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Human Factors Support

For Automatic Dependent 

Surveillance-Broadcast (ADS-B)

The National Transportation Systems Center

Advancing transportation innovation for the public good

U.S. Department of Transportation

Research and Innovative Technology Administration

John A. Volpe National Transportation Systems Center

August 1, 2013

This research is funded by the FAA Human Factors Division in support of the 

Office of Flight Standards and Aircraft Certification Service.
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ADS-B Research Overview

Determine current state of CDTI design (Core)

 ADS-B Industry Survey*

CDTI Symbology: Examine CDTI symbology and display management (Core)

 ADS-B Symbology Study*

 ADS-B Color Coding on Surface Moving Maps*

 Traffic Symbol Information-Accessibility Analysis

 Proximate Status Indication Study 

Analyze CDTI alerting (Core)

 Support to FAA for RTCA SC-186 – Traffic Situation Awareness with Alerts (TSAA)

 Alert Location 

CDTI operational evaluation support (NextGen)

 Support for US Airways CDTI Operational Evaluation and related research*

 Support for the In-Trail Procedure (ITP)/FIM Literature Review*

 CDTI Operational Evaluation for Merging & Spacing (M&S)*

Sponsors: 

 Kathy Abbott, Aviation Safety (AVS)

 Cathy Swider, Aircraft Certification Service (AIR-120)

 Paul VonHoene, Flight Standards Service (AFS-410)

 Don Walker, Aircraft Certification Service (AIR-130)

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ADS-B Projects Funded by the 

“Core” Budget

Determine current state of Cockpit Displays of Traffic 

Information (CDTI) design, and examine CDTI symbology

 ADS-B Industry Survey

 ADS-B Symbology Study

 Use of Color on Airport Moving Maps & CDTIs
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ADS-B Industry Survey

 Purpose: Develop a 

“consumer reports” type 

document that provides a 

listing of systems, features, 

and functions of currently 

available CDTI product

 Catalog of approved 

displays/features will aid 

in approval of proposed 

systems

Excerpted from 2009 Surface Moving 

Map Industry Review
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Example of Manufacturer Page Information

Excerpted from 2009 Surface Moving Map Industry Review
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ADS-B Industry Survey

 Schedule:

 Finalize templates for data collection – August, 2013 

 Draft industry survey report – December, 2013
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ADS-B Symbology Study

Purpose:

 To understand pilots’ perceptions of usefulness of the attributes & states (e.g., 

airborne, directional) on traffic symbols

 To understand which attributes or states are intuitive and which symbol features 

(e.g., fill, shape or color) are most often used to identify the traffic symbols

 Results will provide recommendations for symbols for ADS-B CDTI 

Example subset of symbols used:

Information Type Symbols

Traffic aircraft

Ground vehicles
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ADS-B Symbology Study - Method

 Paper-based questionnaire 

 Symbol attributes examined:

Directional/Non-directional Selected 

Proximate/Non-proximate Low data quality

Airborne/Ground Aircraft/Vehicle

Designated Caution/Warning

 Symbols came from eight manufacturers & six research institutions

 Participants were shown 

 Symbols in use on approved and proposed displays

 Prototype symbols - not currently in use

 Foils: shapes that do not exist
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Symbol Intuitiveness Task (Categorization)

Which symbols best represent airborne traffic and directionality?

1 2 3 4 5 6 7

8 9 10 11 12 13 14

15 16 17 18 19 20 21

Airborne, directional traffic: Traffic aircraft that is in the air with indication of track 

or heading.

Symbol(s) that represent this category is/are:

 

 1, 3, 4, 10, 12, 14, 18 

Reason(s) used for this grouping:

 Showed heading. Didn’t look like a vehicle or truck. 
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Main Findings

 Two intuitive symbols for airborne - symbol shape was the prominent 

feature

 

 No intuitive symbols for ground traffic; four ground vehicle symbols were 

correctly identified 72% of the time 

 

 Non-directional ground vehicle traffic was thought as showing both 

directional and non-directional information 

 Color was the key feature in determining the alert status – caution & 

warning
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ADS-B Symbology

 Schedule:

 Draft Report Phase 1 – July, 2013 (completed)

 Revised Draft Report – December, 2013
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Use of Color on Airport 

Moving Maps & CDTIs

Background: Aircraft Certification asked, “Why is 

ground traffic hard to see on some airport moving 

maps and CDTIs?”

Purpose: Identify issues and best practices for the 

use of color when integrating traffic on airport 

moving maps and CDTIs

 Will be used to support MOPS for ADS-B CDTI
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Approach & Main Issues

Approach

 Review of regulatory & guidance material, color 

literature

 Viewed relevant demonstrations (e.g., SURF-IA)

Some identified issues

 When contrast is poor, symbol will be hard to see

 Red and amber/yellow are used inappropriately

 Potential issues with blue

 A lack of redundant coding
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What Color Is It?
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Example: 

Traffic is Not Always Easy to See

 Evaluation Criteria:

 Evaluate all possible combinations of traffic 

symbol sets and background

o For example, a dark brown may be hard to see 

next to a black background, while a lighter tan 

may be too similar to other traffic (e.g., an 

amber caution alert)
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Use of Color on Surface Moving Maps 

& CDTIs

 Schedule

 Presentation at RTCA SC-186 Meeting – March, 

2013 (completed)

 Preliminary draft report – April, 2013 (completed)

 Revised draft report – August, 2013
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ADS-B Projects Funded by the 

“NextGen” Budget

Provide support to the FAA for operational evaluations and 

input on relevant ADS-B literature

 Flight Interval Management (FIM) Literature Review

 CDTI Operational Evaluation for Merging & Spacing (M&S)

 Support for the In-Trail Procedure
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 Airline operations center (AOC) identifies IM candidate pairs

 AOC determines the time-based assigned spacing goal 

 AOC sends a message via ACARS to the IM Aircraft

 The message contains the 

 Target Aircraft Identification

 The Time-Based ASG

 The Start Point

 The Achieve-by Point 

 Planned Termination Point

 The IM Aircraft flight crew enters the M&S message elements 

into the M&S Application

Flight Interval Management 

(FIM)
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Flight Interval Management 

(FIM) Literature Review

 Purpose: Provide summary and analysis for relevant 

literature and identify potential gaps in research. 

 Aircraft Certification and Flight Standards personnel 

requested this information for use in SC–186

 Will identify what research has been done and what needs 

to be done

Figure from Bone et al., 2007
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FIM Literature Review

 Schedule:

 Draft annotated bibliography/ literature review - August, 

2013
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CDTI Operational Evaluation for 

Merging & Spacing (M&S)

Purpose: Provide human factors support to the FAA 

for US Airways CDTI operational evaluation—focus on 

Merging & Spacing

Do the pilots have the necessary information and tools 

to successfully perform these operations?

 Information will be used by Aircraft Certification and Flight 

Standards in their assessment of the operational trials
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Flight Interval Management

Figure from draft Operational Services and Environment Definition (2012)
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Comment Sheet for Pilot Feedback

 Questions address:

 Acceptability of clearance

 Ease of data entry

 Communication with ATC 

 Frequency of speed 

changes

 Effectiveness of cockpit 

displays

 Experience with alerts

 Perceived workload

 General feedback
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CDTI Operational Evaluation for Merging 

& Spacing (M&S)

 Schedule (depends on schedule of operational trials)

 Draft summary of support of operational evaluation -

March, 2013 (completed)

 Updated summary of support of operational evaluation -

November, 2013

 Update on human factors data collection - August, 2014
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In-Trail Procedure (ITP)

• Purpose: Investigate human factors issues associated with the In-Trail 

Procedure (ITP) in oceanic airspace

 Aircraft Certification and Flight Standards will use this information in 

their assessment of the operational trials

 “Lessons learned” will be applicable to other NextGen applications

Figure from Jones, 2013
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ITP - Overview

 Working with FAA and United Airlines on operational 

evaluation of ITP

 Evaluation began in August 2011 (due to airline merger)

 Human factors data collection recommenced in June 2013

 Two means to collect feedback: 

1) comment forms

2) focus groups (Sept 2013)

Figures from Jones, 2013
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Comment sheets

Continued...
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In-Trail Procedures (ITP)

 Schedule:

 Focus Groups - September, 2013 

 Draft summary of discussions with operators - December, 

2013

 Draft summary of HF issues from evaluation and ‘lessons 

learned’ - August, 2014
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Questions?

Contact: Kim.Cardosi@dot.gov