Trig TT31 Mode S Stack Transponder
Manufacturer Part Number: 00225-00-01
Trig TT31 Stack Transponder
General Description
Trig TT31 Stack Transponder - has unparalleled installation benefits and class leading performance.
Trig’s TT31 transponder is the ideal retro-fit for the popular Bendix King legacy transponders. The TT31 will ‘plug and play’ straight into an existing KT76A, KT76C and KT78A tray. This significantly reduces both installation time and cost. It provides pilots with Class 1 Mode S technology that is also 1090ES ADS-B Out capable too – to the latest international standard.
The TT31 is compatible with many popular GPS position sources including Garmin GNS and GTN navigators and the Trig TN70. This makes installation flexibility the best in class. A free FAA STC allows the TT31 to be installed as a compliant ADS-B Out solution in 650 aircraft types for further information see our U.S. ADS-B page.
2020 ADS-B Compliance Today - As a fully capable 1090 MHz Extended Squitter ADS-B Out transponder, the TT31 is TSO approved by the FAA to C166b. This makes the TT31 compliant with the latest ADS-B requirements and ensures that it is fit
for the future.
The TT31 is compatible with many popular GPS position sources including Garmin GNS 400W / 500W series navigators and the Trig TN70. This makes installation flexibility the best in class.
The TT31 also provides data link support for TIS traffic. Connecting a suitable panel or remote display will show the position of local and conflicting aircraft traffic - this information is sent from TIS ground stations (where available).
The TT31-low power, high performance The transponder has a bright and easy to read backlit display. Operation is simple via a conventional rotary knob, enabling rapid selection of Squawk code and Flight ID. The TT31 comes with additional
features that include a stop watch, flight timer and altitude alarm.
MODE – S AND ADS-B - Mode A and C transponders are now being replaced by Mode S transponders, this technology is optimised for tomorrow’s airspace requirements. The introduction of ADS-B surveillance technology means the modern transponder has now become the hub of future airspace compliance requirements. Here the TT31 remains the class leader, it was the world’s first transponder certified to TSO-C166b. This is latest FAA standard for the U.S. 2020 ADS-B mandate and demonstrates Trig’s advanced levels of compliance. It’s worth remembering that to receive all ADS-B In traffic transmissions in the U.S. the FAA requires a functioning certified ADS-B Out device.
PRODUCT DESIGN - The TT31 uses half the electrical power of legacy transponders, whilst still transmitting at a higher signal power, its efficient design reduces waste heat in the avionics stack. This reduces the load on the aircraft electrical system improving overall reliability. The flexible power input means that both 14 and 28 volt systems can be used without special configuration or dropper resistors (we recommend that any dropper resistor fitted for a previous transponder should always be removed). The TT31 is compatible with both parallel and serial altitude encoders; it can even act as a serial altitude repeater to provide a convenient altitude source for your GPS.
| Specification | TT31 Transponder |
| Type | Class 1 Mode S Level 2 els |
| Certification | ETSO C166A, 2C112B and TSO-C112, C166b |
| Compliance | ED-73B, DO-160E, DO-178B Level B, DO181C, DO-260B Class B1S, DO-254 Level C |
| Supply Voltage (DC) | 11 – 33 V |
| Typical Current Consumption (at 14V) | idle: 0.22 A, active: 0.45 A |
| Nominal Transmitter Power | 240 W at connector |
| Operating Temperature | -20°C to + 70°C |
| Cooling Requirement | No fan required |
| Weight | 1.35 kg |
| Dimensions | In tray – H 40 x W 160 x L 239 mm In tray – H 1.57 x W 6.30 x L 9.4 inches |
| Circuit Breaker | 3 AMP |
ADS-B OUT
(1090ES ADS-B Out is the international standard and can be used worldwide)
ADS-B OUT AND ADS-B IN
This illustrates aircraft operating within a full ADS-B environment. Note that ground services are only available in the U.S. (these include weather and traffic services).
ADS-B uses a Trig transponder, typically combined with a GPS, to transmit highly accurate positional is information to ground controllers and also directly to other aircraft. This transmission is known as ADS-B Out and its accuracy is greater than using conventional radar surveillance. This gives air traffic controllers the potential to reduce the required separation distance between aircraft that are ADS-B equipped.
ADS-B is seen as being vital to maintaining future efficient airspace management in busy airspace. It also provides advantages in remote ‘non radar’ areas too – here suitably equipped aircraft, with a traffic receiver connected to a display can see other aircraft without conventional radar coverage. This enhances aircraft visibility and reduces the risk of air to air collision.
ADS-B uses satellite and transponder technology to provide the following benefits in an ADS-B environment:
More aircraft can operate safely in the same airspace, so congestion is reduced.
ADS-B technology enables more direct aircraft routing – this can generate significant time and fuel savings.
With appropriate equipment it’s possible to have a live ‘traffic picture’ in the cockpit.
ADS-B enhances flight safety and collision avoidance.
Aircraft with ADS-B Out provide air traffic controllers with ‘pin point’ positional and flight information data. Trig supports 1090ES, the ICAO international standard for ADS-B that can be used throughout the world.
- All Trig products come with a two year warranty, starting from the day of installation
- Install manual and Operating manual (in English, German and French)
- Installation kit (including plastic brackets for round mounts)
- Tray
- EASA Form One
TT31 Mode S Transponder
- TT31 Mode S Transponder 1 00220-00-01
- TT31 Mounting Tray 1 00231-00
- TT31 Documentation Kit 1 00233-00
- TT31 Installation Kit 1 00223-00
Installation Kit
- 12 way double sided crimp housing connector 1 00032-00
- 24 way double sided crimp housing connector 1 00033-00
- Crimp Terminal, Female, 18-24 AWG 30 00236-00
- Screw, Pozidrive, Pan Head M3x12mm lg 4 00422-00
- Connector Co-axial Panel Mount Right Angle Blind Mate 1 00239-00
- Circlip 7/16” External 1 00242-00
- Washer 7/16” Plain, Stainless Steel 1 00241-00
- Washer 7/16” Crinkle, Beryllium Copper 1 00317-00
Documentation Kit
- TT31 Transponder Installation Manual 1 00455-00
- TT31 Pilots Operating Manual 1 00454-00
Required Items
Additional items you will require, but which are not in the TT31 package, include:
- Antenna and fixing hardware. The TT31 is compatible with any transponder antenna approved to (E)TSO C74 or C112.
- Altitude encoder. You require an encoding altimeter or a blind encoder with either parallel Gray code or RS232 serial output. For best results, and simpler installation, an encoder with a serial output is recommended.
- Cables. You need to supply and fabricate all required cables. Guidance on cable types is given in section 5 below.
- Fixings. To secure the transponder tray to the airframe you will need at least 6 flat head screws and six self-locking nuts. If the aircraft does not have existing mounting provisions
Why do you call the TT31 the class leader?
The TT31 was also the first transponder in the world to achieve FAA TSO-C166b certification. It is the easiest retro-fit transponder on the market for the popular KT76A, KT76C and KT78A. Mode S is 'plug and play' and configurable serial ports enable the fastest ADS-B Out install, using the existing BK tray. The latest TT31 software also provides the widest compatibility with other third party avionics. In use the TT31 is one of the world’s most energy efficient transponders, producing less heat and using less power. This improves the overall reliability of your entire avionics stack.
How does “plug and play” work?
The TT31 has been specifically designed as a slide in replacement for the Bendix King KT76A, KT76C and KT78A. The transponder and can utilise the existing mounting tray, electrical connector and antenna connector.
The TT31 is also “plug and play” with the KT-76C. The mounting tray can sometimes be a snug fit as the size varies depending on the age of the KT-76C unit.
When I buy a TT31 what comes in the box?
When you purchase a TT31 Transponder (complete kit) you will receive the following items: TT31 unit and tray, install kit, installation and user manuals (in English, German and French) and an EASA Form 1. You will need to supply wiring and have an existing or new antenna.
The TT31 can also be ordered as a kit without the Trig tray.
Should I buy a Trig tray with a new transponder?
If your old transponder is a different model than the KT76A, KT76C or KT78A, or if the condition of the tray is in doubt we would recommend that it is best to buy a new TT31 tray.
Can I get Mode S using my existing tray?
Yes – the TT31 really does provide Mode S straight out of the box. We would of course remind you to ensure compliance with local installation requirements via an approved facility if you have a certified aircraft. The latest version of the TT31 provides the most flexible installation options, that can include installing ADS-B Out using the original tray (this is subject to local STC regulations).
In Europe how do I get a free minor change?
We have an extensive list of free minor changes within our site available to download. If your aircraft type is not included give us a call, we usually know of other third parties who have a TT31 minor change that may be available. You may also consider the alternative EASA approval called CS-STAN this is especially suited to VFR aircraft.
Does the TT31 have an STC?
Yes, Trig has a free STC with an AML list of over 650 types.
You can find the TT31 STC here - www.trig-avionics.com/support/the-tt31-ads-b-faa-stc/
In the U.S. installing a compliant ADS-B Out solution (in a certified aircraft) requires your Trig transponder to utilise a certified WAAS GPS, this provides a compliant ADS-B position source. The FAA also requires that a certified ADS-B installation is completed in accordance with an FAA STC approval (Supplementary Type Certificate).
Our ADS-B STC’s are available free of charge and cover hundreds of aircraft types. Trig STC approvals allow the use of popular WAAS GPS navigators too – making installation more practical and cost-effective. Our TA70 GPS antenna has also been added to our STC equipment list.
Technical Data
- Improved retrofit performance – ‘plug and play’ Mode S installation for KT76A, KT76C and KT78A
- Certified for IFR / VFR flight
- Amongst the lowest power consumption in class
- TIS traffic capabilities – portable and/or panel mounted avionics
- Backlit LED display
- No cavity tube – no warm up time required (no need for dropper resistors)
- Free European Minor Change approvals
- Free FAA ADS-B STC for 650 aircraft types
- Software provides the widest compatibility with third party avionics
- Unbeatable value and quality – designed and manufactured in the U.K.
- Two year worldwide warranty
ADDITIONAL FEATURES - The TT31 is a highly efficient class leading transponder. It’s easy to use and operate, with a clear bright display and simple user interface. Features include a flight timer, stop watch and altitude monitor (can alert you of a deviation from your selected altitude). The TT31 includes data link support for the U.S. TIS traffic service, up-linked from approach radars. TIS traffic can be displayed on a variety of portable and panel mount displays, coverage includes most US terminal areas. The latest performance upgrades are available during the life of your product via Trig software upgrades, avoiding the need for expensive hardware upgrades.
About Trig
Trig Avionics Limited was founded in January 2004. Our ambition is to provide the most innovative certified avionics products for aircraft owners and operators. With a global network of over 800 Approved Trig Dealers, in 42 countries our popularity continues.
Our Edinburgh operation saw expansion in 2018 with the addition of our European office in Amersfoort, in the Netherlands. This has enhanced our service to a growing community of pilots who appreciate our superior products and dedicated customer service. It’s all part of joining the Trig family.
Trig’s CEO Andy Davis, who started Trig, is an entrepreneur and pilot. Andy set out to produce a solid state and energy efficient Mode S transponder. A new generation of transponders were required to meet a European wide mandate for Mode S. At the time, aircraft owners had few options available, so Andy and his team changed this. Our resulting TT31 transponder set a new benchmark in quality, capability and value.
