TruTrak ADI User Manual

ADI Flight Instrument

Installation & User Guide

8300-016 Rev B

TruTrak Flight Systems

1500 S. Old Missouri Rd

Springdale, AR 72764

Toll Free: 866-TRUTRAK

Ph: 479-751-0250

Fax: [phone]

www.trutrakap.com

Table of Contents

ADI Operation ......................................................................................................... 1

ADI Installation ....................................................................................................... 2

ADI Backup Battery Servicing................................................................................ 2

ADI Pin-Out ............................................................................................................ 3

ADI Schematic ........................................................................................................ 3

ADI with Battery Backup ........................................................................................ 4

ADI Block Diagram................................................................................................. 4

ADI Backup Battery Block Connection .................................................................. 5

ADI Backup Battery PIN OUT................................................................................ 5

GPS Setup Guide ..................................................................................................... 6

TROUBLE SHOOTING GUIDE .......................................................................... 11

Revision Date Description Page #

A 07/01/2008 Initial Release

B 12/07/2009 Updated 12

ADI Operation

The artificial horizon, when needed is without a doubt, the most important instrument in the panel. For this reason, the
display must be easy to fly and the instrument very reliable. To achieve this, the ADI combines modern solid state
technology with an easy to see uncluttered mechanical display. In the basic instrument flight panel it is intended for
installation between an airspeed indicator and an altimeter. It is also well suited as the conventional backup in panels
incorporating one of the large glass displays.

The ADI is easy to fly partly because it contains in one instrument, roll, pitch, and direction. Beyond this, it is the
content of each of these displays that make this instrument easy to fly.

The direction display is located in the center of the instrument just below the rotating horizon mask. As is often the case
with an inexperienced pilot caught in IMC, the instrument may be viewed with tunnel vision. For this reason it is good
to have the direction in the center of the tunnel. Of more importance is that this display is track instead of magnetic
heading in that the modern way to navigate is to fly track. When track is presented as a gyro display, the numbers move
sequentially one degree at a time. Experience is showing that direction control with this digital DG placed immediately
below the horizon mask is as easy to fly as the conventional vertical card DG in combination with the conventional
horizon placed nearby.

The bank angle display is driven in a manner similar to that used in the pictorial turn
and bank. The only difference is that in this instrument the display shows bank angle
instead of turn rate. The advantage of this is that the presentation is instantaneous
data only. It cannot drift to accumulate error as is possible with the more complex
AHRS driven systems. It shows bank angles of up to +/- 45° while the requirement
on conventional gyro horizons is +/- 100°. To compensate for this, in the 3 1/8” size
only, flashing red arrows point in the direction the stick is to be moved to level the
aircraft when the bank exceeds +/- 30°. Note that when flying on instruments the
object is to stay level or at least in shallow banks. This instrument is therefore
designed to keep the pilot out of trouble.

The pitch display is perhaps the most beneficial feature of the ADI when compared with conventional horizon
indicators. For short term or immediate movement of the nose up or down, this instrument responds and is flown like
any other gyroscopic pitch indicator. The difference is that after the display has moved in response to an attitude change
the deflection is sustained by the resulting vertical speed. As compared to a pitch attitude display, the vertical speed
display makes it easier to hold altitude and to maintain stable climbs and descents. Also, the movable airplane symbol
does not have to be adjusted to compensate for the angle the fuselage flies when vertical speed is zero. It is recognized
that an aircraft when at the limit of its altitude capability can fly at an ever increasing angle of attack when vertical
speed indicates zero. For this reason an airspeed warning in the form of the letters “A-S” flashing in the DG display is
provided. The answer to this situation is then to observe the airspeed indicator. For stall prevention airspeed is the best
information short of an angle of attack indicator. (Better than attitude)

Another plus regarding this display is that when the airplane is going straight or not turning a wing level presentation is
shown. With this presentation one can disregard the effect of the rudder being out of trim (ball off center) just as
crosswind is not a factor when flying GPS track for direction. This is easier than trying to fly straight with the display
showing a wing down as is the case with a conventional horizon display when the rudder is out of trim. To sum it up, all
of the features described above, in combination, provide what we believe to be the easiest to fly artificial horizon.

TruTrak Flight System 1 ADI Flight Instrument Installation Manual
December 2009 8300-016 Rev B

ADI Installation

Power and ground connections can be made using 22 gage wire with a 2 amp circuit breaker between the avionics buss
and the ADI.

When the unit is purchased in its basic form, the instrument uses the serial output from a GPS (RS-232) for the DG
display. The DG will not display a heading until a ground speed of 5 to 10 knots is achieved.
When the unit contains the built-in GPS receiver, it is only necessary to connect the remote antenna and place the
antenna in view of the sky. On the initial start up it could take up to 15 to 30 minutes to find the satellites, after the
initial startup the GPS will find the satellites in about 5 min the center bar will flash after start up until the GPS receiver
finds the satellites. Then the bar will stop flashing and become steady, at this time the internal GPS is ready for flight.

The internal lighting feature is connected to the instrument panel light bus. The LED will dim to the lowest setting with
a low voltage on the dimmer wire. Confirm that the dimmer system drops to 0 volts when off or the display may stay
very dim and be hard to see in sunlight. The internal lighting is internally grounded.

Apart from the electrical connections, there are standard 1/8” pipe thread receptacles for both pitot and static lines.
Correct tightening is accomplished by starting the adapter by hand until unable to turn, then tightening ½ turn more with
a wrench. Unless the aircraft is pressurized, there is no need to connect the static
line. The airspeed signal is required for the attitude display to function correctly.
Also, it is there to provide the low airspeed warning. This warning is in the form
of the flashing letters “A-S” alternating with the DG number on the DG display
when the airspeed falls below the best rate of climb speed or whatever speed the
owner might choose. Setting of this air speed warning requires a flat blade
screwdriver small enough (approx. ⅛ shaft, tool provided) through the 6-32
female thread. The correct screw driver is provided with the unit.
The lower right instrument screw is removed to gain access to the airspeed
adjustment screw. The procedure for setting the airspeed warning is to fly the
aircraft at the best rate of climb speed (which is also the best glide speed and
attitude sustaining airspeed) or whatever speed suits the owner. While holding
this speed, rotate the adjustment so the flashing “A-S” just appears.

Mounting of the ADI is not angle sensitive as long as the tilt is not more than 10 degrees in any direction, so no
shimming is needed for panel tilt compensation. The mounting screws are 6-32 thread with a maximum length of 3/8”.
Brass screws are preferred.

3 1/8” ADI 3.4”H x 3.4”W x 4.6”D 12-28 volts - Weight - 14 oz
2 ¼” ADI 2.5”H x 2.5”W x 6.7”D 12-28 volts - Weight - 13 oz

ADI Backup Battery & Servicing

Switch label should state, “ADI BACKUP POWER” normally on the switch side that engages the battery
The servicing of the ADI backup battery is simply a matter of inspection of the functionality and confirming charge and
discharge rates.
Recommendation of a function test during the pre-takeoff checklist to confirm the LED switch illuminates with
activation of the backup battery. The ADI should function normally in this mode. Once it has been verified that the
backup battery is properly functioning, return the switch to the normal position.

Once a year a complete function test of the backup battery system is recommended:
Activate the ADI backup battery and confirm LED is illuminated. Continue in this mode, note the time of
activation and confirm minimum one hour function of the ADI.
If function time is less than one hour then remove backup battery and charge on the bench for a minimum of eight hours
and retry function test above.

TruTrak Flight System 2 ADI Flight Instrument Installation Manual
December 2009 8300-016 Rev B

ADI Pin-Out

ADI Connector pin-out

Pin # I/O Connection Pin Function

1 I Power + AVIONICS DC Power (9-30 Volts DC)

2 I 24 V Dimmer controller 24V dimmer input
3 I 12 V Dimmer controller 12V dimmer input
4 I Future AOA module AOA (Future use)
5 -- No Connection Do not connect
6 I

7 -- No Connection Do not connect
8 -- No Connection Do not connect
9 I Aircraft Ground Main DC Ground

ADI Schematic

RS 232 Series Data in

O

RS 232 Serial Data out with Internal GPS

RS-232 input or

RS-232 output with internal GPS

TruTrak Flight System 3 ADI Flight Instrument Installation Manual
December 2009 8300-016 Rev B