Trio Avionics EZ PILOT Specification sheet

EZ PILOT
Operation and Installation Manual
Trio Avionics Corporation
Rev 1.9

Notice and Warnings
Warning: Any failure to comply with the following warnings can lead
to property damage, and serious injury including death.
Although Trio Avionics has taken reasonable steps to test its product, the final determination of safe operation lies
with you, the installer and pilot. Your workmanship in installing, cabling, and testing the autopilot in your airplane is
critical to safety. If you are not the original builder of your aircraft, and do not hold a valid “Repairman’s Certificate”
for your aircraft, you must have the installation done by a qualified A&P aircraft mechanic or the original builder. You
must comply with all current FAA regulations regarding installation of this device in your airplane.
This product is to be used on homebuilt, experimental aircraft only. It is not approved for, nor is it legal to install it in,
certified aircraft. It is not approved by any governmental or non-governmental agency.
Prior to installing or flying this autopilot, read the manual completely. If you have any questions about the installation
or operation of the system, STOP and then call or email Trio Avionics for clarification.
The servo that is a part of this autopilot system is attached directly to your aileron control system. It is possible to
install or adjust it in a manner that may result in improper or unexpected aileron movement that could result in
dangerous aircraft maneuvers. Install it only after you have read and understand the installation instructions. You
must thoroughly inspect and test your installation prior to flight. Mistakes in any modification to your aircraft can be
life threatening!
Each homebuilt aircraft is individual in its construction, maintenance and flying characteristics. Therefore, while
Trio Avionics has tested the product in a variety of aircraft, we do not represent or warrant that it is appropriate or
suitable for use in your particular aircraft. Only you can make that determination and ultimately only you are
responsible for its safe installation and use.
This product is designed for use as an en route navigation aid only, and only at safe altitudes in unobstructed
airspace. It must not be relied upon for any other purpose. It is not to be used for flight in instrument meteorological
conditions (IFR), or approaches into airports in either IFR or visual (VFR) conditions. Power to the servo must be
turned “off” for takeoffs and landings.
In operation, this product relies upon data provided by a GPS receiver. Always keep in mind that GPS signals are
not totally reliable. They may be disrupted by electromagnetic interference, improper placement of antennas, satellite
unavailability and other problems. You must provide data signals from a reliable and properly installed GPS receiver.
The GPS antenna must have a clear “view” of the sky to assure uninterrupted, safe operation. External antennas are
strongly recommended.
When flying an aircraft with this, or any, autopilot enabled, you must be constantly vigilant for any sign of improper
operation of the autopilot. When there is even a suspicion that the autopilot or the GPS receiver is not operating
properly, you must immediately disable the autopilot by any of the various methods detailed in this manual. Do not fly
the autopilot without incorporating the remote servo disconnect switch that is described in this manual.
There may be a tendency to concentrate on the instrument display when test flying this or any other new system in
your aircraft. Do not allow it to distract you from the need to “see and avoid” other aircraft.
The safe practice of aviation demands the consistent exercise of pilot skill, knowledge of airmanship and
weather, judgment and focused attention at a level which is appropriate to the demands of each individual
situation. Pilots who do not possess or exercise the required knowledge, skills and judgment are
frequently injured or killed. Therefore, although an autopilot can serve as a useful navigation aid, no
autopilot can be relied upon and you must be at full attention at all times while flying any aircraft.
If you do not agree to comply with any of the warnings or notices above, do not install or
fly this autopilot system in your aircraft. Call Trio Avionics for a Return Material
Authorization (RMA) and return the unused system for a full refund.

Table of Contents
Page
1.0 Introduction.....................................................................................................................1
2.0 General Information .......................................................................................................2
Track Mode (TRK)............................................................................................................2
Course Mode (CRS).........................................................................................................3
Intercept Mode (INT) ........................................................................................................3
3.0 Control and Display Unit................................................................................................4
3.1 Switch Function and Operation .................................................................................4
3.1.1 On/Off Switch.........................................................................................4
3.1.2 Mode Switch...........................................................................................4
3.1.3 Servo Power Switch...............................................................................5
3.1.4 Display Switch........................................................................................5
3.1.5 Left or Right (L/R) Switch.......................................................................6
3.2 Display Information....................................................................................................7
3.2.1 Power Up Display ..................................................................................7
3.2.2 Initial Logo Screen.................................................................................7
3.2.3 NO GPS Screen.....................................................................................7
3.2.4 GPS Active, Normal Power-Up Display.................................................8
3.2.5 TRK Mode, GPS Signals Present..........................................................8
3.2.6 TRK Mode, BTW (Bearing to Waypoint field)........................................8
3.2.7 Variable Field, Top Line.........................................................................8
3.2.7.1 XTK (Cross Track Error Field) ..................................................8
3.2.8 TRK (Groundtrack Field)........................................................................9
3.2.9 Variable Fields, Bottom Line..................................................................9
3.2.9.1 GS (Groundspeed)....................................................................9
3.2.9.2 ETE (Estimated Time En-route, HH:MM) .................................9
3.2.9.3 ETe (Estimated Time En-route, MM:SS)................................10
3.2.9.4 RNG (Range to Waypoint)......................................................10
3.2.9.5 Waypoint.................................................................................10
3.2.9.6 Digital Turn Coordinator Display.............................................10
3.2.9.7 DIS?........................................................................................10
3.2.9.8 TRN?.......................................................................................11
3.2.9.9 SPD?.......................................................................................11
3.2.10 CRS (Course) Mode ............................................................................11
3.2.11 INT (Intercept) Mode............................................................................12
3.2.12 TOP (Track Offset Position).................................................................12
3.2.13 Automatic Course Reversal.................................................................13
3.2.14 Variable Display Field – Upper Line.....................................................14
3.2.15 Other Display Presentations................................................................14
4.0 Setup Screens...............................................................................................................14
4.1 Contrast Setting (LCD model only)..........................................................................15
4.2 Initial Servo Position and SERVO direction.............................................................15
4.3 Max Turn Rate selection..........................................................................................15
4.4 IO = Dim or Mode? Screen......................................................................................16
4.5 Circle Last WPT? Screen........................................................................................16
4.6 Turn Rate Display selection (EZ Pilot II only)..........................................................17
4.7 Custom Screen Setup .............................................................................................17
4.8 Software Configuration and Serial Number.............................................................17
5.0 Ground Operation and Flight Example ......................................................................17
5.1 Power Up and Initial Settings ..................................................................................17
5.2 Flying to a Courseline or GOTO Waypoint..............................................................19
5.3 Loss of GPS.............................................................................................................19

5.4 CRS Mode Operation..............................................................................................20
5.5 INT Mode Operation................................................................................................21
5.6 Pilot Controlled Steering (PCS)...............................................................................21
6.0 Installing the Control Head..........................................................................................23
6.1 Your GPS ................................................................................................................23
7.0 Servo ..............................................................................................................................25
7.1 Installing the Servo …………………………………………………………………….25
7.2 Servo Mounting Hardware.....................................................................................26
7.3 Selecting a Site for the Servo ................................................................................27
7.4 Install the Servo Pushrod.......................................................................................28
7.5 Setting Servo Override Force (Slip Clutch)............................................................28
7.6 Adjustment of Servo Rotation Direction and Servo Neutral...................................29
7.6.1 Setup Mode Entry...................................................................................29
7.6.2 Servo Rotation Testing ...........................................................................29
7.6.3 Servo Direction Reversal........................................................................30
7.6.4 Servo Neutral Setting..............................................................................30
7.7 In Flight Adjustment of Servo Neutral....................................................................30
7.8 System Optimization, Flight Time, Distance Counters and Totalizers...................31
7.8.1 System Optimization................................................................................31
7.8.2 Flight Time, Distance and Totalizer Counters (EZ Pilot II only)...............33
7.8.2.1 Flight Time and Distance Counters .........................................33
7.8.2.2 Flight Time and Distance Totalizer Displays............................34
8.0 Electrical Requirements..............................................................................................34
8.1 Primary Input Power...............................................................................................34
8.2 Servo Power...........................................................................................................34
8.3 GPS Data Input......................................................................................................34
8.4 Remote Display Brightness....................................................................................34
8.5 Autopilot Servo Disconnect....................................................................................34
8.6 Wiring Diagram ......................................................................................................35
8.7 J1 Connector Pin Mapping Chart...........................................................................35
9.0 Glossary of Terms.........................................................................................................36
10.0 Contact Information ……………………………………………………………………..36

1
EZ Pilot
1.0 Introduction
Congratulations on choosing the EZ Pilot autopilot. It is designed to enhance the navigational
capabilities of your experimental aircraft and offers many innovative features.
While the EZ Pilot is inherently simple to use, this manual will serve as a guide to understanding
its basic functions and employing its many advanced features. The EZ Pilot is so feature-rich that
mastering it all might seem intimidating at first. Be assured that the advanced features are not
necessary for out-of-the-box utilization of the autopilot and that, except for the fine gain settings
and the servo position adjustment, all of the additional parameters are for increased utilization
and enjoyment of your autopilot. Operation is as simple as entering a flight plan into your
GPS and pressing the SERVO button. The sections on installation and adjustment are placed
toward the back of the manual, as you will not normally need to refer to them once your
installation and test flights are complete.
Section 2 examines the elements of operation employed by the EZ Pilot. Here you will get a feel
of what the unit will do for you, and how to employ its three basic modes of navigation.
Section 3 is a detailed description of the Control and Display unit, which will familiarize you with
switch functions and the wealth of information available to you on the alphanumeric display.
Section 4 is a detailed description of the Setup Screens available to you to configure the
autopilot to meet your preferences and the flight dynamics of your aircraft. This is “must read”
information for the initial set up of the EZ Pilot autopilot.
Section 5 takes you along on a flight, with the EZ Pilot handling the navigational duties. As the
flight progresses, you will begin to employ additional features of the autopilot.
Section 6 describes the installation of the Control Head and some initial tests for proper
operation.
Section 7 is devoted to the installation and operation of the Servo. Because the servo is
connected to your ailerons, be sure you read and thoroughly understand this section before
installing the servo. Paragraph 7.8 describes how to adjust the autopilot so that it is “fine tuned”
to your particular aircraft.
Section 8 covers the electrical requirements and wiring of the EZ Pilot system.
Section 9 is a glossary of terms and acronyms that are used in this manual.
Section 10 provides contact information for those wishing to communicate with Trio Avionics

2
2.0 General Information
The EZ Pilot is a small, solid state aircraft autopilot system designed exclusively for
experimental aircraft and is to be used for VFR operations only. This autopilot is not
certified and is not suitable or approved for installation in a normally certificated aircraft.
The EZ Pilot is a single axis autopilot that controls the roll axis for aircraft attitude correction (wing
leveling) and provides area navigation using signals provided by an external GPS receiver. It is
composed of two units, the control/display unit and the roll servo.
The EZ Pilot does not contain a built-in GPS or other navigation data source. You must supply
an appropriate host GPS source and be correctly connected to the Display Head at the time of
installation. (See the Installation Instructions later in this manual.)
The EZ Pilot uses a solid-state inertial rate sensor for attitude stabilization. It uses elements of
the host GPS digital data stream for the navigation function. It accepts either a NMEA 0183,
V2.XX stream format or the Aviation Link format for navigation guidance.
While the EZ Pilot is an excellent “wing leveler,” it finds its greatest strength following a flight plan
that is active on a host GPS. This can be as simple as a “GOTO” command on the GPS, or a
complex, multi-segment flight plan.
Three navigation modes are provided that allow the pilot to follow a selected GPS course or flight
plan.
1. Track mode (TRK)– used for area navigation tracking a host GPS flight plan (or
GOTO data).
Note: The EZ Pilot also uses the GPS derived information to monitor the inertial sensor performance
and provides automatic corrections to the sensor data to correct for drift due to thermal shifts and
inherent sensor drift and noise errors. The EZ Pilot has a flash based EEPROM memory that is
updated automatically with the most current dynamic calibration information during each flight.
WPT
WPTWPT
WPT
Important Warning
Do not use the autopilot to attempt GPS approaches, even though your GPS may provide
this feature. The EZ Pilot is intended to be an aid to en route navigation only.
The Servo should always be disengaged when initiating the landing checklist at altitude.

3
2. Course mode (CRS) – provides vector navigation as illustrated below. CRS also
allows tracking an autopilot-selected course when the host GPS route function is not in
use. CRS mode uses the GPS signal to provide the aircraft groundtrack. This mode can
be useful for avoiding restricted airspace, weather and oncoming air traffic.
3. Intercept mode (INT)– used to intercept a predefined GPS desired track (DTK) as
illustrated below. The INT mode also uses the GPS signal to provide the aircraft
groundtrack. This mode is useful to regain the original flight plan track after
circumnavigating the previously mentioned flight obstacles.
In both the CRS and INT modes the ground track to be followed may be selected by the pilot,
using either the L/R switch or the PCS steering mode of operation
The EZ Pilot will automatically switch from the INT mode to the TRK mode as it nears the
intercept boundary.
Original GPS course line
Intercept Boundary
Variable distance depending on speed
X
A
utopilot flies INT mode to intercept GPS course
A
s the aircraft nears the GPS course line
the autopilot automatically switches to TRK
WPT WPT
GPS course line
X
A
utopilot flies INT
X
WPT WPT
Pilot commands CRS mode
Pilot commands INT mode “intercept”
Autopilot intercepts original course

4
3. Control and Display Unit
The control and display unit is designed to fit in a standard 3 1/8 inch instrument cutout in the
instrument panel and requires approximately a 3 inch clearance behind the instrument panel.
The unit is powered from the airframe +12V DC system. All controls are located on the front
panel.
This unit contains all of the controls and displays that are required for autopilot mode
selection, display data selection, servo power control, setting CRS direction and INT angle
selection.
3.1 Switch Function and Operation
3.1.1 ON/OFF Switch
The ON/OFF switch controls
application of aircraft power to the EZ
Pilot. In the OFF position the EZ Pilot
is completely disconnected from the
aircraft control system. On power up
the display presents a logo and the
current EZ Pilot firmware code version
(or a customized screen) and sets
several default conditions as follows:
Upon power up the TRK mode is
selected and the
TRK LED is illuminated. This mode is
not fully operational until valid GPS
data is available. When GPS is
unavailable for seven seconds, or after
initial power up, the display will default to a flashing "NO GPS" message. In this
condition the autopilot may still be used to provide a wing leveler function and the L-R
switch can be used to initiate turns to the left or right. Once GPS data is present and
validated, full navigation function is available.
Servo power is initially off on power up. The Servo Power Switch must be pressed
momentarily to activate the system servo for either normal navigation or wing leveler
functions. When the SERVO POWER LED is not illuminated the servo motor is
completely disconnected from the aircraft control system.
3.1.2 Mode Switch
The MODE switch controls the selection of the TRK (track), CRS (course) and INT
(intercept) modes. The default mode during power up is TRK.
Pressing the MODE switch momentarily advances the mode from TRK ---> CRS ---> INT
and then back to TRK. The appropriate LED illuminates in each mode.
The automatic transition from the INT mode to the TRK mode is a function of the
L-R
Switch
LED
The MODE switch also provides the “AUTOMATIC COURSE REVERSAL” feature which does an automatic
servo engage and ground track reversal. Please paragraph 3.2.12 for operation instructions for this feature.
Also, the MODE switch function may be connected to an external switch (in lieu of the display dimming
function) to provide a remote method of changing the EZ Pilot mode setting. See paragraph 4.0 for additional
details.
Push Button
Switch

5
crosstrack error (XTK) magnitude. The unit will sequence automatically from INT to TRK
if the track error magnitude is below approximately 0.5 miles (intercept distance
increases with speed). The precise switching distance is displayed as IDS on the upper
right data field when the INT mode is selected. Also, sequencing the mode from CRS to
INT is not possible if the track error is below this variable limit. (At any time while in the
INT mode the pilot may transition to the TRK mode, or through TRK to CRS mode, by
pressing the MODE switch.)
3.1.3 Servo Power Switch
The servo power switch controls power
application to the EZ Pilot servo. When the
SERVO LED is unlighted servo power is
interrupted. This power interruption
disconnects the EZ Pilot completely from
the control system. When the LED is
illuminated the EZ Pilot is providing servo
power and control signals to the autopilot
servo. The servo is turned on or off
(disconnected) by pressing this switch
momentarily. A remote Servo disconnect
switch should also be mounted on the
aircraft control stick (strongly
recommended). When implemented, this
switch will provide important additional
functionality (PCS mode steering).
3.1.4 Display Switch
The Display Switch performs 6 functions, as follows:
1- Display Data Fields
The DISPLAY switch selects what data is presented on the variable fields of the display.
Momentarily pressing (“bumping”) the display switch advances the lower right line
variable display field through the available selections. Pressing and holding the display
button then toggling the L-R switch advances the upper right variable display field
through its display selections (see function 5 below). The displays available are
described in section 3.2.14.
2 - Display Brightness Control
Display brightness control is also accomplished using the front panel DISPLAY switch or
a remote display dimming switch. Pressing the front panel switch and holding it
approximately one second, then releasing the switch,will change the display brightness
level. The DISPLAY switch should be momentarily released after the next dimming
setting is obtained to prevent cycling to the calibration mode (Function 3 below). The
remote display dimming switch, however, steps the display through the dimming levels
each time it is pressed and will initiate the display scanning mode. (There is an option to
reassign the remote dimming switch to MODE switching but the DISPLAY switch on the
front panel will still perform the dimming function and start or stop the scanning mode.)
3 - Entering “Calibration Mode”
Pressing and holding the DISPLAY switch for more than five seconds causes entry into
the CALIBRATION MODE for fine tuning of the autopilot tracking algorithms (all models)

6
and displaying the FLIGHT TIMERS and TOTAL TIME AND DISTANCE counters (EZ
PILOT II only).
4 - Scan Mode Entry
Pressing the DISPLAY switch rapidly two times in quick succession (double-click) will
cause the variable field data in the right part of the lower line to “scan,” providing a
rotating display of the various GPS data elements being received. The turn coordinator
information is not provided in the “scan” mode; however it is available in the upper right
field (see Function 5 below). Exit from the scan mode is accomplished by double-clicking
the display button again. Whenever the SCAN mode is active a small dot will appear in
the display in front of the data field indicating the SCAN mode is active
5 - Top Line Data Selection
Using the DISPLAY switch in conjunction with the L-R switch allows selection of the data
being displayed in the right side of the top display line.
6 - Setup Screen Entry
If the DISPLAY button is pressed when power is applied, the EZ Pilot will go into the
SETUP mode function. In this mode the following screens and operating parameters can
be changed:
•Contrast adjust (LCD model only),
•Servo position
•Remote dim or mode setting
•Turn rate selection (AUTO, or a fixed turn rate from 1 to 3 deg / sec)
•Last waypoint circle
•Rate of turn display (LARGE or SMALL – EZ Pilot II only)
•Start up screen programming (user programmable)
•System Configuration screen (factory software version and serial number)
3.1.5 Left or Right (L- R) Switch
The L-R switch has 4 functions depending on the EZ Pilot mode.
1 – TOP control
In the TRK mode the L-R switch is used to change the Track Offset Position (TOP)
setting.
2 - Groundtrack Adjustment
In either the CRS or the INT modes the L-R switch is used to select the groundtrack that
the autopilot is commanded to follow. Momentarily moving the L-R switch to the left
slews the commanded groundtrack to the left in one-degree increments. Momentarily
moving the L-R switch to the right causes the commanded groundtrack to be moved to
the right by one degree. Holding the switch in either the left or right position for more
than one second will cause the commanded groundtrack to move right or left at a faster
rate until released.