment under free flight, a
set of assumptions, and the RTCA\'s operational need of free flight
concept, the terminal group defined 17 human factors issues associated
with free flight in the terminal environment. These have been
consolidated into the 15 areas discussed briefly below.

### 

### Resistance to Free Flight in Terminal Area

User acceptance emerged as a concern for free flight implementation.
There may be resistance to the free flight concept from the aviation
participants and/or the flying public. There may also be restrictions
placed on free flight in the terminal environment due to environmental
issues such as noise abatement.

### Requirements for Different Aircraft Capabilities

Mixed equipage in the free flight environment poses a complex challenge
for the free flight concept. Specifically, the different requirements
for general aviation, military, commercial, and rotocraft aircraft must
be fully addressed. Some aircraft may be participating in free flight
while others may not. Also, there will be various levels of aircraft
equipage in the system. Some operators may have no alert or detection
systems. Accordingly, the way in which responsibility is distributed and
separation ensured must be examined. Research on a mixed equipage
environment must be conducted and requirements for the different
aircraft must be established.

### Distribution of Responsibility/Mixed Responsibility

In terms of responsibility distribution, the terminal group discussed
the responsibility of decision making and information sharing and how
that responsibility should be distributed. The discussion was focused
primarily on the separation assurance function (SAF) and whose
responsibility it is to ensure aircraft separation. The SAF concept is
based on the underlying assumption that aircraft separation assurance
rests with the ground unless it is advantageous to shift that
responsibility to the air. Given this assumption, the distribution of
responsibility will by dynamic in nature or event driven. Additionally,
in transitioning to the free flight environment, the issue of SAF
responsibility, and procedures for establishing responsibility must be
investigated.

With regard to shifting roles and responsibilities in a dynamic
environment, the issue of pilots and controllers being aware of where
responsibility resides is of concern. When the responsibility shifts
from one party to another, how will all of the appropriate parties know
when that responsibility has been shifted? It is critical that all
participants in the aviation system understand their roles and other's
roles at all times. How this understanding of shared responsibility is
ensured must be fully resolved.

The group also discussed the issue of authority. Authority becomes an
issue when the pilots and controllers have conflicting goals or
intentions. Therefore, who has the final decision making authority must
be determined.

Another element regarding roles and responsibilities in the terminal
environment concerns the requirements for training, technology, and
procedures in the free flight environment. The training needs for pilots
and controllers in the free flight environment must be addressed. New or
different technologies and procedures may be required for this training.
Additionally, the impact on selection and performance evaluation
procedures for the free flight environment was questioned. The various
participants in the free flight system may require different skills than
those in the current environment. Therefore, the aviation community may
be required to modify the selection criteria currently used.

Given the dynamic roles and responsibilities of pilots and controllers,
mixed equipage, and the various levels of free flight in different
areas, the issue of how to handle mixed responsibility is of concern.
Specifically, the issue is whether the pilot is able to decline or
request responsibility for providing his/her own separation. From the
pilot's perspective, there may be times when he/she does not want the
added responsibility and resultant workload. This may be particularly
true in the terminal environment where the aircraft are closer together
and the pilot may be too busy handling the aircraft to assume separation
responsibility as well. This raises another issue of how the controller
will effectively separate aircraft under his/her control from other
aircraft providing their own separation. The confined airspace of the
terminal area make this a particularly difficult and important issue.

### Arrival Flow

A unique issue regarding the dynamic terminal environment pertains to
the arrival flow of aircraft and who is responsible for mediating or
arbitrating the arrivals. Specifically the issue of mediating
responsibility is of concern when there are two or more aircraft
arriving at the same point or when there are "no-fix" arrivals. The
workload associated with nonlinear arrivals (and departures) complicates
this issue. Given the less predictable and structured traffic flows, the
workload of both the pilot and controller may change significantly.

### Phraseology/Terminology

The phraseology used by the various parties in the aviation system must
be standardized. With the new free flight environment, it is necessary
to ensure that effective and standardized phraseology by developed and
used consistently. Both pilots and controllers must understand, accept,
and consistently use this terminology.

Standardized phraseology applies to automated data exchange as well.
There is concern that there will be vast amounts of "intention" data
flowing back and forth that will need to be analyzed and reduced for
relevant presentation both in the cockpit and the ATC site.

### Separation Minima /Display Geometry for Alert Zones

The terminal group discussed the necessity for determining the
requirements for airborne separation. In determining the separation
minima, controller and pilot workload implications must be considered.
Separation minima should be set at a level that limits the time for
conflict resolution, but does not reduce safety.

Another human factors issue in the terminal environment concerns the
display geometry for the alert zones in the different phases of terminal
flight. While in the en route environment, the zones are often referred
to as bubble or hockey puck-like in shape. In the terminal environment,
a headlight-like shape may be more appropriate. The alert zones must be
of sufficient size and shape that controllers and pilots will receive
alert information in sufficient time for them to take appropriate action
to avoid conflicts. Therefore, in determining these shapes and sizes,
reaction times must be considered. The ability to identify conflicts
will depend on the display geometry used, the automation developed,
alerts and alarms of the future system, and must clearly be based on
human capabilities to understand, retain, and act on information.

### Training and Equipment Requirements

The terminal group discussed what training and equipment would be needed
for pilots and controllers to keep protection zones separated. Analyses
using models and prototypes need to be conducted to determine changes in
the training requirements.

### Transition from Controlled to Free Flight Environment and Vice Versa

In the terminal environment, there is an issue of transitioning from a
free flight en route environment to a potentially more controlled
terminal environment and vice versa. The description of concerns for
shifting responsibilities and information requirements are related.
Automation would most likely be employed to assist in this transition.

### Failure Modes

For the implementation of free flight concepts, detailed procedures must
be found to address automation failure and how to handle such failure in
the free flight environment. In the free flight environment, automation
will be relied upon heavily. The terminal group specifically considered
how to handle a frequency outage under free flight operations (e.g., a
stuck microphone switch). Procedures for these rare but realistic
problems must be addressed. Therefore, automation failure issues must be
addressed with further research.

### Allocation of Functions between Pilots, Controllers, and Automation

The allocation of functions was discussed in the terminal group in terms
of the possibilities and likelihood of overloading/underloading the
various aviation parties. The controller's and pilot's ability to
maintain situational awareness requires that the task sharing between
controllers, pilots, and automation be clearly understood at all times.
All parties must be aware at all times what the other parties are doing.

### Increased Terminal Workload

Allowing more aircraft into the en route free flight environment may put
more pressure on and increase the workload in the terminal environment.
How will free flight flow into the terminal be controlled?

### Pilot, Controller, Dispatch, and Automation Coordination

Use of the "team concept" implies additional issues of coordination,
integration, and cooperation. It is indicated in the RTCA select
committee on free flight report the controller is responsible for
keeping the aircraft separated. If the controller has the overlying
responsibility of separation, the integration of team cooperation may be
complicated. The allocation of functions between pilots, controllers,
and the automation, and clarity of these functions (given different
situations and dynamic densities) may require special training and/or
practice to establish \"team\" performance. It was suggested that a Crew
Resource Management (CRM)-like approach be used for achieving "team"
performance.

### Information Requirements

With the inevitable changes in the current aviation system, information
requirements must be carefully addressed. What information must be
available, to whom, and when? Changing information requirements will
most likely require a re-distribution of workload. The group suggested
that a functional analysis be conducted for the free flight environment
that recognizes the system (e.g., pilots, controllers, dispatchers, and
automation) and identifies the implications of the re-distributed
workload. In terms of automation and information display, in an ideal
situation, there would be "seamless" automation meaning that all parties
concerned receive the necessary information in the exact same way using
the same technology.

### Human Factors Certification of the System

The terminal group recognized the need for comprehensive human factors
involvement in the design, development, and certification of the free
flight system. Further integration of human factors into IPTs is
required.

### Interoperability of Air/Ground

In order to ensure interoperability of air/ground, the terminal group
suggested the use of a human factors checklist and the consideration of
system integration during design and evaluation phases.

# Conclusions 

This workshop provided a survey of the technical and managerial actions
necessary to implement the human portions of free flight requirements.
The four working groups generated a great deal of information and issues
to consider in developing the free flight concept. The discussions and
products of each working group indicated that many of the issue areas
are applicable to multiple domains. For example, all four working groups
discussed roles and responsibilities in the free flight environment. The
information can be categorized into 14 different issue areas (see
Appendix B). Of these 14 areas, 13 were addressed by multiple groups.

The working groups came together for a final plenary session and
discussed the working groups' findings. Several general conclusions were
discussed. These conclusions are summarized below.

Free flight development must entail full consideration of the "people"
portion to succeed. Free Flight development and implementation depends
upon the full integration of human performance considerations.
Efficiency in addressing the various human factors efforts requires
extensive collaboration and coordination. Therefore, a central
coordination point is needed for the important elements of free flight
development represented by "people" (the third leg of the RTCA program).

The designation of a central point of contact and coordination for human
factors in free flight should be viewed as the initial step in a process
that provides information on the human factors issues to the development
work including what is known about the issue, what is not known, how to
resolve the unknowns, and where to do the work. Thus, a follow-on
activity that identifies, analyzes, filters, and prioritizes the human
factors work to be done is needed.

The workshop provided only limited, albeit significant, representation
of the larger human factors aviation community. Intentionally, the
workshop was conducted as an initial step in the development and
integration of human factors in free flight. There are now and will be
in the future many other requirements for the coordination and
dissemination of human factors free flight efforts. A planned approach
to this coordination and dissemination requirement is necessary.

In order to satisfy these actions, formal consideration of the human
factors component must be undertaken. The first step in the formal
process should include transmittal of the workshop results to the RTCA
task force and joint ATR/AAR-100 participation in any agency response to
the RTCA work. Other follow-on actions will entail additional
coordination.

# Recommendations

The findings and conclusion of the workshop provide insight into the
challenges associated with human factors and free flight. There were
many specific recommendations made for research efforts, however, the
major general recommendations are:

1.  Designate ATR and AAR-100 as a joint FAA focal point for human
    performance considerations in Free Flight

2.  Charter the FAA focal point with resources and responsibility to:

-   further identify, prioritize, and develop essential human factors
    issues and requirements

-   develop a program to systematically monitor critical human factors
    areas and ensure their resolution

-   ensure that human factors efforts supporting free flight development
    (FAA and industry) are fully coordinated and integrated

1.  Charge the focal point to conduct efforts in support of human
    factors in free flight that:

-   expand the coordination effort initiated by this initial workshop

-   disseminate findings, conclusions, results, and products related to
    future developments in free flight human factors

1.  Establish formal joint ATR/AAR involvement in agency response and
    follow-up to RTCA Free Flight developments by:

-   Formal transmission of this report to RTCA Free Flight Task Force 3

-   Participating in any agency response to the RTCA recommendations

Participating in future agency free flight developments