Trig Avionics TT26 User manual

TT26 ADS-B Transponder
Installation Manual
01633-00-AC
24 January 2017
Trig Avionics Limited
Heriot Watt Research Park
Riccarton, Edinburgh
EH14 4AP
Scotland, UK
Copyright Trig Avionics Limited, 2016

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CONTENTS
1. PREFACE...............................................................................................4
1.1 PURPOSE...........................................................................................4
1.2 SCOPE...............................................................................................4
1.3 CHANGES FROM PREVIOUS ISSUE......................................................4
1.4 DOCUMENT CROSS REFERENCES ......................................................4
2. INTRODUCTION..................................................................................5
2.1 TT26 DESCRIPTION...........................................................................5
2.2 INTERFACES......................................................................................5
2.2.1 TT26 ADS-B Transponder Unit ...............................................5
3. TECHNICAL SPECIFICATIONS.......................................................7
3.1 TT26 TRANSPONDER UNIT (01629-00) ............................................7
3.2 INSTALLATION APPROVAL.................................................................8
3.3 NON-ETSO FUNCTION......................................................................8
4. UNIT AND ACCESSORIES SUPPLIED.............................................9
4.1 TT26 ADS-B TRANSPONDER ITEMS.................................................9
4.2 INSTALLATION KIT............................................................................9
4.3 REQUIRED ITEMS ..............................................................................9
5. INSTALLATION.................................................................................11
5.1 UNPACKING AND INSPECTING EQUIPMENT......................................11
5.2 TRANSPONDER MOUNTING .............................................................11
5.3 COOLING REQUIREMENTS ...............................................................12

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5.4 TT26 TRANSPONDER ELECTRICAL CONNECTIONS..........................12
5.4.1 TT26 Interface –Pinout.........................................................13
5.5 TT26 TRANSPONDER INTERFACE DETAILS .....................................14
5.5.1 Power Input............................................................................14
5.5.2 TMAP Control Port................................................................14
5.5.3 Auxiliary RS-232 Interface.....................................................15
5.5.4 Auxiliary Power .....................................................................15
5.5.5 Squat Switch Input .................................................................16
5.6 DCONNECTOR CRIMP TERMINALS .................................................16
5.7 WIRING CONSIDERATIONS...............................................................17
5.8 GPS ANTENNA................................................................................17
5.9 GPS ANTENNA CABLE....................................................................17
5.10 TRANSPONDER ANTENNA ...............................................................18
5.11 TRANSPONDER ANTENNA CABLE....................................................18
5.12 STATIC PRESSURE CONNECTION .....................................................18
6. INSTALLATION SETUP AND TEST...............................................19
6.1 CORE CONFIGURATION ITEMS.........................................................19
6.1.1 Aircraft Address.....................................................................19
6.1.2 Aircraft Registration ..............................................................19
6.1.3 Aircraft Speed Class...............................................................19
6.1.4 Aircraft Category...................................................................19
6.1.5 Squat Switch Source...............................................................20
6.1.6 Aircraft Length and Width .....................................................20
6.1.7 GPS Antenna Offset ...............................................................20

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6.2 INTERFACE CONFIGURATION...........................................................20
6.2.1 Altimetry Source.....................................................................20
6.2.2 GPS Source............................................................................21
7. POST INSTALLATION CHECKS....................................................22
8. CONTINUED AIRWORTHINESS....................................................23
9. LIMITED WARRANTY.....................................................................24
10. ENVIRONMENTAL QUALIFICATION FORMS ......................25
11. ADS-B COMPLIANCE...................................................................27
11.1 ADS-B PARAMETERS SUPPORTED..................................................27
11.2 FAA 91.227 COMPLIANCE ..............................................................28
11.3 AMC 20-24 COMPLIANCE...............................................................28
12. INSTALLATION DRAWINGS......................................................29
12.1 DIRECT CHASSIS MOUNT ................................................................29
12.2 CONNECTOR ARRANGEMENT..........................................................30
13. BASIC INTERCONNECT DIAGRAM .........................................31

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1. Preface
1.1 Purpose
This manual describes the physical and electrical characteristics and the
installation requirements for a TT26 ADS-B transponder.
1.2 Scope
This document applies to the installation of the TT26 ADS-B Transponder.
At the publication date of this manual the software version identifier for the
TT26 is 1.6 and the FPGA version identifier is 1.5.The software and FPGA
versions are subject to change without notice.
1.3 Changes from Previous Issue
Section 1.4 and 5.5.2: Added document reference for TMAP specification.
Section 3.1: Added C145c class information.
Section 4.1 and 5.2: Removal of quick release tray.
Section 12: Update installation drawings.
1.4 Document Cross References
DEV/TMAP/005
Enhanced TMAP Protocol Specification
Issue 3.0

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2. Introduction
2.1 TT26 Description
The TT26 ADS-B transponder system is an ED-73E compliant Mode S level
2els datalink transponder, with support for ADS-B extended squitter,
elementary surveillance and SI codes, which also meets the relevant
environmental requirements of ED-14G. The TT26 has a nominal power
output of 250 watts, and meets the power output requirements for Class 1.
The TT26 has a built in WAAS GPS receiver which meets the requirements for
DO-229D class Beta1, and provides a position source for ADS-B transmissions
from the transponder. The ADS-B function meets DO-260B class B1S.
The built in pressure sensor provides altitude measurement up to 70,000 feet.
The TT26 is certified to ETSO C10b, ETSO C88b, ETSO C145c, ETSO
C112e and ETSO C166b A2.
The TT26 is controlled using a separate controller; the controller forms part of
the system and is required for full compliance with the altimetry TSO and
transponder TSO.
The TT26 runs from either 14 volt nominal or 28 volt nominal DC power
supply with no configuration changes required.
The TT26 responds to both legacy Mode A/C interrogations and to Mode S
interrogations from both ground radar and airborne collision avoidance
systems. In all cases, the interrogations are received by the TT26 on
1030MHz, and replies are transmitted on 1090MHz.
2.2 Interfaces
2.2.1 TT26 ADS-B Transponder Unit
The TT26 has a single TNC antenna connection to a transponder antenna, a
single SMA connector to an active GPS antenna, a single 25 way D-type

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connector and a static pressure connector. The 25 way D-type interface
provides the following services:
Power Input
The TT26 operates on 11 to 33 volts DC.
Controller Datalink
A two wire data link is used to connect the TT26 and the
controller. Depending on TT26 option, this interface can
be provided over a half-duplex RS-485 interface (TMAP
RS-485 bus) or a full duplex RS-232 interface (TMAP
over RS-232).
Second Datalink
A secondary RS-232 interface provides access to GPS
data.
“On ground” input
Allows automatic flight/ground mode switching for
aircraft with a squat switch.

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3. Technical Specifications
3.1 TT26 Transponder Unit (01629-00)
Specification
Characteristics
Compliance
ETSO C112e Class 1 Level 2els, ETSO
C166b A2 Class B1S, ETSO C10b, ETSO
C88b, ETSO C145c Class Beta 1
FCC Identification
VZI01629
Applicable documents
EUROCAE ED-73E, EUROCAE ED-14G
(RTCA DO-160G), RTCA DO-181E, RTCA
DO-260B, AS8003, AS392C, DO-229D
Software
ED-12B (RTCA DO-178B) Level B
Hardware
DO-254 Level C
Power Requirements
11 –33 volts DC. Typical 8 watts @ 14Volts.
Altitude
70,000 feet
Humidity
Tested to Category A in DO-160G
Operating Temperature
-55°C to +55°C
Transmitter Frequency
1090MHz ± 1MHz
Transmitter Power
250 watts nominal; 125 watts minimum at
antenna after allowing for 0.5dB connector
losses and 1.5dB cable losses.
Transmitter Modulation
8M89 V1D
Receiver Frequency
1030 MHz
Receiver Sensitivity
-74dBm ± 3dB

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Physical Specifications (including connectors)
Height
62 mm (2.44”)
Width
71.5 mm (2.81”)
Length
153 mm (6.02”)
Weight
475 g (1.05 lbs)
3.2 Installation Approval
The conditions and tests required for the TSO approval of the TT26 are
minimum performance standards. It is the responsibility of those desiring to
install this transponder on or within a specific type or class of aircraft to
determine that the aircraft operating conditions are within the TSO standards.
The transponder may be installed only if further evaluation by the user/installer
documents an acceptable installation that is approved by the appropriate
airworthiness authority.
3.3 Non-ETSO Function
The internal altimeter has been qualified to operate at altitudes of up to 70,000
feet. The applicable ETSO certification applies to 50,000 feet. For altitudes
above 50,000 feet the altimeter tolerance extrapolates the allowed value in the
applicable standards; the tolerance at 70,000 feet is not more than 380 feet.