**TABLE OF CONTENTS**

[Section]{.underline} [Page]{.underline}

INTRODUCTION viii

1.0 BENCH TEST 1-1

1.1 Logic 1-2

1.2 Displays 1-16

1.3 Controls 1-34

1.4 Bench Test Evaluation Summary 1-49

2.0 FLIGHT TEST 2-1

2.1 Pre-Departure 2-2

2.2 En Route 2-8

2.3 Transition 2-16

2.4 Approach 2-18

2.5 Missed Approach 2-20

2.6 Autopilot 2-24

2.7 GPS Accuracy 2-26

2.8 Moving Maps 2-28

2.9 Alarms & Alerts 2-30

2.10 Flight Test Evaluation Summary 2-35

APPENDICES

T TSO C129 A1 T1

R RTCA/DO-208 R1

F FAA F1

F1 FAA-AC-20-138 F1

F2 FAA-AC-25-11 F17

F3 FAA-TIA-STO346WI-A F31

M MILITARY M1

M1 MILITARY STANDARD 1472D M1

M2 ESD-TR-86-278 M41

O OTHER O1

O1 NASA FTB 3000 (Rev. A) O1

O2 SAE AIR 1093 O5

O3 SAE ARP 571C O9

O4 SAE ARP 1874 O11

O5 SAE ARP 4102 O15

O6 SAE ARP 4102/7 O19

O7 SAE AS 8034 O23

O8 DISPLAY TECHNOLOGY O27

BIBLIOGRAPHY B1

**LIST OF ACRONYMS**

AC Advisory Circular

ACO Air Certification Office

AFM airplane flight manual

AI articulation index

AMS aeronautical material specification

ANSI American National Standards Institute

ARP airport reference point

BRG bearing

CD chromaticity difference

CDI course deviation indicator

CDU control display unit

CIELUV Commission Internationale de l'Eclairage

chromaticity specification system (1976)

CRT cathode ray tube

DER designated engineering representative

EM electromagnetic

EFIS electronic flight instruments system

FAF final approach fix

FTE flight technical error

GPS global positioning system

HDG heading

HDOP horizontal dilution of precision

HSI horizontal situation indicator

IAF initial approach fix

IFR instrument flight rules

ILS instrument landing system

LDA landing directional aid

MEL minimum equipment list

MLS microwave landing system

MRT modified rhyme test

MTBF mean time between failures

NAD-83 North American datum database

NDB nondirectional beacon

OBS omni bearing selector

PB phonetically balanced

RAIM receiver autonomous integrity monitoring

RNAV area navigation

SA selective availability

SAE Society of Automotive Engineers

SDF standiford field

SID standard instrument departure

STAR standard terminal arrival route

STC supplemental type certificate

TACAN tactical aircraft control and navigation

TAE track angle error

TC type certificate

TSO Technical Standard Order

VFR visual flight rules

VNAV vertical navigation

VOR very high frequency omni-directional radio range

VORTAC combined VOR and TACAN navigational facility

WGS-84 world geodetic survey database

XTE cross track error

**FAA AIRCRAFT CERTIFICATION HUMAN FACTORS AND OPERATIONS CHECKLIST FOR
STANDALONE**

**GPS RECEIVERS (TSO-C129 CLASS A)**

**INTRODUCTION**

This checklist is designed to assist FAA certification personnel and GPS
receiver manufacturers in the evaluation of the pilot-system interface
characteristics of GPS receivers to be certified according to TSO C129
A1, RTCA/DO-208, and AC 20-138. Controls, displays, and operating
characteristics are the main focus of this checklist. Presently the
checklist does not address receiver hardware and functional
characteristics that do not require direct pilot involvment, such as
data reliability, failure protection, and data continuity during
aircraft maneuvering.

This checklist is arranged in three major sections: Bench Test, Flight
Test, and Appendices. The Bench Test is designed to evaluate GPS
receiver design characteristics that do not require aircraft
installation and flight. Three topic areas are covered in the Bench
Test: Logic, Displays, and Controls. The Logic section focuses on
waypoint entry and flight planning functions. The Display section covers
alarms and alerts, moving maps, and general display characteristics. The
Controls section covers knob, button, keyboard, coding, and labeling
design characteristics.

The Flight Test is designed to evaluate receiver design characteristics
and functions under actual flight conditions (e.g., Waypoint Sequencing
& Turn Anticipation). The Flight Test is provided in the context of
Departure, En Route, Transition, Approach and Missed Approach flight
segments. In addition, Autopilot, GPS Accuracy, Moving Map, Alarms, and
Alerts are covered.

The Appendices are designed to provide reference material for the
specific topics covered in the checklist. It should be noted that the
reference materials (including the TSO C129 A1 and the RTCA/DO-208) are
not complete, but contain only the extracted portions from the original
documents which are directly relevant to the specific checklist items.

**INSTRUCTIONS**

[Evaluation material]{.underline}. Evaluation topics are presented as a
set of facing pages. The left-hand page lists the section, evaluation
title, purpose, test procedure, and evaluation considerations. The
Purpose describes what the evaluation topic covers. The Test Procedure
provides the user with a suggested method of examining a particular
function or characteristic of the receiver. Evaluation Considerations
are given to assist in decision making.

[Scoring, comments, and references]{.underline}. On the right-hand page,
an evaluation box is given that corresponds to the letter of the
evaluation consideration (e.g. A, E, or EM). Each evaluation box
contains a space to indicate either a "fail", "pass with exception", or
"pass" score. The particular rating chosen is dependent upon the
requirements specified in the TSO C129 A1, AC 20-138, and RTCA/DO-208
documents and sound engineering judgment as determined by the
certification specialist. In addition, a space is provided for comments,
concerns, or notes.

The lower portion of the right-hand page contains a listing of
information that was used to develop the evaluation material on the
left-hand page. Information relevant to the TSO C129 A1 and/or the
RTCA/DO-208 is listed under the Requirements header. Military, FAA
(e.g., AC 20-138), and other human factors related information sources
are listed under the Guidelines header. All referenced material is
provided in the appendices. Additional discussions can be found in
McAnulty (1994) "A Review of Principles and Guidelines for the Design of
Controls and Displays for Standalone GPS and LORAN Receivers."

Requirements and guidelines are cross-referenced in **bold** with the
information contained on the left-hand page. For each requirement or
guideline listed, three pieces of information are provided to assist the
user during the evaluation. First, a cross-reference number is provided
that corresponds with the evaluation material on the left-hand page.
Second, the page number where the requirement or guideline information
can be found in the appendix is given. Lastly, the appendix and section
are listed.

+-----------------------------------------------------------------------+
| Example of Cross Referencing:                                         |
|                                                                       |
| "**(1)** (p. R3), R 2.2.1.4" refers to cross referenced item number   |
| one, page R3, section 2.2.1.4, of appendix R. If the user wants       |
| direct access to the reference material cross referenced with a       |
| **(1)**, the page number and section of the appendix are readily      |
| available.                                                            |
+-----------------------------------------------------------------------+

[Summary scoring sheet]{.underline}. A summary scoring sheet is provided
at the end of each test section. The summary scoring sheet lists the TSO
C129 A1 and RTCA/DO-208 requirements that were addressed and
cross-references them with the corresponding checklist evaluation topic
and page number. In addition, "fail", "pass with exception", and "pass"
score boxes are given to provide the user with an overall perspective of
the evaluation scores. Any areas of concern will quickly be noticeable
because the scores would not line up in the rightmost column (i.e.,
pass).

1.0 BENCH TEST 1-1

1.1 Logic 1-2

1.1.1 Waypoint Entry 1-2

1.1.2 Route Programming 1-4

1.1.3 Route Editing 1-6

1.1.4 Route Review 1-8

1.1.5 Route Reversal & Activation 1-10

1.1.6 Direct-To Navigation 1-12

1.1.7 Nearest Waypoint Function 1-14

1.2 Displays 1-16

1.2.1 Display Brightness & Contrast 1-16

1.2.2 Color Discrimination 1-18

1.2.3 Color Coding 1-20

1.2.4 Readability Of Alphanumerics 1-22

1.2.5 Moving Map Appearance 1-24

1.2.6 Quality Of Auditory Alarms \... 1-26

1.2.7 Synthetic & Natural Speech Alarms 1-28

1.2.8 Auditory Alarm Discrimination 1-30

1.2.9 Alert Deactivation 1-32

1.3 Controls 1-34

1.3.1 Knob & Button Physical Characteristics 1-34

1.3.2 Knob & Button Functional Characteristics 1-36

1.3.3 Keyboard Physical Characteristics 1-38

1.3.4 Keyboard Functional Characteristics 1-40

1.3.5 Color Coding 1-42

1.3.6 Shape/Size Coding 1-44

1.3.7 Labels 1-46

1.4 Bench Test Evaluation Summary 1-49

**1.1 LOGIC**

1.1.1 [Waypoint Entry]{.underline}

[Purpose]{.underline}:

> To determine the usability and resolution associated with single
> waypoint entry procedures.

[Test Procedure]{.underline}:

> Enter a waypoint for "direct-to" navigation using the following three
> methods:
>
> 1\. According to the Lat/Lon , resolution of 0.01 minutes **(2)**
>
> 2\. According to bearing & range from another waypoint with a
> resolution of 0.1 nm & 0.1 degree **(2)**
>
> 3\. According to waypoint identifier name

[Evaluation Considerations]{.underline}:

> A\) Resolution
>
> • Lat/Lon resolution of 0.01 minutes **(2)**
>
> • Bearing/range resolution of 0.1 nm & 0.1 degree **(2)**
>
> B\) Data Entry Procedures **(1, 3)**
>
> • Feedback during entry **(4)**
>
> • Programming steps simple & easy **(4)**
>
> • Confirmation of action prior to final entry or activation **(4)**
>
> C\) Display Information **(1, 3)**
>
> • Waypoint category information displayed
>
> • Prompts understandable **(6, 8)**
>
> • Ability to verify data entry **(4)**
>
> W\) Workload **(1, 3)**
>
> • Dependence on memory to complete task
>
> • Number of control inputs

If errors occurred, consider the following criteria:

> EM) Error Management **(3, 5)**
>
> • Ease of error identification **(7)**
>
> • Simple method of recovery **(4)**

1.1.1 [Waypoint Entry]{.underline}

**Evaluation**

  ------------- ------------------- ------------------- -------------------
                Fail                Pass with excptn    Pass

  A                                                     

  B                                                     

  C                                                     

  W                                                     

  EM                                                    
  ------------- ------------------- ------------------- -------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. R2), R2.1.7
>
> **(2)** (p. T7), T(a)(3)(ix)2.
>
> **Guidelines:**
>
> **(3)** (pp. F3-4), F1 7(b)(7) **(7)** (pp. M51-53), M2 4.3
>
> **(4)** (pp. M42-43), M2 1.0 **(8)** (p. M54), M2 4.4
>
> **(5)** (pp. M48-49), M2 3.5
>
> **(6)** (pp. M49-51), M2 4.0

**1.1 LOGIC**

1.1.2 [Route Programming]{.underline}

[Purpose]{.underline}:

> To determine the usability of route programming procedures.

[Test Procedure]{.underline}:

> 1\. Enter a 9 waypoint route (include at least 2 waypoints of each
> category: APT, VOR, NDB, & INT) **(2)**
>
> 2\. Store the route (**SAVE FOR LATER USE**)

[Evaluation Considerations]{.underline}:

> A\) Number of Waypoints
>
> • Route accepts a minimum of 9 waypoints **(2, 3)**
>
> B\) Data Entry Procedures **(1, 4)**
>
> • Feedback during entry **(5)**
>
> • Programming steps simple & easy **(3)**
>
> • Confirmation of action prior to final entry or activation **(5)**
>
> C\) Display Information **(1, 4)**
>
> • Waypoint category information displayed
>
> • Route legs identifiable
>
> • Route identifiable
>
> • Prompts understandable **(7, 9)**
>
> • Ability to verify data entry **(5)**
>
> W\) Workload **(1, 4)**
>
> • Dependence on memory to complete task
>
> • Amount of head-down time

If errors occurred, consider the following criteria:

> EM) Error Management **(4, 6)**
>
> • Ease of error identification **(8)**
>
> • Simple method of recovery **(6)**

1.1.2 [Route Programming]{.underline}

**Evaluation**

  ------------- ------------------- ------------------- -------------------
                Fail                Pass with excptn    Pass

  A                                                     

  B                                                     

  C                                                     

  W                                                     

  EM                                                    
  ------------- ------------------- ------------------- -------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. R2), R 2.1.7
>
> **(2)** (p. T8), T (a)(3)(x)(3)
>
> **(3)** (p. T19) T (a)(3)(xxii)
>
> **Guidelines:**
>
> **(4)** (pp. F3-4), F1 7(b)(7) **(7)** (pp. M49-51), M2 4.0
>
> **(5)** (pp. M42-43), M2 1.0 **(8)** (p. M51), M2 4.3.1
>
> **(6)** (pp. M48-49), M2 3.5 **(9)** (p. M54), M2 4.4

**1.1 LOGIC**

1.1.3 [Route Editing]{.underline}

[Purpose]{.underline}:

> To determine the usability of waypoint editing procedures.

[Test Procedure]{.underline}:

> Perform the following steps:
>
> 1\. Retrieve the 9 waypoint route that was created and stored in
> section 1.1.2
>
> 2\. Delete waypoints in positions 3 & 8 **(2)**
>
> 3\. Add a new waypoint between waypoints 4 & 5 **(2)**
>
> 4\. Change waypoints in positions 5 & 9 **(2)**
>
> 5\. Store new route (**SAVE FOR LATER USE**)

[Evaluation Considerations]{.underline}:

> A\) Data Entry **(1, 3)**
>
> • Feedback during entry **(4)**
>
> • Programming steps simple & easy **(4)**
>
> • Confirmation of action prior to final entry or activation **(4)**
>
> B\) Display Information **(1, 3)**
>
> • Waypoint to be edited clearly denoted **(2)**
>
> • Prompts understandable **(6, 8)**
>
> W\) Workload **(1, 3)**
>
> • Dependence on memory to complete task
>
> • Amount of head-down time

If errors occurred, consider the following criteria:

> EM) Error Management **(3, 5)**
>
> • Ease of error identification **(7)**
>
> • Simple method of recovery **(4)**

1.1.3 [Route Editing]{.underline}

**Evaluation**

  ------------- ------------------- ------------------- -------------------
                Fail                Pass with excptn    Pass

  A                                                     

  B                                                     

  W                                                     

  EM                                                    
  ------------- ------------------- ------------------- -------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. R2), R 2.1.7
>
> **(2)** (p. T19), T (a)(3)(xxii)
>
> **Guidelines:**
>
> **(3)** (pp. F3-4), F1 7(b)(7) **(6)** (pp. M49-51), M2 4.0
>
> **(4)** (pp. M42-44), M2 1.0 **(7)** (pp. M51-53), M2 4.3
>
> **(5)** (pp. M48-49), M2 3.5 **(8)** (p. M54), M2 4.4

**1.1 LOGIC**

1.1.4 [Route Review]{.underline}

[Purpose]{.underline}:

> To determine the usability of route retrieve and route review
> procedures.

[Test Procedure]{.underline}:

> Perform the following steps:
>
> 1\. Retrieve the 9 waypoint route that was created and stored in
> section 1.1.3
>
> 2\. Scroll through the waypoints & legs of the route **(2)**

[Evaluation Considerations]{.underline}:

> A\) Data Entry **(1, 2, 3)**
>
> • Route retrieval
>
> • Review of waypoints & legs
>
> B\) Display Information **(1, 3)**
>
> • Identification of active waypoint
>
> • Ability to preview next waypoint or leg (i.e., for activation)
>
> • Indication of active vs. inactive waypoints
>
> W\) Workload **(3)**
>
> • Dependence on memory to complete task
>
> • Amount of head-down time

1.1.4 [Route Review]{.underline}

Evaluation

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    

  W                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. R4), R 2.2.1.7
>
> **(2)** (p. T19), T (a)(3)(xxii)
>
> **Guidelines:**
>
> **(3)** (pp. F3-4), F1 7(b)(7)

**1.1 LOGIC**

1.1.5 [Route Reversal & Activation]{.underline}

[Purpose]{.underline}:

> To determine the usability of route reversal and route activation
> procedures.

[Test Procedure]{.underline}:

> Perform the following steps:
>
> 1\. Retrieve the 9 waypoint route that was created and stored in
> section 1.1.3
>
> 2\. Reverse the route (if possible)
>
> 3\. Activate the route

[Evaluation Considerations]{.underline}:

> A\) Data Entry **(2, 3)**
>
> • Route reversal function
>
> • Route activation
>
> • Ability to confirm route prior to route activation **(4)**
>
> B\) Display Information **(3)**
>
> • Distinction between "old" & "new" routes
>
> • Identification of active waypoint
>
> • Bearing to active waypoint
>
> • Distance to active waypoint
>
> • Display of CDI information
>
> W\) Workload **(1, 2, 3)**
>
> • Dependence on memory to complete task
>
> • Amount of head-down time

1.1.5 [Route Reversal & Activation]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    

  W                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. R2), R 2.1.4
>
> **(2)** (p. T2), T (a)(3)(i)
>
> **Guidelines:**
>
> **(3)** (pp. F3-4), F1 7(b)(7)
>
> **(4)** (p. M48), M2 3.5.7

**1.1 LOGIC**

1.1.6 [Direct-To Navigation]{.underline}

[Purpose]{.underline}:

> To determine the usability of the Direct-To function.

[Test Procedure]{.underline}:

> Perform the following steps:
>
> 1\. Enter a waypoint to navigate to
>
> 2\. Activate Direct-To function

[Evaluation Considerations]{.underline}:

> A\) Data Entry **(1, 3)**
>
> • Direct-To function activated with a **single** control action
> **(2)**
>
> • Waypoint entry
>
> • Ability to confirm waypoint prior to activation **(4)**
>
> B\) Display Information **(1, 3)**
>
> • Identification of active waypoint
>
> • Bearing to active waypoint
>
> • Distance to active waypoint
>
> • CDI information display
>
> W\) Workload **(3)**
>
> • Dependence on memory to complete task
>
> • Amount of head-down time

1.1.6 [Direct-To Function]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    

  W                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. R3), R 2.2.1.4
>
> **(2)** (p. T9), T (a)(3)(xi)(1)
>
> **Guidelines:**
>
> **(3)** (pp. F3-4), F1 7(b)(7)
>
> **(4)** (p. M48), M2 3.5.7

**1.1 LOGIC**

1.1.7 [Nearest Waypoint Function]{.underline}

[Purpose]{.underline}:

> To determine the usability of the nearest waypoint function.

[Test Procedure]{.underline}:

> Perform the following steps:
>
> 1\. Activate the nearest waypoint function and select a waypoint from
> each category (e.g., APT, VOR, NDB, & INT)

[Evaluation Considerations]{.underline}:

> A\) Data Entry **(1, 2, 3)**
>
> • Nearest waypoint activation function
>
> • Selectability of waypoints
>
> • Waypoint confirmation prior to activation **(4)**
>
> B\) Display Information **(3)**
>
> • Identification of active/selected waypoint
>
> • Identification of waypoint category
>
> • Critical information displayed (e.g., additional runways,
> communication frequencies, etc.)
>
> W\) Workload **(1, 2, 3)**
>
> • Dependence on memory to complete task
>
> • Amount of head-down time

1.1.7 [Nearest Waypoint Function]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    

  W                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. R2), R 2.1.4
>
> **(2)** (p. T2), T (a)(3)(i)
>
> **Guidelines:**
>
> **(3)** (pp. F3-4), F1 7(b)(7)
>
> **(4)** (p. M48), M2 3.5.7

**1.2 DISPLAYS**

1.2.1 [Display Brightness & Contrast]{.underline}

[Purpose]{.underline}:

> To evaluate display brightness and contrast under various ambient
> lighting conditions.

[Test Procedure]{.underline}: **(3, 4)**

> Examine the display information under the following conditions:
>
> 1\. Dark room (no lights, curtains closed)
>
> 2\. Room lighting & reflections (lights on, curtains open, observer
> facing window)
>
> 3\. Room lighting & a glare source (lights on, curtains open, and
> sunlight shining on display)

[Evaluation Considerations]{.underline}:

> A\) Brightness & Contrast Adjustments for: **(1, 2, 3, 4, 6, 8)**
>
> • Dark room
>
> • Lighting with reflections
>
> • Lighting with glare source
>
> B\) Automatic Brightness Control **(6, 8)**
>
> • Rapid changes when ambient light is increased
>
> • Slow changes when ambient light is decreased
>
> C\) Reflection Level **(3, 4, 5, 7, 9)**
>
> • No distraction
>
> • No interference with displayed information

1.2.1 [Display Brightness & Contrast]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    

  C                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. R8), R 3.1.2
>
> **(2)** (p. T2), T(a)(3)(iv)
>
> **Guidelines:**
>
> **(3)** (pp. F3-4), F1 7(b)(7) **(7)** (p. M8), M1 5.2.4.7
>
> **(4)** (p. F26), F2 6(b)(1) **(8)** (p. O12), O4 5.2.2
>
> **(5)** (p. M4), M1 5.2.1.4.4 **(9)** (p. O14), O4 5.2.6
>
> **(6)** (p. M8), M1 5.2.4.6

**1.2 DISPLAYS**

1.2.2 [Color Discrimination]{.underline}

[Purpose]{.underline}:

> To determine if colors on the display are discriminable.

[Test Procedure]{.underline}:

> If possible, simulate a flight along a route and scan through the
> pages of the route, waypoint, navigation, and system modes. Evaluate
> the differences between the colors used on the display.

[Evaluation Considerations]{.underline}:

> A\) Color Differences **(1)**
>
> • Colors appear different from each other (e.g., does yellow look
> different from green) **(4)**
>
> B\) Coding **(1)**
>
> • Small symbol discriminability
>
> • Small alphanumeric discriminability
>
> C\) Safety Critical Features **(1)**
>
> • Color coding discriminability (Note: Some older pilots report
> difficulty seeing blue- and magenta- coded features on displays) **(2,
> 3)**

1.2.2 [Color Discrimination]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    

  C                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **Guidelines:**
>
> **(1)** (pp. F18-25), F2 5
>
> **(2)** (p. M6), M1 5.2.2.1.18.f.
>
> **(3)** (p. M9), M1 5.2.6.8.7
>
> **(4)** (p. O14), O4 5.2.5

**1.2 DISPLAYS**

1.2.3 [Color Coding]{.underline}

[Purpose]{.underline}:

> To evaluate color coding on the display.

[Test Procedure]{.underline}:

Examine all screens and displays. Evaluate the color coding.

[Evaluation Considerations]{.underline}:

> A\) Color Coding
>
> • Application of color followed the established guidelines:
>
> **(1, 2, 3, 4, 8)**

  ----------------------------------------- -------------- -----------------------------
  ASSOCIATED INFORMATION                                   COLOR SET 1

  Warning or danger                                        Red

  Caution or abnormality                    Amber/Yellow   

  Fixed reference symbols                   White          

  Current data or values                    White          

  Armed modes                               White          

  Selected data or values                   Green          

  Selected heading                          Magenta        

  Active route/flight plan                  Magenta        
  ----------------------------------------- -------------- -----------------------------

> NOTE: In general, avoid the use of BLUE; Flashing RED can be used to
> denote an emergency/critical condition. Additional color use sets are
> shown in Section 5 (a) (3), pp. F2-3 of Appendix F2, and Sections 7.2,
> p. O15, and 7.3, p. O17 of Appendix O5.
>
> • Redundant coding of critical information **(6)**
>
> B\) Discriminability
>
> • Color discriminability under the full range of cockpit lighting
> conditions (e.g., Section 1.2.1) **(1, 3)**
>
> • 5 or fewer colors used **(7)**
>
> • Flashing lights used **(5)**

1.2.3 [Color Coding]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **Guidelines:**
>
> **(1)** (pp. F3-4), F1 7(b)(7) **(5)** (p. M6), M1 5.2.2.1.19
>
> **(2)** (pp. F18-19), F2 5(a)(2-3) **(6)** (p. O16), O5 7.1.2
>
> **(3)** (p. F26), F2 6(b)(1) **(7)** (p. O16), O5 7.1.3
>
> **(4)** (p. M5), M1 5.2.2.1.18 **(8)** (p. O16), O5 7.2

**1.2 DISPLAYS**

1.2.4 [Readability Of Alphanumerics]{.underline}

[Purpose]{.underline}:

To evaluate the readability of display characters.

[Test Procedure]{.underline}:

> View each screen or display. Read the display characters at a distance
> equal to the likely cockpit installation.

[Evaluation Considerations]{.underline}:

> A\) Character Identification **(1, 2, 4, 5)**
>
> • Characters embedded in text
>
> • Upper and lower case **(3)**
>
> B\) Coding
>
> • Small symbol discriminability
>
> • Small alphanumeric discriminability

1.2.4 [Readability Of Alphanumerics]{.underline}

Evaluation

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **Guidelines:**
>
> **(1)** (pp. F3-4), F1 7(b)(7) **(4)** (p. M8), M1 5.2.6.8.4
>
> **(2)** (p. F24), F2 5(e) **(5)** (p. O24), O7 4.2
>
> **(3)** (p. M9), M1 5.2.6.8.5

**1.2 DISPLAYS**

1.2.5 [Moving Map Appearance]{.underline}

[Purpose]{.underline}:

To evaluate the general appearance of moving map displays.

[Test Procedure]{.underline}:

> If possible, simulate a flight along a route and scan through the
> pages of route, waypoint, navigation, and system modes. Evaluate the
> appearance of the moving map display at a distance consistent with
> likely cockpit installation.

[Evaluation Considerations]{.underline}:

> A\) Readability **(1, 2, 3, 4, 6)**
>
> • Quick and easy interpretation
>
> • Short viewing duration required
>
> B\) Symbology **(2, 3, 5, 6)**
>
> • Distinction between overlapping symbols (e.g., own aircraft and
> in-bound course line)
>
> • Clear indication of 'own' position

-   Discriminability of symbols

> • Intuitive symbols
>
> • Distinction between symbols in close proximity
>
> C\) Mode Characteristics **(1, 2)**
>
> • Clear indication between track-up and north-up
>
> • Display of map scale
>
> D\) Map Motion **(1, 2)**
>
> • Distraction level
>
> • Shape integrity
>
> • Screen update/refresh rate

-   Alphanumeric readability **(6, 7)**

-   Symbol recognition

> E\) Potential Utility **(2)**
>
> • Useful for intended navigation purposes

1-24

1.2.5 [Moving Map Appearance]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    

  C                                                    

  D                                                    

  E                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. T2), T (a)(3)(i)
>
> **Guidelines:**
>
> **(2)** (pp. F3-4), F1 7(b)(7) **(6)** (p. M8), M1 5.2.6.8.4
>
> **(3)** (pp. F27-28), F2 6(b)(4) **(7)** (p. M9), M1 5.2.6.8.5
>
> **(4)** (p. M7), M1 5.2.4.2
>
> **(5)** (p. M8), M1 5.2.6.8.3

**1.2 DISPLAYS**

1.2.6 [Quality Of Auditory Alarms]{.underline}

[Purpose]{.underline}:

To evaluate the quality of auditory alarms.

[Test Procedure]{.underline}:

> Activate all possible auditory alarms. Pay attention to the quality of
> the alarms.

[Evaluation Considerations]{.underline}:

> A\) Audibility **(5)**
>
> • Loudness
>
> • Pitch
>
> • Duration
>
> B\) Distraction Level **(1, 2, 3, 4)**
>
> • Loudness
>
> • Pitch
>
> • Duration

1.2.6 [Quality Of Auditory Alarms]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **Guidelines:**
>
> **(1)** (p. M10), M1 5.3.3.2.2.3 **(5)** (p. O28), O8 c
>
> **(2)** (p. O2), O1 c
>
> **(3)** (p. O2), O1 d
>
> **(4)** (p. O28), O8 a

**1.2 DISPLAYS**

1.2.7 [Synthetic & Natural Speech Alarms]{.underline}

[Purpose]{.underline}:

> To evaluate the quality of synthetic and natural speech displays.

[Test Procedure]{.underline}:

> Activate all possible speech alarms. Pay attention to the quality of
> speech.

[Evaluation Considerations]{.underline}:

> A\) Audibility **(1, 4)**
>
> B\) Duration **(1, 4)**
>
> • Short duration
>
> • Non-distracting
>
> C\) Speech Rate **(1, 4)**
>
> D\) Accent/Dialect **(1, 4)**
>
> E\) Message Content Intelligibility **(1, 2, 3, 4)**

F\) Ability to Distinguish from Controllers **(1, 4)**

1.2.7 [Synthetic & Natural Speech Alarms]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    

  C                                                    

  D                                                    

  E                                                    

  F                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **Guidelines:**
>
> **(1)** (p. M12), M1 5.3.5.3.1
>
> **(2)** (pp. M13-14), M1 5.3.12
>
> **(3)** (p. O3), O1 (e-f)
>
> **(4)** (p. O3), O1 h

**1.2 DISPLAYS**

1.2.8 [Auditory Alarm Discrimination]{.underline}

[Purpose]{.underline}:

To evaluate the ability to discriminate between alarms.

[Test Procedure]{.underline}:

> Activate all possible auditory alarms. Pay attention to alarm
> discriminability.

[Evaluation Considerations]{.underline}:

> A\) Alarm Discriminability **(1, 2, 3, 4)**
>
> • Pitch
>
> • Loudness
>
> • Type or pattern (e.g., steady tone vs. synthetic speech)
>
> B\) Discriminability Between Critical and Non-Critical Alarms **(1, 2,
> 3)**
>
> • Loudness
>
> • Pitch
>
> • Duration or pattern (several short tones vs. one long tone)
>
> • Message (e.g., \"Critical-airspace violation\" alert)

1.2.8 [Auditory Alarm Discrimination]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **Guidelines:**
>
> **(1)** (p. M9), M1 5.3.2.3

**(2)** (pp. M11-12), M1 5.3.4.3

**(3)** (p. M12), M1 5.3.4.5

**(4)** (p. O2), O1 b

**1.2 DISPLAYS**

1.2.9 [Alert Deactivation]{.underline}

[Purpose]{.underline}:

To evaluate the alert deactivation procedures.

[Test Procedure]{.underline}:

> Activate and deactivate all possible alerts.

[Evaluation Considerations]{.underline}:

> A\) Pilot Controllability of Deactivation **(1, 2, 5, 6)**
>
> • Alerts easily deactivated
>
> B\) Memory Requirements **(1, 2, 3)**
>
> • Alert status indicated redundantly (e.g., display text, light)
>
> • Additional warnings if problem not corrected when alert has been
> deactivated **(4, 5)**
>
> • Low distraction caused by reoccurring alert **(4, 5)**

1.2.9 [Alert Deactivation]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. R2), R 2.1.7
>
> **(2)** (p. T2), T (a)(3)(i)
>
> **Guidelines:**
>
> **(3)** (pp. F3-4), F1 7(b)(7)
>
> **(4)** (p. M12), M1 5.3.4.5.1
>
> **(5)** (p. M13), M1 5.3.5.6.1
>
> **(6)** (p. M13), M1 5.3.6.1

**1.3 CONTROLS**

1.3.1 [Knob & Button Physical Characteristics]{.underline}

[Purpose]{.underline}:

> To determine if all knobs and buttons are easy to locate, reach, and
> activate with a minimum of operating errors.

[Test Procedure]{.underline}:

> Operate all knobs and buttons according to the intended use.

[Evaluation Considerations]{.underline}:

> A\) Accessibility **(4, 5, 9)**
>
> • Require single hand for operations **(2)**
>
> • Reach distances acceptable
>
> • Identifiable
>
> • Use does not obscure display
>
> • High frequency use or emergency knobs/buttons are easily accessible
> **(8)**
>
> B\) Activation **(1, 4, 9)**
>
> • Force required to activate knobs/buttons
>
> • Feedback adequate
>
> • Minimal risk of inadvertent activation or
>
> deactivation **(3, 6, 7)**

1.3.1 [Knob & Button Physical Characteristics]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. R2), R 2.1.4 **(4)** (p. T2), T (a)(3)(i)
>
> **(2)** (p. R2), R 2.1.7 **(5)** (p. T2), T (a)(3)(ii)
>
> **(3)** (p. R8), R 3.1.4
>
> **Guidelines:**
>
> **(6)** (pp. F3-4), F1 7(b)(7)
>
> **(7)** (pp. M20-21), M1 5.4.1.8
>
> **(8)** (p. M14), M1 5.4.1.3.3
>
> **(9)** (pp. M21-27), M1 5.4.2

**1.3 CONTROLS**

1.3.2 [Knob & Button Functional Characteristics]{.underline}

[Purpose]{.underline}:

> To determine if knobs and buttons are functionally easy to operate.

[Test Procedure]{.underline}:

> Operate all knobs and buttons according to the intended use.

[Evaluation Considerations]{.underline}:

> A\) Arrangement **(3, 4, 5, 6, 7, 11)**
>
> • Logical arrangement according to functional groups
>
> • Logical arrangement according to sequence of use **(8)**
>
> • Logical arrangement according to frequency of use **(9)**
>
> B\) Operations **(1, 2, 3, 4, 5, 6)**
>
> • Usability
>
> • Logical functioning (knobs turned clockwise
>
> increase value) **(10)**

-   Minimal chance of error

-   Easy error recovery

1.3.2 [Knob & Button Functional Characteristics]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. R2), R 2.1.4 **(4)** (p. T2), T (a)(3)(ii)
>
> **(2)** (p. R2), R 2.1.7 **(5)** (p. T2), T (a)(3)(iv)
>
> **(3)** (p. T2), T (a)(3)(i)
>
> **Guidelines:**
>
> **(6)** (pp. F3-4), F1 7(b)(7) **(10)** (p. M14), M1 5.4.1.2.1
>
> **(7)** (p. M2), M1 5.1.2.1 **(11)** (p. M14), M1 5.4.1.3.1
>
> **(8)** (p. M2), M1 5.1.2.1.1
>
> **(9)** (p. M2), M1 5.1.2.1.1.2

**1.3 CONTROLS**

1.3.3 [Keyboard Physical Characteristics]{.underline}

[Purpose]{.underline}:

> To determine if the keyboard is easy to locate, reach, and activate
> with a minimum of operating errors.

[Test Procedure]{.underline}:

> Operate each key of the keyboard according to the intended use.

[Evaluation Considerations]{.underline}:

> A\) Accessibility **(4, 5, 6, 7, 10)**
>
> • Require single hand for operations **(2)**
>
> • Reach distances acceptable
>
> • Keys easily identified
>
> • Use of keys does not obscure display
>
> B\) Activation **(4, 10)**
>
> • Force required to activate key is acceptable **(1)**
>
> • Clear feedback provided when key activated (e.g., tactile and
> audible feedback combined with change in display) **(11)**
>
> • Minimal risk of inadvertent activation or
>
> deactivation **(1, 3, 7, 8, 9)**

Dimension guidelines if keyboard appears difficult to use: **(10)**

+------------------------------------------+-------------+-------------+
| **DIMENSION**                            | **MINIMUM** |             |
|                                          |             |             |
|                                          | (inches)    |             |
|                                          | (mm)        |             |
+------------------------------------------+-------------+-------------+
| Height/Width                             | 0.385       | 10.0        |
+------------------------------------------+-------------+-------------+
| Displacement                             | 0.05        | 1.3         |
+------------------------------------------+-------------+-------------+
| Horizontal Spacing                       | 0.25        | 6.0         |
|                                          |             |             |
| (edge-to-edge)                           |             |             |
+------------------------------------------+-------------+-------------+
| Vertical Spacing                         | 0.25        | 6.0         |
|                                          |             |             |
| (edge-to-edge)                           |             |             |
+------------------------------------------+-------------+-------------+

1.3.3 [Keyboard Physical Characteristics]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. R2), R 2.1.4 **(4)** (p. T2), T (a)(3)(i)
>
> **(2)** (p. R2), R 2.1.7 **(5)** (p. T2), T (a)(3)(ii)
>
> **(3)** (p. R8), R 3.1.4 **(6)** (p. T2), T (a)(3)(iv)
>
> **Guidelines:**
>
> **(7)** (pp. F3-4), F1 7(b)(7) **(10)** (pp. M28-33), M1
>
> 5.4.3.1.3 **(11)** (p. M33), M1 5.4.3.1.3.6
>
> **(8)** (pp. M20-21), M1 5.4.1.8
>
> **(9)** (p. M27), M1 5.4.2.2.2.6

**1.3 CONTROLS**

1.3.4 [Keyboard Functional Characteristics]{.underline}

[Purpose]{.underline}:

> To determine if keyboards are functionally easy to operate.

[Test Procedure]{.underline}:

> Operate keyboard according to the intended use.

[Evaluation Considerations]{.underline}:

> A\) Arrangement **(4, 5, 6, 7)**
>
> • Numeric keys arranged in a 3 x 3 + 1 matrix with zero digit centered
> on bottom row
>
> • Alphabetic keys arranged in groups of 3 superimposed on numeric keys
> in telephone keypad layout
>
> (e.g., 2 + ABC, 3 + DEF, etc.)
>
> B\) Operations **(4, 6)**
>
> • Key-press enters letter or character associated with label on key
>
> • Clear, Backup, or Delete key to correct or reverse keyed input **(8,
> 9, 10, 11)**

1.3.4 [Keyboard Functional Characteristics]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. T2), T (a)(3)(ii)
>
> **(2)** (p. T2), T (a)(3)(iv)
>
> **Guidelines:**

**(3)** (pp. F3-4), F1 7(b)(7) **(7)** (p. M49), M2 3.5.10

**(4)** (pp. M28-33), M1 5.4.3.1.3 **(8)** (p. M49), M2 3.5.13

**(5)** (p. M42), M2 1.0.11

**(6)** (p. M46), M2 1.3.33

**1.3 CONTROLS**

1.3.5 [Color Coding]{.underline}

[Purpose]{.underline}:

> To determine if color coding is designed to support usability.

[Test Procedure]{.underline}:

> Examine the colors used to code all controls.

[Evaluation Considerations]{.underline}:

> A\) General Use **(1, 3, 4)**
>
> • Colors used only when necessary to distinguish controls **(2)**
>
> • Redundant coding of critical information **(4)**
>
> B\) Color Use **(1, 3, 4)**
>
> • Colors discriminable under full range of cockpit lighting conditions
>
> • Minimize the number of colors used **(5)**
>
> • Application should follow established conventions (e.g., RED for
> critical, emergency-specific controls)

1.3.5 [Color Coding]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. T2), T (a)(3)(iv)
>
> **Guidelines:**
>
> **(2)** (p. M15), M1 5.4.1.4.1
>
> **(3)** (p. M19-20), M1 5.4.1.4.5
>
> **(4)** (p. O16), O5 7.1.2
>
> **(5)** (p. O16), O5 7.1.3

**1.3 CONTROLS**

1.3.6 [Shape/Size Coding]{.underline}

[Purpose]{.underline}:

> To determine if shape/size coding is designed to support usability.

[Test Procedure]{.underline}:

> Examine the shapes/sizes used to code all controls.

[Evaluation Considerations]{.underline}:

> A\) Knob Shape **(1, 2, 3, 4, 6)**
>
> • Aids pilot use

-   Does not interfere with use

-   Discriminability

> B\) Knob Size **(2, 3, 4)**

-   Easy to distinguish between different sizes tactually and visually
    (minimum difference = 0.5 inches/10.0 nm) **(5)**

> • Aids pilot use

-   Does not interfere with use

1.3.6 [Shape/Size Coding]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. R2), R 2.1.4
>
> **(2)** (p. T2), T (a)(3)(iv)
>
> **Guidelines:**
>
> **(3)** (pp. F3-4), F1 7(b)(7)
>
> **(4)** (p. M15), M1 5.4.1.4.1
>
> **(5)** (p. M15), M1 5.4.1.4.3

**(6)** (p. M18), M1 5.4.1.4.4

**1.3 CONTROLS**

1.3.7 [Labels]{.underline}

[Purpose]{.underline}:

> To determine if labeling facilitates usability.

[Test Procedure]{.underline}:

> Examine each label.

[Evaluation Considerations]{.underline}:

> A\) Construction **(1, 2, 3)**
>
> • Printed in capital letters without punctuation **(11)**
>
> • Printed in black on light background **(10)**
>
> Guidelines for label dimensions: **(12, 13, 14, 15, 16)**

+------------------------------------------+-------------+-------------+
| **DIMENSION**                            | **MINIMUM** |             |
|                                          |             |             |
|                                          | (Inches)    |             |
|                                          | (mm)        |             |
+------------------------------------------+-------------+-------------+
| Character Height                         | 0.18        | 4.7         |
+------------------------------------------+-------------+-------------+
| Character Width                          | 0.108       | 2.8         |
+------------------------------------------+-------------+-------------+
| Character Stroke Width                   | 0.02        | 0.7         |
+------------------------------------------+-------------+-------------+
| Space Between Characters                 | 1 stroke    |             |
|                                          | width       |             |
+------------------------------------------+-------------+-------------+
| Space Between Words                      | 1 character |             |
|                                          | width       |             |
+------------------------------------------+-------------+-------------+
| Space Between Lines                      | 0.09        | 2.35        |
+------------------------------------------+-------------+-------------+

> B\) Label Placement **(1, 2, 3, 4)**
>
> • Horizontal orientation from left-to-right **(5)**
>
> • Location on or adjacent to controls they identify **(6)**
>
> • Readable under all lighting conditions (see Section 1.2.1)
>
> • Consistent placement across panel **(7)**
>
> • Unobstructed by controls (e.g., knobs, keys, etc.) **(6)**
>
> • Unobstructed during control use (e.g., hands, arms, etc.) **(6)**
>
> C\) Terminology **(1, 2, 3)**
>
> • Familiar and meaningful words/symbols **(9)**
>
> • Labels describe function of knob or button

-   Consistency across receiver **(7)**

> • Abbreviations and acronyms conform to aviation usage **(8)**
>
> • Words of 4 letters or less spelled out

1.3.7 [Labels]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    

  C                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. T2), T (a)(3)(i)
>
> **(2)** (p. T2), T (a)(3)(ii)
>
> **(3)** (p. T2), T (a)(3)(iv)
>
> **Guidelines:**
>
> **(4)** (pp. F3-4), F1 7(b)(7) **(11)** (p. M37), M1 5.5.5.4.1
>
> **(5)** (p. M36), M1 5.5.2.1 **(12)** (p. M38), M1 5.5.5.6
>
> **(6)** (p. M36), M1 5.5.2.2 **(13)** (p. M38), M1 5.5.5.8
>
> **(7)** (p. M36), M1 5.5.2.3 **(14)** (p. M38), M1 5.5.5.11
>
> **(8)** (p. M37), M1 5.5.3.2 **(15)** (p. M38), M1 5.5.5.12
>
> **(9)** (p. M37), M1 5.5.4.2 **(16)** (p. M38), M1 5.5.5.13
>
> **(10)** (p. M37), M1 5.5.5.1

**1.4 BENCH TEST EVALUATION SUMMARY**

+----------------+---------------------+------+-----+---------+------+
| *              | **Checklist**       |      | **  | **Pass  | **Pa |
| *Requirement** |                     |      | Fai | with    | ss** |
|                |                     |      | l** | e       |      |
|                |                     |      |     | xcptn** |      |
+----------------+---------------------+------+-----+---------+------+
| **Title**      | **Title**           | **P  |     |         |      |
|                |                     | g.** |     |         |      |
+----------------+---------------------+------+-----+---------+------+
| Accessibility  | Knob & Button       | 1-34 |     |         |      |
| of Controls    |                     |      |     |         |      |
|                | Physical Char.      | 1-36 |     |         |      |
|                |                     |      |     |         |      |
|                | Knob & Button       | 1-38 |     |         |      |
|                |                     |      |     |         |      |
|                | Functional Char.    | 1-40 |     |         |      |
|                |                     |      |     |         |      |
|                | Keyboard            | 1-42 |     |         |      |
|                |                     |      |     |         |      |
|                | Physical Char.      | 1-44 |     |         |      |
|                |                     |      |     |         |      |
|                | Keyboard            | 1-46 |     |         |      |
|                |                     |      |     |         |      |
|                | Functional Char.    |      |     |         |      |
|                |                     |      |     |         |      |
|                | Color Coding        |      |     |         |      |
|                |                     |      |     |         |      |
|                | Shape/Size Coding   |      |     |         |      |
|                |                     |      |     |         |      |
|                | Labels              |      |     |         |      |
+----------------+---------------------+------+-----+---------+------+
| Control/       | Waypoint Entry      | 1-2  |     |         |      |
| Display        |                     |      |     |         |      |
|                | Route               | 1-4  |     |         |      |
| Capability     |                     |      |     |         |      |
|                | Programming         | 1-6  |     |         |      |
|                |                     |      |     |         |      |
|                | Route Editing       | 1-18 |     |         |      |
|                |                     |      |     |         |      |
|                | Color               | 1-20 |     |         |      |
|                |                     |      |     |         |      |
|                | Discrimination      | 1-22 |     |         |      |
|                |                     |      |     |         |      |
|                | Color Coding        | 1-24 |     |         |      |
|                |                     |      |     |         |      |
|                | Readability of      | 1-26 |     |         |      |
|                |                     |      |     |         |      |
|                | Alphanumerics       | 1-28 |     |         |      |
|                |                     |      |     |         |      |
|                | Moving Map          | 1-30 |     |         |      |
|                |                     |      |     |         |      |
|                | Appearance          | 1-32 |     |         |      |
|                |                     |      |     |         |      |
|                | Quality of          | 1-34 |     |         |      |
|                |                     |      |     |         |      |
|                | Auditory Alarms     | 1-36 |     |         |      |
|                |                     |      |     |         |      |
|                | Synthetic &         |      |     |         |      |
|                |                     |      |     |         |      |
|                | Natural Speech      |      |     |         |      |
|                |                     |      |     |         |      |
|                | Auditory Alarm      |      |     |         |      |
|                |                     |      |     |         |      |
|                | Discrimination      |      |     |         |      |
|                |                     |      |     |         |      |
|                | Alert Deactivation  |      |     |         |      |
|                |                     |      |     |         |      |
|                | Knob & Button       |      |     |         |      |
|                |                     |      |     |         |      |
|                | Physical Char.      |      |     |         |      |
|                |                     |      |     |         |      |
|                | Knob & Button       |      |     |         |      |
|                |                     |      |     |         |      |
|                | Functional Char.    |      |     |         |      |
+----------------+---------------------+------+-----+---------+------+

**1.4 BENCH TEST EVALUATION SUMMARY (Continued)**

+----------------+---------------------+------+-----+---------+------+
| *              | **Checklist**       |      | **  | **Pass  | **Pa |
| *Requirement** |                     |      | Fai | with    | ss** |
|                |                     |      | l** | e       |      |
|                |                     |      |     | xcptn** |      |
+----------------+---------------------+------+-----+---------+------+
| **Title**      | **Title**           | **P  |     |         |      |
|                |                     | g.** |     |         |      |
+----------------+---------------------+------+-----+---------+------+
| Control/       | Keyboard            | 1-38 |     |         |      |
| Display        |                     |      |     |         |      |
| Capability     | Physical Char.      | 1-40 |     |         |      |
|                |                     |      |     |         |      |
| (continued)    | Keyboard            | 1-42 |     |         |      |
|                |                     |      |     |         |      |
|                | Functional Char.    | 1-44 |     |         |      |
|                |                     |      |     |         |      |
|                | Color Coding        | 1-46 |     |         |      |
|                |                     |      |     |         |      |
|                | Shape/Size Coding   |      |     |         |      |
|                |                     |      |     |         |      |
|                | Labels              |      |     |         |      |
+----------------+---------------------+------+-----+---------+------+
| Control/       | Display Brightness  | 1-16 |     |         |      |
| Display        |                     |      |     |         |      |
|                | Knob & Button       | 1-34 |     |         |      |
| Readability    |                     |      |     |         |      |
|                | Physical Char.      | 1-36 |     |         |      |
|                |                     |      |     |         |      |
|                | Knob & Button       | 1-38 |     |         |      |
|                |                     |      |     |         |      |
|                | Functional Char.    | 1-40 |     |         |      |
|                |                     |      |     |         |      |
|                | Keyboard            | 1-42 |     |         |      |
|                |                     |      |     |         |      |
|                | Physical Char.      | 1-44 |     |         |      |
|                |                     |      |     |         |      |
|                | Keyboard            | 1-46 |     |         |      |
|                |                     |      |     |         |      |
|                | Functional Char.    |      |     |         |      |
|                |                     |      |     |         |      |
|                | Color Coding        |      |     |         |      |
|                |                     |      |     |         |      |
|                | Shape/Size Coding   |      |     |         |      |
|                |                     |      |     |         |      |
|                | Labels              |      |     |         |      |
+----------------+---------------------+------+-----+---------+------+
| Display        | Display Brightness  | 1-16 |     |         |      |
| Visibility     |                     |      |     |         |      |
+----------------+---------------------+------+-----+---------+------+
| Flight Path    | Direct-To           | 1-12 |     |         |      |
|                |                     |      |     |         |      |
| Selection      | Navigation          |      |     |         |      |
+----------------+---------------------+------+-----+---------+------+
| Flight Path    | Route               | 1-4  |     |         |      |
| Capability     |                     |      |     |         |      |
|                | Programming         | 1-6  |     |         |      |
|                |                     |      |     |         |      |
|                | Route Editing       | 1-8  |     |         |      |
|                |                     |      |     |         |      |
|                | Route Review        |      |     |         |      |
+----------------+---------------------+------+-----+---------+------+
| Inadvertent    | Knob & Button       | 1-34 |     |         |      |
| Turnoff        |                     |      |     |         |      |
|                | Physical Char.      | 1-38 |     |         |      |
|                |                     |      |     |         |      |
|                | Keyboard            |      |     |         |      |
|                |                     |      |     |         |      |
|                | Physical Char.      |      |     |         |      |
+----------------+---------------------+------+-----+---------+------+

**1.4 BENCH TEST EVALUATION SUMMARY (Continued)**

+----------------+---------------------+------+-----+---------+------+
| *              | **Checklist**       |      | **  | **Pass  | **Pa |
| *Requirement** |                     |      | Fai | with    | ss** |
|                |                     |      | l** | e       |      |
|                |                     |      |     | xcptn** |      |
+----------------+---------------------+------+-----+---------+------+
| **Title**      | **Title**           | **P  |     |         |      |
|                |                     | g.** |     |         |      |
+----------------+---------------------+------+-----+---------+------+
| Operation of   | Route Reversal      | 1-10 |     |         |      |
|                |                     |      |     |         |      |
| Controls       | Nearest Waypoint    | 1-14 |     |         |      |
|                |                     |      |     |         |      |
|                | Color               | 1-18 |     |         |      |
|                |                     |      |     |         |      |
|                | Discrimination      | 1-20 |     |         |      |
|                |                     |      |     |         |      |
|                | Color Coding        | 1-22 |     |         |      |
|                |                     |      |     |         |      |
|                | Readability of      | 1-24 |     |         |      |
|                |                     |      |     |         |      |
|                | Alphanumerics       | 1-26 |     |         |      |
|                |                     |      |     |         |      |
|                | Moving Map          | 1-28 |     |         |      |
|                |                     |      |     |         |      |
|                | Appearance          | 1-30 |     |         |      |
|                |                     |      |     |         |      |
|                | Quality of          | 1-32 |     |         |      |
|                |                     |      |     |         |      |
|                | Auditory Alarms     | 1-34 |     |         |      |
|                |                     |      |     |         |      |
|                | Synthetic &         | 1-36 |     |         |      |
|                |                     |      |     |         |      |
|                | Natural Speech      | 1-38 |     |         |      |
|                |                     |      |     |         |      |
|                | Auditory Alarm      | 1-40 |     |         |      |
|                |                     |      |     |         |      |
|                | Discrimination      | 1-46 |     |         |      |
|                |                     |      |     |         |      |
|                | Alert Deactivation  |      |     |         |      |
|                |                     |      |     |         |      |
|                | Knob & Button       |      |     |         |      |
|                |                     |      |     |         |      |
|                | Physical Char.      |      |     |         |      |
|                |                     |      |     |         |      |
|                | Knob & Button       |      |     |         |      |
|                |                     |      |     |         |      |
|                | Functional Char.    |      |     |         |      |
|                |                     |      |     |         |      |
|                | Keyboard            |      |     |         |      |
|                |                     |      |     |         |      |
|                | Physical Char.      |      |     |         |      |
|                |                     |      |     |         |      |
|                | Keyboard            |      |     |         |      |
|                |                     |      |     |         |      |
|                | Functional Char.    |      |     |         |      |
|                |                     |      |     |         |      |
|                | Labels              |      |     |         |      |
+----------------+---------------------+------+-----+---------+------+
| Waypoint       | Waypoint Entry      | 1-2  |     |         |      |
|                |                     |      |     |         |      |
| Entry          |                     |      |     |         |      |
+----------------+---------------------+------+-----+---------+------+
| Waypoint       | Route Review        | 1-8  |     |         |      |
|                |                     |      |     |         |      |
| or             | Direct-To           | 1-12 |     |         |      |
|                |                     |      |     |         |      |
| Leg Sequencing | Navigation          | 1-18 |     |         |      |
|                |                     |      |     |         |      |
|                | Color               |      |     |         |      |
|                |                     |      |     |         |      |
|                | Discrimination      |      |     |         |      |
+----------------+---------------------+------+-----+---------+------+
| Waypoint       | Route               | 1-4  |     |         |      |
| Storage        |                     |      |     |         |      |
|                | Programming         |      |     |         |      |
+----------------+---------------------+------+-----+---------+------+

**1.4 BENCH TEST EVALUATION SUMMARY (Continued)**

  --------------------------------------- ---------- ------------- ----------
  **Checklist**                           **Fail**   **Pass with   **Pass**
                                                     excptn**      

  **OVERALL RATING**                                               
  --------------------------------------- ---------- ------------- ----------

  -----------------------------------------------------------------------
  **OVERALL COMMENTS:**

  -----------------------------------------------------------------------

2.0 FLIGHT TEST 2-1

2.1 Pre-Departure 2-2

2.1.1 Electromagnetic Compatibility 2-2

2.1.2 Types of Alarms & Alerts 2-4

2.1.3 Flight Plan Entry & RAIM Check 2-6

2.2 En Route 2-8

2.2.1 Flight Plan Review & Modification 2-8

2.2.2 Tracking Accuracy 2-10

2.2.3 Waypoint Sequencing & Turn Anticipation 2-12

2.2.4 Display Quality Evaluation 2-14

2.3 Transition 2-16

2.3.1 Approach Transition 2-16

2.4 Approach 2-18

2.4.1 Non Precision Approach With A Procedure

Turn 2-18

2.5 Missed Approach 2-20

2.5.1 Missed Approach With Course Reversal

Back To The FAF 2-20

2.5.2 Missed Approach With A Heading To

Intercept A Bearing To A Waypoint 2-22

2.6 Autopilot 2-24

2.6.1 Autopilot Integration With GPS Receiver 2-24

2.7 GPS Accuracy 2-26

2.7.1 Verification Of GPS Accuracy 2-26

2.8 Moving Maps 2-28

2.8.1 Moving Map Appearance 2-28

2.9 Alarms & Alerts 2-30

2.9.1 Discriminating Alerts 2-30

2.9.2 Auditory Quality Of Alerts 2-32

2.10 Flight Test Evaluation Summary 2-35

**2.1 PRE-DEPARTURE**

2.2.1 [Electromagnetic Compatibility]{.underline}

[Purpose:]{.underline}

> Determine use of selective radio frequencies on GPS operations. Note:
> Reevaluation of installed VHF transceiver performance is not necessary
> if the filter insertion loss is 2 dB or less.

[Test Procedure]{.underline}:

> Fly direct to a waypoint:
>
> 1\. While en route, tune each of the following frequencies for at
> least 20 seconds & activate mike repeatedly (Note: coordinate with ATC
> if local frequencies) **(1)**:
>
> 121.125 Mhz 131.200 MHz
>
> 121.150 MHz 131.225 MHz
>
> 121.175 MHz 131.250 MHz
>
> 121.200 MHz 131.275 MHz
>
> 121.225 MHz 131.300 MHz
>
> 121.250 Mhz 131.325 MHz
>
> 131.350 MHz

[Evaluation Considerations]{.underline}:

> A\) Influence on: **(2, 3)**
>
> CDI indication
>
> Display quality
>
> Digital cross track error
>
> Distance to waypoint
>
> Alerts and warnings
>
> B\) Influence on satellite HDOP value Sat **(2, 3)**

2.1.1 [Electromagnetic Compatibility]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. F32), F3 (f)
>
> **Guidelines:**

**(2)** (p. F6), F1 7(c)(iv)(C)

**(3)** (p. F9), F1 8(b)(6)

**2.1 PRE-DEPARTURE**

2.1.2 [Types Of Alarms & Alerts]{.underline}

[Purpose]{.underline}:

To ensure that alarms & alerts activate appropriately. **(1)**

[Evaluation Considerations]{.underline}:

> Each of the following alarms & alerts shall be "timely" (shall take
> place within the specified time to alarm for the phase of flight in
> progress) and shall be as follows:
>
> A\) A navigation warning flag shall be displayed on the navigation
> display in the following cases: **(2, 3)**
>
> • The absence of power required for the navigation function
>
> • Loss of navigation function
>
> • Inadequate or invalid navigation data in the approach mode detected
> in accordance with RTCA- DO- 208
>
> • The loss of the RAIM detection function in the approach mode at the
> final approach fix.
>
> • Loss of the RAIM detection function in the approach mode, after
> passing the final approach fix. (Only if the RAIM detection function
> is lost for more than 5 minutes.)
>
> B\) RAIM alerts **(1, 2, 3)**
>
> • When RAIM is not available, inadequate navigation data due to poor
> space vehicle geometry such that the probability that navigation error
> exceeds the position integrity performance requirements in RTCA/DO-208
> is greater than or equal to 0.5
>
> • The RAIM function detects a position error that exceeds the GPS
> position integrity performance requirements in RTCA/DO-208
>
> • Loss of the RAIM function
>
> • Predicted unavailability of the RAIM detection function
>
> • When operating in the approach mode without RAIM and navigation
> performance is degraded because HDOP exceeds 4.0

2.1.2 [Types Of Alarms & Alerts]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (pp. T12-17), T (a)(3)(xiii)
>
> **Guidelines:**
>
> **(2)** (p. F4), F1 7(b)(8)
>
> **(3)** (p. F12), F1 8(c)(1)(iv)(B)

**2.1 PRE-DEPARTURE**

2.1.3 [Flight Plan Entry & RAIM Check]{.underline}

[Purpose]{.underline}:

> To evaluate procedures required for flight plan entry & RAIM check.

[Test Procedure]{.underline}:

> While on ground:
>
> 1\. Enter a 9 waypoint flight plan **(4, 6, 8)**
>
> 2\. Conduct RAIM check for ETA **(5)**

[Evaluation Considerations]{.underline}:

> A\) Control easy to access and identify **(7)**

• Reach distance

• Identification of controls and control operation

• Visibility of displays when using controls

> B\) Control use sequence requires minimal reliance on memory &
> promotes error free operation **(1, 2, 3, 6, 7)**

• Number and combination of controls used

• Number of control actions required

• Probability of data entry errors

• Ease of error detection

• Ease of error recovery

• Pilot knowledge of what to do next

C\) Display output **(6, 7)**

• Readability with acceptable change in body position **(3)**

• Messages understandable

2.1.3 [Flight Plan Entry & RAIM Check]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    

  C                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. R2), R 2.1.4 **(4)** (p. T8), T (a)(3)(x)(3)
>
> **(2)** (p. T2), T (a)(3)(i) **(5)** (p. T19), T (a)(3)(xv)3.b
>
> **(3)** (p. T2), T (a)(3)(iv) **(6)** (p. T22), T (a)(3)(xxii)
>
> **Guidelines:**
>
> **(7)** (pp. F3-4), F1 7(b)(7)
>
> **(8)** (p. F12), F1 8(c)(1)(iv)(A)

**2.2 EN ROUTE**

2.2.1 [Flight Plan Review & Modification]{.underline}

[Purpose]{.underline}:

> Evaluate ease of reviewing and modifying a flight plan while in
> flight.

[Test Procedure]{.underline}:

> Fly several consecutive legs in the flight plan. While flying to a
> waypoint in the flight plan:

1\. Review legs or segments of the flight plan **(8)**

2\. Obtain distance, bearing & name of the active waypoint **(8)**

3\. Change two consecutive intermediate waypoints **(8)**

[Evaluation Considerations]{.underline}:

> A\) Operation of waypoint sequencing **(6)**
>
> B\) Accessibility of flight critical information
>
> C\) Display readability **(4, 5, 7)**
>
> D\) Ease of locating waypoints in database **(1, 2, 4, 7)**
>
> E\) Clarity of waypoint categories
>
> W\) Workload: **(7)**
>
> • Adequate situational awareness
>
> • Minimal mental effort
>
> • Minimal number of control actions

2.2.1 [Flight Plan Review & Modification]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    

  C                                                    

  D                                                    

  E                                                    

  W                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. R2), R 2.1.4 **(4)** (p. T2), T (a)(3)(iv)
>
> **(2)** (p. R2), R 2.1.5 **(5)** (p. F32), F3 (h)
>
> **(3)** (p. T2), T (a)(3)(i) **(6)** (p. F33), F3 (m)
>
> **Guidelines:**
>
> **(7)** (pp. F3-4), F1 7(b)(7)

**(8)** (p. F12), F1 8(c)(1)(iv)(A)

**2.2 EN ROUTE**

2.2.2 [Tracking Accuracy]{.underline}

[Purpose:]{.underline}

> To evaluate ease of course intercept and tracking accuracy (with and
> without autopilot).

[Test Procedure]{.underline}:

> Perform the following both with and without the autopilot:
>
> 1\. Intercept a segment & fly to a waypoint in flight plan **(4)**

[Evaluation Considerations:]{.underline}

> A\) Utility of track angle error information and CDI for course
> intercept **(2)**
>
> B\) Effort required to maintain FTE at less than 1.0 nm **(5)**
>
> C\) Ability to intercept route segment **(6)**
>
> D\) Ability to adjust CDI sensitivity in flight **(3)**

0

2.2.2 [Tracking Accuracy]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    

  C                                                    

  D                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. R2), R 2.1.10 **(5)** (p. F33), F3 (l)
>
> **(2)** (pp. T3-4), T (a)(3)(vii)(2) **(6)** (p. F33), F3 (m)
>
> **(3)** (p. T6), T (a)(3)(viii)
>
> **(4)** (pp. T9-10), T (a)(3)(xi)
>
> **Guidelines:**

**2.2 EN ROUTE**

2.2.3 [Waypoint Sequencing & Turn Anticipation]{.underline}

[Purpose]{.underline}:

> To evaluate waypoint sequencing procedure, associated display
> indications, and turn anticipation.

[Test Procedure]{.underline}:

> While in flight plan mode, fly to a waypoint and:

-   Fly to the left and right of a "fly by" waypoint at the intersection
    of two flight plan segments defining a 90º turn. **(7)** This will
    require the following passes by the "corner" waypoint:

> • Fly a course parallel with the approaching en route segment with the
> CDI nearly pegged to the outside (left of course) and follow turn
> anticipation advisory
>
> • Repeat with CDI nearly pegged to the inside (right of course)
>
> • Repeat with CDI on center line

-   Repeat with CDI on center line using autopilot

[Evaluation Considerations]{.underline}

> A\) Waypoint alert visibility **(7)**
>
> B\) Turn anticipation facilitates smooth transition to next segment
> using not more than a standard rate turn **(1, 6)**
>
> C\) Information provided to pilot by CDI and message display not
> misleading **(4)**
>
> D\) Waypoint sequencing consistent and facilitates accurate
>
> tracking of airway **(2, 3, 6, 7)**
>
> E\) Verify full scale deflection of CDI +/- 5.0 nm **(3)**
>
> F\) Verify resolution of crosstrack error at least 0.10 nm **(3)**

2.2.3 [Waypoint Sequencing & Turn Anticipation]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    

  C                                                    

  D                                                    

  E                                                    

  F                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. R2), R 2.1.10 **(5)** (p. F32), F3 (h)
>
> **(2)** (p. R4), R 2.2.1.7 **(6)** (p. F33), F3 (m)
>
> **(3)** (p. T5), T (a)(3)(viii)
>
> **(4)** (pp. T9-10), T (a)(3)(xi)
>
> **Guidelines:**
>
> **(7)** (p. F14), F1 8(c)(1)(iv)(M)

**2.2 EN ROUTE**

2.2.4 [Display Quality Evaluation]{.underline}

[Purpose:]{.underline}

> Evaluate influences of sunlight on display readability.

[Test Procedure]{.underline}:

> Exit flight plan & fly direct to waypoints which will position the
> aircraft in each of the following orientations: **(3, 6)**
>
> • Directly into the sun
>
> • With the sunlight shining across the display from a side window

[Evaluation Considerations]{.underline}:

> A\) Readability of symbols, letters, numbers, and graphics **(7)**
>
> B\) Visibility of CDI display **(6, 7)**
>
> C\) Range of brightness adjustment **(2, 7)**
>
> • Manual adjustment
>
> • Automatic adjustment
>
> D\) Display location **(1)**
>
> E\) Visibility of alerts & warnings **(4, 5)**
>
> F\) Color discriminability

2.2.4 [Display Quality Evaluation]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    

  C                                                    

  D                                                    

  E                                                    

  F                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. R7), R 3.1.1 **(4)** (p. T10), T(a)(3)(xii)(a, c)
>
> **(2)** (p. R8), R 3.1.2 **(5)** (p. T12), T(a)(3)(xiii)
>
> **(3)** (p. T2), T (a)(3)(iv) **(6)** (p. F32), F3 (h)
>
> **Guidelines:**
>
> **(7)** (pp. F3-4), F1 7(b)(7)

**2.3 TRANSITION**

2.3.1 [Approach Transition]{.underline}

[Purpose]{.underline}:

> To evaluate receiver functions involved in transition from en route to
> approach mode.

[Test Procedure]{.underline}:

> 1\. Approach terminal area while in flight plan mode, from beyond 30
> miles from the airport
>
> 2\. Select an IAF for an appropriate procedure which includes a course
> reversal & fly to the IAF
>
> [During this procedure]{.underline}: **(2)**
>
> • Observe terminal area alert
>
> • Enable approach mode
>
> • Request RAIM check **(6)**

[Evaluation Considerations]{.underline}:

> A\) Clarity of IAF options **(1)**
>
> B\) Ability to select one IAF option **(1)**
>
> C\) Action required to select approach mode **(2, 4)**
>
> D\) Smoothness of changes in CDI sensitivity **(3)**
>
> E\) Ease of understanding status of receiver mode **(5)**
>
> F\) Understandability of displayed messages
>
> G\) Approach enable alert
>
> • At a radial distance of 30 nm from the destination airport (not
> distance along the flight plan route) **(2, 5)**
>
> H\) Barometric pressure alert **(5, 7)**
>
> • Informs the pilot of the need to manually insert the barometric
> pressure setting (unless the automatic altitude input utilizes
> barometric corrected altitude data). **(2)**

2.3.1 [Approach Transition]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    

  C                                                    

  D                                                    

  E                                                    

  F                                                    

  G                                                    

  H                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. T8), T (a)(3)(x)b **(5)** (p. T17), T (a)(3)(xiii)4
>
> **(2)** (p. T10), T (a)(3)(xii)1.a **(6)** (p. T19), T (a)(3)(v)c
>
> **(3)** (pp. T10-11), T (a)(3)(xii)1.b, 5.b
>
> **(4)** (p. T11), T (a)(3)(xii)1.c
>
> **Guidelines:**
>
> **(7)** (p. F11), F1 8(b)(10)

**2.4 APPROACH**

2.4.1 [Non Precision Approach With A Procedure Turn]{.underline}

[Purpose]{.underline}:

> To check receiver operations involved in transitioning from initial
> approach fix to final approach fix when a procedure turn is required.

[Test Procedure]{.underline}:

> Fly from IAF, where IAF is on the airport or coincident with the FAF,
> fly the procedure turn, and fly inbound to the missed approach point.

[Evaluation Considerations]{.underline}:

> A\) Course guidance outbound & inbound **(5)**
>
> B\) Message displays readable & understandable
>
> C\) Receiver mode status indicator **(7)**
>
> D\) Transitions between terminal & approach mode **(8)**
>
> E\) Waypoint sequencing & timing of waypoint alerts **(4)**
>
> F\) Procedures required to enable a course reversal procedure **(5)**
>
> G\) Access to ground speed, distance, XTE, bearing & track angle error
> information **(1, 2, 3)**
>
> H\) CDI sensitivity changes smooth, and at appropriate
>
> locations **(6)**
>
> I\) Information on active waypoint **(2)**
>
> J\) Operation consistent with pilot expectations
>
> K\) Sensitivity change alert **(7)**
>
> • At a distance of 3 nm inbound to the final approach fix an
> annunciation shall indicate that a change will occur in the
> sensitivity of the analog CDI.
>
> L\) Approach enable alert shall be repeated **(7)**
>
> • At 3nm from the FAF if the approach mode was not previously
> activated.
>
> W\) Workload: **(9, 10)**
>
> • Pilot situational awareness
>
> • Mental effort

• Number of control actions required

2.4.1 [Non Precision Approach With A Procedure Turn]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    

  C                                                    

  D                                                    

  E                                                    

  F                                                    

  G                                                    

  H                                                    

  I                                                    

  J                                                    

  K                                                    

  L                                                    

  W                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. R3), R 2.2.1.2 **(6)** (pp. T10-11), T(a)(3)(xii)1.b,5.b
>
> **(2)** (p. R4), R 2.2.1.8 **(7)** (p. T11), T (a)(3)(xii)1.c
>
> **(3)** (pp. T3-4), T (a)(3)(vii) **(8)** (p. T11), T (a)(3)(xii)1.d
>
> **(4)** (p. T8), T (a)(3)(x)2.b **(9)** (p. F32), F3 (i)
>
> **(5)** (p. T9), T (a)(3)(xi)2
>
> **Guidelines:**
>
> **(10)** (pp. F3-4), F1 7(b)(7)

**2.5 MISSED APPROACH**

2.5.1 [Missed Approach With Course Reversal Back To The FAF]{.underline}

[Purpose]{.underline}:

> Evaluate receiver function when missed approach requires a course
> reversal back to FAF using "DIRECT TO" function to enable course
> guidance to the hold point.

[Test Procedure]{.underline}: **(8)**

> 1\. Activate the "DIRECT TO" button while flying the runway heading,
> reverse course and follow CDI guidance to the FAF
>
> 2\. Fly the published hold at the FAF using the OBS function to select
> inbound leg to the hold waypoint.

[Evaluation Considerations]{.underline}:

> A\) Receiver shift out of automatic waypoint sequencing at the MAP
> **(5)**
>
> B\) Positive course guidance provided as an extension of the inbound
> track and distance from the MAP until manual selection of the next
> waypoint **(5)**
>
> C\) Actions required to return to the FAF **(5)**
>
> D\) OBS function use for the holding pattern **(4)**
>
> E\) Missed approach holding waypoint as "fly over"
>
> waypoint **(1, 2)**
>
> F\) Course guidance to the FAF **(2)**
>
> G\) Sensitivity change for the missed approach **(6)**
>
> W\) Workload **(7, 9)**

-   Pilot situational awareness

-   Mental effort

-   Number of control actions required

-   Frequency of reference to receiver display required

2.5.1 [Missed Approach With Course Reversal Back To The FAF]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    

  C                                                    

  D                                                    

  E                                                    

  F                                                    

  G                                                    

  W                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. T3), T (a)(3)(v) **(5)** (p. T10), T (a)(3)(xi)3
>
> **(2)** (p. T8), T (a)(3)(x)b **(6)** (p. T11), T (a)(3)(xii)5.b
>
> **(3)** (p. T9), T (a)(3)(x)(4) **(7)** (p. F32), F3 (i)
>
> **(4)** (p. T9), T (a)(3)(xi)2.b **(8)** (p. F33), F3 (k)
>
> **Guidelines:**
>
> **(9)** (pp. F3-4), F1 7(b)(7)

**2.5 MISSED APPROACH**

2.5.2 [Missed Approach With A Heading To Intercept A Bearing To A
Waypoint]{.underline}

[Purpose]{.underline}:

> Evaluate receiver operation when intercepting a bearing to a holding
> point using the OBS function.

[Test Procedure]{.underline}:

> 1\. Fly the center line extension & select the bearing to the waypoint
> using the OBS function.
>
> 2\. Intercept the course and fly to the hold point.

[Evaluation Considerations]{.underline}:

> A\) Use of OBS function for course to hold waypoint **(2)**
>
> B\) The readability of the OBS setting **(2)**
>
> C\) Turn anticipation at point of intercept for course change to hold
> point **(1)**
>
> W\) Workload: **(3)**

-   Pilot situational awareness & mental effort

-   Number of control actions required

-   Required reference to receiver display

2.5.2 [Missed Approach With A Heading To Intercept A Bearing To A
Waypoint]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    

  C                                                    

  W                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. R2), R 2.1.10
>
> **(2)** (p. T9), T (a)(3)(xi)2.b
>
> **Guidelines:**
>
> **(3)** (pp. F3-4), F1 7(b)(7)

**2.6 AUTOPILOT**

2.6.1 [Autopilot Integration With GPS Receiver]{.underline}

[Purpose:]{.underline}

> To evaluate the function of the GPS receiver when used with an
> autopilot during en route, terminal, and approach operations.

[Test Procedure:]{.underline}

> 1\. Couple the GPS receiver to the autopilot **(4)**
>
> 2\. Fly the following: **(1, 5)**

-   Transition from en route to fly an approach

-   Fly a missed approach & hold

[Evaluation Considerations]{.underline}:

> A\) Course tracking smoothness & precision **(2)**
>
> B\) Performance: **(1)**

-   Direct to operations

-   Turn anticipation

-   Course reversals

-   Waypoint sequencing

> C\) Adequacy of information necessary for pilot situation awareness
> regarding system status & operation.
>
> D\) Operation consistent with pilot expectations
>
> W\) Workload **(3)**

-   Mental effort required

-   Number of control actions required

-   Required reference to receiver display

2.6.1 [Autopilot Integration With GPS Receiver]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    

  C                                                    

  D                                                    

  W                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. F32), F3 (c)
>
> **(2)** (p. F33), F3 (l)
>
> **Guidelines:**
>
> **(3)** (pp. F3-4), F1 7(b)(7)
>
> **(4)** (p. F4), F1 7(b)(9)

**(5)** (p. F6), F1 7(c)(1)(iv)(B)

**2.7 GPS ACCURACY**

2.7.1 [Verification Of GPS Accuracy]{.underline}

[Purpose]{.underline}:

Verify the GPS accuracy over a surveyed position on the ground.

[Test Procedure:]{.underline}

> 1\. [In the en route, terminal, and approach modes:]{.underline}
> **(1)**
>
> • Conduct at least 5 low altitude (\<100 ft AGL) passes of one or more
> surveyed locations (survey location data must be in either the WGS-84
> or NAD-83 coordinate datum; e.g., waypoint at the runway threshold).
> **(3)**
>
> • Push the "save position" button that will record Lat/Lon when the
> aircraft crosses the designated location and compare with known survey
> coordinates.

[Evaluation Considerations:]{.underline}

A\) Recorded Lat/Lon measurements **(1)**

+---------------+-----------------+-----------------+-----------------+
| Box Mode:     | En Route        | Terminal        | Approach        |
+---------------+-----------------+-----------------+-----------------+
| Accuracy      | 0.124 nm        | 0.124 nm        | 0.056 nm        |
| Required      |                 |                 |                 |
+---------------+-----------------+-----------------+-----------------+
| Known         |                 |                 |                 |
|               |                 |                 |                 |
| Lat/Lon       |                 |                 |                 |
+---------------+-----------------+-----------------+-----------------+
| Recorded      |                 |                 |                 |
|               |                 |                 |                 |
| Lat/Lon       |                 |                 |                 |
|               |                 |                 |                 |
| 1             |                 |                 |                 |
+---------------+-----------------+-----------------+-----------------+
| 2             |                 |                 |                 |
+---------------+-----------------+-----------------+-----------------+
| 3             |                 |                 |                 |
+---------------+-----------------+-----------------+-----------------+
| 4             |                 |                 |                 |
+---------------+-----------------+-----------------+-----------------+
| 5             |                 |                 |                 |
+---------------+-----------------+-----------------+-----------------+

2.7.1 [Verification Of GPS Accuracy]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (p. F33), F3 (j)
>
> **Guidelines:**
>
> **(2)** (p. F3), F1 7(b)
>
> **(3)** (p. F6), F1 7(c)(1)(iv)(D)

**2.8 MOVING MAPS**

2.8.1 [Moving Map Appearance]{.underline}

[Purpose]{.underline}:

To evaluate the appearance of the moving map display in flight.

> Observe the appearance of the map in en route and approach modes
> during straight flight and during changes in heading and course.

[Test Procedure]{.underline}:

> Examine the appearance of the moving map display during straight
> flight and heading changes.

[Evaluation Considerations]{.underline}:

> A\) Apparent readability of display **(1)**
>
> B\) Appearance of small symbols and fine lines during map movement
> **(1, 2, 3, 4, 5, 6)**
>
> C\) Clarity of location and heading of aircraft symbol on plan &
> profile views **(1, 2, 4, 5)**
>
> D\) Map scale appropriate and clear **(1)**
>
> E\) Map update rate appropriate for en route and terminal operations
> **(1, 7)**

2.8.1 [Moving Map Appearance]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    

  C                                                    

  D                                                    

  E                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **Guidelines:**
>
> **(1)** (pp. F3-4), F1 7(b)(7) **(5)** (p. M8), M1 5.2.6.8.4
>
> **(2)** (p. F27), F2 6(b)(4) **(6)** (p. M9), M1 5.2.6.8.5
>
> **(3)** (p. M7), M1 5.2.4.2 **(7)** (p. O12), O4 5.2.1
>
> **(4)** (p. M8), M1 5.2.6.8.3

**2.9 ALARMS & ALERTS**

2.9.1 [Discriminating Alerts]{.underline}

[Purpose:]{.underline}

> To ensure that all alerts can be discriminated from each other and
> from background noise. **(1)**

[Test Procedure:]{.underline}

> For each alert evaluate the following:

[Evaluation Considerations]{.underline}:

> A\) Ability of alert to get pilot's attention
>
> B\) Ease of discriminating alert from background
>
> C\) Ease of discriminating critical alerts from other alerts
>
> D\) Clarity of alert message
>
> E\) Alert contribution to "noisy" cockpit
>
> • Distraction
>
> F\) Effort to deactivate alert
>
> G\) Alert reminders if alert turned off and situation not reconciled

2.9.1 [Discriminating Alerts]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    

  C                                                    

  D                                                    

  E                                                    

  F                                                    

  G                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (pp. T12-17), T (a)(3)(xiii)
>
> **Guidelines:**

**2.9 ALARMS & ALERTS**

2.9.2 [Auditory Quality Of Alerts]{.underline}

[Purpose:]{.underline}

> To ensure that auditory alarms are appropriate. **(1)**

[Test Procedure:]{.underline}

> For each alarm & alert evaluate the following:

[Evaluation Considerations]{.underline}:

> A\) Clarity of alarm
>
> • Loudness
>
> • Pitch
>
> • Duration
>
> B\) Synthetic or natural speech quality & intelligibility in terms of:
>
> • Speech rate
>
> • Accent/dialect
>
> • Gender
>
> • Distinguishable from controllers
>
> C\) Length of auditory alarm
>
> • Minimal distraction
>
> • Minimal amount of attention to extract message

2.9.2 [Auditory Quality Of Alerts]{.underline}

**Evaluation**

  ---------- -------------------- -------------------- --------------------
             Fail                 Pass with excptn     Pass

  A                                                    

  B                                                    

  C                                                    
  ---------- -------------------- -------------------- --------------------

**Summary Evaluation**

  ----------------------- ----------------------- -----------------------
  Fail                    Pass with excptn        Pass

                                                  
  ----------------------- ----------------------- -----------------------

**Comments:**

  -----------------------------------------------------------------------

  -----------------------------------------------------------------------

> **Requirements:**
>
> **(1)** (pp. T12-17), T (a)(3)(xiii)
>
> **Guidelines:**

**2.10 FLIGHT TEST EVALUATION SUMMARY**

+----------------+---------------------+------+-----+---------+------+
| *              | **Checklist**       |      | **  | **Pass  | **Pa |
| *Requirement** |                     |      | Fai | with    | ss** |
|                |                     |      | l** | e       |      |
|                |                     |      |     | xcptn** |      |
+----------------+---------------------+------+-----+---------+------+
| **Title**      | **Title**           | **P  |     |         |      |
|                |                     | g.** |     |         |      |
+----------------+---------------------+------+-----+---------+------+
| Accessibility  | Quality             | 2-14 |     |         |      |
+----------------+---------------------+------+-----+---------+------+
| Accessibility  | Flight Plan Entry   | 2-6  |     |         |      |
| of Controls    |                     |      |     |         |      |
|                | RAIM Check          | 2-8  |     |         |      |
|                |                     |      |     |         |      |
|                | Flight Plan         |      |     |         |      |
|                |                     |      |     |         |      |
|                | Review/Modify       |      |     |         |      |
+----------------+---------------------+------+-----+---------+------+
| Control/       | Moving Map          | 2-28 |     |         |      |
| Display        |                     |      |     |         |      |
|                | Appearance          |      |     |         |      |
| Capability     |                     |      |     |         |      |
+----------------+---------------------+------+-----+---------+------+
| Control/       | Flight Plan Entry/  | 2-6  |     |         |      |
|                |                     |      |     |         |      |
| Display        | RAIM Check          | 2-8  |     |         |      |
|                |                     |      |     |         |      |
| Readability    | Flight Plan         | 2-14 |     |         |      |
|                |                     |      |     |         |      |
|                | Review/Modify       |      |     |         |      |
|                |                     |      |     |         |      |
|                | Display Quality     |      |     |         |      |
+----------------+---------------------+------+-----+---------+------+
| Display        | Display Quality     | 2-14 |     |         |      |
|                |                     |      |     |         |      |
| Visibility     |                     |      |     |         |      |
+----------------+---------------------+------+-----+---------+------+
| Failure Status | Types of Alarms &   | 2-4  |     |         |      |
|                |                     |      |     |         |      |
| Indicators     | Alerts              | 2-30 |     |         |      |
|                |                     |      |     |         |      |
|                | Discriminating      | 2-32 |     |         |      |
|                |                     |      |     |         |      |
|                | Alerts              |      |     |         |      |
|                |                     |      |     |         |      |
|                | Auditory Quality    |      |     |         |      |
|                |                     |      |     |         |      |
|                | of Alarms &         |      |     |         |      |
|                |                     |      |     |         |      |
|                | Alerts              |      |     |         |      |
+----------------+---------------------+------+-----+---------+------+
| Flight Plan    | Flight Plan Entry/  | 2-6  |     |         |      |
|                |                     |      |     |         |      |
| Capability     | RAIM Check          |      |     |         |      |
+----------------+---------------------+------+-----+---------+------+
| Manuever       | Flight Plan         | 2-8  |     |         |      |
|                |                     |      |     |         |      |
| Anticipation   | Review/Modify       | 2-10 |     |         |      |
|                |                     |      |     |         |      |
|                | Tracking Accuracy   | 2-12 |     |         |      |
|                |                     |      |     |         |      |
|                | Waypoint            |      |     |         |      |
|                |                     |      |     |         |      |
|                | Sequencing &        |      |     |         |      |
|                |                     |      |     |         |      |
|                | Turn Anticip.       |      |     |         |      |
+----------------+---------------------+------+-----+---------+------+

**2.10 FLIGHT TEST EVALUATION SUMMARY (Continued)**

+-----------------+-------------------+-------+---+------+---+---------+------+
| **Requirement** | **Checklist**     |       |   | **Fa |   | **Pass  | **Pa |
|                 |                   |       |   | il** |   | with    | ss** |
|                 |                   |       |   |      |   | e       |      |
|                 |                   |       |   |      |   | xcptn** |      |
+-----------------+-------------------+-------+---+------+---+---------+------+
| **Title**       | **Title**         | **    |   |      |   |         |      |
|                 |                   | Pg.** |   |      |   |         |      |
+-----------------+-------------------+-------+---+------+---+---------+------+
| Non-Numeric     | Tracking          | 2-10  |   |      |   |         |      |
|                 |                   |       |   |      |   |         |      |
| Display         | Accuracy          |       |   |      |   |         |      |
| Information     |                   |       |   |      |   |         |      |
+-----------------+-------------------+-------+---+------+---+---------+------+
| Numeric Display | Flight Plan       | 2-8   |   |      |   |         |      |
| Information     |                   |       |   |      |   |         |      |
|                 | Review/Modify     | 2-28  |   |      |   |         |      |
|                 |                   |       |   |      |   |         |      |
|                 | Moving Map        |       |   |      |   |         |      |
|                 |                   |       |   |      |   |         |      |
|                 | Appearance        |       |   |      |   |         |      |
+-----------------+-------------------+-------+---+------+---+---------+------+
| Operation of    | Flight Plan       | 2-6   |   |      |   |         |      |
|                 | Entry/            |       |   |      |   |         |      |
| Controls        |                   | 2-8   |   |      |   |         |      |
|                 | RAIM Check        |       |   |      |   |         |      |
|                 |                   | 2-28  |   |      |   |         |      |
|                 | Flight Plan       |       |   |      |   |         |      |
|                 |                   |       |   |      |   |         |      |
|                 | Review/Modify     |       |   |      |   |         |      |
|                 |                   |       |   |      |   |         |      |
|                 | Moving Map        |       |   |      |   |         |      |
|                 |                   |       |   |      |   |         |      |
|                 | Appearance        |       |   |      |   |         |      |
+-----------------+-------------------+-------+---+------+---+---------+------+
| RAIM            | Flight Plan       | 2-6   |   |      |   |         |      |
| Implementation  | Entry/            |       |   |      |   |         |      |
|                 |                   |       |   |      |   |         |      |
|                 | RAIM Check        |       |   |      |   |         |      |
+-----------------+-------------------+-------+---+------+---+---------+------+
| Waypoint or     | Tracking          | 2-10  |   |      |   |         |      |
|                 |                   |       |   |      |   |         |      |
| Leg             | Accuracy          | 2-12  |   |      |   |         |      |
|                 |                   |       |   |      |   |         |      |
| Sequencing      | Waypoint          | 2-20  |   |      |   |         |      |
|                 |                   |       |   |      |   |         |      |
|                 | Sequencing &      | 2-22  |   |      |   |         |      |
|                 |                   |       |   |      |   |         |      |
|                 | Turn Anticip.     |       |   |      |   |         |      |
|                 |                   |       |   |      |   |         |      |
|                 | MAP With Course   |       |   |      |   |         |      |
|                 |                   |       |   |      |   |         |      |
|                 | Reversal FAF      |       |   |      |   |         |      |
|                 |                   |       |   |      |   |         |      |
|                 | MAP With HDG      |       |   |      |   |         |      |
|                 |                   |       |   |      |   |         |      |
|                 | Intercept BRG     |       |   |      |   |         |      |
+-----------------+-------------------+-------+---+------+---+---------+------+
| Waypoint        | Flight Plan       | 2-6   |   |      |   |         |      |
| Storage         | Entry/            |       |   |      |   |         |      |
|                 |                   | 2-20  |   |      |   |         |      |
|                 | RAIM Check        |       |   |      |   |         |      |
|                 |                   | 2-22  |   |      |   |         |      |
|                 | MAP With Course   |       |   |      |   |         |      |
|                 |                   |       |   |      |   |         |      |
|                 | Reversal FAF      |       |   |      |   |         |      |
|                 |                   |       |   |      |   |         |      |
|                 | MAP With HDG      |       |   |      |   |         |      |
|                 |                   |       |   |      |   |         |      |
|                 | Intercept BRG     |       |   |      |   |         |      |
+-----------------+-------------------+-------+---+------+---+---------+------+

**2.10 FLIGHT TEST EVALUATION SUMMARY (Continued)**

  --------------------------------------- ---------- ------------- ----------
  **Checklist**                           **Fail**   **Pass with   **Pass**
                                                     excptn**      

  **OVERALL RATING**                                               
  --------------------------------------- ---------- ------------- ----------

  -----------------------------------------------------------------------
  **OVERALL COMMENTS:**

  -----------------------------------------------------------------------

**(a)(3)(i) Operation of Controls**

Add the following requirement to paragraph 2.1.4 of RTCA/DO-208:

Controls shall be designed to maximize operational suitability and
minimize pilot workload. Reliance on pilot memory for operational
procedures shall be minimized.

**(a)(3)(ii) Accessibility of Controls**

Add the following requirement to paragraph 2.1.5 of RTCA/DO-208:

Controls that are normally adjusted in flight shall be readily
accessible and properly labeled as to their function.

**(a)(3)(iii) Sensor Interfaces**

In lieu of paragraph 2.1.6 of RTCA/DO-208, substitute the following
requirement:

The interfaces with other aircraft equipment must be designed such that
normal or abnormal RNAV equipment operation shall not adversely affect
the operation of other equipment nor shall normal or abnormal operation
of other equipment adversely affect the RNAV equipment operation.

**(a)(3)(iv) Control/Display Readability**

In lieu of paragraph 2.1.8 of RTCA/DO-208, substitute the following
requirement:

The equipment shall be designed so that all displays and controls shall
be readable under all normal cockpit conditions and expected ambient
light conditions (total darkness to bright reflected sunlight). All
displays and controls shall be arranged to facilitate equipment usage.

**(a)(3)(v) Maneuver Anticipation**

Add the following requirement to paragraph 2.1.10 of RTCA/DO-208:

For systems approved for non precision approaches (class A1 equipment),
maneuver anticipation (turning prior to the \"to\" waypoint) shall not
be implemented at the missed approach fix or the missed approach holding
fix.

**(a)(3)(vi) Update Rate**

In lieu of paragraph 2.1.11 of RTCA/DO-208, substitute the following
requirement:

Navigation information used for display shall be updated at an interval
of 1.0 second or less.

**(a)(3)(vii) Numeric Display Information**

In lieu of paragraph 2.2.1.1.1 of RTCA/DO-208, substitute the following
requirement:

1\. Equipment certified to class A2 shall continuously provide either a
display or electrical output with the following requirements:

a\. The display shall be as accurate as the resolution required for the
displayed full scale range, referenced to a centered CDI display (see
table in paragraph (a)(3)(viii)).

b\. The equipment shall provide a numeric display or electrical output
of cross-track deviation to at least [+]{.underline} 20 nm (left and
right). A minimum resolution of 0.1 nm up to 9.9 nm and 1.0 nm beyond
shall be provided. The display may be pilot selectable.

2\. Equipment certified to class A1, shall, in addition to the
requirements for class A2:

a\. Provide a numeric (digital) display or electrical output of
cross-track deviation to a resolution of 0.01 nm for deviations less
than 1.0 nm.

b\. Compute and display track angle error (TAE) to the nearest one
degree. Track angle error is the difference between desired track and
actual track (magnetic or true). In lieu of providing a numeric display
of track angle error, non-numeric track angle error may be displayed in
conjunction with the display required in paragraph (a)(3)(viii) of this
TSO.

*[NOTE 1]{.underline}: While the numeric display need not be located
with the non-numeric cross-track display (subparagraph 2.2.1.1.2) or in
the pilot\'s primary field of view, flight technical error (FTE) can be
reduced when the numeric display is integrated with the non-numeric
display or is located within the pilot\'s primary field of view. Both
digital cross track and track angle error have been shown to reduce FTE.
This information should be displayed together (either within the CDU or
remotely displayed near the non-numeric display) for better tracking
performance.*

*[NOTE 2]{.underline}: The use of non-numeric cross track data
integrated with non-numeric track angle error data into one display may
provide the optimum of situation and control information for the best
overall tracking performance.*

**(a)(3)(viii) Non-Numeric Display Information**

In lieu of paragraph 2.2.1.1.2 of RTCA/DO-208, substitute the following
requirements:

1\. The equipment shall continuously provide either a display or
electrical output with the following requirements:

+----------------------+-------------+---------------+---------------+
|                      | *           | **Approach**  | **No          |
|                      | *Enroute/** |               | n-Precision** |
|                      |             | **T           |               |
|                      | *           | ransition\*** | *             |
|                      | *Terminal** |               | *Approach\*** |
+----------------------+-------------+---------------+---------------+
| Full-Scale           | 5.0         | 1.0           | 0.3           |
| Deflection           |             |               |               |
| ([+]{.underline} nm) | [\<]{.un    | [\<]{.        | ≥0.3          |
|                      | derline}1.0 | underline}0.1 |               |
| Readability (Display |             |               | ≥0.01         |
| only, nm)            | [\<]{.un    | [\<]{.u       |               |
|                      | derline}0.1 | nderline}0.01 | 1%            |
| Minimum Discernible  |             |               |               |
| Movement (Display    | 1%          | 1%            | 0.01          |
| only, nm)            |             |               |               |
|                      | 0.2         | 0.1           | 20%           |
| Resolution of        |             |               |               |
| Electrical Output    | 20%         | 20%           |               |
| Percentage of Full   |             |               |               |
| Scale                |             |               |               |
| ([+]{.underline})    |             |               |               |
|                      |             |               |               |
| Accuracy of Centered |             |               |               |
| Display              |             |               |               |
| ([+]{.underline} nm) |             |               |               |
|                      |             |               |               |
| Linearity of Display |             |               |               |
| or Electrical Output |             |               |               |
| ([+]{.underline})    |             |               |               |
+----------------------+-------------+---------------+---------------+

> \*These displays required only for equipment certified to class A1.

2\. The applicable non-numeric display information shall be
automatically presented upon activation of the appropriate operating
mode.

3\. A means shall be provided for manual pilot selection of the
available display sensitivities including those automatically selected
by the system (overriding an automatically selected sensitivity, during
an approach, shall cancel the approach mode annunciation). Additionally,
the equipment shall display the non-numeric scale sensitivity.

4\. In lieu of a linear lateral deviation scale for the final approach
segment (final approach fix to missed approach point), an angular
deviation display that emulates the nominal ILS localizer/MLS azimuth
display resolution may be used, beginning with a full-scale cross-track
deflection of [+]{.underline}0.3 nm at the final approach fix decreasing
to [+]{.underline}0.0576 nm at the runway threshold.

**(a)(3)(ix) Waypoint Entry**

In lieu of paragraphs 2.2.1.5 and 2.2.1.9 of RTCA/DO-208, substitute the
following requirements:

1\. Equipment certified to class A2 shall at least provide the
capability to manually enter and display (prior to its utilization in
the flight plan) the coordinates of a waypoint in terms of latitude and
longitude with a resolution of 0.1 minute or better. If the equipment
provides the ability to enter a waypoint as a range and bearing from
another waypoint, the waypoint input resolution shall be 0.1 nm and 1
degree or better.

*[NOTE]{.underline}: Systems providing input resolution of only 0.1
minute may require modification in the future as changes to the National
Airspace System occur.*

**(a)(3)(ix) Waypoint Entry (Continued)**

2\. Equipment certified to class A1 shall at least provide the
capability to manually enter and display (prior to its utilization in
the flight plan) the coordinates of a waypoint in terms of latitude and
longitude with a resolution of 0.01 minute or better. If the equipment
provides the ability to enter a waypoint as a range and bearing from
another waypoint, the waypoint input resolution shall be 0.1 nm and 0.1
degree or better.

**(a)(3)(x) Waypoint Storage**

In lieu of paragraph 2.2.1.6 of RTCA/DO-208, substitute the following
requirement:

1\. The equipment shall provide an appropriately updatable navigational
data base containing at least the following location information in
terms of latitude and longitude with a resolution of 0.01 minute or
better for the area(s) in which IFR operations are to be approved: all
airports, VORs (and VORTACs), NDBs, and all named waypoints and
intersections shown on route and terminal area charts, Standard
Instrument Departures (SIDs), and Standard Terminal Arrival Routes
(STARs).

*[NOTE]{.underline}: Manual entry/update of navigation data base data
shall not be possible. (This requirement does not preclude the storage
of \"user defined data\" within the equipment.)*

2\. Equipment certified to class A1, in addition to the requirements of
paragraph (a) (3) (x)1., shall provide the following:

a\. The equipment navigation data base shall also include all waypoints
and intersections included in published non-precision instrument
approach (except localizer, LDA, and SDF) procedures.

b\. The equipment shall store all waypoints, intersections, and/or
navigation aids and present them in the correct order for a selected
approach as depicted on published non-precision instrument approach
procedure charts. The sequence of waypoints shall consist of at least
the following: selected initial approach fix (IAF), intermediate
approach fix(es) (when applicable), final approach fix, missed approach
point, and missed approach holding point. For procedures with multiple
IAFs, the system shall present all IAFs and provide the capability for
pilot selection of the desired IAF. Selection of the desired IAF shall
automatically insert the remaining waypoints in the approach procedure
in the proper sequence.

c\. Waypoints utilized as a final approach fix or issued approach point
in a non-precision approach procedure shall be uniquely identified as
such to provide proper approach mode operation.

d\. Modification of data associated with published instrument approach
procedures by the user shall not be possible.

e\. Waypoint data utilized in non-precision approach procedures shall be
in terms of latitude and longitude and cannot be designated in terms of
bearing (radial) and distance to/from a reference location.

f\. When in the approach mode, except for holding patterns and procedure
turns, the equipment must establish the desired flight path in terms of
the path between defined endpoints up to the missed approach point.

3\. The equipment shall provide the capability for entering, storing,
and designating as part of the active flight plan a minimum of nine
discrete waypoints (including the active waypoint). In addition, for
class A1 equipment, it shall store and designate as part of the active
flight plan the complete sequence of waypoints from the navigation data
base necessary to complete the selected approach, including the missed
approach.

4\. Waypoints shall be coded in the navigation data base to identify
them as \"fly by\" (turn anticipation permitted) or \"fly over\" (turn
anticipation not permitted) as required by the instrument approach
procedure, SID, or STAR. Waypoints which define the missed approach
point and missed approach holding point in instrument approach
procedures shall be coded as \"fly over.\"

5\. Navigation data bases shall meet the standards specified in sections
3, 4, and 5 of RTCA/DO-200, \"Preparation, Verification and Distribution
of User Selectable Navigation Data Bases\" and sections 2 through 7 of
RTCA/DO-201, \"User Recommendations for Aeronautical Information
Services.\"

**(a)(3)(xi) Waypoint or Leg Sequencing**

Add the following requirement to paragraph 2.2.1.7 of RTCA/DO-208:

1\. The equipment shall provide the capability to fly from the present
position direct to any designated waypoint. Access to this feature shall
be by means of a single action by the pilot. Selection of the desired
\"TO\" waypoint may require additional actions.

2\. The equipment shall provide the capability for accomplishment of
holding patterns and procedure turns. Activation of this function shall
at least:

a\. Change automatic waypoint sequencing to manual.

b\. Permit the pilot to readily designate a waypoint and select a
desired course (by means of a numerical keypad entry, HSI course
pointer, CDI omni bearing selector, etc.) to or from the designated
waypoint (TO/FROM mode operation is acceptable).

c\. Retain all subsequent waypoints in the active flight plan in the
same sequence.

d\. Permit the pilot to readily return to automatic waypoint sequencing
at any time prior to the designated fix (\"TO\" waypoint) and continue
with the existing flight plan.

3\. Class A1 equipment, unless incorporating or interfaced with an
appropriate situational awareness display (i.e., an electronic map),
shall be designed to prevent automatic waypoint sequencing from the
missed approach waypoint to the missed approach holding waypoint. Except
for equipment with an approved electronic map display, course guidance
shall display an extension of the inbound track and distance from the
missed approach waypoint until manual selection of the next desired
waypoint.

**(a)(3)(xii) Approach Mode Selection**

**and Sequencing**

Add the following requirement to RTCA/DO-208:

1\. For accomplishment of non-precision approaches, when an approach is
included in the active flight plan, class A1 equipment shall provide the
following:

a\. At a radial distance of 30 nm from the destination airport (not
distance along the flight plan route), the equipment shall provide an
approach enable alert. After display of this alert, a means shall be
provided to enable the approach mode with a single action by the pilot.
The approach mode shall not engage unless previously enabled by the
pilot. Concurrent with the approach enable alert, a suitable means to
alert the pilot of the need to manually insert the barometric pressure
setting shall be provided (unless the automatic altitude input utilizes
barometric corrected altitude data).

b\. Upon activation of the approach mode, the equipment shall provide a
smooth transition from 5 nm non-numeric display sensitivity to 1 nm
sensitivity.

c\. At a distance of 3 nm inbound to the final approach fix, the
equipment shall provide an annunciation indicating an automatic
non-numeric display sensitivity change will occur. If the approach mode
was not previously activated, the approach enable alert shall be
repeated.

d\. At a distance of 2 nm inbound to the final approach fix, the
equipment shall:

i\. Immediately transition from terminal integrity performance to
approach integrity performance as specified in Table 2-1 of RTCA/DO-208.

ii\. Provide a linear transition from 1 nm non-numeric display
sensitivity to 0.3 nm sensitivity at the final approach fix.

5\. If the pilot manually sequences to the missed approach holding
point, the equipment shall:

a\. Transition from approach integrity performance to terminal integrity
performance as specified in Table 2-1 of RTCA/DO-208.

b\. Provide a smooth transition from 0.3 nm non-numeric display
sensitivity to 1 nm sensitivity.

6\. A means shall be provided for deselection of the approach mode with
a single action by the pilot. Deselection of the approach mode shall:

a\. Transition from RNAV (non-precision) approach integrity performance
to terminal integrity performance as specified in Table 2-1 of
RTCA/DO-208.

b\. Provide a smooth transition from 0.3 nm non-numeric display
sensitivity to 1 nm sensitivity.

7\. If the ability to perform DME arcs is provided, the equipment shall
permit the pilot to readily accomplish such procedures in accordance
with published non-precision approach procedures utilizing piloting
techniques similar to those applicable to use of the reference DME
facility.

**(a)(3)(xiii) Failure/Status Indications**

In lieu of paragraph 2.2.1.10 of RTCA/DO-208, substitute the following
requirement:

The equipment shall indicate, independent of any operator action, the
following:

1\. By means of navigation warning flag on the navigation display:

a\. The absence of power required for the navigation function.

b\. Any probable equipment malfunction or failure affecting the
navigation function.

c\. Loss of navigation function.

d\. For equipment certified to class A1, inadequate or invalid
navigation data in the approach mode detected in accordance with RTCA
DO-208 paragraph 2.2.1.13, Table 2-1, and paragraph (a) (3) (xv) of this
TSO.

e\. For equipment certified to class A1, the loss of the RAIM detection
function in the approach mode at the final approach fix.

f\. For equipment certified to class A1, loss of the RAIM detection
function in the approach mode, after passing the final approach fix.
However, the navigation warning flag shall not be displayed until the
RAIM detection function is lost for more than five minutes.

2\. By means of an appropriately located annunciator:

a\. When RAIM is not available, inadequate navigation data due to poor
space vehicle geometry such that the probability that navigation error
exceeds the position integrity performance requirements in RTCA/DO-208
(Table 2-1) is greater than or equal to .05.

b\. The RAIM function detects a position error that exceeds the GPS
position integrity performance requirements in RTCA/DO-208 (Table
2-1).c.

c\. Loss of the RAIM function. Display of the integrity annunciation may
be delayed for a period of time consistent with the requirements of
paragraph (a) (3) (xiv) of this TSO.

d\. For equipment certified to class A1, predicted unavailability of the
RAIM detection function as specified in paragraph (a)(3)(xv)1.

e\. For equipment certified to class A1, when operating in the approach
mode without RAIM and navigation performance is degraded because HDOP
exceeds 4.0.

**TABLE 2-1**

**GPS POSITION INTEGRITY PERFORMANCE REQUIREMENTS**

  ----------------- ------------- --------------- ------------ --------------
                    Performance                                
                    Item                                       

  Phase of Flight   Alarm Limit   Maximum         Time to      Minimum
                                  Allowable Alarm Alarm        Detection
                                  Rate                         Probability

  En Route          2.0 nmi       0.002/hr        30 seconds   0.999
  (Oceanic,                                                    
  Domestic, Random                                             
  & J/V Routes)                                                

  Terminal          1.0 nmi       0.002/hr        10 seconds   0.999

  RNAV Approach     0.3 nmi       0.002/hr        10 seconds   0.999
  (Non-Precision)                                              
  ----------------- ------------- --------------- ------------ --------------

**[NOTES]{.underline}:**

a\. A failure is defined to exist when the GPS horizontal radial
position error is outside the specified alarm limit for the phase of
flight in progress. Conversely, no failure exists when the error is
within the specific bound.

b\. Maximum allowable alarm rate refers to the total alarm rate with the
equipment in normal operation with no satellite malfunction. It is
anticipated that most integrity alarms, even though rare, will be
induced by the normal effects of selective availability, propagation
uncertainties and receiver noise. Alarms due to unannounced satellite
malfunctions are expected to be extremely rare. The alarm rate specified
allows an average of only one alarm per 15,000 two-minute intervals.
(Correlation times of selective availability are assumed to be
approximately two minutes.) The specified alarm rate does not include
those periods when the integrity system is declared inoperable due to
poor detection geometry of the satellites. This alarm rate applies
globally at all times regardless of the constellation at hand.

c\. Time to alarm is defined to be the maximum allowable elapsed time
from the onset of the failure, as defined in (a.) above, until the time
that the integrity alarm is annunciated.

d\. Detection probably is defined as 1 - miss probability. Miss
probability is the conditional probability that the detection algorithm
decides that a failure is not present when, in fact, a failure exists.
The integrity system shall meet the specified detection probability
globally at all times for single satellite failures, except for those
conditions where integrity cannot be assured and the flag is displayed
accordingly (see subparagraph 2.2.1.13.2 b). The specified detection
probability shall apply regardless of the constellation at hand. This
probability is such as to provide an undetected failure rate of 3.8E-8
per flying hour, provided that the rate of unannounced gradual satellite
failures is no greater than one failure per nine months for the entire
24-satellite constellation. (This is the equivalent of an MTBF of 18
years for this type of failure for individual satellites.)

e\. Equipment manufacturers have the option of using more stringent
requirements than those given in this table. For example, some
manufacturers may choose to have only two levels of alarm limits, 0.3
nmi for non-precision approach and 1.0 nmi for all other phases of
flight. Such a deviation is within the intent of this table.

f\. All of the specifications given in this table must be met with
selective availability in progress on all satellites being used. See
subparagraph 2.5.2.5 for the assumptions about selective availability
that are to be used for testing.

These failure/status indication(s) shall occur independently of any
operator action.

*[NOTE]{.underline}: It is impractical for the operator to monitor,
unaided, the changing parameters that affect accuracy. Therefore, the
equipment should monitor those parameters for degraded performance that
may result from propagation, reception, geometry, selective availability
(SA) or other effects to the extent possible and be capable of automatic
compensation, deselection or manual deselection following annunciation
of degraded performance.*

3\. Additional navigation data (such as distance to waypoint, time to
waypoint, ground speed, etc.) shall be removed or flagged when the
adequacy of navigation information upon which this data is based cannot
be assured.

*[NOTE]{.underline}: Presentation of a failure/status annunciation does
not require removal of navigation information from the navigation
display. Consideration should be given to continue display of navigation
information concurrent with the failure/status annunciation when
conditions warrant.*

*[NOTE]{.underline}: It is impractical for the operator to monitor,
unaided, the changing parameters that affect accuracy. Therefore, the
equipment should monitor those parameters for degraded performance that
may result from propagation, reception, geometry, selective availability
(SA) or other effects to the extent possible and be capable of automatic
compensation, deselection, or manual deselection following annunciation
of degraded performance.*

4\. Approach mode status/annunciations. Equipment certified to class A1
shall provide:

a\. An annunciation that the approach mode is enabled.

b\. An annunciation that the system is in the approach mode (RAIM in
RNAV (non-precision) approach integrity performance and non-numeric
display in approach sensitivity).

c\. An annunciation of impending automatic non-numeric display
sensitivity change to approach sensitivity.

d\. An annunciation to alert the pilot of the need to manually insert
the barometric pressure (unless automatic altitude input utilizing
barometric corrected altitude data is available).

e\. An annunciation to alert the pilot to enable the approach mode.

**(a)(3)(xiv) Annunciation of Integrity Alarm**

Delete the second sentence of the opening paragraph 2.2.1.13.2 of
RTCA/DO-208 and replace with:

1\. A separate and distinctive indication shall be raised in each of the
following two circumstances.

Add the following requirement to paragraph 2.2.1.13.2 of RTCA/DO-208:

a\. In order to minimize nuisance integrity alarms when system
navigation accuracy is otherwise not in doubt, properly substantiated
compensating features (such as clock coasting, inertial data, other
sensors, etc.) may be incorporated into the system. The alarm under
these conditions may be delayed for a period of time consistent with the
worst cases of undetected clock drift or other failures that would cause
the position error to exceed the accuracy required for that phase of
flight. The applicant must develop appropriate test procedures to
demonstrate that the proposed compensating features provide the required
level of navigation accuracy and integrity.

**(a)(3)(xv) RAIM Implementation**

Add the following requirement to paragraph 2.2.1.13.3 of RTCA/DO-208:

1\. The RAIM function shall provide terminal integrity performance as
specified in Table 2-1 of RTCA/DO-108 within 30 nm of the departure and
destination points. In addition, approach mode (class A1 equipment)
integrity performance shall be provided from 2 nm prior to the final
approach fix to the missed approach point. En route integrity
performance shall be provided during other conditions.

2\. The equipment shall automatically select the appropriate RAIM
integrity performance requirements.

3\. Equipment certified to class A1 shall:

a\. Upon transition to approach integrity, automatically verify (via the
RAIM prediction function) that satellite vehicle geometry will be
suitable during non-precision approaches to enable the RAIM function to
be available upon arrival at the final approach fix and the missed
approach point. Satellite vehicle failures (detected and deselected by
the equipment) that occur after the final approach fix which prevent the
RAIM detection function do not require annunciation for a period of 5
minutes.

b\. Provide the pilot, upon request, a means to determine if RAIM will
be available at the planned destination at the estimated time of arrival
(ETA) (within at least [+]{.underline}15 minutes computed in intervals
of 5 minutes or less). Once complete almanac data has been received,
this capability shall be available at any time after the destination
point and estimated time of arrival at that point are established. The
availability of corrected barometric altitude (either by automatic or
manual altimeter setting input) may be assumed for this purpose (for the
purposes of this calculation, an acceptable value of sbaro is 50
meters).

c\. Display, upon request, RAIM availability at the ETA and over an
interval of at least [+]{.underline}15 minutes computed in intervals of
5 minutes or less about the ETA.

**(a)(3)(xxii) Flight Plan Capability**

Add the following requirement to RTCA/DO-208:

The equipment shall provide the capability to create, display, and edit
a flight plan consisting of a minimum of 9 waypoints. A means shall be
provided to readily display each waypoint, individually or together, of
the active flight plan (in sequence) for review.

**2.0 Equipment Performance Requirements**

**and Test Procedures**

**2.1 General Requirements**

The following general requirements shall be met by all RNAV equipment.

**2.1.4 Operation of Controls**

Controls intended for use during flight shall be designed to minimize
errors and, when operated in all possible combinations and sequences,
shall result in a condition whose presence or continuation would not be
detrimental to the continued performance of the equipment.

**2.1.5 Accessibility of Controls**

Controls that are not normally adjusted in flight shall not be readily
accessible to the operator.

**2.1.7 Control/Display Capability**

A suitable interface shall be provided to allow data input, data output
and control of equipment operation. It shall be possible for the
operator to manually select waypoint(s). The control/display shall be
operable with the use of only one hand.

**2.1.10 Maneuver Anticipation**

Maneuvers such as turns to intercept a new course; transitions to an
established direct-to leg; changes in climb, descent, level-off or
change of ascent/descent angle must be anticipated when operating in the
airspace. This anticipation may be accomplished through computational
techniques within the equipment, operational procedures or a combination
of both. Regardless of the method chosen to implement maneuver
anticipation, aircraft performance envelopes directly influence the
effectiveness of this requirement (see Subsection 3.2 and Appendix H).

**2.2 2D RNAV Functional and Accuracy**

**Requirements - Standard Conditions**

**2.2.1 Equipment Functional Requirements**

**2.2.1.2 Waypoint Distance Display**

Distance to the waypoint shall be displayed on demand with a resolution
of 0.1 nmi or better up to a range of 99.9 nmi from the waypoint, and it
shall be 1.0 nmi or better at greater ranges. The equipment shall have
the capability to display values of distance to waypoints of at least
150 nmi for TO-FROM equipment and at least 260 nmi for TO-TO equipment.

*[NOTE]{.underline}: For en route operation with random route clearance,
a much greater distance between waypoints may be desirable.*

**2.2.1.3 TO-FROM Indication**

For TO-FROM equipment, a continuous display or electrical output shall
be provided to show whether the aircraft is behind or ahead of the
active waypoint relative to an imaginary line perpendicular to the
desired path and passing through the active waypoint.

For TO-TO equipment, which allows overflying of the active waypoint, a
continuous display or electrical output shall be provided to show when
the aircraft has passed an imaginary line perpendicular to the desired
path and is passing through the active TO waypoint.

**2.2.1.4 Flight Path Selection**

The equipment shall provide a means of selecting and displaying a flight
path defined by two waypoints. Additionally, if a TO-FROM mode is
provided, the equipment shall provide a means of selecting and
displaying an active waypoint and a desired course through the waypoint.
The entry and display resolution of such a selected course shall be one
degree or finer.

*[NOTE]{.underline}: It is assumed herein that the selected course is
entered digitally. If analog techniques are used, it shall be
demonstrated that the error in selecting the course does.*

*not exceed 0.5 degree*

**2.2.1.7 Waypoint or Leg Sequencing**

Means shall be provided, either manually or automatically, to utilize a
series of stored waypoints in any selected order. Provisions shall be
made to display the identification of the active waypoint and to preview
the next waypoint or leg available for activation. The active and stored
waypoints need not be displayed simultaneously. Means shall be provided
to indicate whether or not the displayed waypoint is the active
waypoint.

**2.2.1.8 Position Display**

The computed aircraft position shall be available for display in terms
of range and bearing to or from the active or parent waypoint.
Resolution of range and bearing shall be at least 0.1 nmi and 1.0 degree
up to 99.9 nmi, then at least 1.0 nmi and 1.0 degree beyond. Some
equipment may also display this information in latitude/longitude. If
displayed, it shall have a resolution of at least 0.1 minute.

*[NOTE]{.underline}: The intent of this requirement is to permit the
operator to provide this information to ATC upon request.*

**2.2.1.11 Satellite Selection and Indication**

The equipment shall provide the capability to:

a\. automatically select satellites for use in navigational computation.

b\. determine suitability of each satellite for use by data content
including all appropriate parameters such as \"health\" status, complete
almanac data, correct ephemeris and correctness of parity.

c\. remove satellite from use when it is not suitable.

> d\. provide a warning consistent with the integrity requirements for
> the intended phase of flight.

**2.2.1.12 Equipment Computational Response**

**Time After Waypoint Entry**

The time lag between time of waypoint data input and display of
navigation guidance derived from the data shall not exceed five seconds.

*[NOTE]{.underline}: Equipment outputs may be filtered or \"eased on\"
consistent with desired aircraft dynamics and operating conditions.*

**2.2.1.13 Integrity Alarm for GPS Receivers**

**2.2.1.13.1 General Integrity Requirements**

The equipment shall provide integrity assurance. Regardless of the
method used to ensure integrity, the integrity system shall meet the
general specifications given in Table 2-1. The explanatory notes
accompanying Table 2-1 are an essential part of the table.

**2.2.1.13.2 Annunciation of Integrity Alarm**

The GPS equipment must give a clear and timely annunciation of alarm for
each phase of flight being conducted. The alarm shall be raised in
either of the following two circumstances:

a\. The integrity monitoring equipment indicates that the GPS horizontal
radial position error is outside the specified alarm limit for the phase
of flight in progress.

b\. There exists an absence of a positive integrity check of the
navigation solution for any reason, be it poor satellite geometry,
inadequate satellite redundancy, potential equipment failure, etc.

The term \"timely\" means that the alarm annunciation shall take place
within the specified time to alarm for the phase of flight in progress.

No special form for the alarm presentation is specified in this
document, except that for non-precision approach there must be an
annunciation on the primary navigation display that indicates invalid
integrity verification for this phase of flight.

**2.2.1.13.3 RAIM Implementation**

GPS equipment manufacturers have the option of using any RAIM technique
that will meet the specifications given in Table 2-1 and other
specifications stated in subparagraph 2.2.1.13.2 of this document. The
equipment manufacturer shall be required to demonstrate compliance with
these specifications (see subparagraph 2.5.2.5).

**2.3 (VNAV) Functional and Accuracy**

**Requirements - Standard Conditions**

**2.3.1 Equipment Functional Requirements**

In addition to the 2D RNAV requirements listed in Subsection 2.2, the
following set of functional requirements are those that VNAV equipment
shall meet, as a minimum, to operate safely and efficiently. These are
established to ensure acceptable operation in the vertical plane
regardless of VNAV equipment type.

**2.3.1.1 Waypoint Altitude**

The equipment shall provide a manual means of entering and storing an
altitude directly associated with the active waypoint. The resolution of
waypoint altitude entry shall be 100 ft. or better for en route and
terminal flight phases and 10 ft. or better for the approach phase. This
requirement shall be met over the altitude range as specified by the
equipment manufacturer.

**2.3.1.2 Vertical Path Deviation**

The equipment shall continuously provide an electrical output or other
means for determination of the magnitude and direction of the vertical
deviation from the desired vertical profile. Means of determining the
vertical deviation shall provide not less than [+]{.underline}500 ft.
range for en route and terminal, and [+]{.underline}150 ft. for
approach, and with resolutions not greater than 100 ft. and 30 ft.,
respectively.

**2.3.1.3 Vertical Profile**

> a\. For ascents, if the capability is provided in the system, the
> equipment shall provide a reference vertical profile that aids in
> compliance with altitude constraints at waypoints.

b\. For level flight segments, if the capability is provided in the
system, the equipment shall provide a reference vertical profile that
aids in compliance with the specified altitude.

c\. For descent segments prior to the final approach fix waypoint, the
equipment shall provide a reference vertical profile that aids in
compliance with altitude constraints at waypoints. Straight line
profiles may be used but are not required.

d\. In the approach phase starting with the final approach fix waypoint,
the equipment shall provide a means of specifying a constant altitude
rate (linear variation of along-track distance with altitude vertical
profile) to be followed. This profile may take the form of a line
connecting two waypoints with their associated altitudes or a line
terminating at or emanating from a specified waypoint (with its
associated altitude) at a specific gradient angle.

> e\. For equipment that specifies gradient angles, the angle resolution
> shall be 0.1 degree or better.

**3.0 Installed Equipment Performance**

**3.1 Equipment Installation**

**3.1.1 Accessibility**

Controls installed for in-flight operation shall be readily accessible
from the pilot\'s seated position.

**3.1.2 Display Visibility**

The appropriate flight crew member(s) shall have an unobstructed view of
displayed data when in the seated position. Displays used for maneuver
anticipation and for failure annunciation shall be located within the
pilot\'s primary field of view. The brilliance of any display shall be
adjustable to levels suitable for data interpretation under all cockpit
ambient light conditions ranging from total darkness to reflected
sunlight.

The approach mode annunciation and distance to waypoint in the approach
mode shall be clearly visible to the pilot with the least practicable
deviation from his normal position and from his line of vision when he
is looking forward along the flight path.

*[NOTE]{.underline}: Visors, glareshields or filters may be an
acceptable means of obtaining daylight visibility.*

**3.1.4 Inadvertent Turnoff**

There shall be a minimal risk of inadvertent turnoff.

**3.3.5 Warm-Up Period**

Unless otherwise specified, all tests shall be conducted after the
manufacturer\'s specified warm-up (stabilization) period. This period
shall not exceed 15 minutes.

**4.0 Operational Characteristics**

**4.1 Required Operational Characteristics**

**4.1.2 Navigation Displays**

Each of the required displays for determining position and relationship
of the airplane to the desired course shall be available for use.

**4.1.3 Navigation Controls**

Each cockpit control required for proper operation of the equipment
shall be available for use.

**4. BACKGROUND**

g\. [General Operational Limitations.]{.underline}

> \(3\) [IFR Navigation Equipment]{.underline}. GPS equipment for IFR
> navigation is for use as a supplemental navigation system. The
> installation of GPS equipment does not affect the requirement for
> primary means of navigation appropriate to the route intended to be
> flown. Within the contiguous United States, Alaska, Hawaii, and
> surrounding coastal waters, this requirement can be met with an
> operational, independent VOR receiver. Additional navigation equipment
> redundancy may be required for operation in oceanic and remote
> airspace.

6\. SYSTEM ACCURACY

> b\. [Flight Technical Error (FTE)]{.underline}. Since FTE factors are
> normally beyond the control of equipment manufacturers or installers,
> these error sources are not included in the accuracy specifications in
> paragraph 6a(1). The FAA has determined that when properly installed
> in an aircraft, Class A equipment meeting the operational and display
> characteristics contained in this AC and TSO-C129 provided for
> acceptable values of FTE. FTE should not exceed 1.0 nmi for en route,
> 1.0 nmi for approach transition, or 0.25 nmi for approach operating
> modes on a 95 percent basis.

7\. AIRWORTHINESS CRITERIA FOR GPS

INSTALLATIONS USED AS A

SUPPLEMENTAL NAVIGATION

SYSTEM LIMITED TO VISUAL

FLIGHT RULES (VFR) ONLY

a\. [Application Process.]{.underline}

> \(1\) The initial (first-time airworthiness approval) certification of
> a GPS navigation system should be accomplished via the TC or STC
> approval process.
>
> \(2\) Subsequent (follow-on) installations of the same GPS navigation
> system (hardware and software) in other aircraft are approved using a
> less extensive evaluation process since the basic engineering design
> of the GPS equipment has already been evaluated. Approval of follow-on
> installations may be accomplished via the TC, STC, or FAA Form 337
> process. The extent of required regulations depends upon the degree of
> integration of the GPS system with other aircraft systems, the
> similarity between the initial and follow-on aircraft models, and
> other changes that may have been incorporated in the GPS navigation
> system. The decision to allow an applicant to use FAA approved
> engineering data in support of an FAA Form 337 approval is left to the
> field inspector\'s judgement. The FAA Airworthiness Inspector\'s
> Handbook (FAA Order 8300.10) provides guidance applicable to GPS
> equipment installations.
>
> b\. [Airworthiness Considerations]{.underline}. GPS equipment approved
> for VFR use only does not require TSO-C129 authorization, however it
> must at least meet the en route/terminal system accuracy criteria
> (0.124 nmi, 95 percent probability) contained in paragraph 6a of this
> AC. Airworthiness considerations should include the following.
>
> \(4\) [Navigation Source Annunciator]{.underline}. A navigation source
> annunciator is provided on or near each affected display if the GPS
> installation supplies any information to displays such as a horizontal
> situation indicator (HSI), course deviation indicator (CDI), distance
> display, electronic map, etc., which can also display information from
> other systems normally used for aircraft navigation.
>
> \(7\) [System Controls, Displays and Annunciators]{.underline}. All
> displays, controls, and annunciators must be easily readable under all
> normal cockpit conditions and expected ambient light conditions (total
> darkness to bright reflected sunlight). Night lighting provisions must
> be consistent with other cockpit lighting. All displays and controls
> should be arranged to facilitate equipment usage. Controls that are
> normally adjusted in flight shall
>
> be accessible and properly labeled as to their function. System
> controls and displays should be designed to maximize operational
> suitability and minimize pilot workload. System controls should be
> arranged to provide adequate protection against inadvertent system
> turnoff. Reliance on pilot memory for operational procedures shall be
> minimized.
>
> \(8\) [Navigation/Integrity Annunciation]{.underline}. The GPS
> equipment should indicate, independent of any operation action:
>
> \(i\) The following conditions by means of a navigation warning flag
> on the navigation display:
>
> \(A\) The absence of power necessary for the navigation function.
>
> \(B\) Probable equipment malfunctions or failures affecting the
> navigation function.
>
> \(C\) Loss of navigation function.
>
> \(ii\) If an integrity monitoring function such as RAIM is provided,
> an appropriately located annunciator shall be provided to indicate
> loss of the integrity monitoring function.
>
> **Note 1:** For equipment not incorporating an external navigation
> display (CDI, HSI, etc.) complete blanking of the Control Display Unit
> (CDU) display is acceptable.
>
> **Note 2:** Presentation of a failure/status annunciation (flag or
> integrity annunciation) does not require removal of navigation
> information from the navigation display.
>
> \(9\) [Autopilot/Flight Director Coupling]{.underline}. The GPS
> navigation system may be coupled to autopilot and/or flight director
> system, if a deviation or steering output that is compatible with the
> copilot/flight director system is provided and no unusual interface is
> required.
>
> \(10\) [VFR Limitation Placard]{.underline}. A placard stating \"GPS
> limited to VFR use only\" must be installed in clear view of, and
> readable by, the pilot.
>
> c\. [VFR Airworthiness Approval]{.underline}. There are two types of
> VFR airworthiness approvals which refer significantly as to test
> requirements and data analysis.
>
> \(1\) [First-Time VFR Airworthiness Approval Criteria (for a
> Particular Type of GPS Equipment)]{.underline}. This type of approval
> refers to the very first time an applicant presents a particular
> (hardware and software configuration) model GPS navigation system for
> FAA airworthiness installation approval and certification for VFR
> navigation use. The first approval of a particular GPS navigation
> system must be accomplished through the TC or STC process. Each new
> model of GPS equipment or significant changes (hardware or software)
> to existing equipment shall undergo the same approval process as the
> original equipment unless it can be shown by analysis and tests
> acceptable to the administrator that the new model will function as
> well or better than the approved equipment. The first-time approval is
> conducted in four phases:
>
> \(i\) [Lab/Bench Tests and Equipment Data Evaluation]{.underline}.
> This phase consists of the following:
>
> \(A\) Review of the manufacturer\'s procedures for development of
> software and review of supporting documentation in accordance with the
> guidelines of paragraph 7b(5) of this AC.
>
> \(B\) Analysis of failure modes and annunciations.
>
> \(C\) Review of reliability data to establish that all probable
> failures affecting the navigation function are detected.
>
> \(D\) Review of installation and maintenance manuals.
>
> \(E\) Evaluation of the operator\'s manual (pilot\'s guide).
>
> \(iv\) [Flight Test Evaluations]{.underline}. Flight tests are
> conducted to verify proper operation and accuracy of the GPS equipment
> as installed in the aircraft. Flight tests should include at least the
> following:
>
> **Note**: Required flight evaluations for the first-time airworthiness
> approval of a particular GPS system are accomplished by the cognizant
> Aircraft Certification Office (ACO) unless specific tests are
> delegated by the ACO to a flight test pilot designated engineering
> representative (DER).
>
> \(A\) Evaluation of installed GPS navigation system to verify that it
> is functioning properly, safely, and operates in accordance with the
> manufacturer\'s specifications.
>
> \(B\) Evaluation of steering response while the autopilot and/or
> flight director coupled to the GPS equipment during a variety of
> different track and mode changes. All available display sensitivities
> should be evaluated.
>
> \(C\) Evaluation to verify the GPS installation does not adversely
> affect other onboard equipment (this test may be partially
> accomplished as a ground test).

\(D\) Validate GPS navigation system accuracy by at least 5 low altitude
overflights of one or more surveyed locations (ensure survey point
coordinates are relative to WGS-84/NAD-83). An acceptable method of
conducting this accuracy demonstration is to accomplish low altitude
(less than 100 feet AGL) overflight of a runway threshold and record the
GPS position as the aircraft crosses the threshold. The system accuracy
is the distance between the coordinate position of the surveyed location
(runway threshold). Runway threshold coordinates may be obtained from
the airport operator. If coordinate data conversion WGS-84/NAD-83 is
necessary, contact the National Flight Data Center at (202) 267-9277.

> \(E\) Evaluation of the accessibility of all controls pertaining to
> the GPS installation.
>
> \(F\) Evaluation of the visibility of the controls, displays, and
> annunciators relating to the GPS installation during day and night
> lighting conditions. No distracting cockpit glare or reflections may
> be introduced and all controls must be illuminated for identification
> and ease of use. Flight lighting shall be consistent with other
> cockpit lighting.

8\. AIRWORTHINESS CRITERIA FOR

GPS INSTALLATIONS USED AS A

SUPPLEMENTAL NAVIGATION

SYSTEM UNDER INSTRUMENT

**FLIGHT RULES (IFR)**

a\. [Application Process.]{.underline}

> \(1\) The initial (first-time airworthiness approval) certification of
> a GPS navigation or sensor system requires extensive engineering and
> flight test evaluations and must be accomplished via the TC or STC
> approval process.
>
> \(2\) Subsequent (follow-on) installations of the same GPS navigation
> system (hardware and software) in other aircraft are approved using a
> less extensive evaluation process since the basic engineering design
> of the GPS equipment has already been evaluated. Approval of follow-on
> installations may be accomplished via the TC, STC, or FAA Form 337
> process. The extent of required evaluations depends upon the degree of
> integration of the GPS system with other aircraft systems, the
> similarity between the initial and follow-on aircraft models, and
> other changes that may have been incorporated in the GPS navigation
> system. The decision to allow an applicant to use FAA approved
> engineering data in support of an FAA Form 337 approval is left to the
>
> field inspector\'s judgment. The FAA Airworthiness
>
> Inspector\'s Handbook (FAA Order 8300.10) provides
>
> guidance applicable to GPS equipment installations. Changes to
> software accomplishing navigation, integrity, or availability
> functions or significant changes to operating limitations cannot be
> accomplished using the FAA Form 337 process.
>
> b\. [Airworthiness Considerations]{.underline}. GPS navigation
> equipment approved as a supplemental navigation system for oceanic and
> remote en route, domestic en route, terminal, and non-precision
> instrument approach (except localizer, LDA, and SDF) operations does
> not require TSO-C129 authorization, however it must meet the minimum
> navigation performance and operation standards of Class A1 or A2
> equipment, as applicable, specified in TSO-C129 and this AC.
> Airworthiness considerations should include the following:
>
> \(1\) [System Integrity and Software Development]{.underline}. Loss of
> navigation information is considered to be a major failure condition
> for the aircraft as defined in AC 25.1309-1A; AC 23.1309-A; AC 27-1;
> or AC 29-2A, as applicable to the aircraft. Providing/presenting
> hazardously misleading information to the flight crew is also
> considered to be a major failure condition for the aircraft. GPS
> navigation data is considered to be hazardously misleading when
> unannunciated position errors exist that are greater than those
> specified by the GPS position integrity performance requirements in
> Table 2-1 of RTCA/DO-208. The applicant should conduct a safety
> assessment of the GPS equipment installation to verify that design
> errors and failure modes that produce major failure conditions are
> improbable.
>
> \(2\) [Display Format/Operating Procedure Changes]{.underline}.
> Changes to navigational display formats and navigation/function
> operating procedures (implemented through hardware or software) may
> constitute major changes requiring additional evaluation.
>
> \(3\) [Location of the GPS Display]{.underline}. Each display element
> (i.e., the cross track deviation display (CDI), horizontal situation
> indicator (HSI), map display, etc.), used as a primary flight
> instrument in the guidance and control of
>
> the aircraft, for maneuver anticipation, or for
> failure/status/integrity annunciation, shall be located where it is
> visible to the pilot (in the pilot\'s primary field of view) with the
> least practicable deviation from the pilot\'s normal position and line
> of vision when looking forward along the flight path.
>
> **Note 1:** CDI displays contained in the CDU will most likely not be
> acceptable for IFR operations.
>
> **Note 2:** Flight technical error (FTE) can be reduced when numeric
> display information is integrated with the non-numeric display or is
> located within the pilot\'s primary field of view. Both digital cross
> track and track angle error have been shown to reduce FTE. This
> information should be displayed together (either within the CDU or
> remotely displayed near the non-numeric display) for better tracking
> performance. The use of non-numeric cross track data integrated with
> non-numeric track angle error data into one display may provide the
> optimum of situation and control information for the best overall
> tracking performance.
>
> \(4\) [Failure Protection]{.underline}. Any probable failure of the
> airborne GPS navigation system shall not degrade the normal operation
> of other required equipment or create a flight hazard. Likewise,
> normal operation of the GPS equipment installation shall not adversely
> affect the performance of other aircraft equipment. The interfaces
> with other aircraft equipment must be designed such that normal or
> abnormal GPS equipment operation shall not adversely affect the
> operation of other equipment nor shall normal or abnormal operation of
> other equipment adversely affect the GPS equipment operation.
>
> \(6\) [Electromagnetic Compatibility]{.underline}. The GPS navigation
> system should not be the source of objectionable electromagnetic
> interference, nor be adversely affected by electromagnetic
> interference from other equipment in the aircraft.
>
> \(8\) [System Controls, Displays and Annunciators]{.underline}. All
> displays, controls, and annunciators must be readable under all normal
> cockpit conditions and expected ambient light conditions (total
> darkness to bright reflected sunlight). Night lighting provisions must
> be compatible with other cockpit lighting. All displays and controls
> must be arranged to facilitate equipment usage. Controls that are
> normally adjusted in flight shall be accessible and properly labeled
> as to their function. System controls and displays shall be designed
> to maximize operational suitability and minimize pilot workload.
> System controls shall be arranged to provide adequate protection
> against inadvertent system turnoff. Reliance on pilot memory for
> operational procedures shall be minimized.
>
> \(9\) [Navigation Data Base]{.underline}. The GPS equipment shall
> incorporate an appropriately updatable navigation data base (in the
> WGS-84 or NAD-8 coordinate datum) containing at least the following
> location information in terms of latitude and longitude with a
> resolution of 0.01 minute or better for the area(s) in which IFR
> operations are to be conducted: all airports, VORs (and VORTACs),
> NDBs, and all named waypoints and intersections shown on en route and
> terminal area charts, Standard Instrument Departures (SIDs) and
> Standard Terminal Arrival Routes (STARs). For Class A1 equipment, the
> navigation data base must also include all waypoints and intersections
> included in published non-precision instrument approach (except
> localizer, LDA, and SDF) procedures. Instrument approaches must be
> conducted using a current data base. User entry or modification of
> navigation data base data shall not be possible. (This does not
> preclude the storage of \"user defined data\" within the equipment.)
> Additional data base coding, storage, and approach waypoint
> presentation requirements as specified in TSO-C129 must be provided.
> Navigation data bases shall meet the standards specified in sections
> 3, 4, and 5 of RTCA/DO-200, \"Preparation, Verification and
> Distribution of User Selectable Navigation Data Bases\" and sections 2
> through 7 of RTCA/DO-201, \"User Recommendations for Aeronautical
> Information Services.\"
>
> \(10\) [Pressure/Barometric Altitude Inputs]{.underline}. An
> appropriate input of pressure and/or barometric altitude must be
> provided to the GPS equipment.
>
> c\. [IFR Airworthiness Approval]{.underline}. There are two types of
> IFR airworthiness approval which differ significantly as to test
> requirements and data analysis.
>
> \(1\) [First-Time IFR Airworthiness Approval (for a Particular Type of
> GPS Equipment)]{.underline}. This type of approval refers to the very
> first time an applicant presents a particular (hardware and software
> configuration) model GPS navigation system for FAA airworthiness
> installation and approval and certification for IFR navigation use.
> The first approval for a particular GPS navigation system must be
> accomplished through the Type Certificate (TC) or Supplemental Type
> Certificate (STC) process. Each new model of GPS equipment or
> significant changes (hardware or software) to existing equipment shall
> undergo the same approval process as the original equipment unless it
> can be shown by analysis and tests acceptable to the administrator
> that the new model will function as well or better than the approved
> equipment. A first-time approval is conducted in four phases:
>
> \(i\) [Lab/Bench Tests and Equipment Data Evaluation]{.underline}.
> This phase consists of the following:
>
> \(C\) Verification of compliance with the minimum performance and
> operation standards applicable to Class A equipment specified in
> TSO-C129.
>
> \(D\) Analysis of failure modes and annunciations.
>
> \(F\) Evaluation of the ease of use of the controls and of the viewing
> ease (e.g., brightness, contrast, intensity, dimming, etc.) of the
> displays and annunciations from a human factors point of view.
>
> \(H\) Evaluation of the operator\'s manual (pilot\'s guide).
>
> \(ii\) [Aircraft Installation Data Evaluation]{.underline}. Normally
> the manufacturer of the GPS equipment will provide an aircraft as a
> test bed for the first time installation approval. This approval will
> serve as a basis for subsequent installation approvals regardless of
> aircraft type or model. The following assessments are to be made:
>
> \(B\) Evaluation of the cockpit layout of the installed equipment with
> emphasis on equipment controls, applicable circuit breakers (labels
> and accessibility), switching arrangement, and related indicators,
> displays, annunciators, etc.
>
> \(iv\) [Flight Test Evaluations]{.underline}. The flight tests are
> conducted to verify proper operation and accuracy of the GPS system in
> the aircraft. Flight tests should include at least the following:
>
> **Note**: Required flight evaluations for the first-time airworthiness
> approval of a particular GPS system are accomplished by the cognizant
> Aircraft Certification Office (ACO) unless specific tests are
> delegated by the ACO to a Flight Designated Engineering Representative
> (DER).
>
> \(A\) Evaluation of the overall operation of the GPS equipment is to
> include at least the following: the ability to readily create and
> modify a flight plan, perform \"DIRECT TO\" functions, hold a
> designated waypoint, intercept and track to or from a waypoint on a
> selected course, turn anticipation, waypoint sequencing, and the
> general presentation of navigational data (depiction of the \"TO\"
> waypoint, distance to waypoint, estimated time of arrival, estimated
> time en route, ground speed, etc.).
>
> \(B\) Review of various failure modes and associated annunciations,
> such as loss of electrical power, loss of signal reception, GPS
> equipment failure, autopilot/flight director response to GPS flags,
> etc.
>
> \(C\) Evaluation of steering response while autopilot and/or flight
> director is coupled to the GPS equipment during a variety of different
> track and mode changes. This evaluation shall include, as applicable,
> transition from en route to approach, transition to approach modes and
> vice-versa. Additionally, all available display sensitivities shall be
> evaluated.
>
> \(D\) Evaluation of displayed GPS navigation parameters on interfaced
> cockpit instruments such as HSI, CDI, distance display, electronic
> flight instruments system (EFIS), moving maps, fuel management
> systems, etc.
>
> \(G\) Evaluation of the accessibility of all controls pertaining to
> the GPS installation.
>
> \(H\) Evaluation of the visibility of the controls, displays, and
> annunciators relating to the GPS installation during day and night
> lighting conditions. No distracting cockpit glare or reflections may
> be introduced and all controls must be illuminated for identification
> and ease of use. Night lighting shall be consistent with other cockpit
> lighting.
>
> \(I\) Analysis of crew workload when operating the GPS equipment in
> association with other piloting requirements.
>
> \(J\) Validate GPS accuracy in each operating mode by at least 5 low
> altitude overflights of one or more surveyed locations (ensure survey
> point coordinates are relative to WGS-84 or NAD-83). An acceptable
> method of conducting this accuracy demonstration is to accomplish low
> altitude (less than 100 feet AGL) overflight of a runway threshold and
> record the GPS position as the aircraft crosses the threshold. The
> system accuracy is the distance between the coordinate position
> determined by the GPS and the
>
> coordinate position of the surveyed location (runway threshold).
> Runway threshold coordinates may be obtained from the airport
> operator. If coordinate data conversion to WGS-84/NAD-83 is necessary,
> contact the National Flight Data Center at (202) 267-9277.
>
> \(K\) Verify continuity of navigation data during normal aircraft
> maneuvering including holding patterns and turns at up to at least 30
> degrees of bank for one minute.
>
> \(L\) Verify that flight technical error (FTE) can be maintained at
> less than 1.0 nmi for en route, 1.0 nmi for approach transition, and
> 0.25 nmi for approach operating modes both with and without autopilot
> and /or flight director use, as applicable.
>
> \(M\) For equipment approved for approach, conduct a sufficient number
> of approaches and transitions from en route to terminal to approach
> operations using the navigation data base to verify proper operation
> of the GPS navigation system in the approach environment. This
> evaluation should include at least: turn anticipation, waypoint
> sequencing, display sensitivity changes, annunciations, procedure
> turns at the final approach fix (FAF), holding patterns at the missed
> approach holding fix, transitions from TO-FROM operation to TO-TO
> operation, heading legs after the initial approach fix (IAF) to
> intercept the final approach course both before and after the FAF, and
> DIRECT TO operation before and after the IAF.
>
> \(2\) [Follow-on IFR Airworthiness Installation
> Approvals]{.underline}. This type of approval refers to installation
> approvals after a first time airworthiness approval of the particular
> GPS equipment has been issued. Follow-on approvals may use the first
> time airworthiness approval, which was either a TC or an STC, as a
> basis for installation approval.
>
> \(iii\) Conduct a data evaluation similar to that outlined in
> paragraph 8c(1)(ii) of this AC.
>
> \(iv\) Conduct a functional flight evaluation covering the following
> items:
>
> \(A\) Overall operation of the installed GPS equipment, including
> interface from other equipment in the aircraft.
>
> \(C\) If interfaced with an autopilot and/or flight director, steering
> response while the autopilot and/or flight director is coupled to the
> GPS equipment.
>
> \(D\) Displayed GPS navigation parameters on all interfaced cockpit
> instruments.
>
> \(G\) Accessibility and visibility (day and night conditions) of all
> controls pertaining to the GPS installation
>
> \(H\) Validate GPS accuracy in each operating mode as specified in
> paragraph 8c(1)(iv)(J) of this AC.
>
> \(I\) Verify continuity of navigation data during 360 degree left and
> right turns at 30 degrees of bank.
>
> \(J\) Monitor displayed cross-track error during en route and, if
> applicable, approach transition and approach operations to verify FTE
> is less than 1.0 mi (en route and approach transition) and 0.25 nmi
> (approach), both with and without use of the autopilot and flight
> director (if installed).
>
> \(K\) For equipment approved for approach, conduct at least three
> published instrument approaches (retrieved from the data base) to
> verify proper operation of the equipment in the approach environment.
>
> **Note**: Required flight evaluations will be conducted by the
> cognizant Aircraft Certification Office (ACO) or, when authorized, by
> a flight test pilot designated engineering representative (DER) in
> accordance with the procedures used by the cognizant ACO. Depending
> upon the level of similarity between the initial and follow-on
> installations, including aircraft type, the ACO may accept flight
> evaluations conducted by the installer.

9\. OPERATIONAL CONSIDERATIONS

> c\. [Alternate Airport Requirement]{.underline}. An alternate airport
> (if required by the applicable operating rules) must be served by an
> approved instrument approach procedure based on a navigation system
> other than GPS and the aircraft must be properly equipped to conduct
> that approach.
>
> d\. [Operational Area]{.underline}. Operators and their flight crews
> must consult the approved flight manual supplement for their aircraft
> to determine approved operational areas that may apply to particular
> systems. Flight crews must be aware that operational areas for
> different systems may be different, and the appropriate operating
> area(s) for a particular system can only be determined by reference to
> the approved flight manual supplement or other FAA-approved documents.

**5. Information Separation**

a\. [Color Standardization]{.underline}

\(1\) Although color standardization is desirable, during the initial
certification of electronic displays color standards for symbology were
not imposed (except for cautions and warnings per 25.1322). At that time
the expertise did not exist within industry or the FAA, nor did
sufficient service experience exist, to rationally establish a suitable
color standard.

\(2\) In spite of the permissive CRT color atmosphere that existed at
the time of initial EFIS certification programs, an analysis of the
major certifications to date reveals many areas of common color design
philosophy; however, if left unrestricted, in several years there will
be few remaining common areas of color selection. If that is the case,
information transfer problems may begin to occur that have significant
safety implications. To preclude this, the following colors are being
recommended based on current day common usage. Deviations may be
approved with acceptable justification.

\(3\) The following depicts acceptable display colors related to their
functional meaning recommended for electronic display systems.

\(i\) Display features should be color coded as follows:

Warnings Red

Flight envelope and system limits Red

Cautions, abnormal sources Amber/Yellow

Earth Tan/Brown

Scales and associated figures White

Engaged modes Green

Sky Cyan/Blue

ILS deviation pointer Magenta

Flight director bar Magenta/Green

\(ii\) Specified display features should be allocated colors from one of
the following color sets:

+------------------------------------+-----------------+--------------+
|                                    | Color           | Color [Set   |
|                                    |                 | 2]           |
|                                    | [Set            | {.underline} |
|                                    | 1]{.underline}  |              |
+------------------------------------+-----------------+--------------+
| Fixed reference symbols            | White           | Yellow^\*^   |
|                                    |                 |              |
| Current data, values               | White           | Green        |
|                                    |                 |              |
| Armed modes                        | White           | Cyan         |
|                                    |                 |              |
| Selected data, values              | Green           | Cyan         |
|                                    |                 |              |
| Selected heading                   | Magenta^\*\*^   | Cyan         |
|                                    |                 |              |
| Active route/flight plan           | Magenta         | White        |
+------------------------------------+-----------------+--------------+

^\*^ The extensive use of the color yellow for other than
caution/abnormal information is discouraged.

^\*\*^ In color set 1, magenta is intended to be associated with those
analog parameters that constitute \"fly to\" or \"keep centered\" type
information.

\(iii\) Precipitation and turbulence areas should be coded as follows:

Precipitation 0 - 1 mm/hr Black

Precipitation 1 - 4 mm/hr Green

Precipitation 4 - 12 mm/hr Amber/Yellow

Precipitation 12 - 50 mm/hr Red

Precipitation above 50 mm/hr Magenta

Turbulence White or Magenta

\(iv\) Background color (gray or other shade)

Background color may be used to enhance display presentation.

\(4\) When there is a deviation from any of the above symbol color
assignments, the manufacturer should ensure that the chosen color set is
not susceptible to confusion or color meaning transference problems due
to dissimilarities with this standard. The FAA test pilot should be
familiar with other systems in use and evaluate the system specifically
for confusion in color meaning.

\(5\) The FAA does not intend to limit electronic displays to the above
colors, although they have been shown to work well. The colors available
from a symbol generator/display unit combination should be carefully
selected on the basis of their chrominance separation. Research studies
indicate that regions of relatively high color confusion exist between
red and magenta, magenta and purple, cyan and green, and yellow and
orange (amber). Colors should track with brightness so that chrominance
and relative chrominance separation are maintained as much as possible
over day-night operation. Requiring the flightcrew to discriminate
between shades of the same color for symbol meaning in one display is
not recommended.

\(6\) Chrominance uniformity should be in accordance with the guidance
provided in SAE Document ARP 1874. As designs are finalized, the
manufacturer should review his color selections to ensure the presence
of color works to the advantage of separating logical electronic display
functions or separation of types of displayed data. Color meanings
should be consistent throughout the color CRT displays in the cockpit.
In the past, no criteria existed requiring similar color schemes for
left and right side installations using electromechanical instruments.

b\. [Color Perception vs. Workload]{.underline}

\(1\) When color displays are used, colors should be selected to
minimize display interpretation workload. Symbol coloring should be
related to the task or crew operation function. Improper color coding
increases response times for display item recognition and selection, and
increases the likelihood of errors in situations where response rate
demands exceed response accuracy demands. Color assignments that differ
from other displays in use, either electromechanical or electronic, or
that differ from common usage (such as red, yellow, and green for
stoplights), can potentially lead to confusion and information
transferal problems.

\(2\) When symbology is configured such that symbol characterization is
not based on color contrast alone, but on shape as well, then the color
information is seen to add a desirable degree of redundancy to the
displayed information. There are conditions in which pilots whose vision
is color deficient can obtain waivers for medical qualifications under
Part 61 of the FAR. In addition, normal aging of the eye can reduce the
ability to sharply focus on red objects, or discriminate blue/green. For
pilots with such deficiency, display interpretation workload may be
unacceptably increased unless symbology is coded in more dimensions than
color alone. Each symbol that needs separation because of the
criticality of its information content should be identified by at least
two distinctive coding parameters (size, shape, color, location, etc.).

\(3\) Color diversity should be limited to as few colors as practical,
to ensure adequate color contrast between symbols. Color grouping of
symbols, annunciations, and flags should follow a logical scheme. The
contribution of color to information density should not make the display
interpretation times so long that the pilot perceives a cluttered
display.

c\. [Standard Symbology]{.underline}. Many elements of electronic
display formats lend themselves to standardization of symbology, which
would shorten training and transition times when pilots change airplane
types. At least one industry group (SAE) is working toward identifying
these elements and proposing suitable standards. Future revisions of
this advisory circular may incorporate the results of such industry
efforts.

d\. [Symbol Position]{.underline}

\(1\) The position of a message or symbol within a display conveys
meaning to the pilot. Without the consistent or repeatable location of a
symbol in a specific area of the electronic display, interpretation
errors and response times may increase. The following symbols and
parameters should be position consistent:

\(i\) Autopilot and flight director modes of operation.

\(ii\) All warning/caution/advisory annunciation locations.

\(iii\) All sensor data: altitude, airspeed, glideslope, etc.

\(iv\) All sensor failure flags. (Where appropriate, flags should appear
in the area where the data is normally placed.)

\(v\) Either the pointer or scale for analog quantities should be fixed.
(Moving scale indicators that have a fixed present value may have
variable limit markings.)

\(2\) An evaluation of the positions of the different types of alerting
messages and annunciations available within the electronic display
should be conducted, with particular attention given to differentiation
of normal and abnormal indications. There should be no tendency to
misinterpret or fail to discern a symbol, alert, or annunciation, due to
an abnormal indication being displayed in the position of a normal
indication, and having similar shape, size, or color.

\(3\) Pilot and copilot displays may have minor differences in format,
but all such differences should be evaluated specifically to ensure that
no potential for interpretation error exists when pilots make cross-side
display comparisons.

\(4\) If the display incorporates slow rate \"dithering\" to reduce
phosphor burn from stationary symbology, the entire display should be
moved at a slow rate in order to not change the spatial relationships of
the symbology collection as a whole.

> e\. [Clutter]{.underline}. A clutter display is one which uses an
> excessive number and/or variety of symbols, colors, or small spatial
> relationships. This causes increased processing time for display
> interpretation. One of the goals of display format design is to convey
> information in a simple fashion in order to reduce display
> interpretation time. A related issue is the amount of information
> presented to the pilot. As this increases, tasks become more difficult
> as secondary information may detract from the interpretation of
> information necessary for the primary task. A second goal of display
> format design is to determine what information the pilot actually
> requires in order to perform the task at hand. This will serve to
> limit the amount of information that needs to be presented at any
> point in time. Addition of information by pilot selection may be
> desirable, particularly in the case of navigational displays, as long
> as the basic display modes remain uncluttered after pilot deselection
> of secondary data. Automatic deselection of data has been allowed in
> the past to enhance the pilot\'s performance in certain emergency
> conditions (deselection of AFCS engaged mode annunciation and flight
> director in extreme attitudes).

g\. [Attention-Getting Requirements]{.underline}

\(1\) Some electronic display functions are intended to alert the pilot
to changes: navigation sensor status changes (VOR flag), computed data
status changes (flight director flag or commend cue removal), and flight
control system normal mode changes (annunciator changes from armed to
engaged) are a few examples. For the displayed information to be
effective as an attention-getter, some easily noticeable change must be
evident. A legend change by itself is inadequate to annunciate automatic
or uncommanded mode changes. Color changes may seem adequate in low
light levels or ambient light levels. Motion is an excellent
attention-getting device. Symbol shape changes are also effective, such
as placing a box around freshly changed information. Short-term flashing
symbols (approximately 10 seconds or flash until acknowledge) are
effective attention-getters. A permanent or long-term flashing symbol
that is noncancellable should not be used.

\(2\) In some operations, continued operation with inoperative equipment
is allowed (under provisions of an MEL). The display designer should
consider the applicant\'s MEL desires, because in some cases a
continuous strong alert may be too distracting for continued dispatch.

> h\. [Color Drive Failure]{.underline}. Following a single color drive
>
> failure, the remaining symbology should not present
>
> misleading information, although the display does not
>
> have to be usable. If the failure is obvious, it may be
>
> assumed that the pilot will not be susceptible to
>
> misleading information due to partial loss of
>
> symbology. To make this assumption valid, special
>
> cautions may have to be included in the AFM
>
> procedures that point out to the pilot that important
>
> information formed from a single primary color may be

lost, such as red flags.

**6. Display Visual Characteristics**

b\. [Chromaticity and Luminance]{.underline}.

\(1\) Readability of the displays should be satisfactory in all
operating and environmental lighting conditions expected in service.
Four light conditions known to be critical for testing are:

\(i\) Direct sunlight on the display through a side cockpit window
(usually short term with conventional window arrangements).

\(ii\) Sunlight through a front window illuminating white shirts which
are reflected in the CRT (a function of the CRT front plate filter).

\(iii\) Sun above the forward horizon and above a cloud deck in the
pilot\'s eyes (usually a prolonged situation and the most critical of
these four).

\(iv\) Night and/or dark environment. Brightness should be controllable
to a dim enough setting such that outside vision is not impaired while
maintaining an acceptable presentation.

\(2\) When displays are evaluated in these critical lighting situations,
the display should be adjusted to a brightness level representative of
that expected at the end of the CRT\'s normal useful life (5,000 to
20,000 hours), or adjusted to a brightness level selected by the
manufacturer as the minimum acceptable output and measurable by some
readily accomplishment maintenance tests. If the former method is used,
adequate evaluations should be performed to ensure that the expected end
of life brightness levels are met. Some manufacturers have found, and
the FAA has accepted, that 50 percent of original brightness level is a
realistic end of life value. If the latter method is used, procedures
should be established to require periodic inspections, and these limits
should then become part of the service life limits of the airplane
system.

\(3\) Large fields used in color displays as background (e.g., blue sky
and brown earth for attitude) for primary flight control symbols need
not be easily discriminated in these high ambient light levels, provided
the proper sense of the flight control information is conveyed with a
quick glance.

\(4\) Electronic display systems should meet the luminance (photometric
brightness) levels of SAE Document ARP 1874. A system designed to meet
these standards should be readily visible in all the lighting conditions
listed in paragraphs 6b(1) and 6b(2), and should not require specific
flight testing for luminance if the system has been previously installed
in another airplane with similar cockpit window arrangements. If the
display evaluation team feels that some attributes are marginal under
extreme lighting conditions, the following guidelines may be used:

\(i\) The symbols that convey quick-glance attitude and flight path
control information (e.g., horizon line, pitch scale, fixed airplane
symbol and/or flight path symbol, sky pointer and bank indices, flight
director bars) should each have adequate brightness contrast with its
respective background to allow it to be easily and clearly discernible.

\(ii\) The combination of color and brightness of any subset of these
symbols which may, due to relative motion of a dynamic display, move
adjacent to each other and use color as an aid for symbol separation
(e.g., flight director bars and fixed airplane symbol), should render
each symbol distinctly identifiable in the worst case juxtaposition.

\(iii\) Flags and annunciations that may relate to events of a time
critical nature (including warnings and cautions defined in paragraph 10
of this AC, as well as flight control system annunciations of mode
reversions) should have a sufficient contrast with their background and
immediate environment to achieve an adequate level of attensity
(attention getting properties). Color discrimination in high brightness
ambient levels may not be necessary if the symbol remains unambiguous
and clearly distinct from adjacent normal state or alphanumeric
characters.

\(iv\) Analog scale displays (heading, air data, engine data, CDIs, or
course lines) should each have adequate brightness with its respective
background to allow it to be easily and clearly discernible. Colored
warning and caution markings on scales should retain color
discrimination. Symbols used as targets and present value pointers in
juxtaposition to a scale should remain distinct. If color is required to
convey the meaning of similar shaped targets or indices, the color
should remain easily discernible.

\(v\) Flags and annunciations should still be visible at low display
brightness when the display is adjusted to the lowest usable level for
flight with normal symbology (day or night).

\(vi\) Raster fields conveying information such as weather radar
displays should allow the raster to be independently adjustable in
luminance from overlaid stroke symbology. The range of luminance control
should allow detection of color difference between adjacent small raster
areas no larger than 5 milliradians in principal dimension; while at
this setting, overlying map symbology, if present, should be
discernible.

**18B. The Flight Test Pilot/Engineer are requested to:**

c\) Evaluate steering response while the autopilot is coupled to the GPS
during a variety of different track and mode changes. This evaluation
should include transition from en route to approach transition to
approach modes and vice-versa. All available display sensitivities shall
be evaluated.

f\) Verify satisfactory electromagnetic compatibility between the GPS
installation and other onboard equipment (can be partially accomplished
as a ground test). Demonstrate satisfactory isolation from harmonic
interference of VHF communication transceivers by tuning each VHF
transmitter to the frequencies listed below for a period of 20 seconds
while observing the signal status of each satellite being received.
Degradation of individually received satellite signals below a point
where navigation is no longer possible is not acceptable. This
evaluation should be accomplished in each operating mode.

+---------------------------------------+------------------------------+
| 121.150 MHz                           | 131.250 MHz                  |
|                                       |                              |
| 121.175 MHz                           | 131.275 MHz                  |
|                                       |                              |
| 121.200 MHz                           | 131.300 MHz                  |
+---------------------------------------+------------------------------+

NOTE: Reevaluation of installed VHF transceiver performance is not
necessary if the filter insertion loss is 2 dB or less.

h\) Evaluate visibility of all controls, displays, and annunciators
relating to the GPS 155 installation during day and night lighting
conditions. No distracting cockpit glare or reflections may be
introduced and all controls must be illuminated for identification and
ease of use. Night lighting shall be consistent with other cockpit
lighting.

i\) Conduct an analysis of crew workload when operating the GPS 155
system in association with other piloting requirements. This evaluation
should include all operating modes, transition between modes, instrument
approaches, en route operations, accomplishment of SIDs and STARs, etc.
The pilot workload subjective evaluation forms attached to this TIA
should be used to complete this evaluation.

j\) Validate GPS 155 accuracy in each operating mode by conducting at
least 5 low altitude passes (\<100 ft AGL) over one or more surveyed
locations (survey location data must be in either the WGS-84 or NAD-83
coordinate datum). The displayed GPS 155 position shall be recorded when
the aircraft crosses the designated location and compared to the known
location coordinates. System accuracy is the difference between the
coordinate position determined by the GPS 155 and the coordinate
position of the surveyed location. Accuracy requirements are 0.124 nm in
the en route and terminal modes and 0.056 nm in the approach mode.

k\) Verify continuity of navigation data during normal aircraft
maneuvering, including holding patterns and turns at up to at least 30
degrees of bank for one minute.

l\) Verify that flight technical error (FTE) can be maintained at less
than 1.0 nm for en route, 1.0 nm for approach transition, and 0.25 nm
for approach operating modes both with and without autopilot use.

m\) Conduct a sufficient number of approaches and transitions from en
route to terminal to approach operations using the navigation system in
the approach environment. A variety of approach geometries and general
arrangements should be used. Operations should include air traffic
vectoring and pilot navigation. This evaluation should include at least:

\(1\) Turn anticipation

\(2\) Waypoint sequencing

\(3\) Display sensitivity changes

\(4\) Annunciations

\(5\) Procedure turns at the final approach fix (FAF)

\(6\) Holding patterns at the missed approach holding fix

\(7\) Transitions from TO-FROM operation to TO-TO operation

\(8\) Heading legs after the initial approach fix (IAF) to intercept the
final approach course both before and after the FAF

\(9\) DIRECT TO operation before and after the IAF

**5.1 Control/Display Integration**

**5.1.1.1 Relationship**

The relationships of a control to its associated display and the display
to the control shall be immediately apparent and unambiguous to the
operator. Controls should be located adjacent to (normally under or to
the right of) their associated displays and positioned so that neither
the control nor the hand normally used for setting the control will
obscure the display.

**5.1.1.2 Design**

Control-display relationships shall be apparent through proximity,
similarity of groupings, coding, framing, labeling, and similar
techniques.

**5.1.2.1 Functional Grouping**

Functionally related controls and displays shall be located in proximity
to one another\--arranged in functional groups (e.g., power, status,
test).

**5.1.2.1.1 Functional Group Arrangement**

**5.1.2.1.1.1 Sequence**

Functional groups of controls and displays shall be located to provide
for left-to-right (preferred) or top-to-bottom order of use, or both.

**5.1.2.1.1.2 Access**

Providing that the integrity of grouping by function and sequence is not
compromised, the more frequently used groups and the most important
groups should be located in areas of easiest access. Control-display
groups required solely for maintenance purposes shall be located in
positions providing a lesser degree of access relative to operating
groups.

**5.1.2.1.1.3 Functional Group Marking**

Functional groups may be set apart by outlining with contrasting lines
which completely encompass the groups. Where such coding is specified by
the procuring activity, and where gray panels are used, noncritical
functional groups (i.e., those not associated with emergency operations)
shall be outlined with a 1.5 mm (1/16 in) black border (27038 of
FED-STD-595), and those involving emergency or extremely critical
operations shall be outlined with a 5 mm (3/16 in) red border (21136 of
FED-STD-595). As an alternate method, contrasting color pads or patches
may be used to designate both critical and noncritical functional areas,
subject to prior approval by the procuring activity. When red
compartment lighting is used, an orange-yellow (23538 of FED-STD-595)
and black (27038 of FED-STD-595) striped border shall be used to outline
functional groups involving emergency or extremely critical operations.
Control-display areas in aircraft crew stations shall be delineated in
accordance with MIL-M-18012.

**5.1.2.1.1.4 Consistency**

Location of recurring functional groups and individual items shall be
similar from panel to panel. Mirror image arrangements shall not be
used.

**5.1.2.3 Arrangement Within Groups**

Controls and displays within functional groups shall be located
according to operational sequence or function, or both.

**5.2 Visual Displays**

**5.2.1.1 Display Illumination**

When the degree of dark adaptation required is not maximum, low
brightness white light (preferably integral), adjustable as appropriate,
shall be used; however, when complete dark adaptation is required, low
luminance (0.07-0.34 cd/m^2^) red light (greater than 620 nm) shall be
provided.

**5.2.1.2 Light Distribution**

Where multiple displays are grouped together, the displays shall appear
of equal brightness across the range of full ON to full OFF. Light
distribution for integrally illuminated instruments shall be
sufficiently uniform such that the ratio of standard deviation of
indicator element luminances to mean indicator luminance shall not be
more than 0.25, using eight or more equally spaced test measurements.

**5.2.1.4.4 Reflection**

Displays shall be constructed, arranged, and mounted to prevent
reduction of information transfer due to the reflection of the ambient
illumination from the display cover. Reflection of instruments and
consoles in windshields and other enclosures shall be avoided. If
necessary, techniques (such as shields and filters) shall be employed to
insure that system performance will not be degraded.

**5.2.2 Transilluminated Displays**

**5.2.2.1.9 Luminance**

The luminance of transilluminated displays shall be compatible with the
expected ambient illuminance level, and shall be at least 10% greater
than the surrounding luminance. Where glare must be reduced, the
luminance of transilluminated displays should not exceed 300% of the
surrounding luminance.

**5.2.2.1.10 Luminance Control**

When displays will be used under varied ambient illuminance, a dimming
control shall be provided. The range of the control shall permit the
displays to be legible under all expected ambient illuminance. The
control shall be capable of providing multiple step or continuously
variable illumination. Dimming to full OFF may be provided in
non-critical operations, but shall not be used if inadvertent failure to
turn on an indicator could lead to critical operator failures (i.e.,
failure to detect or perform a critical step in an operation).

**5.2.2.1.11 False Indication or Obscuration**

Provision shall be made to prevent direct or reflected light from making
indicators appear illuminated when they are not, or to appear
extinguished when they are illuminated. Self-reflection shall be
minimized by proper orientation of the display with respect to the
observer.

**5.2.2.1.12 Contrast Within the Indicator**

The luminance contrast (see 3.17) within the indicator shall be at least
50%. This 50% luminance contrast requirement does not apply to special
displays specifically designed for legibility in sunlight or where
legibility is obtained through color contrast (and other techniques)
rather than luminance contrast. For low ambient illumination
applications (e.g., MIL-L-25467), this ratio should be at least 90% (see
3.17), with the background luminance less than the figure luminance.

**5.2.2.1.18 Color Coding**

With the exception of aircrew station signals which shall conform to
MIL-STD-411, and training equipment which shall conform to MIL-T-23991,
transilluminated displays shall conform to the following color coding
scheme, in accordance with Type I - Aviation colors of MIL-C-25050.

a\. RED shall be used to alert an operator that the system or any
portion of the system is inoperative, or that a successful mission is
not possible until appropriate corrective or override action is taken.
Examples of indicators which should be coded RED are those which display
such information as \"no-go\", \"error\", \"failure\", \"malfunction\",
etc.

b\. FLASHING RED shall be used only to denote emergency conditions which
require operator action to be taken without undue delay, or to avert
impending personnel injury, equipment damage, or both.

c\. YELLOW shall be used to advise an operator that a condition exists
which is marginal. YELLOW shall also be used to alert the operator to
situations where caution, recheck, or unexpected delay is necessary.

d\. GREEN shall be used to indicate that the monitored equipment is in
tolerance or a condition is satisfactory and that it is all right to
proceed (e.g., \"go-ahead\", \"in-tolerance\", \"ready\", \"function
activated\").

e\. WHITE shall be use to indicate system conditions that do not have
\"right\" or \"wrong\" implications, such as alternative functions
(e.g., Missile No. 1 selected for launch, etc.) or transitory conditions
(e.g., action or test in progress, function available), provided such
indication does not imply success or failure of operations.

f\. BLUE may be used for an advisory light, but preferential use of BLUE
should be avoided.

**5.2.2.1.19 Flashing Lights**

The use of flashing lights shall be minimized. Flashing lights should be
used only when it is necessary to call the operator\'s attention to some
condition requiring immediate action. The flash rate shall be within 3
to 5 flashes per second with approximately equal amounts of ON and OFF
time. Flashing lights which could be simultaneously active should have
synchronized flashes. If the indicator is energized and the flasher
device fails, the light shall illuminate and burn steadily (see
5.3.2.4).

**5.2.2.2.3 Positive vs. Negative Legend**

When the operator\'s dark adaptation must be maintained, or where
legibility in high ambient illumination is critical, illumination
label/opaque background format shall be used and illuminated
background/opaque label format shall be used only for critical alerting
indicators (e.g., master warning lights). Where operator dark adaptation
is not required, illuminated background/opaque label format should be
used; contrast reversal may be employed under these conditions to
designate displays which have physical appearance similar to legend
switches on the same panel.

**5.2.2.2.5 Visibility and Legibility**

In other than aircrew stations, and with the exception of warning and
caution indicators, the lettering on single-legend indicators shall be
visible and legible whether or not the indicator is energized.

**5.2.4 Cathod Ray Tube (CRT) Displays**

**5.2.4.1 Signal Size**

When a target of complex shape is to be distinguished from a nontarget
shape that is also complex, the target signal should subtend not less
than 6 mrad (20 minutes) of visual angle and should subtend not less
than 10 lines or resolution elements. Image quality shall be consistent
with the operator\'s needs.

**5.2.4.2 Viewing Distance**

A 400 mm (16 in) viewing distance shall be provided whenever
practicable. When periods of scope observation will be short, or when
dim signals must be detected, the viewing distance may be reduced to 250
mm (10 in). Design should permit the observer to view the scope from as
close as desired. Displays which must be placed at viewing distances
greater than 400 mm (16 in) due to other considerations shall be
appropriately modified in aspects such as display size, symbol size,
brightness ranges, line-pair spacing, and resolution.

**5.2.4.3 Screen Luminance**

The ambient illuminance shall not contribute more than 25% of screen
brightness through diffuse reflection and phosphor excitation. A control
shall be provided to vary the CRT luminance from 10% of minimum ambient
luminance to full CRT luminance. A control shall be provided to vary the
luminous symbol/dark background or dark symbol/luminous background
contrast ratio. Contrast adjustment shall not be included in flight deck
displays because they are disallowed by FAA regulation.

**5.2.4.5 Luminance Range of Adjacent Surfaces**

The luminance range of surfaces immediately adjacent to scopes shall be
between 10% and 100% of screen background luminance. With the exception
of emergency indicators, no light source in the immediate surrounding
area shall be of a greater luminance than the CRT signal.

**5.2.4.6 Ambient Illuminance**

The ambient illuminance in the CRT area shall be appropriate for other
visual functions (e.g., setting controls, reading instruments,
maintenance) but shall not interfere with the visibility of signals on
the CRT display. When a CRT display is used in variable ambient
illuminance, illuminance controls shall be provided to dim all light
sources, including illuminated panels, indicators and switches in the
immediate surround. Automatic adjustment of CRT brightness may be used
if the CRT brightness is automatically adjusted as a function of ambient
illuminance and the range of automatic adjustment is adequate for the
full range of ambient illuminance.

**5.2.4.7 Reflected Glare**

Reflected glare shall be minimized by proper placement of the scope
relative to the light source, use of a hood or shield, or optical
coatings on the CRT or filter control over the light source.

**5.2.6 Other Displays**

**5.2.6.8.3 Symbol Definition**

The smallest definition for a dot matrix shall be 5 by 7 dots, with 7 by
9 preferred. If system requirements call for symbol rotation, a minimum
of 8 by 11 is required, with 15 by 21 preferred.

**5.2.6.8.4 Alphanumeric Character and Symbol Sizes**

Alphanumeric and symbolic characters shall not subtend less than 4.7
mrad (16 min) of visual angle. Flight display characters, which must be
read under aircraft environmental conditions, shall not subtend less
than 7 mrad (24 min) of visual angle.

**5.2.6.8.5 Use of Upper Case**

Alphanumeric characters shall be upper case.

**5.2.6.8.6 Viewing Angle**

The optimum viewing angle is perpendicular to the display. Dot matrix or
segmented displays should not be presented for viewing at an angle
larger than 610 mrad (35°) off axis.

**5.2.6.8.7 Emitter Color**

Monochromatic displays shall use the following colors in order of
preference: green (555nm), yellow (575nm), orange (585nm), and red
(660nm). Blue emitters should be avoided.

**5.2.6.8.8 Intensity Control**

Dimming controls shall be provided where applicable to maintain
appropriate legibility and operator dark adaptation level.

**5.3 Audio Displays**

**5.3.2.2.2 Single Element Signal**

When reaction time is critical, signals shall be of short duration. If a
single element signal is permissible, all essential information shall be
transmitted in the first 0.5 second.

**5.3.2.3 Caution Signals**

Caution signals shall be readily distinguishable from warning signals
and shall be used to indicate conditions requiring awareness, but not
necessarily immediate action.

**5.3.3.1 Frequency**

**5.3.3.1.1 Range**

The frequency range shall be between 200 and 5,000 Hz and, if possible,
between 500 and 3,000 Hz. When signals must travel over 300 m (985 ft),
sounds with frequencies below 1,000 Hz should be used. Frequencies below
500 Hz should be used when signals must bend around obstacles or pass
through partitions. The selected frequency band shall differ from the
most intense background frequencies and shall be in accordance with
other criteria in this section.

**5.3.3.1.2 Spurious Signals**

The frequency of a warning tone shall be different from that of the
electric power employed in the system, to preclude the possibility that
a minor equipment failure may generate a spurious signal.

**5.3.3.2.2.3 Discomfort**

Audio warning signals should not be of such intensity as to cause
discomfort or \"ringing\" in the ears as an after-effect.

**5.3.4.1 Audibility**

A signal-to-noise ratio of at least 20 dB shall be provided in at least
one octave band between 200 and 5,000 Hz at the operating position of
the intended receiver.

**5.3.4.2.4 Headset**

When the operator is wearing earphones covering both ears during normal
equipment operation, the audio warning signal shall be directed to the
operator\'s headset as well as to the work area. Binaural headsets
should not be used in any operational environment below 85 dB (A) when
that environment may contain sounds that provide the operator with
useful information when that information cannot be directed to the
operator\'s headset. Such sounds may include voices, machine noise that
indicates wear or malfunction, and other auditory indications of system
performance/mission status.

**5.3.4.3 Discriminability**

**5.3.4.3.1 Use of Different Characteristics**

When several different audio signals are to be used to alert an operator
to different types of conditions, discriminable difference in intensity
pitch or use of beats and harmonics shall be provided. If absolute
discrimination is required, the number of signals to be identified shall
not exceed four.

**5.3.4.3.2 Coding**

Where discrimination of warning signals from each other will be critical
to personnel safety or system performance, audio signals shall be
appropriately coded. Alarms that are perceptibly different shall
correlate with different conditions requiring critically different
operator responses (e.g., maintenance, emergency conditions, and health
hazards). Such signals shall be sufficiently different to minimize the
operator\'s search of visual displays.

**5.3.4.3.5 Differentiation from Routine Signals**

Audio alarms intended to bring the operator\'s attention to a
malfunction or failure shall be differentiated from routine signals,
such as bells, buzzers, and normal operation noises.

**5.3.4.3.6 Prohibited Types of Signals**

The following types of signals shall not be used as warning devices
where possible confusion might exist because of the operational
environment:

a\. Modulated or interrupted tones that resemble navigation signals or
coded radio transmissions.

b\. Steady signals that resemble hisses, static, or sporadic radio
signals.

c\. Trains of impulses that resemble electrical interference whether
regularly or irregularly spaced in time.

d\. Simple warbles which may be confused with the type made by two
carriers when one is being shifted in frequency
(beat-frequency-oscillator effect).

**5.3.4.3.6 Prohibited Types of Signals (Continued)**

e\. Scramble speech effects that may be confused with cross modulation
signals from adjacent channels.

f\. Signals that resemble random noise, periodic pulses, steady or
frequency modulated simple tones, or any other signals generated by
standard countermeasure devices (e.g., \"bagpipes\").

g\. Signals similar to random noise generated by air conditioning or any
other equipment.

**5.3.4.5 Masking**

**5.3.4.5.1 Other Critical Channels**

Audio warning signals shall not interfere with any other critical
functions or warning signals, or mask any other critical audio signals.

**5.3.5.2 Intensity**

Verbal alarms for critical functions shall be at least 20 dB above the
speech interference level at the operating position of the intended
receiver.

**5.3.5.3.1 Type of Voice**

The voice used in recording verbal warning signals shall be distinctive
and mature.

**5.3.5.4 Speech Processing**

Verbal warning signals shall be processed only when necessary to
increase or preserve intelligibility, such as by increasing the strength
of consonant sounds relative to vowel strength. Where a signal must be
relatively intense because of high ambient noise, peak-clipping (see
3.24) may be used to protect the listener against auditory overload.

**5.3.5.5 Message Content**

In selecting words to be used in audio warning signals, priority shall
be given to intelligibility, aptness, and conciseness in that order.

**5.3.5.6.1 Critical Warning Signals**

Critical warning signals shall be repeated with not more than a 3-second
pause between messages until the condition is corrected or overridden by
the crew.

**5.3.6.1 Automatic or Manual Shut-Off**

When an audio signal is designed to persist as long as it contributes
useful information, a shut-off switch controllable by the operator, the
sensing mechanism, or both, shall be provided, depending on the
operational situation and personnel safety factors.

**5.3.6.5 Duration**

Audio warning signal duration shall be at least 0.5 second, and may
continue until the appropriate response is made. Completion of a
corrective action by the operator or by other means shall automatically
terminate the signal.

**5.3.12 Speech Intelligibility**

**5.3.12.1 General**

When information concerning the speech intelligibility of a system is
required, three recommended methods are available, with the appropriate
selection being dependent upon the requirements of the test.

a\. The ANSI standard method of measurement of phonetically balanced
(PB) monosyllabic word intelligibility, S3.2-1960, should be used when a
high degree of test sensitivity and accuracy is required.

**5.3.12.1 General (Continued)**

b\. The modified rhyme test (MRT) (See Human Engineering Guide to
Equipment Design) should be used if the test requirements are not as
stringent or if time and training do not permit the use of the ANSI
method.

c\. The articulation index (AI) calculations should be used for
estimations, comparisons and predictions of system intelligibility based
upon ANSI S3.5-1969.

**5.4 Controls**

**5.4.1.2 Direction of Movement**

**5.4.1.2.1 Consistency of Movement**

Direction of control movement shall be consistent with the related
movement of an associated display, equipment component, or vehicle. In
general, movement of a control forward, clockwise, to the right, or up,
or pressing a control, shall turn the equipment or component on, cause
the quantity to increase, or cause the equipment or component to move
forward, clockwise, to the right, or up. Valve controls are excepted
(see 5.4.1.2.4).

**5.4.1.3 Arrangement and Grouping**

**5.4.1.3.1 Grouping**

All controls which function in sequential operation necessary to a
particular task, or which operate together, shall be grouped together
along with their associated displays. When several steps of a sequence
are selected by one control, the steps shall be arranged by order of
occurrence to minimize control movements and prevent cycling through
unnecessary steps. Cycling through the control\'s ON/OFF position shall
be avoided.

**5.4.1.3.3 Location of Primary Controls**

The most important and frequently used controls shall have the most
favorable position with respect to ease of reaching and grasping
(particularly rotary controls and those requiring fine settings).

**5.4.1.3.4 Consistency**

The arrangement of functionally similar, or identical, primary controls
shall be consistent from panel to panel throughout the system,
equipment, or vehicle (e.g., a movement of a control to the right or
left should result in a corresponding movement of a display element to
the right or left).

**5.4.1.4 Coding**

**5.4.1.4.1 Methods and Requirements**

The use of a coding mode (e.g., size and color) for a particular
application shall be governed by the relative advantages and
disadvantages of each type of coding. Where coding is used to
differentiate among controls, application of the code shall be uniform
throughout the system. (See Table VIII for advantages and
disadvantages).

**5.4.1.4.3 Size Coding**

No more than three different size of controls shall be used in coding
controls for discrimination by absolute size. Controls used for
performing the same function on different items of equipment shall be
the same size. When knob diameter is used as the coding parameter,
differences between diameters shall not be less than 13 mm (0.5\"). When
knob thickness is the coding parameter, differences between thickness
shall not be less than 10 mm (0.4\").

**5.4.1.4.4 Shape-Coding**

Primary use of shape coding for controls is for identification of
control knobs or handles by \"feel;\" however, shapes shall be
identifiable both visually and tactually. When shape coding is used:

a\. The coded feature shall not interfere with ease of control
manipulation.

b\. Shapes shall be identifiable by the hand regardless of the position
and orientation of the control knob or handle.

c\. Shapes shall be tactually identifiable when gloves are worn, where
applicable.

d\. A sufficient number of identifiable shapes shall be provided to
cover the expected number of controls that require tactual
identification.

e\. Shape coded knobs and handles shall be positively and non-reversibly
attached to their shafts to preclude incorrect attachment when
replacement is required.

f\. Shapes should be associated with or resemble control functions, and
not alternate functions.

**5.4.1.4.5 Color-Coding**

**5.4.1.4.5.1 Choice of Colors**

Controls shall be black (17038, 27038 or 37038) or gray (26231 or
36231). If color coding is required, only the following colors
identified in FED-STD-595 shall be selected for control coding.

a\. Red, 11105, 21105, 31105

b\. Green, 14187

c\. Orange-Yellow, 13538, 23538, 33538

d\. White, 17875, 27875, 37875

e\. Blue, 15123 shall be used if an additional color is absolutely
necessary.

**5.4.1.4.5.2 Immediate Action Controls**

Color coding of immediate action controls for aircraft shall conform to
MIL-M-18012.

**5.4.1.4.5.3 Relation to Display**

When color-coding must be used to relate a control to its corresponding
display, the same color shall be used for both the control and the
display.

**5.4.1.4.5.4 Control Panel Contrast**

The color of the control shall provide contrast between the panel
background and the control.

**5.4.1.4.5.5 Ambient Lighting and**

**Color-Coding Exclusion**

Color coding shall be compatible with anticipated ambient lighting
throughout the mission. Color-coding shall not be used as a primary
identification medium if the spectral characteristics of ambient light
during the mission, or the operator\'s adaptation to that light, varies
as the result of such factors as solar glare, filtration of light, and
variation from natural to artificial light. If red lighting is to be
used during a portion of the mission, controls which would otherwise be
coded red shall be coded by orange-yellow and black striping.

**5.4.1.8 Prevention of Accidental Actuation**

**5.4.1.8.1 Location and Design**

Controls shall be designed and located so that they are not susceptible
to being moved accidentally, particularly critical controls whose
inadvertent operation might cause damage to equipment, injury to
personnel or degradation of system functions.

**5.4.1.8.3 Rapid Operation**

Any method of protecting a control from inadvertent operation shall not
preclude operation within the time required.

**5.4.1.8.4 Methods**

For situations in which controls must be protected from accidental
actuation, one or more of the following methods, as applicable, shall be
used:

a\. Locate and orient the controls so that the operator is not likely to
strike or move them accidentally in the normal sequence of control
movements.

b\. Recess, shield, or otherwise surround the controls by physical
barriers. The control shall be entirely contained within the envelope
described by the recess or barrier.

c\. Cover or guard the controls. Safety or lock wire shall not be used.

d\. Provide the controls with interlocks so that extra movement (e.g., a
side movement out of a detent position or a pull-to-engage clutch) or
the prior operation of a related or locking control is required.

e\. Provide the controls with resistance (i.e., viscous or coulomb
friction, spring-loading, or inertia) so that definite or sustained
effort is required for actuation.

f\. Provide the controls with a lock to prevent the control from passing
through a position without delay when strict sequential activation is
necessary (i.e., the control moved only to the next position, then
delayed).

g\. Design the controls for operation by rotary action.

**5.4.2 Rotary Controls**

**5.4.2.1 Discrete Rotary Controls**

**5.4.2.2.1.2 Dimensions, Torque and Separation**

The dimensions of knobs shall be within the limits specified in Figure
7. Within these ranges, knob size is relatively unimportant, provided
the resistance is low and the knob can be easily grasped and
manipulated. When panel space is extremely limited, knobs should
approximate the minimum values and should have resistance as low as
possible without permitting the setting to be changed by vibration or
merely touching the control. Resistance and separation between adjacent
edges of knobs shall conform to Figure 7.

**5.4.2.2.2 Ganged Control Knobs**

**5.4.2.2.2.1 Application**

Ganged knob assemblies may be used in limited applications when panel
space is at a premium. Two-knob assemblies are preferred. Three-knob
configurations should be avoided. Ganged knob configurations should not
be used under the following conditions:

a\. Extremely accurate or rapid operations are required.

b\. Frequent changes are necessary.

c\. Heavy gloves must be worn by the operator.

d\. Equipment is exposed to the weather or used under field conditions.

**5.4.2.2.2.2 Dimensions and Separation**

Dimensions and separation should conform to Figure 8.

**5.4.2.2.2.3 Resistance**

Resistance shall conform to requirements in Figure 8. Knobs should be
serrated. Fine serrations should be used on precise adjustment knobs;
coarse serrations should be used on gross adjustment knobs.

**5.4.2.2.2.4 Marking**

An indexing mark or pointer shall be provided on each knob. Marks or
pointers should differ sufficiently to make it apparent which knob
indexing mark is being observed.

**5.4.2.2.2.5 Knob/Display Relationship**

When each knob of a ganged assembly must be related to an array of
visual displays, the knob closest to the panel shall relate to the
left-most display in a horizontal array, or the uppermost display in a
vertical array (see Figure 8).

**5.4.2.2.2.6 Inadvertent Operation**

When it is critical to prevent inadvertent activation of one knob as the
other is being adjusted, a secondary knob control movement shall be
required (e.g., pressing the top knob before it can be engaged with its
control shaft). Where inadvertent movement is undesirable but not
necessarily critical, knob diameter/depth relationships should be
optimized as shown in Figure 8. Contrasting colors between knobs may
also be used to improve individual knob identification.

**5.4.3 Linear Control**

**5.4.3.1.1 Push Buttons (Finger or Hand Operated)**

**5.4.3.1.1.1 Use**

Push buttons should be used when a control or an array of controls is
needed for momentary contact or for activating a locking circuit,
particularly in high-frequency-of-use situations. Push buttons should
not be used for discrete control where the functions status is
determined exclusively by position of the switch (i.e., an on-off push
button that is pressed in and retained to turn a circuit on and pressed
again to release the push button and turn the circuit off).

**5.4.3.1.1.2 Shape**

The push button surface should normally be concave (indented) to fit the
finger. When this is impractical, the surface shall provide a high
degree of frictional resistance to prevent slipping.

**5.4.3.1.1.3 Positive Indication**

A positive indication of control actuation shall be provided (e.g., snap
feel, audible click, or integral light).

**5.4.3.1.1.4 Channel or Cover Guard**

A channel or cover guard shall be provided when it is imperative to
prevent accidental actuation of the controls. When a cover guard is in
the open position, it shall not interfere with operation of the
protected device or adjacent controls.

**5.4.3.1.1.5 Dimensions, Resistance,**

**Displacement, and Separation**

Except for use of push buttons in keyboards, control dimensions,
resistance, displacement, and separation between adjacent edges of
finger or hand-operated push buttons shall conform to the criteria in
Figures 11A and 11B.

**5.4.3.1.1.6 Interlocks or Barriers**

Mechanical interlocks or barriers may be used instead of the spacing
required by Figure 11.

**5.4.3.1.3 Keyboards**

**5.4.3.1.3.1 Use**

Arrangements of push buttons in the form of keyboards should be used
when alphabetic, numeric or special function information is to be
entered into a system.

**5.4.3.1.3.2 Layout and Configuration**

The key configuration and the number of keys are dependent upon the
predominant type of information to be entered into the system. The major
forms that keyboards can take, which aid in the entry of such
information, are given below:

> a\. [Numeric Keyboard]{.underline}: The configuration of a keyboard
> used to enter solely numeric information should be a 3 x 3 + 1 matrix
> with the zero digit centered on the bottom row.

**5.4.3.1.3.3 Dimension, Resistance,**

**Displacement, and Separation**

The control dimensions, resistance, displacement, and separation between
adjacent edges of the push buttons which form keyboards shall conform to
the criteria in Table 10. For a given keyboard these criteria shall be
uniform for all individual keys. For those applications where operation
while wearing (trigger finger) arctic mittens is required, the minimum
key size shall be 19 mm (0.76 in). Other parameters are unchanged from
those of bare-handed operation (see Table 10).

**5.4.3.1.3.6 Feedback**

Feedback shall be provided to inform the operator whether:

a\. the key was pressed,

b\. the intended key was pressed, and

c\. the next operation may be initiated, where applicable.

**5.4.3.1.8 Discrete Push-Pull Controls**

**5.4.3.1.8.1 Applications**

Push-pull controls may be used when two discrete functions are to be
selected. However, such applications should be used sparingly and for
applications in which such configurations are typically expected (e.g.,
vehicle headlight switch, choke, etc.). They may also be used in certain
cases where limited panel space suggests a miniaturized knob that may be
used to serve two related, but distinct functions (e.g., an
ON-OFF/Volume switch for a T.V. monitor). A three-position push-pull
control is acceptable in isolated instances where the criticality of
inadvertent selection of the wrong position has no serious consequences
(e.g., the typical vehicle headlight switch configuration that provides
three \"pull\" positions\--Off/Park/Headlight\--plus a rotary panel
light and dome light switch).

**5.4.3.1.8.2 Handle Dimensions,**

**Displacement and Clearances**

Push-pull control handles shall conform to criteria in Table XI.

**5.4.3.1.8.3 Rotation**

Except for combination push-pull/rotate switch configurations, push-pull
control handles shall be keyed to a non-rotating shaft, unless the
control is to be used for a special application (e.g., the handle is
rotated to disengage the brake setting). When the control system
provides a combination push-pull/rotate functional operation, using a
round style knob, the rim of the knob shall be serrated to denote
(visually and tactually) that the knob can be rotated, and to facilitate
a slip-free finger grip.

**5.4.3.1.8.4 Detents**

Mechanical detents shall be incorporated into push-pull controls to
provide tactile indication of positions.

**5.4.3.1.8.5 Snagging and Inadvertent Contact**

Use, location and operating axis of push-pull type controls shall
preclude the possibility of the operator:

> a\. Bumping a control while getting into or out of position (as in a
> vehicle).
>
> b\. Snagging clothing, communication cables, or other equipment items
> on the control.
>
> c\. Inadvertently deactuating the control setting while reaching for
> another control.

**5.4.3.1.8.6 Direction of Control Motion**

Control direction shall be as follows:

a\. Pull towards the operator for ON or actuation; push away for OFF or
deactuation.

b\. Clockwise for actuation or increasing function of combination
pull/rotary switches.

**5.4.3.1.8.7 Resistance**

Force for pulling a panel control with fingers should be not more than
18 N (4 lb), for pulling a T-bar with four fingers should be not more
than 45 N (10 lb).

**5.5 Labeling**

**5.5.2.1 Orientation**

Labels and information thereon should be oriented horizontally so that
they may be read quickly and easily from left to right. Vertical
orientation may be used only when labels are not critical for personnel
safety or performance and where space is limited. When used, vertical
labels shall read from top to bottom.

**5.5.2.2 Location**

Labels shall be placed on or very near the items which they identify, so
as to eliminate confusion with other items and labels. Labels shall be
located so as not to obscure any other information needed by the
operator. Controls should not obscure labels.

**5.5.2.3 Standardization**

Labels shall be located in a consistent manner throughout the equipment
and system.

**5.5.3.2 Abbreviations**

Standard abbreviations shall conform to MIL-STD-12, MIL-STD-411, or
MIL-STD-783. If a new abbreviation is required, its meaning shall be
obvious to the intended reader. Capital letters shall be used. Periods
shall be omitted except when needed to preclude misinterpretation. The
same abbreviation shall be used for all tenses and for both singular and
plural forms of a word.

**5.5.4.1 Brevity**

Labels shall be as concise as possible without distorting the intended
meaning or information and shall be unambiguous. Redundancy shall be
minimized. Where the general function is obvious, only the specific
function shall be identified (e.g., frequency as opposed to frequency
factor).

**5.5.4.2 Familiarity**

Words shall be chosen on the basis of operator familiarity whenever
possible, provided the words express exactly what is intended. Brevity
shall not be stressed if the results will be unfamiliar to operating
personnel. For particular users (e.g., maintenance technicians), common
technical terms may be used even though they may be unfamiliar to
nonusers. Abstract symbols (e.g., squares and Greek letters) shall be
used only when they have an accepted meaning to all intended readers.
Common, meaningful symbols (e.g., % and +) may be used as necessary.

**5.5.5.1 Black Characters**

Where the ambient illuminance will be above 10 lux (0.9 ft-c), black
characters shall be provided on a light background.

**5.5.5.4.1 Labels**

Labels shall be printed in all capitals; period shall not be used after
abbreviations.

**5.5.5.5 Letter Width**

The width of letters should be 3/5 of the height, except for \"M\" and
\"W\", which shall be 4/5 of the height, and \"I\", which shall be one
stroke wide.

**5.5.5.6 Numeral Width**

The width of numerals shall preferably be 3/5 of the height, except for
the \"4\", which shall be one stroke width wider, and the \"1\", which
shall be one stroke wide.

**5.5.5.8 Stroke Width Normal**

For black characters on a white (or light) background, the stroke width
shall be 1/6 to 1/7 of the height.

**5.5.5.11 Character Spacing**

The minimum space between characters shall be one stroke width.

**5.5.5.12 Word Spacing**

The minimum space between words shall be the width of one character.

**5.5.5.13 Line Spacing**

The minimum space between lines shall be one-half character height.

**5.5.5.15 Character Height and Viewing Distance**

For general dial and panel design, with the luminance normally above 3.5
cd/m^2^ (1 ft-L), character height should conform to the values given
below for various distances:

[Viewing Distance]{.underline} [Minimum Height]{.underline}

a\. less than 500 mm (19.7 in) 2.3 mm (0.09 in)

b\. 0.5 - 1.0 m (19.7 - 39.4 in) 4.7 mm (0.18 in)

c\. 1.0 - 2.0 m (39.4 - 78.7 in) 9.4 mm (0.37 in)

d\. 2.0 - 4.0 m (78.7 - 157.5 in) 19 mm (0.75 in)

e\. 4.0 - 8.0 m (157.4 - 315.5 in) 38 mm (1.50 in)

**5.5.6.2.4b Location**

b\. Labels should normally be placed above the controls and displays
they describe. When the panel is above eye level, labels may be located
below if label visibility will be enhanced thereby.

**5.5.6.2.4e Location**

Label location throughout a system and within panel groupings shall be
uniform.

**1. Data Entry**

**1.0 General**

**1.0.9 Explicit ENTER Action**

Always require a user to take an explicit ENTER action to initiate
processing of entered data; do **not** initiate processing as a side
effect of some other action.

EXAMPLE: As a negative example, returning to a menu of control options
should **not** by itself result in computer processing of data just
keyed onto a display.

EXCEPTION: In routine, repetitive data entry transactions, successful
completion of one entry may automatically lead to initiation of the
next, as in keying ZIP codes at an automated post office.

COMMENT: Deferring processing until after an explicit ENTER action will
permit a user to review data and correct errors before computer
processing. This is particularly helpful when data entry is complex
and/or difficult to reverse.

**1.0.11 Explicit CANCEL Action**

Require a user to take an explicit action in order to cancel a data
entry; data cancellation should **not** be accomplished as a side effect
of some other action.

EXAMPLE: As a negative example, casual interruptions of a data entry
sequence, such as paging through forms or detouring to HELP displays,
should **not** have the effect of erasing partially completed data
entries.

COMMENT: If a requested sequence control action implies a more definite
interruption, such as LOG-OFF command or a command to return to a menu
display, then the user should be asked to confirm that action and
alerted to the loss of any data entries that would result.

**1.0.12 Feedback for Completion of Data Entry**

Ensure that the computer will acknowledge completion of a data entry
transaction with a confirmation message if data entry was successful, or
else with an error message.

EXCEPTION: In a sequence of routine, repetitive data entry transactions,
successful completion of one entry might result simply in regeneration
of the initial (empty) data entry display, in order to speed the next
entry in the sequence.

COMMENT: Successful data entry should **not** be signaled merely by
automatic erasure of entered data from the display, except possibly in
the case of repetitive data entries. For single data entry transactions,
it may be better to leave entered data on the display until the user
takes an explicit action to clear the display.

**1.0.13 Feedback for Repetitive Data Entries**

For a repetitive data entry task that is accomplished as a continuing
series of transactions, indicate successful entry by regenerating the
data entry display, automatically removing the just-entered data in
preparation for the next entry.

COMMENT: Automatic erasure of entered data represents an exception to
the general principle of control by explicit user action. The interface
designer may adopt this approach, in the interest of efficiency, for
data entry transactions that task analysis indicates will be performed
repetitively.

COMMENT: In addition to erasure of entered data, a message confirming
successful data entry might be displayed. Such a message may reassure
uncertain users, especially in system applications where computer
performance is unreliable.

**1.0.14 Feedback when Changing Data**

If a user requests change (or deletion) of a data item that is not
currently being displayed, offer the user the option of displaying the
old value before confirming the change.

EXCEPTION: Expert users may sometimes wish to implement data changes
without displayed feedback, as in global replace transactions, accepting
the attendant risk.

COMMENT: Displayed feedback will help prevent inadvertent data change,
and is particularly useful in protecting delete actions. Like other
recommendations intended to reduce error, it assumes that accuracy of
data entry is worth extra effort by the user. For some tasks, that may
not be true.

**1.0.24 Prompting Data Entry**

Provide prompting for the required formats and acceptable values for
data entries.

EXAMPLE: (Good) Vehicle type: \_\_

c = Car

t = Truck

b = Bus

(Bad) Vehicle type: \_\_

EXCEPTION: Prompting may not be needed by skilled users and indeed may
hinder rather than help their performance in situations where display
output is slow (as with Teletype displays); for such users prompting
might be provided as an **optional** aid.

COMMENT: Prompting is particularly needed for coded data entries. Menu
selection may be appropriate for that purpose, because menu selection
does not require the user to remember codes but merely to choose among
displayed alternatives. Other methods of prompting include labeling data
fields, such as: **Vehicle type (c/t/b): \_\_** and/or providing
optional guidance displays.

**1.3 Text**

**1.3.32 Confirming Actions in DELETE Mode**

If a DELETE mode is used, highlight any text specified by a user for
deletion and require the user to confirm the DELETE action before the
computer will process it.

COMMENT: Requiring a user to confirm actions in DELETE mode is
particularly important when the control entries for cursor positioning
(e.g., WORD, SENTENCE, PARAGRAPH, PAGE) are also used to specify text
for deletion, which is often the case. Users will associate the
specification of text units primarily with cursor positioning, which is
the most frequent action in text editing. In a DELETE mode, after
specifying text units for deletion, a user may press a PARAGRAPH key
intending to move to the next paragraph but accidentally delete the next
paragraph. Confirmation of DELETE actions will tend to prevent such
errors.

COMMENT: An alternative approach to this problem is not to provide a
continuing DELETE mode, but instead require double keying to accomplish
deletions. In a DELETE mode, a user might press a DELETE key followed by
unlimited repetitions of a WORD key (or keys specifying other units of
text). With double keying, the user would have to press DELETE before
**each** selection of a text unit to be deleted.

**1.3.33 Reversible Actions**

Design text editing logic so that any user action is immediately
reversible.

EXAMPLE: If a user centers a heading and then decides it would look
better flush against the left margin, an UNDO action should reverse the
centering and move the heading back to its original location.

EXAMPLE: If a user underlines a paragraph of text and then decides it
should be in all capital letters instead, an UNDO action should reverse
the underlining. The user should **not** be required to delete the
paragraph and retype it just to erase the underscoring.

COMMENT: Reversible actions are particularly important in a text editing
environment because text formatting often involves experimentation with
features such as underscoring, bolding, and spacing. If users know that
they can reverse whatever they do, they will feel more free to delete
text and experiment with formatting features.

COMMENT: An UNDO capability is currently available in some interface
designs. In some applications, however, this capability is provided
through the use of an UNDO key which can only reverse the most recent
control action. For text editing, users must be able to reverse such
formatting features as centering and bolding at any time. Therefore, if
control actions are to be made reversible, an UNDO action should be able
to reverse more than the most recent command, perhaps by requiring the
user to specify which command to undo, and/or to place the cursor at the
location of the format feature that is to be reversed.

COMMENT: When text segments have been deleted, it should be possible to
retrieve more than the most recent deletion. Some systems do this by
storing all deletions in a special file. Deleted text which the user
wishes to retrieve can then be moved from the deletion file to the file
in which the user is presently working.

**1.3.34 User Confirmation of Editing Changes**

When a user signals completion of document editing, allow the user to
confirm that changes should be made to the original document, or else to
choose alternative options.

COMMENT: A user will generally wish to replace the original document
with its edited version. However, sometimes a user may decide that
editing mistakes have been made, and wish to discard the new version
while saving the original. Or a user might wish to save the new version
as a separate document, while saving the original unchanged. Such
decisions can be made best at the end of an editing session, when the
user knows what has been accomplished, rather than before a session is
begun.

COMMENT: During text editing, the computer should always retain a copy
of the original document until the user confirms that it should be
changed. The original document should **not** be changed automatically
as the user enters each editing change.

**3. Sequence Control**

**3.0.1 Flexible Sequence Control**

Provide flexible means of sequence control so that users can accomplish
necessary transactions involving data entry, display, and transmission,
or can obtain guidance as needed in connection with any transaction.

EXAMPLE: In scanning a multipage display the user should be able to go
forward or back at will. If user interface design permits only forward
steps, so that the user must cycle through an entire display series to
reach a previous page, that design is deficient.

COMMENT: Necessary transactions should be defined in task analysis prior
to software design.

**3.0.7 Logical Transaction Sequences**

When designing a sequence of related transactions for some information
handling task, employ task analysis to ensure that those transactions
will constitute a logical unit or subtask from a user\'s viewpoint, and
to determine what control options users will need at any point.

COMMENT: A logical unit to the user is not necessarily the same as a
logical unit of the computer software that mediates the transaction
sequence. It might be, for example, that a user should enter ten items
of data in a single transaction, because those data all come from one
particular paper form, even though the computer will use five of those
items for one purpose and five items for another in its subsequent
internal processing.

**3.5 Error Management**

**3.5.7 User Confirmation of Destructive Entries**

When a control entry will cause any extensive change in stored data,
procedures and/or system operation, and particularly if that change
cannot be easily reversed, notify the user and require confirmation of
the action before implementing it.

**3.5.9 Distinctive CONFIRM Action**

Provide an explicitly labeled CONFIRM function key, different from the
ENTER key, for user confirmation of questionable control and data
entries.

COMMENT: Confirmation should **not** be accomplished by pushing some
other key **twice**.

COMMENT: Some interface designers recommended that in special cases
confirmation should be made more difficult still, (e.g., by keying the
separate letters C-O-N-F-I-R-M). Even such extreme measures, however,
cannot guarantee that users will not make errors.

**3.5.10 UNDO to Reverse Control Actions**

Ensure that any user action can be immediately reversed by an UNDO
command.

EXAMPLE: If a user is overhasty in confirming a destructive action, and
realizes the mistake right away (i.e., before taking another action),
then an UNDO action might be taken to reverse the damage.

COMMENT: UNDO itself should be reversible, so that a second UNDO action
will do again whatever was just undone.

COMMENT: Such an UNDO capability is currently available in many
interface designs, and should be provided more generally. Even with an
UNDO capability, however, a user may make an irretrievable mistake, if
succeeding actions intervene before a prior destructive action is
noticed.

**3.5.13 Flexible BACKUP for Error Correction**

Allow users to BACKUP easily to previous steps in a transaction sequence
in order to correct an error or make any other desired change.

**4. User Guidance**

**4.0 General**

**4.0.16 Familiar Wording**

When wording labels, prompts and user guidance messages, adopt
terminology familiar to users.

EXAMPLE:

(Good) Data requires special access code; call Data Base Admin, X 9999.

(Bad) IMS/VS DBMS private data; see DBSA, 0/99-99.

**4.0.17 Task-Oriented Wording**

Adopt task-oriented wording for labels, prompts and user guidance
messages, incorporating whatever special terms and technical jargon may
be customarily employed in the users\' tasks.

COMMENT: Jargon terms may be helpful, if they represent the jargon of
the **user** and not of the designer or programmer. The rule here should
be to know the users and adapt interface design to their vocabulary
instead of forcing them to learn new wording.

**4.0.18 Wording Consistent with Control Entry**

Choose wording for user guidance that is consistent with the words used
for control entries.

EXAMPLE:

(Good) To delete a paragraph, press DELETE and then PARAGRAPH.

(Bad) To erase a paragraph, press DELETE and then PARAGRAPH.

EXAMPLE: If a user must complete a control form to specify printer
settings, the words used as labels on that form should also be used in
any error messages and HELP displays which may guide that process.

COMMENT: When selecting or composing control entries, a user will tend
to mimic the vocabulary, format, and word order used in computer
displays, including labels, error messages, HELP displays, etc. If
displayed wording is consistent with required entries, a user will be
more likely to make a correct entry on the first try.

COMMENT: Consistent wording of user guidance will be particularly
helpful for dialogues based on constrained natural language. If a
designer begins by determining which words and formats users are likely
to choose naturally, and then reinforces that usage by incorporating
such wording in user guidance, much of a user\'s interaction with the
computer will be predictable. Therefore, the \"natural language\" need
not accommodate the full range of possible entries, but only those
entries which users are likely to make.

**4.3 Error Feedback**

**4.3.1 Informative Error Messages**

When the computer detects an entry error, display an error message to
the user stating what is wrong and what can be done about it.

EXAMPLE:

(Good) Code format not recognized; enter two letters, then three digits.

(Bad) Invalid input.

COMMENT: Users should **not** have to search through reference
information to translate error messages.

COMMENT: Error messages can be regarded as the most important form of
system documentation. Well designed error messages will give help to
users automatically, at the point where help is most needed.

**4.3.3 Task-Oriented Error Messages**

Adopt wording for error messages which is appropriate to a user\'s task.

EXAMPLE:

(Good) Contract number not recognized; check the file and enter a
current number.

(Bad) Entry blocked. Status Flag 4.

COMMENT: Error messages that can be understood only by experienced
programmers (and interface designers) will have no value for ordinary
users.

**4.3.5 Brief Error Messages**

Make error messages brief but informative.

EXAMPLE:

(Good) Entry must be a number.

(Bad) Alphabetic entries are not acceptable because this entry will be
processed automatically.

COMMENT: Often a user will recognize that an error has been made, and
the message will serve merely as a confirming reminder. In such
instances, short error messages will be scanned and recognized more
quickly.

COMMENT: For a user who is truly puzzled, and who needs more information
than a short error message can provide, auxiliary HELP can be provided
either on-line or by reference to system documentation.

COMMENT: If an on-line HELP explanation is not available, a user may
have to refer to system documentation for a coded listing of possible
errors. Under those circumstances, some designers display each error
message with an identifying code, to facilitate rapid reference to
documentation. That practice might help experienced users, who would
gradually come to recognize the codes.

**4.3.6 Neutral Wording for Error Messages**

Adopt neutral wording for error messages; do **not** imply blame to the
user, or personalize the computer, or attempt to make a message
humorous.

EXAMPLE:

(Good) Entry must be a number.

(Bad) Illegal entry.

(Bad) Don\'t be dumber, use a number

COMMENT: Error messages should reflect a consistent view that the
computer is a tool, with certain limitations that a user must take into
account in order to make the tool work properly. If error messages
reflect an attitude that the computer (or its programmer) imposes rules,
or establishes \"legality\", the user may feel resentful. If error
messages reflect personalization of the computer, as if it were a
friendly colleague, a naive user may be misled to expect human abilities
the machine does not actually possess. If error messages are worded
humorously, any joke will surely wear thin with repetition, and come to
seem an intrusion on a user\'s concern with efficient task performance.

COMMENT: The same considerations apply for the wording of
computer-generated prompts and other instructional material.

**4.4 Job Aids**

**4.4.7 Prompting Entries**

Provide advisory messages and other prompts to guide users in entering
required data and/or control parameters.

COMMENT: Prompting in advance of data/control entry will help reduce
errors, particularly for inexperienced users.

COMMENT: If a default value has been defined for null entry, that value
should be included in the prompting information.

**4.4.9 Consistent Format for Prompts**

Use consistent phrasing and punctuation in all prompts.

EXAMPLE:

(Good) Save as new file or Overwrite old file (S/O):

and

Create new file or Edit old file (C/E):

(Bad) (S)ave as new file or (O)verwrite old file:

and

Would you like to create a new file or edit an old file (C/E):

**a) Extended Exposure**

Exposure to loud noise for an extended period of time can cause
permanent hearing loss. The degree of exposure that will result in
damage depends on intensity and individual susceptibility.

**b) Communication**

Even low levels of noise can interfere with communication.

**c) Task Complexity**

Noise can adversely affect performance, with the effects being greater
for more complex tasks.

**d) Intermittent Noise**

Intermittent noise has more adverse effects than steady-state noise.

**Adverse Effects**

General effects of a noisy environment include fatigue, distractibility,
sleep disturbance, irritation, and aggressive behavior.

**Psychological Factors:**

People are generally less sensitive to noise related to their
well-being.

People are more sensitive to unpredictable noise.

People are more sensitive to noise they feel is unnecessary.

People who are most sensitive to noise become increasingly disturbed as
the noise persists, whereas the annoyance level of less sensitive
individuals remains constant over time.

The perceived abrasiveness of certain sounds is subjective and varies
considerably among individuals.

**e) Purpose**

The acoustical design goals are to establish a satisfactory environment
relative to the human environment relative to the human response to
noise, to prevent hearing loss, to minimize disruption of speech
communications, and to minimize noise-induced annoyance/stress factors.

**f) Intelligibility**

For satisfactory communication of most voice messages in noise, 75%
intelligibility is required. The ratio of speech level to background
noise level affects intelligibility.

**g) Distance**

The distance from speaker to listener, background noise level, and voice
level are important considerations. Ambient air pressure and gaseous
composition of the air are important considerations, because they affect
voice efficiency and frequency content.

**h) General**

Currently, aural displays are used primarily to present caution and
warning messages. The addition of verbal content might decrease response
time and increase intelligibility. This function will become
particularly critical in single-pilot operations, when the pilot will be
responsible for monitoring cockpit instruments and vehicle systems even
when his or her attention is directed to the outside scene during NOE
flight.

Because auditory messages are limited in duration, important information
may be lost if messages are not understood the first time they occur.
For this reason, redundant visual displays of critical messages are
necessary.

Although intelligibility remains a problem, synthesized speech warning
messages can be understood as easily as digitized human speech once the
pilots become familiar with the messages (Hartzell, Aiken, & Moorhees,
1984).

Synthetic voice messages are attention getting because the voice quality
is different than human communications. Synthetic speech places greater
demands on short-term memory and does not have the same redundancy as
human speech. Furthermore, there is a greater decrement in
intelligibility for synthesized messages presented in a noisy background
(Crittenden, 1986).

**3. General Environment**

**3.2 Marking Requirements**

a\. Light characters on dark background

b\. Minimum character brightness - 0.3 Foot

Lamberts

c\. Brightness contrast

White on Black - 12 (or greater)

Gray on Black

Yellow on Black - 5 (or greater)

White on Grey

d\. Color of illumination - white

**4. Numeral, Letter and Dial Requirements**

**4.2 Dimensions**

+--------------------+--------+--------+-------------+---------------+
|                    | M      |        | Width to    | Stroke Width  |
|                    | inimum |        |             | to Height     |
|                    | Cha    |        | Height      | Ratio         |
|                    | racter |        |             |               |
|                    | Height |        | Ratio       |               |
+--------------------+--------+--------+-------------+---------------+
| [Flat              | [IN]   | [MM]   | 3/5^1^      | 1/7 to 1/8^2^ |
| Dials]{.underline} | {.unde | {.unde |             |               |
|                    | rline} | rline} | 3/5^1^      | 1/7 to 1/8^2^ |
| Fixed              |        |        |             |               |
|                    | 0.15   | 3.81   |             |               |
| Moving             |        |        |             |               |
|                    | 0.2    | 5.08   |             |               |
+--------------------+--------+--------+-------------+---------------+
| [Cou               | 0.187  | 4.75   | 3/5 to      | 1/7 to 1/8^2^ |
| nters]{.underline} |        |        | 1/1^1^      |               |
|                    | 0.25   | 6.35   |             |               |
| (Cylindrical)      |        |        |             |               |
|                    |        |        |             |               |
| Fixed (Settable)   |        |        |             |               |
|                    |        |        |             |               |
| Moving             |        |        |             |               |
+--------------------+--------+--------+-------------+---------------+

^1^ Except for the numerals \"1\" and \"4\" and the letters \"I, \"
\"M\" and \"W\".

The \"1\" shall be one stroke width.

The \"4\" shall be one stroke wider than the others.

The \"I\" shall be one stroke width.

The \"M\" and \"W\" shall be approximately 20% wider than the other
letters.

^2^ Assuming direct illumination. When figures are transilluminated, a
stroke-width/height range of 1/8 to 1/10 should be considered.

**4.3 Grouping**

Character spacing - 1 stroke width, minimum.

Word spacing - 1 character width, minimum.

Graduation - Character spacing - 1 stroke width, minimum.

**7. Displays**

**7.2 Display Devices**

**7.2.2 Character Size**

Character styles and height-to-width ratio shall be 0.65 minimum with a
height of no less than 20 arc minutes (0.006 Radians) of visual angle
for the overhead panel and no less than 15 arc minutes (0.0045 Radians)
of visual angle for all other applications.

**7.2.3 Legibility**

The display shall be legible under all normally encountered ambient
lighting conditions. Means of display brightness adjustment shall be
provided. Automatic adjustment after the crew\'s initial setting is
desirable. The display shall be designed so that the flight crew will
not be exposed to undue fatigue due to flickering, unfocused characters,
etc.

**7.3 Dedicated Displays**

**7.3.3 Navigation Equipment Displays**

It is desirable that the Captain and First Officer each be provided with
indication of all navigational information; however, it is permissible,
as specified in this ARP, to provide a single display common to both
pilots.

Where a display may be switched to provide information to the crew from
more than one source, means must be provided to indicate clearly to
which source the display is currently connected. Display of selected
source must be in the direct vision of the respective crew member when
looking at the relevant display, and shall give an indication consistent
with navigation control selection.

If auto-tune is considered, station identification shall be displayed,
and frequency may be displayed.

**5.1 Display Physical Characteristics**

**5.1.3 Symbol Alignment**

Symbols which are interpreted relative to each other (that is, cursors
on scales, command bars against reference points, etc.) shall be aligned
at their midpoints to within 0.7 mr from any point within the
instrument\'s viewing envelope.

**5.1.10 Symbol Quality**

Symbols should have a high quality painted-on appearance with no bright
spots, tails, squiggles, skews, or gaps; the distorted dimension should
not exceed one half the local line width.

**5.1.12 Symbol Motion**

For those elements of the display that are normally in motion, any
jitter, jerkiness or ratcheting effect shall not be distracting or
objectionable.

**5.2 Photo-Colormetric Characteristics**

**5.2.1 General**

The display symbology should be clearly readable under all ambient
lighting levels ranging from 1.1 1x (0.1 fc) to sunshafting illumination
of 86 400 1x (8000 fc) at 45 deg incidence to the face of the display.

**5.2.2 Luminance**

The display luminance shall be sufficient to provide a comfortable level
of viewing with rapid adaptation when transitioning from looking outside
the cockpit. These recommendations were developed from tests in which
symbology not only had to be readable in the extreme ambient conditions,
but the color of the symbology had to be ascertained without regard to
symbol shape.

**5.2.2.1 Maximum Luminance**

With manual and automatic luminance controls at a maximum, the display
luminance of the primary colors when measured in a dark ambient should
be at least the following for application in which symbols are single
line construction (larger geometries need less luminance) and area
subjects that present meaningful information (for example, weather
radar) rather than just an aesthetic background. This luminance
requirement (in units of candela per square meter and foot lamberts)
shall apply over the normal useful life of the equipment including
end-of-life.

+-------------------------------------+--------------------------------+
| **Symbol Lines**                    | **Area Subjects**              |
+-------------------------------------+--------------------------------+
| Red 48 cd/m2 (14 fL)                | 9.3 cd/m2 (2.7 fL)             |
|                                     |                                |
| Green 103 cd/m2 (30 fL)             | 20 cd/m2 (5.8 fL)              |
|                                     |                                |
| Blue 17 cd/m2 ( 5 fL)               | 3.9 cd/m2 (1.15 fL)            |
+-------------------------------------+--------------------------------+

Based on subject with 0.67 mr line width

**5.2.2.2 Minimum Luminance**

To achieve acceptable viewing in dark conditions, the minimum display
luminance of the primary colors under which the performance requirements
of this ARP shall be met when measured in a dark ambient should be no
greater than:

+---------------------------------------+------------------------------+
| **Symbol Lines**                      | **Area Subjects**            |
+---------------------------------------+------------------------------+
| Red 0.192 cd/m2 (0.056 fL)            | 0.113 cd/m2 (0.033 fL)       |
|                                       |                              |
| Green 0.420 cd/m2 (0.120 fL)          | 0.247 cd/m2 (0.072 fL)       |
|                                       |                              |
| Blue 0.068 cd/m2 (0.024 fL)           | 0.041 cd/m2 (0.012 fL)       |
+---------------------------------------+------------------------------+

Where applicable, the automatic brightness control shall be inhibited
for these requirements.

NOTE: These minimum luminance values have been established for
dark-adapted cockpits. These values may be increased for applications
where the cockpit ambient lighting design precludes a high degree of
night vision adaptation.

Under night lighting, with the display brightness set at the lowest
usable level for flight with normal symbology, all flags and
annunciators shall be adequately visible.

**5.2.3 Color**

Color definitions shall be based on the CIE 1976 Uniform Chromaticity
Scale u´, v´ coordinates.

**5.2.4 Color Uniformity**

A symbol of a specified color shall have a chrominance which is uniform
over the entire screen. The chromaticity difference (CD) between any two
points on the screen of the same color shall not exceed 0.034.

**5.2.5 Color Difference**

Displayed symbology shall be distinguished from its background and from
other symbols by means of luminance differences or chromaticity
differences, or both, in all ambient conditions defined in 5.2.1.

The most credible color different system is CIELUV, which is described
in Supplement 2 to CIE Publication No. 15; but it does not consider
symbol size and does not offer criteria for perception. Except in cases
where an absolute chromaticity is desired (for example, robin\'s egg
blue for sky shading), colors should be selected which maximize color
differences. Results should be analyzed using the CRITERIA system.
[There is no adequate basis for specifying a minimum acceptable
difference at this time.]{.underline}

**5.2.6 Reflections**

The display surface should have a reflection-reducing coating with
performance characteristics per AMS 2521A. Surfaces in the optical path
should be treated appropriately to reduce specular reflections.

**7. Color**

**7.1 General**

**7.1.1**

Color shall have the same operational significance throughout the flight
deck for all mechanical, electromechanical, and electronic equipment.

**7.1.2**

Color coding shall be supported by a redundant means of coding (e.g.,
shape, position, function) for all operationally significant
indications.

**7.1.3**

Color shall be used with the aim of enhancing the distinction between
indications, symbols and annunciations, but the number of colors and
extent of usage should be minimized to avoid loss of discrimination.

**7.1.4**

Colors shall maintain their discriminability over the full range of
ambient light conditions (dark night to direct sunlight) and all
brightness settings.

**7.2 Color Set**

**7.2.1**

Colors shall be selected from the following set of nine: Red, Tan/Brown,
Amber, Yellow, Green, Cyan, Blue, Magenta, and White.

NOTE: Care must be taken to ensure that sufficient contrast is
maintained where red, brown, or amber colors are superimposed or used in
close proximity to each other.

**7.3 Color Coding for Electronic Displays**

**7.3.1**

The following display features shall be color coded as below:

Warnings Red

Flight envelope and critical

parameter limits Red

Cautions, abnormal sources Amber/Yellow

Earth Tan/Brown

Scales and associated figures White

Engaged modes Green

Sky Cyan/Blue

ILS deviation pointers Magenta

Flight director bars Magenta or Green

**7.3.2**

The following display features shall be allocated a color from a single
acceptable code. Codes 1 and 2 below have been found acceptable.

+---------------------------------+-----------------+------------------+
|                                 | **Code 1**      | **Code 2**       |
+---------------------------------+-----------------+------------------+
| Fixed reference symbols         | White           | Yellow           |
|                                 |                 |                  |
| Current data, values            | White           | Green            |
|                                 |                 |                  |
| Armed modes                     | White           | Cyan             |
|                                 |                 |                  |
| Selected data, values           | Green           | Cyan             |
|                                 |                 |                  |
| Selected heading                | Magenta         | Cyan             |
|                                 |                 |                  |
| Active route/flight plan        | Magenta         | White            |
+---------------------------------+-----------------+------------------+

**7.3.3**

Precipitation and turbulence areas shall be coded as below:

+----------------------------------------+-----------------------------+
| Precipitation up to 3 mm/hr            | Green                       |
|                                        |                             |
| 4 - 12 mm/hr                           | Amber/Yellow                |
|                                        |                             |
| 12 - 50 mm/hr                          | Red                         |
|                                        |                             |
| Above 50 mm/hr                         | Magenta                     |
|                                        |                             |
| Turbulence                             | White or Magenta            |
+----------------------------------------+-----------------------------+

O17

**7.3.4**

Bearing pointers should be color coded to comply with paragraph 7.1.1.

**7.3.5**

Background color (grey or other shade) may be used to enhance display
presentation and improve legibility.

**6.3 Primary Flight Instruments-EHSI/ND**

**6.3.1**

The instrument shall provide a clear and unmistakable display of
aircraft position, heading the track relative to desired course/track.
It shall require a minimum of pilot computation or interpretation.

**6.3.2**

In addition to the compass rose format EHSI/ND equipment shall generate
a moving map format upon which weather radar data may be superimposed,
and should provide a plan format for verification of stored flight
plans.

**6.3.3**

The compass rose format when installed shall present the following
information:

\(i\) Magnetic/true heading/track and scale

\(ii\) Selected heading

\(iii\) Selected source/desired track

\(iv\) Aircraft reference symbol

\(v\) Vertical path deviation and scale

\(vi\) Lateral path deviation and scale

\(vii\) Bearing pointer(s) (optional)

\(viii\) To/from indication

\(ix\) Distance to waypoint

\(x\) Annunciation of manually selected navaids

\(xi\) Failure flags

**6.3.4**

The map format shall incorporate the following features:

\(i\) Data areas shall not degrade moving symbols or tracks

\(ii\) Alphanumeric legends shall remain upright with map rotation
except compass numerals on the heading scale

\(iii\) Waypoints, VORs, NDBs, airports, reporting points,
intersections, etc., shall be identified by conventional terminology and
abbreviations

\(iv\) Symbols shall reflect accepted navigation chart usage

\(v\) Courses and desired track lines shall remain in view when their
origin or termination is not visible

\(vi\) Actual courses or projected track lines shall be clearly
distinguishable when coincident with planned courses or track angles

\(vii\) Movement of symbols and lines shall be smooth during map
rotation and parameter selection

\(viii\) Automatic and/or manual de-clutter as a function of flight
phase shall be provided

**6.3.5**

The map format shall present the following information:

Items (i), (ii), (iii), (iv), (ix), (x), (xi), of paragraph 6.3.3 and:

\(xii\) Lateral path deviation from desired track

\(xiii\) Wind speed and direction (if available)

\(xiv\) Range marks/scale

\(xv\) Weather radar data identifying precipitation rates and/or
turbulence levels

\(xvi\) Active flight plan

\(xvii\) Waypoint/VOR/NDB/Airport/Reporting point/Intersection data

**6.3.6**

The map format may present the following information:

\(i\) Lateral and/or vertical path deviation and scale

\(ii\) Drift angle/track angle error

\(iii\) Ground speed

\(iv\) Wind on nose/tail and/or crosswind component

\(v\) Time to go

\(vi\) ETA/ETE/ETO

\(vii\) Radial from selected navaid

\(viii\) Frequency and/or identification of active navaid

\(ix\) Bearing pointers

\(x\) To/from indication

\(xi\) SIDs, Holding patters and STARs

\(xii\) Area minimum altitudes

\(xiii\) Obstructions

\(xiv\) Predictive track (inhibited for turn rates less than 0.5
deg/second and removed when bank angle exceeds 35 deg)

\(xv\) Optimum climb/descent, including top of climb/descent and bottom
of climb/descent

\(xvi\) Altitude intercept arc

\(xvii\) Waypoint constraints

\(xviii\) Time marks/deviation

\(xix\) Collision avoidance indication

**3.1**

**3.1.1.6 Integral Lighting**

**4.2 Viewing Characteristics**

**4.2.2 Symbol Alignment**

Symbols which are interpreted relative to each other, including
mechanically produced symbols that are interpreted relative to
electronically produced symbols, shall be aligned, including parallax
misinterpretation of information.

**4.2.3 Positional Accuracy**

The display absolute positional accuracy shall be better than 5% of the
maximum diagonal dimension of the display. In no case shall the absolute
positional error cause erroneous data to be presented.

**4.2.5 Line Width**

Line widths shall be of sufficient size and sharpness to display the
intended information with no distracting visual effects or ambiguities.

**4.2.8 Symbol Quality**

Lines, symbols, and characters shall have no tails, squiggles, skews, or
gaps discernible from the design eye viewing envelope which cause
erroneous interpretation.

**4.3 Photocolorimetric Characteristics**

**4.3.2.1 Luminance**

The display luminance shall be sufficient to provide a usable display
under the maximum ambient illumination level appropriate to the display
type (as defined in paragraph 2 of this AS) and application.

**4.3.2.2 Luminance Uniformity**

The luminance of a given symbol, line, character, or generated
background shall not vary more than:

1\) [+]{.underline}30% when located within the useful display area, or

2\) [+]{.underline}20% when located within the central 80% of the

useful display area.

These requirements apply for any luminance control setting.

**4.3.2.3 Manual Luminance Control**

The display system shall have capability for manual luminance control.

**4.3.2.4 Automatic Luminance Control**

If the display system has automatic luminance compensation, the
operation of this compensation shall function so that the system meets
the requirements of paragraph 4.3.1 under changing cockpit ambient light
levels. Manual luminance control shall not be adversely affected by
failure of the automatic luminance control.

**4.3.2.5 Luminance Tracking**

When the luminance of the display is varied from maximum to minimum, the
relative luminance of all displayed symbols, characters, lines, and
generated backgrounds shall visually remain constant. In no case shall
any symbols or characters become invisible at the minimum luminance
setting while other characters or symbols are visible.

**4.3.3 Color**

Where multiple colors are used to enhance discrimination, the use of
color shall not result in the erroneous ambiguous interpretation of the
displayed information. In no case should colors be selected which
conflict with the requirements of paragraph 4.3.1.

In general, color should not be used as the only coding dimension for
critical information.

**4.3.4 Color Uniformity**

The color difference between any symbols of the same color located at
any position within the useful display area shall not be sufficient to
cause an ambiguity or an incorrect identification of an assigned color
over the entire range of luminance control.

**4.3.5 Convergence**

When a display element is a composite of multiple traces (such as
multiple guns of a shadow mask CRT, or alternate fields of a beam
penetration CRT), the beam centers shall be converged. This convergence
value at any point shall be within the average of the line widths of the
respective traces at that point. This requirement applies over the
useful display area for all symbol intensity settings.

a\) While the use of auditory information may help to alleviate visual
clutter, overuse can lead to auditory clutter (p. 48). Auditory displays
are, by their very nature, intrusive and distracting. They may, under
certain conditions, disrupt concentration. Simon and Marchionda-Frost
(1984) point out that the listener typically does not comprehend the
meaning of a speech message until transmission is nearly complete.

b\) p. 49 - The use of speech is likely to be more effective in
conditions of high workload and stress, when the meaning of coded
signals may well be forgotten (Edman, 1982).

c\) Nonspeech signals may be more easily comprehended by users who have
hearing difficulties as well as by those who are not familiar with
spoken English.