DOT/FAA/AM-02/21

Kevin W. Williams

Civil Aerospace Medical Institute

Federal Aviation Administration

Oklahoma City, OK 73125

Alan Yost

Volpe National Transportation Systems Center

Cambridge, MA 02142-1093

Jeff Holland

Aircraft Certification Office

Federal Aviation Administration

Wichita, KS 67209

Robert R. Tyler

Trios Associates, Inc.

Washington, DC 20024

December 2002

Final Report

This document is available to the public

through the National Technical Information

Service, Springfield, VA 22161.

Assessment of Advanced

Cockpit Displays for

General Aviation Aircraft –

The Capstone Program

Office of Aerospace Medicine

Washington, DC 20591
NOTICE

This document is disseminated under the sponsorship of

the U.S. Department of Transportation in the interest of

information exchange. The United States Government

assumes no liability for the contents thereof.
i

Technical Report Documentation Page

1. Report No. 2. Government Accession No. 3. Recipient's Catalog No.

DOT/FAA/AM-02/21

4. Title and Subtitle 5. Report Date

Assessment of Advanced Cockpit Displays for December 2002

General Aviation Aircraft – The Capstone Program 6. Performing Organization Code

7. Author(s) 8. Performing Organization Report No.

Williams KW1, Yost A2, Holland J3, and Tyler RR4

9. Performing Organization Name and Address 10. Work Unit No. (TRAIS)

1

FAA Civil Aerospace Medical Institute, Oklahoma City, OK 73125 2

USDOT Volpe Center, Cambridge, MA 02142-1093

3

FAA Aircraft Certification Office, Wichita, KS 67209 11. Contract or Grant No.

4

Trios Associates, Inc., Washington, DC 20024

12. Sponsoring Agency name and Address 13. Type of Report and Period Covered

Office of Aerospace Medicine

Federal Aviation Administration

800 Independence Avenue, S.W.

Washington, DC 20591 14. Sponsoring Agency Code

15. Supplemental Notes

This work was performed under Task AHRR-521.

16. Abstract

Since the inception of the Capstone Program, approximately 150 aircraft in the area of Bethel, Alaska have

received a suite of ADS-B displays. Despite the opportunity provided by the large number of ADS-B-capable

aircraft in the Bethel area, very little information has been collected from the owner/operators and pilots of these

aircraft that might help in transitioning the technology to the rest of the country. To remedy this situation, a team

of human factors experts was tasked with travelling to Bethel in March 2002 to collect data regarding the use of

these displays in day-to-day flight activities. A total of 41 pilots participated in the interview process, representing

nine different flight companies in the Bethel area. All of the pilots were male. The average age was 37, ranging

from 21 to 58. The average number of flight hours for the pilots was 4,962 hours, ranging from 950 hours to

30,000 hours. The median number of total flight hours was 3,250. Over 95% (39) of the pilots were instrument

rated. Results from the pilot interviews and self-administered questionnaires revealed a number of human factors

design, safety, and training issues. Discussion of these results will focus on display design and training

recommendations for ADS-B displays that will ease the training burden, mitigate safety hazards, and accentuate

safety improvements.

17. Key Words 18. Distribution Statement

ADS-B Displays, General Aviation Navigation Displays,

Cockpit Displays, Psychology, Applied Psychology

Document is available to the public through the

National Technical Information Service,

Springfield, Virginia 22161

19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price

Unclassified Unclassified 36

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized
1

ASSESSMENT OF ADVANCED COCKPIT DISPLAYS

FOR GENERAL AVIATION AIRCRAFT – THE CAPSTONE PROGRAM

INTRODUCTION

Background

In an effort to improve flight safety in Alaska, the

Federal Aviation Administration (FAA) has been conducting an assessment of new cockpit avionics for

general aviation (GA) aircraft. The assessment is being performed under the FAA’s Alaska Capstone Program, which has focused its efforts in and around the

town of Bethel, located in the southwest region of the

state. The avionics system, developed by UPS Aviation Technologies, consists of a multi-function display unit, the Apollo MX-20, and an accompanying

Global Positioning System (GPS) display, an Apollo

GX-60. In addition, each aircraft is equipped with a

Universal Access Transceiver (UAT), which is a remote-mounted (i.e., outside of the cockpit) radio that

provides datalink communication between the aircraft and a ground station or from one

aircraft to another aircraft. Participants

in the assessment are Part 135 airline

operators and pilots in the Bethel area.

Approximately 150 GA aircraft have

been equipped with the advanced avionics equipment. Figure 1 shows the

avionics that are installed in each aircraft

participating in the Capstone program.

Display Capabilities

The Capstone displays provide pilots

with a moving-map display that shows

ownship (i.e., display aircraft) position.

Flight plans that are input into the GPS

display are presented as a magenta line

on the moving map. The map can display an instrument flight chart, with

airways, intersections, airports, and other

navigational points, or a visual flight

rules (VFR) sectional chart that includes

terrain features. Many types of information can be overlaid on the map at the

pilot’s discretion. The display can also

show relative terrain in the form of red,

green, yellow, or black colored blocks

that indicate the relative height of terrain to the aircraft. Using a custom map

page, pilots can overlay relative terrain

with airport and other information. The display also

provides traffic and weather information to the pilot.

Certain capabilities available with the Capstone displays, like the display of traffic information, are dependent on a ground/air/space infrastructure known

as Automatic Dependent Surveillance – Broadcast, or

ADS-B. Some of the capabilities being offered to the

GA community under the Capstone program have

only been generally available before to commercial

airlines and high-end GA aircraft. The ability to see

traffic and weather on a cockpit display is usually

provided by expensive onboard detection systems. To

provide such capabilities in a less expensive manner, a

ground-, air-, and satellite-based infrastructure was

created — ADS-B. Unlike radar systems that bounce

radio waves off of airborne targets and then interpret

the reflected signal, ADS-B relies on position information that is transmitted by the UAT from each

Figure 1: Capstone Avionics displays.
2

individual aircraft based on GPS technology. Each

ADS-B-equipped aircraft broadcasts its precise position in space via a digital datalink, along with other

data that includes the aircraft call sign. This information can be transmitted directly from one aircraft to

another, or it can be transmitted to a ground station,

combined with other aircraft data, and re-transmitted

back to any aircraft within range of the ground station. The information can also be transmitted by

landlines or other means to air traffic controllers in

distant locations. ADS-B allows pilots in the cockpit

and air traffic controllers on the ground to “see”

aircraft traffic with much more precision than has ever

been possible before. Unlike conventional radar, ADSB works at low altitudes and is effective in remote

areas or in mountainous terrain where there is no

radar coverage, or where radar coverage is limited.

In addition to information related to other aircraft,

other types of information can be broadcast from

ground stations to UAT-equipped airplanes. Flight

Information Services – Broadcast, or FIS-B, include

graphical weather depictions, as well as text-based

weather. Future implementations will include other

information such as notifications to airmen

(NOTAMS). Since weather plays a part in many

aircraft accidents, the display of current weather conditions in an easily interpreted graphical format is

expected to be of great help to pilots. The graphical

depiction of NOTAMS, such as the fact that a runway

has been closed at a particular airport, should also

make it easier for pilots to maintain awareness of

important information both before and during their

flights. At present, however, only graphical and textual weather information is transmitted to pilots in

the Bethel area.

Safe Flight 21 – Human Factors Team

An opportunity was provided by the large number

of ADS-B capable aircraft in the Bethel area to collect

information from owner/operators and pilots of these

aircraft that might help in transitioning the technology to the rest of the country. To take advantage of

this situation, the FAA’s Safe Flight 21 Office formed

a team of human factors experts to collect subjective

data from the airline operators and pilots in the Bethel

area. Safe Flight 21 and the Capstone Office are

partners in the development of data link technologies.

The human factors team, aided by personnel from the

University of Alaska at Anchorage (UAA), traveled to

Bethel to collect data regarding the use of these displays in day-to-day flight activities. While it is assumed that some flight activities are unique to the

Alaska area, and some design issues are unique to the

MX-20 and GX-60, it was also believed that information could be collected that would relate to safety,

training, and human factors design that could generalize

to other multi-function ADS-B displays. This report is

a summary of the Bethel data collection effort.

METHOD

Instruments

A set of data collection instruments was created.

This set included a self-administered questionnaire

that focused primarily on training and normal usage

issues, an interview form for gathering data about the

strengths and weaknesses of the display, and a form

for collecting demographic data from each of the

participants. The Demographic Data Form is shown

in Appendix A. The Interview Form is presented in

Appendix B, and the Self-Administered Questionnaire is shown in Appendix C. In addition, team

members flew on 5 scheduled flights to observe the

actual operation of the equipment.

Participants

A total of 41 pilots participated in the interview

process. Twenty-seven of the 41 also filled out the

self-administered questionnaire form. The 41 pilots

that participated represented 9 flight companies in the

Bethel area. Only 2 companies with Capstoneequipped aircraft were not represented in the interview or questionnaire process. Both of these companies

were single-pilot operations.

All of the pilots were male. Their average age was

37, ranging from 21 to 58. The mean number of flight

hours for the pilots was 4,962 hours, ranging from

950 hours to 30,000 hours. The median number of

flight hours was 3,250. Over 95% (39) of the pilots

were instrument rated. Approximately 63% (26) of

the pilots had used a handheld GPS unit, typically one

of the Garmin models. Mean use of Capstone equipment was 884 hours, ranging from 6 to 3,000 hours.

Procedure

A team of four members of the Safe Flight 21

Human Factors Group visited Bethel from March 9th

to the 17th,2002. They were accompanied to Bethel by

Professor Leonard Kirk, from the UAA, who had

conducted much of the training for the Capstone

equipment and was familiar with most of the pilots

and company owners in the area. Initial contact with

many of the flight companies was through Mr. Kirk.

Except for one focus group of 5 pilots, all interviews were conducted in a one-on-one manner. During initial contact with each of the flight companies,
3

the self-administered questionnaires were given to

whomever was in charge to distribute to each of the

company pilots. Each day, all flight companies were

visited to conduct interviews with available pilots and

to pick up any completed questionnaires. Approximately 60 self-administered questionnaires were delivered. The 27 questionnaires returned yields a

response rate of 45%.

RESULTS AND DISCUSSION

Negative Safety Implications

Degradation of Conventional Flying Skills

Pilots were asked to rate how they felt their conventional navigational skills had been affected as a result

of using the Capstone avionics. Results are presented

in Figure 2. The majority of pilots (23) felt that their

conventional navigational skills had not been affected.

However, a large proportion of pilots (17, or 41%)

believed there had been some degree of deterioration

in their navigational skills. The chief concern among

these pilots was whether they could fly and navigate

using conventional methods (i.e. radio navigation

aids, pilotage, dead-reckoning) if their Capstone equipment failed or malfunctioned. As more of this equipment makes its way into GA cockpits, more pilots

could become dependent on these displays and lose

conventional navigational skills.

Even if conventional navigational skills do not

deteriorate, there is still a danger of being unable to

navigate after the loss of a moving-map display. This

is because most conventional methods of navigation

rely on the periodic update of information in a specific manner. Pilots must prepare before a flight to

navigate using, for example, VORs and NDBs. They

must know which frequencies to use during the flight

to make use of this equipment, and they must know

during the flight the relative position of VOR and

NDB stations. The same can be said regarding deadreckoning skills. If pilots have not kept track of how

long a specific heading has been held, they will be

unable to use dead-reckoning skills mid-flight to

judge location.

Mixed Equipage

Thirteen pilots (32%) commented during interviews that mixed equipage was a problem, focusing

around the idea that pilots start to rely too heavily on

the traffic display and forget to look outside for

aircraft. Similar problems with failing to look outside

the cockpit have been documented among Part 121

pilots using the Traffic Collision Avoidance System

(TCAS) (Foy & McGuinness, 2000). Several pilots

reported near mid-air collisions with non-Capstone

equipped aircraft. One example in particular involved

a near-miss with a B-727. The pilot stated that he was

8-9 miles from Dillingham when he observed a B-727

pass within 60-80 feet to the left side of his aircraft at

his altitude. The pilot stated that what probably saved

him was that he was slightly off course to one side of

the localizer. The pilot commented that “in order for

this equipment to really enhance safety, all aircraft

must be participating.”

Terrain Database Inaccuracies

An incomplete terrain database can lead to a dangerous situation. One of the pilots noted during an

interview that some “mud volcanoes” did not appear

in the terrain database or on the map page. Since these

terrain features rise up to over 600 feet, they pose a

danger to pilots that might not be aware of their exact

position, especially in low visibility conditions. However, it should be noted that the inaccuracy of the

database could not be verified.

Incorrect Barometric Pressure Reports

The relative terrain mode can be inaccurate if the

current altimeter setting is input incorrectly or not at

all, or if pressure changes drastically during the flight,

thereby rendering the altimeter setting incorrect. A

second problem, mentioned by one of the pilots

during an interview, is that the barometric pressures

noted at certain locations are often inaccurate because

of the sparse availability of reporting stations in the

area. Another problem area involving barometric pressure is that pilots are required to input barometric

pressure in both the GPS and MFD separately, as well

as the altimeter display, which increases pilot workload

and the chance for human error.

12% 29% 56% 0% 2%

Figure 2: Rate the amount you feel your

conventional navigational skills have

been affected as a result of using

Capstone avionics?
4

Increased Head-Down Time

The introduction of new systems into GA cockpits

has the potential to increase pilot workload and reduce pilot situation awareness, particularly immediately after installation (Williams, 2002). Many of the

pilots reported that they had very little training or

understanding of the system before actually flying

alone with it. Responses from the self-administered

questionnaire indicated that only 50% of the pilots,

averaged across the functions, received formal training on specific functions on the MX-20. For the GX60, 40% of the pilots, on average, received formal

training on specific functions. Individual pilot training was the responsibility of each flight company, and

many companies did not have a formal training curriculum for pilots using the systems. Pilots stated that

during these early flights they spent a considerable

amount of head-down time attempting to select and

exercise system functions.

Increased Risk-Taking

Participants were asked whether the use of the

displays would increase pilot risk-taking behavior.

Results are shown in Figure 3.

Eighty-three percent (34) of the interviewed pilots

believed that there would be or already is an increased

tendency to fly under lower visibility conditions using

the displays than if they were unavailable. Between

40% and 60% of the interviewed pilots also believed

that there would be an increased tendency to fly at

lower altitudes under low visibility conditions, to fly

closer to hazardous terrain features, such as mountains and hills, under low visibility conditions, and to

fly through mountain passes when weather is questionable or visibility is low. Two “Other” types of risktaking behaviors mentioned were flying in all types of

hazardous weather conditions and flying to a new destination without using any paper maps or charts.

Positive Safety Implications

Increased Navigational Awareness

Despite the above-stated negative safety implications of how these displays were used, many positive

points were brought out in the interviews and questionnaires. One statement made by the pilots was that

the moving map display increased their awareness of

terrain and airports during flight. The moving map

display is thought to be especially useful for maintaining awareness of the location of a runway under lowvisibility conditions. The map display was also helpful

for locating runways that had never been visited

or had been visited rarely. Another way in which

the moving map display assisted in navigation was

in helping the pilot to distinguish between mountain passes that look very similar out-the-window.

Pilots filling out the self-administered questionnaire reported that relative terrain information was used approximately 10% of the time, on

average. Individual usage varied from 0% to 100%.

The finding that pilots did not use the terrain

information very often makes sense, given that

most of the flying done in the area is under visual

flight rules. Pilots stated that, when they were

somewhat unfamiliar with an area or unsure of the

location of the correct pass, they would call up the

Terrain mode (or use the Custom mode with

relative altitude displayed) to isolate the correct

pass. This was particularly helpful when visibility

was limited and it was more difficult to see distinguishing terrain features. Once inside a pass, it

was reportedly not unusual to experience decreasing visibility to the point that all visual references

with the surrounding terrain would be lost. The

extreme case of loss of visual contact with the

ground would occur when the snow-covered

ground and clouds would cause a “whiteout”

condition where everything outside of the aircraft

83% 41% 51% 59% 27% 5% 2%

Figure 3. Has the Capstone equipment increased, or

will it increase any of the following types of risktaking behaviors: 1) Flying under lower visibility

conditions; 2) Flying at lower altitudes under low

visibility conditions; 3) Flying closer to hazardous

terrain features (mountains, hills) under low visibility

conditions; 4) Flying through mountain passes

when weather is questionable or visibility is low; 5)

Flying closer to other aircraft, even if it is difficult to

maintain constant visual awareness of their position;

6) Other types of risk-taking behavior; or 7) The

equipment will have no effect on risk-taking

behavior?
5

looked white. One pilot reported that the Capstone

equipment essentially saved his roommate’s life when he

inadvertently entered a whiteout condition while flying

through a pass. His roommate told him that he selected

the terrain page and flew through the pass, staying within

the yellow color-coded area on the display.

When asked about the effect that the equipment

had on conventional navigational skills, one pilot

stated that his skills had significantly improved as a

result of using the Capstone equipment. His reasoning was that the GPS display gives you an instant

picture of the required wind correction angle to hold

a course (i.e. Wind correction angle = current heading

- current track when current track = desired track).

The only way to accomplish that with ground based

navigational displays is by “bracketing” a course until

you eliminate the drift. This “precise” experience with

GPS navigation helps the pilot make better estimates

of drift correction when relying solely on ground aids.

Also, at distances over 30 miles from the station, a

course line to or from a VOR becomes wider than a

GPS course line to the same location. Because CDI

sensitivity is generally set to 5 miles for en route GPS

navigation, a pilot could see a GPS CDI that is slightly

off-center when the VOR CDI is fully centered. The

converse of this is true near the VOR because the VOR

course is narrower than the same GPS course. These

differences could be significant when precise navigation is required to avoid obstacles. Pilots with GPS

experience might make better decisions because they

are more likely to be aware of the limitations of both

forms of navigation.

Increased Ability to Avoid Traffic

Unlike the display of relative terrain, pilots would

always display traffic on their MX-20, either with the

dedicated traffic page or as an overlay on another

page. Pilots were asked what effect they believe the

traffic display will have on the rate of near mid-air

collisions. Results are presented below in Figure 4.

The majority of pilots interviewed believe that the

display of traffic reduces the possibility of mid-air

accidents. Pilots believe they become aware of traffic

more quickly using the MX-20 traffic display. Pilots also

believe they are able to alter their flight path earlier to

avoid close contact with other aircraft in the area.

Maintaining Aircraft Separation during Holding

Procedures

Nineteen pilots (46%) commented during their

interview that the traffic display was most useful

during holding procedures for maintaining aircraft

spacing. During marginal VFR weather conditions,

aircraft reportedly are sometimes required to remain in a

holding pattern for long periods of time (reportedly up

to an hour and a half) while IFR aircraft under the

control of Anchorage Center are landing. The marginal

weather conditions make it difficult to maintain visual

contact with other aircraft in the holding pattern.

Ability to be Visible If Communications are Lost

Two pilots mentioned during their interview that if

radio communications failed in the aircraft, they would

be comforted because most of the other pilots in the

vicinity could still see them on their traffic display.

Recognizing Waypoint Entry Errors

After pilots input a waypoint into a flight plan or

use the direct-to function, the route from the current

aircraft position to the waypoint is indicated on the

moving map display. This route line provides a validation to the pilot that the waypoint information was

input correctly. Two pilots noted that they became

aware of incorrectly entering a waypoint after noticing

the route line depiction on the moving map display.

Training Implications

Familiarity with Display Features

Two pilots remarked during the interviews that it

was disconcerting that traffic could not be overlaid on

the terrain page. These pilots were not aware that

traffic could be overlaid on the terrain page using the

custom map, but that it had to be accomplished

through a different menu and that it took several

keystrokes. During times when much traffic was presented on the screen, pilots would select different

range values to declutter the display. Two pilots

remarked that there were times when too many aircraft

49% 27% 17% 2% 5%

Figure 4: What effect (if any) will the Capstone

equipment have on the rate of near mid air

collisions?
6

were presented on the display. These pilots were not

aware of the altitude band function (± 2000 feet from

the own aircraft altitude) that was available. Other

pilots, who were aware of the altitude band, wanted

the capability to select a narrower band, such as ±

1500 feet or ± 1000 feet, to further declutter the

display.

Transmitted Altitude

Three pilots revealed that they knew of pilots who

were not inputting the correct barometric pressure,

but rather inputting a pressure that would indicate

they were higher than they were actually flying. These

pilots assumed that in doing this, they were protecting

themselves from possible punitive action by the FAA

for flying below legal altitude limits. These pilots were

not aware that the encoded altitude transmitted via

the data link is based on standard pressure altitude

(i.e., 29.92 inches) and, therefore, not affected by the

barometric pressure setting.

Training Consistency

The receipt of adequate training and familiarity

with this type of equipment continues to be a problem. Pilots operating out of Bethel have had a range of

training on this equipment. During one-on-one interviews, some pilots reported they were only shown how

to turn it on and bring up the Map page for the MX20, and perform a Direct-To with the GPS (the GX60). Other pilots stated they received extensive training

on both the GX-60 and MX-20 from instructors at the

University of Alaska, Anchorage (UAA). This training

was conducted over a 2-day period and included

training on inserting and editing a flight plan, selection of display options, and other functions associated

with the system. These pilots seemed the most knowledgeable of the system. However, even for these pilots,

the complexity of the system and reliance on memory

to access information and select various functions,

caused many of them to focus on and use a small

subset of system functions.

Pilots filling out the self-administered questionnaire indicated, for each of several functions on both

the MX-20 and GX-60, what type of training they

received for that function. Pilots indicated whether

they learned the function through formal training

provided by their flight company or the UAA; through

self-study with the system manual and equipment; by

means of a Capstone or other computer simulation;

by being shown the procedure by another pilot; or that

they had received no training for the function. Figure

5 indicates the results of the pilot responses, averaged

across functions, for both the MX-20 and the GX-60.

Figure 5 shows that 51% of the pilots, on average,

claimed they received formal training on the set of

MX-20 functions listed in the questionnaire. On the

other hand, only 40% of the pilots said they received

formal training on GX-60 functions. This list of functions can be found in Appendix C and also in the next

section entitled “Use of Minimum Functionality.”

Use of Minimum Functionality

Pilots that filled out the self-administered questionnaire were asked to indicate how often they made

use of particular functions on both the MX-20 and

GX-60. Pilots indicated, for each of several functions,

whether the function was used all the time, sometimes, rarely, or never. Results are shown below in

Figures 6a-q, listed under “MX-20 Functions” and

7a-t, listed under “GX-60 Functions.”

51

40

24

17 1411 11

5 2

8

0

10

20

30

40

50

60

Mean % of 

Pilots MX-20

GX-60

Figure 5: Training type estimates across functions for MX-20 and GX-50 units.
7

MX-20 Functions

a. Selecting the Map Type

The MX20 displays 3 types of moving map—IFR, VFR and Custom. The IFR selection depicts an IFR chart.

The VFR map displays color-coded terrain and surface features (roads, lakes, etc) similar to a sectional chart.

The CUSTOM map is a pilot-customizable version of the VFR map. It provides several menu pages of selections

to display airways, navaids, airports, surface features, and relative terrain information.

b. Selecting the Map Orientation

The MX20 will display the moving map in the following orientations:

Track Up – the actual ground track of the aircraft is toward the top of the display.

Track up Arc– same as Track Up with a semicircle compass rose and the aircraft’s track displayed at the top

of the screen.

Track up 360 – same as Track Up with the ownship symbol in the center of a compass rose, in the center

of the display.

Desired Track Up– the course to be followed is oriented toward the top of the screen.

North Up – Magnetic North is always at the top of the display.

The pilot can select any of these in each map page.

Pilots answering the self-administered questionnaire were asked to indicate the percentage of time that they

spent in each of the various map orientations. Results indicated that 1 pilot used the North up orientation

exclusively. One pilot switched between North Up and Track Up. The rest of the pilots (25 of 27, or 93%) used

one or more of the Track Up orientations. None of the pilots used the Desired Track Up (DTK) orientation.

Averaging the percentages across pilots, we find the following usage estimates:

•Track Up: 15%

•Track Up Arc: 38%

•Track Up 360: 43%

• Desired Track Up: 0%

• North Up: 7%

0

5

10

15

20

25

Always Sometimes Rarely Never

Selecting the Map Type (VFR, IFR, Custom)

93% 7% 0% 0%

a

0

5

10

15

20

Always Sometimes Rarely Never

Selecting the Map Orientation (North Up, Track Up, Etc.)

74% 11% 11% 4%

b
8

It should be noted that the validity of these percentages is suspect for a variety of reasons. Pilots did not ensure

that individual percentage estimates across orientations added up to 100%. One pilot, for example, estimated

that he spent 90% of the time in the North Up orientation and 90% of the time in the Track Up orientation.

It is also unclear whether pilots understood the different types of track up orientations. What is fairly certain

is that most pilots used one of the track up orientations, a couple of pilots used the North Up orientation, and

no pilots used the Desired Track Up orientation.

c. Selection of Map Data for Display/

Decluttering

Each map type has various levels of information

to display. (navaids, airways, intersections, etc.)

The pilot can selectively display the symbols and

labels with the menu keys on the right-hand side of

the display.

d. Range Selection (Zoom)

The pilot can scale the map presentation

with the (+,-) Zoom keys on the bottom of the

display. The range scale could be varied between 1⁄4 mile and 200 miles. There is also an

AUTO setting that will keep the ownship and

the active waypoint on the screen by increasing

the range scale if necessary.

Range selection varied from 2 to 5 miles for

ground operations, 5 to 20 miles while in the

terminal area and from 5 to 75 miles while en

route. Six of the pilots (22%) indicated that they

used the AUTO setting while en route.

e. Selecting the Range Defaults for Ground

and Flight

The pilot can select the default zoom level for

ground operations and flight operations, and the

aircraft ground speed at which the zoom level will

change from ground to flight and vice versa.

f. Use of the Pan Mode

The Pan Mode allows the pilot to move the map

up, down, left or right. This is useful to give a full

route presentation at a usable/readable zoom level,

or simply to see what is ahead.

Twelve pilots elaborated on why they rarely or

never used the pan mode. Eleven of the 12 stated

that they did not need the feature during normal

operating procedures. The 12th pilot stated that he

only used the feature when travelling to an unfamiliar area to get an idea of what to expect.

0

10

20

30

Always Sometimes Rarely Never

Range Selection (Zoom)

81% 15% 4% 0%

d

0

5

10

15

Always Sometimes Rarely Never

Selection of Map Data for Display/Decluttering

41% 33% 4% 7%

c

0

5

10

15

Always Sometimes Rarely Never

Selecting Default Zoom Levels (Ground, Flight)

44% 26% 7% 11%

e

0

5

10

15

Always Sometimes Rarely Never

Use of the Pan Mode

15% 41% 41% 4%

f
9

g. Acquiring Database Information

The MX20 has an extensive database of airport/fix/navaid information

that is accessible to the pilot from the

Flight Plan page or the INFO button

on the map pages. In the PAN mode,

the INFO button displays information about the airport nearest the

aircraft’s current location. In the normal mode, the INFO button displays

information about the active

waypoint.

h. Graphic Traffic Screen

The MX20 has a dedicated ADS-B

traffic page that shows the ownship

symbol in the center of a compass rose

(Track up 360 or arc presentation),

the flight plan, and ADS-B targets

(traffic). Each target is tagged with its

call sign, altitude, a velocity vector

and a climb or descent arrow if appropriate. Traffic may also be filtered to

depict only those targets within 2000

feet of ownship.

i. Using the Text Traffic Screen

The text traffic screen lists all received ADS-B targets, their call signs,

altitudes, ground speeds, and a clock

position/distance from ownship.

j. Individual Target Selection

Each target can be individually selected by the pilot to display additional information. This information

includes the ground speed of the target, its estimated relative position (e.g.,

2 o’clock) and distance.

0

2

4

6

8

10

12

Always Sometimes Rarely Never

Acquiring Database Information

30% 26% 41% 4%

g

0

5

10

15

20

Always Sometimes Rarely Never

Using the Graphic Traffic Screen

67% 11% 19% 4%

h

0

2

4

6

8

10

12

Always Sometimes Rarely Never

Using the Text Traffic Screen

41% 22% 19% 19%

i

0

2

4

6

8

10

12

Always Sometimes Rarely Never

Individual Target Selection

41% 30% 22% 7%

j
10

k. Target Altitude Display

(Relative, Absolute)

The altitudes displayed can be either the absolute altitude of the target, or relative altitude of the target to

ownship.

l. Modifying Broadcast Aircraft

Call Sign

The MX20 allows the pilot to

choose the call sign that is broadcast

by the UAT. This feature was added

to accommodate the potential need

for more flexibility or to accommodate a company call sign.

Most of the pilots who rarely or

never used this function indicated

that the reason it was not used was

that it was unnecessary. One pilot

wrote that he had been instructed

by the Capstone office not to use the

function.

m. Selecting Terrain Depiction

Terrain is depicted on the VFR map

as it is on a sectional chart, with colorcoding. Lower terrain is green and higher

terrain is in increasingly darker shades

that range from yellow to orange. The

CUSTOM map allows the pilot to

choose between this “absolute” mode

and a “relative” mode. In the relative

terrain mode, the terrain changes color

relative to the aircraft’s indicated altitude. In Alaska, the following color-coding is used:

• Red means terrain is 300 ft. below, to above the aircraft’s altitude

• Yellow indicates terrain is from 301 – 1000 ft. below the aircraft

• Green indicates terrain is from 1001 – 2000 ft. below the aircraft

• Black indicates terrain that is more than 2000 ft. below the aircraft.

There is also a dedicated terrain page that provides only relative terrain and flight plan information. It is

imperative that the aircraft and MX-20 have a correct altimeter setting for the relative terrain information to

be accurate.

0

5

10

15

Always Sometimes Rarely Never

Target Altitude Display (Relative, Absolute)

56% 15% 11% 19%

k

0

2

4

6

8

10

12

Always Sometimes Rarely Never

Modifying Broadcast Aircraft Call Sign

0% 15% 44% 41%

l

0

2

4

6

8

10

12

Always Sometimes Rarely Never

Selecting Terrain Depiction

22% 41% 26% 11%

m
11

n. Using the Weather Screen

The MX-20 can display broadcast

graphical weather data (e.g., NEXRAD)

on dedicated screens. The weather screen

shows the ownship symbol, flight plan

and the received weather returns.

When explaining why the function was

not used, the most common answer (12

pilots) was that the information was not

available most of the time. During pilot

interviews, pilots suggested that the

weather data were available only about

25% of the time or less. One pilot mentioned that the information only covered a small area around Bethel.

Three pilots claimed the information was unnecessary.

o. Using the Flight Information Service Screen

The MX-20 can display broadcast

textual weather data (e.g., METARS,

TAFS) on dedicated screens. The Flight

Information screen allows the pilot to

select and view all received TAF and

METAR reports.

Similar responses were given for not

using the textual weather information as

were given for the graphical weather

information. Six pilots stated that the

data was unavailable most of the time; 5

pilots said that the information was not

needed; 2 pilots stated that the information was too limited in scope to be useful; and 3 pilots were unaware of

the feature.

p. Displaying the Flight Plan Screen

The flight plan screen lists all the

waypoints in the current flight plan,

the active waypoint, and current navigation information. The pilot can

scroll through the waypoints and view

database information about each

waypoint.

Thirteen pilots stated that this

function was not needed. As was mentioned earlier, many pilots did not

use the flight planning function of

the GX-60 (see Figure 7a below).

Three claimed the function was too

complex.

0

2

4

6

8

10

12

Always Sometimes Rarely Never

Using the Weather Screen

7% 15% 37% 41%

n

0

2

4

6

8

10

12

Always Sometimes Rarely Never

Using the Flight Information Service Screen

15% 26% 30% 30%

o

0

5

10

15

Always Sometimes Rarely Never

Displaying the Flight Plan Screen

4% 26% 22% 48%

p
12

q. Using the Message Screen

The message screen allows the pilot

to view and clear system messages

such as imminent entry into restricted

airspace or entry into a terminal area.

Eight pilots stated this function

was not necessary. Three said that the

message light on the unit blinked continually and they had learned to ignore it. Two claimed that the messages

were neither important nor interesting.

Figures 6 a-q show MX-20 function usage estimates.

GX-60 Functions

a. Entering/Copying/Saving/Editing/Deleting Flight Plans

The GX60 allows the pilot to store up to 30

named flight plans. The pilot has full control

over the waypoints in each flight plan and can

copy them from one location to another,

rename, reverse, and delete them. Each flight

plan is stored under a user-given name. When

activated, the stored flight plan becomes the

“Active” flight plan, which is uploaded to the

MX20 for display.

Ten pilots stated that the feature was unnecessary. Two said they had not received any

training. One pilot claimed the function was

too complex. One stated that, when flying to multiple airports, the flight plan would move too quickly to the

next leg, before the previous leg had been completed. This made the flight plan function unusable.

b. Viewing ETA’s, ETE’s and waypoint

distances

The pilot can scroll through the NAV

pages on the GX60 to view estimated time of

arrival (ETA), estimated time en route (ETE)

and distances to all waypoints in the active

flight plan.

c. Using the Direct-To function

Like all GPS navigators, the GX60’s simplest function is to navigate direct to a waypoint.

The pilot pushes the Direct-To button, selects

the waypoint, and presses Enter. The GX60

will then provide guidance along a course from

the aircraft’s present position to the selected

waypoint.

0

2

4

6

8

10

12

Always Sometimes Rarely Never

Using the Message Screen

22% 22% 11% 41%

q

0

5

10

15

Always Sometimes Rarely Never

Entering/Copying/Saving/Deleting/Editing Flight Plans

19% 52% 15% 15%

a

0

5

10

15

20

25

Always Sometimes Rarely Never

Viewing ETAs, ETEs, & Waypoint Distances 

85% 7% 7% 0%

b

0

5

10

15

20

25

Always Sometimes Rarely Never

Using the Direct-To Function

81% 19% 0% 0%

c
13

d. Using Database INFO

Functions

The GX60 has an extensive database of airport and navaid information. The pilot can access this directly

from the database by selecting the

DB (database) button along the bottom of the navigator. Access can also

be gained by pressing the INFO button when the desired waypoint is

displayed on the active waypoint or

flight plan page.

e. Loading/ Unloading/Changing

Flying IAPs

The GX60 is a C129 GPS navigator approved for approach navigation. When an airport with an

approved GPS approach is the destination waypoint in a flight plan,

pressing SELECT will load an instrument approach procedure (IAP).

When loaded, the fixes for that approach are added to the flight plan.

Once an approach is loaded, the pilot has the option to unload, change,

or disable the approach procedure.

Instrument approaches are rarely

flown in the Bethel area. Twelve of

the pilots stated that the function

was not needed. Four pilots were

unaware of the function. Two pilots

said that the company did not allow

use of the function.

f. Using RAIM Prediction

All C129 GPS navigators are required to provide integrity monitoring of the GPS signal to ensure an

accurate signal for approach navigation. The Receiver Autonomous Integrity Monitoring (RAIM) function

is accessed on a NAV page of the

GX60. The pilot can enter an ETA at

the destination airport and the RAIM

function will predict whether or not

GPS signal integrity will be available

at that time. This allows the pilot to know in advance whether GPS approaches at that airport will be available.

Because instrument procedures are rarely used, there is little need for this function.

0

2

4

6

8

10

12

Always Sometimes Rarely Never

Using Database/INFO Functions

41% 37% 22% 0%

d

0

5

10

15

20

Always Sometimes Rarely Never

Loading/Unloading/Changing and Flying IAPs

0% 59% 19% 22%

e

0

5

10

15

20

Always Sometimes Rarely Never

Using RAIM Prediction

4% 15% 11% 67%

f
14

g. Flying Specific Radials To/From

Waypoints

As GPS navigation makes use of standard

VOR and other navigation waypoints, it is necessary for the pilot to be able to intercept and fly

specific courses to and from waypoints. This is

accomplished on the GX60 by making the desired waypoint the active waypoint, pressing

Direct-To twice and entering the course to be

flown.

h. Storing and Using User-Defined Waypoints

The GX60 offers the pilot the capability to

store and navigate using user-defined waypoints.

This can be useful for a variety of reasons such as

search and rescue and plotting courses around

terrain features.

Most of the pilots that rarely or never use the

function (11) stated that the function was not

needed.

i. Using Hold/Continue Functions

Normally the GX60 will automatically

sequence through the waypoints in a flight

plan as the flight progresses. However, the

pilot can control this sequencing with the

Hold/Continue functions. This is normally

accomplished in an IFR conFigured aircraft

with the annunciator panel, but the pilot can

elect to leave the current waypoint as the

active waypoint after the aircraft has passed

it by selecting the Hold function on the

GPS. When the pilot selects “Continue,”

normal sequencing will resume.

j. Using the Parallel Track Offset

Function

This function allows the pilot to

offset the desired track by a user specified number of miles. This may be

useful to avoid head-on traffic situations on busy routes.

Nine pilots said the function was

not necessary; 2 said they had received no or not enough training on

the function; 4 pilots were unaware

of the function.

0

5

10

15

Always Sometimes Rarely Never

Flying Specific Radials To/From Waypoints

15% 11% 30% 44%

g

0

5

10

15

Always Sometimes Rarely Never

Storing and Using User-Defined Waypoints

11% 26% 19% 44%

h

0

5

10

15

20

Always Sometimes Rarely Never

Using Hold/Continue Functions

4% 15% 11% 70%

i

0

5

10

15

Always Sometimes Rarely Never

Using the Parallel Track Offset Function

7% 11% 22% 56%

j
15

k. Using the Nearest Function

The nearest function displays the distance and bearing to the 20 nearest waypoints

(airports, navaids, intersections, airspaces,

etc) to the aircraft’s present position. Using

this function, along with the INFO function, allows the pilot to select a suitable site

for an unanticipated landing, or simply as a

way to quickly enter a course to a nearby

waypoint.

l. Viewing Messages

System messages will warn the pilot of

entry into protected airspace, loss of satellite signal, and transitions from one

waypoint to another during navigation.

Pilots can view these messages by pressing

the MSG button on the display unit.

Responses by pilots that never or rarely

used the function were similar to those

given for viewing MX-20 messages. Three

pilots stated the function was unnecessary.

One pilot said no or not enough training

was received. Two of the pilots said that the

messages were always the same.

m. Using the GX-60 Moving Map

Pilots can display a moving map on

the GX-60 display screen showing the

position of airports, navaids, boundaries,

and various geographical features (roads,

waterways, etc.).

n. Using Communications Radio

Functions

The GX60 includes a communications

transceiver that has several advanced functions. It functions in the same manner as

most aircraft transceivers, allowing the pilot

to enter and select between active and standby

frequencies.

0

5

10

15

Always Sometimes Rarely Never

Using the Nearest Function

44% 30% 19% 7%

k

0

2

4

6

8

10

Always Sometimes Rarely Never

Viewing Messages

22% 26% 33% 15%

l

0

5

10

15

20

Always Sometimes Rarely Never

Using the GX-60 Moving Map

59% 4% 15% 22%

m

0

5

10

15

20

25

Always Sometimes Rarely Never

Using Communications Radio Functions

81% 7% 4% 4%

n
16

o. Using the Monitor Function

The MONITOR function allows the

selected standby frequency to be monitored. Any transmission on the ACTIVE

frequency will override this function.

p. Using the Recall Function

The pilot can access a database of frequencies through the RECALL function.

By selecting this function, the pilot can

access frequencies referenced to the current To/From waypoints or destination, the

last 10 frequencies used, the frequencies for the

last time the NEAREST or INFO function was

activated, user stored frequencies, weather frequencies, and the emergency channel (121.5).

Nine of the pilots stated that they had not

received enough training, or no training at all on

the use of this particular function. Eight other

pilots said that the function was not necessary.

q. Using the Memorize Function

The MEMORIZE function allows the pilot

to store any frequency in the database.

Eleven pilots thought the function unnecessary. Ten were unaware of the function. Only

nine of the pilots (33%) stated they had received formal training regarding the function.

r. Selecting CDI Sensitivity

This function allows the pilot to manually

select the number of miles represented by a fullscale deflection of the CDI. This is normally left

at 5 miles for en route operations. During approach operations the CDI will automatically

scale from 5 miles to 0.3 miles.

Ten pilots said the function was not necessary.

Five were unaware of the function. Two pilots

stated that no or not enough training was received

for the function.

s. Customizing NAV pages

The GX60 allows the pilot to customize what

types of navigation information will be displayed

on the various NAV pages. He/she may select

from items such as Desired Track, Bearing, Track

Angle Error, an Electronic CDI, ETA, ETE, etc.

These data can be displayed in many different

combinations. Once these pages are set, the pilot

can choose between scrolling through them manually or automatically.

0

2

4

6

8

10

12

Always Sometimes Rarely Never

Using the Monitor Function

33% 41% 7% 19%

o

0

5

10

15

20

Always Sometimes Rarely Never

Using the Recall Function

11% 11% 15% 63%

p

0

5

10

15

20

25

Always Sometimes Rarely Never

Using the Memorize Function

0% 7% 15% 78%

q

0

5

10

15

Always Sometimes Rarely Never

Selecting CDI Sensitivity

4% 19% 22% 56%

r

0

5

10

15

Always Sometimes Rarely Never

Customizing NAV Pages

15% 15% 19% 52%

s
17

Ten pilots claimed the function was not necessary.

Four were unaware of the function. Ten (37%) stated

that they had received formal training for the function.

t. Selecting Direct-To Entry Options

This function allows the pilot to choose whether a

DIRECT-TO entry will always clear the active flight

plan. If set to YES, any DIRECT-TO will clear the

active flight plan even if the entered waypoint is in the

active flight plan. If set to NO, a DIRECT-TO to a

waypoint in the flight plan will simply create another

leg with DIRECT-TO as the FROM waypoint.

Figures 7a-t depict GX-60 function usage estimates.

Over half of the pilots that filled out the selfadministered questionnaire (14 of 27) stated that they

never used the flight planning function of the GX-60.

Instead, they would use the nearest and/or direct-to

function to navigate to each of the waypoints in turn.

This behavior is probably due in large part to the type

of flying that is performed in the Bethel area. Pilots do

very little instrument flying. They also will usually

navigate from one village to another using the directto function during each leg of the trip.

0

5

10

15

Always Sometimes Rarely Never

Selecting Direct-To Entry Options

48% 22% 7% 19%

t

Table 1: MX-20 Function evaluation items with mean evaluation rating across participants.

MX-20 Function Evaluation Item Mean SD

Ease of reading map data 4.26 0.7642

Ease of reading and accessing of Text Weather data (METARS, TAFS) 2.76 1.3317

Ease of reading and using Traffic data 3.89 0.8006

Ease of accessing and using Terrain data 3.70 0.8689

Ease of accessing database information (runway lengths, frequencies, etc) 4.19 0.9214

Ease of using the function/item Select keys 3.92 0.7961

Ease of using the MX-20 under local environmental conditions 3.89 1.0127

Overall rating of the MX-20 4.15 0.9885

Table 2: GX-60 Function evaluation items with mean evaluation rating across participants.

GX-60 Function Evaluation Item Mean SD

Ease of reading the text on the screen 3.56 0.8916

Ease of use of function key/knobs 3.59 0.9711

Usefulness of the built in moving map 3.27 1.4016

Ease of accessing database information (i.e., runway lengths, frequencies, etc) 3.77 1.0318

Usefulness of the alerting functions (Waypoint crossings, airspace, etc) 3.31 1.0107

Ease of entering/editing Flight Plans 3.15 0.9672

Ease of entering/using user waypoints 3.19 0.9214

Ease of using the Approach functions 2.89 1.0485

Ease of using the Comm functions 3.77 0.7646

Using the GX-60 to conduct a non-precision approach 3.29 1.0690

Acceptability of the GX-60 under local environmental conditions 4.00 0.8771

Overall rating of the GX-60 3.88 0.9364

Human Factors Design Issues

Pilots that filled out the self-administered questionnaire were asked to rate several aspects of both MX-20

multi-function display and the GX-60 GPS display.

Responses ranged from 1 to 5 with 1 = “Unacceptable,”

2 = “Marginally Acceptable,” 3 = “Acceptable,” 4 = “Very

Acceptable,” and 5 = “Excellent.” Table 1 shows the MX20 functions that were evaluated, along with the mean

and standard deviation of the ratings across all participants. Table 2 shows the GX-60 functions that were

evaluated, along with the mean and standard deviation

evaluation across all participants. Highlighted items are

those features that were evaluated as less than acceptable

on average.
18

In general, pilots rated most functions as acceptable or higher for both the MX-20 and GX-60 units.

The lowest rated item for the MX-20 was the ease of

reading and accessing textual weather data. For the

GX-60 the lowest rated item was the ease of using the

approach functions. Both of these functions are not

used regularly by pilots in the Bethel area, as is attested

to by the usage estimates for those functions given in

Figures 5 and 6. A paired t-test was conducted to

compare the overall rating of the GX-60 with the overall

rating of the MX-20. The result showed that the MX-20

was rated higher than the GX-60 at a marginal level of

significance, t(27) = 2.033, p = 0.052.

 Multi-function Display Page Hierarchy

(MX-20 Display)

Pilots reported that the Terrain mode was a minimum of 2 button activations away from the Custom

Map page. Since many pilots preferred to quickly

switch back and forth from the Custom Map page to

the Terrain page, the 2-button push and heads down

time required to perform this task was considered

quite undesirable and a potential safety hazard.

One common complaint expressed about the traffic display (5 pilots) was that the dedicated Traffic

page should be one button push away from the Map

page and other major pages. As currently designed,

this system required a minimum of 2 button activations to access the dedicated traffic page. Pilots were

concerned about the amount of heads-down time and

having to divert their attention from other cockpit

tasks. The few extra seconds required to select the

dedicated traffic page, especially when flying close to

the surface or when weather conditions were poor,

was objectionable.

The effect of MFD information hierarchy decisions on pilot performance has been demonstrated by

other researchers (Roske-Hofstrand & Paap, 1986;

Reising & Curry, 1987; Sirevaag et al., 1993). It is

critical that attempts be made to optimize display

page organization so as to maximize pilot performance with the displays. While there have been attempts to develop structured approaches to the design

of an optimal display hierarchy (e.g., Francis, 2000;

Roske-Hofstrand & Paap, 1986), it is likely that the

process will remain iterative. Feedback from users of the

systems will remain a critical part of the organization of

the menu and display structure of these systems.

Availability of Information Key

There is a need to provide a key to pilots to inform

them of the meaning of the colors used in the relative

terrain display mode. Four of the pilots, during their

interview, admitted that they did not know the exact

meaning of the four relative terrain colors (red, yellow, green, and black).

Overlaying Information

Typically, the terrain mode is not used in normal

day-to-day operations. The primary reason for this is

that with the display of this information the pilot

must forfeit topographical information, along with

airport, navigation aids, airways, and other types of

information that may be displayed on the Custom

Map page. Some pilots reported that they would

periodically switch back and forth between the Custom Map page and the Terrain Page when in marginal

visual conditions to maintain better situation awareness. However, since the Custom Map page provided

such good position awareness, most pilots simply flew

with that page selected unless they were in or near

hazardous terrain or visibility was near zero. Consequently, pilots expressed the desire to display relative

terrain with topographical and other navigational data.

Five pilots mentioned that the magenta route line

on the MX-20 display would sometimes obscure traffic information such as the altitude of other aircraft.

It was suggested that the priority of the traffic information be increased so that it would not be obscured

by a portion of the route line.

Auditory Alerts

Presentation of only a visual alert for warning the

pilot of impending hazardous terrain ahead was not

adequate. One pilot noted that unless he was watching

or continuously checking the display, a terrain alert

could be generated and not noticed for some length of

time. For such critical safety related information, an

aural alert should accompany a terrain warning to

ensure timely pilot awareness. However, there is a

likelihood that a continuous warning sound would

become extremely annoying to pilots and would,

therefore, be turned off permanently.

Zooming and Panning Problems

Two pilots complained that when viewing information on the dedicated traffic display, they were

required to change the zoom level and/or pan to a

different portion of the map to see a particular aircraft. After changing the zoom level and/or panning,

they would return to the original map screen with the

new zoom/pan conditions in effect. They were then

required to re-adjust the display to obtain the original

zoom/pan conditions. This required several button

presses to accomplish.
19

Better Logic for Traffic Warnings

Four of the pilots suggested changes in the display

of traffic warnings that could reduce the number of

warnings received by the pilots and/or improve the

information the pilot receives. One pilot suggested

highlighting traffic on the display that triggered the

warning so pilots could more quickly react. A second

pilot suggested having some sort of indication of the

direction of threatening traffic (such as a popup

arrow). One pilot suggested certain types of transponder-related information be included with the traffic

symbology, specifically “emergency,” “lost communication,” or “hijack” information.

RECOMMENDATIONS AND

CONCLUSIONS

Training Recommendations

Using Conventional Navigation Instruments

Referring back to Figure 3, several of the pilots who

claimed there had been no loss of navigational skill said

that they used the conventional navigation instruments

consistently during most flights as a backup. In a separate

question, 80% of the pilots (32) indicated that they used

conventional navigational instruments as a secondary

source of navigation information while flying Capstoneequipped aircraft. It is recommended that, during training, pilots are encouraged to continue using their

conventional navigation instruments. This should help

to maintain skills with those instruments and would also

provide adequate navigational information to the pilot if

the moving map or GPS display should fail.

Mixed Equipage Training

During training, instructors should periodically emphasize that not all aircraft in an area will be equipped

with ADS-B technology. The pilots must learn not to

rely too heavily on the traffic display to ensure that there

is no traffic in the area. In addition, it might be useful to

conduct research regarding how different levels of equipage in a particular region will affect pilot reliance on the

traffic display.

Training to Avoid Traffic

There are established maneuvers that pilots use to

avoid oncoming traffic. These maneuvers should be

emphasized during training so that potential traffic

conflicts can be resolved quickly. Some of the pilots

commented that even though they could see potentially

conflicting traffic on their displays, there were times

when the maneuvers of both pilots would not quickly

resolve the conflict, but instead would keep the planes on

a collision course. Review of standard avoidance

maneuvers should eliminate these situations.

Risk-Taking and Aeronautical Decision-Making

The potential abuse of these displays remains high,

and part of the training should focus on encouraging the

pilot not to use the displays to “push the envelope.”

Design Recommendations

Minimizing Control Inputs

• Stand-alone GPS receivers and traffic and terrain

awareness systems must be designed for ease of use.

Minimum performance standards should be developed that define pilot interface requirements in terms

of task complexity, number of actions, reliance on

memory and time-to-perform.

• All primary pages (moving-map, traffic, weather,

relative terrain) should be available with a single

button press.

• Zooming and panning functions should be independent between pages, or a means should be provided to

discard the changes and return to original zoom and

pan settings.

• Users should not be required to enter barometric

pressure more than once during system updates.

• Barometric pressure entry on the MX-20 would be

much easier and faster with a knob instead of push

buttons.

Use of a Display Information Key

Displays showing relative terrain should contain a

readily available color code key. This information

should be accessible so pilots do not have to search for

it within the menu structure.

Information Overlay Issues

• Manufacturers should be encouraged to design systems that permit the overlay of terrain data over other

types of topographical and navigational data.

• The depicted course line sometimes obscures traffic

information, such as the traffic altitude. While it is

true that navigation should be primary on a display,

it makes sense to allow a portion of the course line to

be covered by pertinent textual information, such

as traffic altitudes, since such obscuration would

not affect the basic information conveyed by the

course line.

• In the track-up display mode, heading information is

displayed at the top of the moving map display.

Locating the heading at this position means that it will

obscure a portion of the depicted course. It is suggested

that the heading information be located elsewhere on

the display so that as much of the course line as

possible can be presented to the pilot.
20

Aural Alerts

For safety critical information such as cautions and

warnings of terrain hazards, visual cautions and warnings should be accompanied by an associated aural

caution and warning.

Additional Design Features for Consideration

Manufacturers designing similar avionics should

consider implementing the following features:

• Altitude-filtering of traffic with a 500 foot resolution;

• Improved traffic threat information;

• Simpler flight plan entry.

Other Issues

Accuracy of Terrain Database

Accuracy of the terrain database is critical to the

effectiveness of these displays.

Availability of Weather Information

Pilots did not make much use of the depiction of

weather, either graphical or textual, because this information was not available very often. It is likely that

there is a critical level of availability that must be

achieved for pilots to get into the habit of utilizing this

information. If availability does not achieve this critical level, pilots will simply not incorporate the checking of weather displays into their flight routines. The

critical level of availability is not known at this time.

Pilot Demographics

The pilot population in the Bethel area is probably

slightly different from the general pilot population in

terms of demographics. The average age of the Bethel

pilots was 37, whereas in the pilot population of GA

pilots the average is approximately 45 (FAA, 2000).

The percentage of instrument-rated pilots was 95%

for the Bethel pilots, which is much greater than the

approximately 30% of pilots with instrument ratings

in the private pilot population (FAA, 2000). Finally,

although we do not have statistics to verify the statement,

it is likely that the Bethel pilots fly much more often than

the general aviation pilot population. All of these differences could have an impact on the ability of pilots to

remain proficient with these types of displays.

REFERENCES

FAA, (2000). US civil airmen statistics. Information

available on the internet at URL http://

api.hq.faa.gov/CivilAir/index.htm. Web site of the

FAA Office of Aviation Policy and Plans (APO).

Foy, L. & McGuinness, B. (2000). Implications of

cockpit automation for crew situational awareness. Proceedings of the Conference on Human Performance, Situation Awareness and Automation:

User-Centered Design for the New Millennium, pp.

101-6.

Francis, G. (2000). Designing multifunction displays:

An optimization approach. International Journal

of Cognitive Ergonomics, 4(2), 107-124.

Reising, J., & Curry, D. (1987). A comparison of voice

and multifunction controls: Logic design is the

key. Ergonomics, 30, 1063-77.

Roske-Hofstrand, R.J. & Paap, K.R. (1986). Cognitive

networks as a guide to menu organization: An

application in the automated cockpit. Ergonomics,

29(11), 1301-11.

Sirevaag, E., Kramer, A., Wickens, C., Reisweber, M.,

Strayer, D., & Grenell, J. (1993). Assessment of

pilot performance and mental workload in rotary

wing aircraft. Ergonomics, 36, 1121-40.

Williams, K.W. (2002). Impact of Aviation Highwayin-the-Sky Displays on Pilot Situation Awareness.

Human Factors, 44(1), 18-27.1

1

All Office of Aerospace Medicine technical reports are available in

full-text from the Civil Aerospace Medical Institute’s publications

Web site: http://www.cami.jccbi.gov/aam-400A/index.html
A1

APPENDIX A

Demographic Data Form

Part I – Demographics------To be completed by each pilot

General

Male

Female

Age

Previous Occupation

Years of Education past high school

Field of Study

Personal Computer User level Advanced (programming, application development)

General (office use, word, excel)

Basic (Internet, Email)

None

Ratings and Certificates

Private

Commercial

Airline Transport Pilot

Single Engine Land

Single Engine Sea

Multi Engine Land

Multi Engine Sea

Glider

Rotorcraft

Instrument

Certified Flight Instructor

Certified Instrument Instructor

Multi Engine Instructor

Ground Instructor

Advanced Ground Instructor

Please list type ratings held:
A2

Commercial pilot experience

Years of Part 91 experience (flight

instruction, corporate, etc.)

Years of Part 135 experience

Years Part 137 (AG)experience

Years of Part 121 experience

Flight Time Estimates Total Last Year

Hours Logged:

 Civilian Hours:

 Military Hours:

Day VFR

Night VFR

Day IFR

Night IFR

GPS experience Approx.

Hours of

Use

Please List Model Names with which you have any

experience.

Handheld GPS

Panel Mount GPS under VFR

Panel Mount GPS under IFR

Loran

TCAS

FMS

MFD (MultiFunction Display )
B1

APPENDIX B

Interview Form

Pilot Operations

1. In flying a non-capstone-equipped airplane, I generally navigate by:

P=Primary S=Secondary N=Not Used

Method Rating

Charts and

Landmarks

Headings and

Times

Radio Aids

Other GPS

2. In flying a Capstone equipped airplane, I generally navigate by:

P=Primarily S=Secondary N=Not Used

Method Rating

GX-60 only (MX20

turned off or not

referred to)

MX-20 only(just

follow the magenta

line)

GX-60 and MX-20

together

Charts and Landmarks

Heading and Time

Radio Aids

Other GPS

3. Under what circumstances (if any) is the Terrain Mode most useful?

4. Under what circumstances (if any) is the Terrain mode distracting, confusing or

dangerous?
B2

5. What suggestions do you have for making the Terrain mode more useful?

6. What effect (if any) will the Capstone equipment have on controlled flight into terrain

accidents?

___Significant reduction

___Moderate reduction

___Slight reduction

___No reduction

___Increase

7. Under what circumstances has the presentation of Traffic proved most useful?

8. Have you ever preferred NOT to display the traffic? (yes/no), If so, under what

circumstances?

9. What suggestions do you have for making the Traffic presentation more useful?

10. What effect (if any) will the Capstone equipment have on the rate of near mid air

collisions?

___Significant reduction

___Moderate reduction

___Slight reduction

___No reduction

___Increase

11. Have you ever been asked to operate the Capstone equipment during a flight check?

If so, what Capstone functions were you asked to perform?
B3

12. Rate the amount you feel your conventional navigational skills have been affected as

a result of using Capstone avionics?

1- significant deterioration of conventional skills

2

3- some deterioration of conventional skills

4

5- no affect

6

7 -some improvement of conventional skills

8

9- significant amount of improvement of conventional skills

13. Has the Capstone equipment ever alerted you or anyone you know to a potential

conflict with traffic or terrain that would likely have otherwise resulted in an accident? If

yes, please describe the incident.

14. Has the Capstone equipment ever alerted you to a navigational error? If yes, please

describe the incident.

15. Has the Capstone equipment ever helped you handle any other potentially serious

situation? If so please describe the incident.

16. Has your or another’s use of the Capstone equipment ever created a hazardous

situation? If so please describe it.

17. Have you ever noticed a GPS bearing error or timeout error on the GX-60? or any

other problems in the functioning of the GX-60 or MX-20? If so, please describe the

problem and say whether it was flagged by the GPS unit.
B4

18. What effect, in your opinion, has the Capstone equipment had, or will it have on risktaking behavior (Check all that apply).

___ Some pilots will be more likely to fly under lower visibility conditions.

___ Some pilots will be more likely to fly at lower altitudes (closer to the ground) under

low visibility conditions.

___ Some pilots will be more likely to fly closer to hazardous terrain features (mountains,

hills) under low visibility conditions.

___ Some pilots will be more likely to fly through hazardous mountain passes when

weather is questionable or visibility is low.

___ Some pilots will be more likely to fly closer to other aircraft even if it is difficult to

maintain constant visual awareness of their position.

___ Other (Briefly describe) .

___ It will have absolutely no affect on it risk-taking behavior.

19. What are the most significant safety hazards associated with this equipment?
C1

APPENDIX C

Self-Administered Questionnaire

Feature Use-MX-20

Features Feature

Use in Day to

Day Operations

A=Always

S=Sometimes

R=Rarely

N= Never

If Feature is Never used ,

why:

1- Not applicable or

necessary to my

operation

2- No or not enough

training

3- Complexity of

feature

4- Not aware of feature

5- Other (please state

reason)

Training Method for features

that are used, list all that apply

F – Company/UAA provided

formal training

M- Self Study with Manual

and equipment

S - Capstone or PC simulation.

P- Another pilot showed me.

N- No Training

Selecting the Map Type

(VFR,IFR, Custom)

Selecting the Map

Orientation

(North up, Track up, etc)

Selection of map data to

display/decluttering

Range selection(Zoom)

Selecting Range

Defaults(Ground, Flight)

Use of the PAN mode

Acquiring Database

information (INFO)

Using the Graphic Traffic

Screen

Using the Text Traffic

Screen

Individual Target

Selection
C2

Features Feature

Use in Day to Day

Operations

A=Always

S=Sometimes

R=Rarely

N= Never

If Feature is Never used ,

why:

1. Not applicable or

necessary to my

operation

2. No or not enough

training

3. Complexity of

feature

4. Not aware of feature

5. Other (please state

reason)

Training Method for features

that are used, list all that apply

F – Company/UAA provided

formal training

M- Self Study with Manual

and equipment

S- Capstone or PC simulation.

P- Another pilot showed me.

N – No Training

Target Altitude

display (relative,

absolute)

Modifying the

broadcast

information(Privacy

mode)

 Terrain Modes

(relative,sectional

dedicated Screen)

Weather Screen

Flight Information

Service Screen

Using the FlightPlan

Screen

Using the Message

Screen
C3

Feature Use-GX-60

Features Feature

Use in Day to

Day Operations

A=Always

S=Sometimes

R=Rarely

N= Never

If Feature is Never used ,

why:

1- Not applicable or

necessary to my

operation

2- No or not enough

training

3- Complexity of

feature

4- Not aware of feature

5- Other (please state

reason)

Training Method for features

that are used, list all that

apply

F – Company/UAA provided

formal training

M- Self Study with Manual

and equipment

S- Capstone or PC

simulation.

P- Another pilot showed me.

N – No Training

Entering/Copying/Saving/Deleti

ng/Editing Flight Plans

Viewing ETA’s ETE’s,

Waypoint Distances

Direct To Function

Database/INFO functions

Loading/Unloading/

Changing and Flying IAPs

RAIM Prediction

Flying specific radials to/from

waypoints

Storing and using User defined

Waypoints

Holding (Hold,Continue,

Functions)

Parallel Track Offset

Nearest Functions

Viewing Messages

GX-60 Moving Map

Comm radio

Comm radio Functions:

 Monitor Function

 Recall Function

 Memorize Function

System Functions:

 Selecting CDI sensitivity

 Customizing NAV

 pages

 Direct To Entry Options
C4

Equipment Design-MX-20

Please rate the following on this scale:

0=Don’t Know

1 = Unacceptable

2 = Marginally Acceptable

3=Acceptable

4 = Very Acceptable

5=Excellent

Rating Comments

Readability of map data

Readability and accessability of Text

Weather data

Readability/Usability of Traffic data

Usability of the Terrain data

Accessibility of database information

Ease of using the function//Item Select keys

Acceptability of the MX-20 under local

environmental conditions

Overall rating of the MX-20
C5

Equipment Design GX-60

Please rate the following on this scale:

0=Don’t Know

1 = Unacceptable

2 = Marginally Acceptable

3=Acceptable

4 = Very Acceptable

5=Excellent

Rating Comments

Readability of textual data

Ease of use of function keys/knobs

Usability of built in moving map

Accessibility of database information

Acceptability of alerting functions (Waypoints,

airspace, etc)

Acceptability of Flight Plan Entry/Editing functions

Acceptability of User Waypoint functionality

Acceptability of Approach functions
C6

Rating Comments

Acceptability of the Comm functions

Usability of the GX-60 to conduct a non-precision

approach

Acceptability of the GX-60 under local

environmental conditions

Overall usability of the GX-60

Pilot Preferences and General Questions - MX-20

Approx percentage of

time spent in each Map

orientation mode

Track-Up North-Up Track-Up 360 Track-Up Arc

Approx percentage of

time in each Terrain Mode

Sectional page Relative Mode Dedicated Terrain

Page

None

Approx percentage of

time spent in each

Chart/Traffic mode

VFR IFR Custom(MAP) Graphic Traffic Text Traffic

If you use a particular

range setting for a

particular phase of flight

please list them.

Under what circumstances

do you use the PAN

mode?

Do you normally correct

the MX-20 altimeter

setting when the system

requests it?

Were you supplied with a

personal MX-20 user

manual?

Pilot Recommendations and Comments:
C7

Pilot Preferences and General Questions- GX-60

Do you customize your

NAV page data?

If so- list data displayed

on primary NAV page.

Is the GX-60 interfaced to

an external HSI/CDI on

any aircraft you typically

fly?

Is the GX-60 coupled to

the autopilot on any

aircraft you typically fly?

Is the GX-60 coupled to a

Fuel Computer on any

aircraft you currently fly?

Were you supplied with a

personal GX-60 users

manual?

Pilot Recommendations and Comments:
C8