Part #: 00710-00

Model: TT21




Trig Avionics


Remote Mount Mode S Transpnder System

Part Number :

  • Smallest & lightest Class 2 Mode S Transponder
  • Designed for Light Aviation
  • For a Higher Performance Aircraft Option, View TT22 
  • Class 2 Transponder is suitable for aircraft cruising slower than 175 knots, and operating below 15,00 feet, VFR or IFR.
  • Remote Mount 2 Part Transponder System: panel controller & transponder box 
  • 130 Watts nominal output
  • Control includes an integrated altitude encoder, up to 35,000 ft
  • Total weight just over 1 lb
  • Minimal Panel Space, can be installed in standard 2¼" (57mm) cut-out or compact mounting just 42mm high
  • Simple Installation
  • Controller acts as a configuration module for the system - easily swap transponder box without reprogramming
  • Fully certified and compliant with all transponder requirements TSO approved for European & FAA registered aircraft
  • Includes TIS (Traffic Information Service) functionality
  • NOTE: While the TT21 is capable of 1090ES ADS-B Out with the appropriate GPS, it is NOT an acceptable ADS-B transponder for certified aircraft because of its Class 2 status. (Due to current FAA regulations)

Additional TT21 Information: TT21 Brochure TT21 Pilot's Guide TT21 Installation Manual Trig vs. Becker Comparison Table

Type: Class 2 Mode S Level 2els Supply Voltage: 9 - 33V DC
Certification: ETSO C88a, 2C112b, C166a & TSO C88b, C112c, C166a, approved for IFR & VFR flight Compliance: ED-73B, ED-14F / DO-160F, DO-178B level B, DO-254 level C, DO-260A class B0, DO-181C
Current Consumption (@ 14V): Idle: 0.15 A; Active 0.28 A Transmitter Power: 130W nominal at connector
Operating Temp: -40 to +70°C Transponder; -25 to +70°C Controller Cooling: No fan required
Weight: 1.0 lbs (150 g) Controller Dimensions: 2.52" x 1.77" x 1.77" (64 x 45 x 45 mm)
Transponder Dimensions: 2.44" x 1.77" x 5.55" (62 x 45 x 141 mm)    
Part Number Transponder Description:
00565-00 Remote Mode S Transponder - Unit Only
00649-00 Mode S Controller - Unit Only
00710-00 Remote Mount Mode S Transponder - System


- Remote Mount Mode S Transpnder System

NSN: 9905-01-579-3551

Price Condition Status

Click on a question below to see the answer. If you have a question about this model that is not answered below, please contact

In relation to NE (New) parts, many OEMs change their prices and availability without any notice to dealers or the industry. Therefore, through the REQUEST or RFQ indication, we ask that customers contact us for the most accurate price and availability.

In relation to SV & OH parts, the used parts aftermarket in the aviation industry is not an infinite supply. It is a dynamic, constantly changing market that is significantly affected by and susceptible to highs and lows in supply and demand. Therefore, although we attempt to, at times, we are unable to predict the exact moment when an item may be available. Once again, through the REQUEST or RFQ indication on our website, we ask that customers contact us for the most current and accurate price and availability.

Automatic Dependent Surveillance-Broadcast (ADS-B) is a component of the Next-Generation (Next Gen) Air Transportation System. ADS-B is an advanced surveillance technology that combines an aircraft's positioning source (GPS), aircraft avionics, and a ground infrastructure to create an accurate surveillance interface between the aircraft & aircraft traffic control. ADS-B provides consistent position accuracy regardless of the aircraft's range from the receiver.

The improved accuracy and update rate of ADS-B is a critical segment of the NextGen infrastructure.

The FAA has determined that it will be necessary for all aircraft operating in specific airspaces to be equipped with ADS-B Out by 2020. A nationwide infrastructure of ground stations is scheduled for completion during 2013.

As of June 2010, only ADS-B Out is being mandated. ADS-B Out provides the ATC with real-time position information. ADS-B In is the aircraft's ability to receive and display other aircraft broadcasted information as well as the services provided by the ground stations.

ADS-B requires the use of a Positioning Source. As of June 2010, any positioning source is allowed; however, WAAS is the only positioning service that provides the equivalent availability required.

A Broadcast Link is also required for ADS-B functionality. There are two available options: 1090 MHz Extended Squitter (ES) or Universal Access Transceiver (UAT). FL 180 (the lower boundary of Class A airspace) is the ceiling for operating an aircraft equipped with UAT only.

ADS-B will eventually provide weather services, air traffic information, terrain maps and other flight information services for all pilots through satellite based data and ground stations. In accordance with NextGen, ADS-B will provide benefits that address some shortcomings over other, existing surveillance systems.

Some of these benefits include:
  • Air-to-air surveillance capability
  • Surveillance in remote areas where radar coverage is unavailable
  • Real-time traffic information for aircraft not equipped with active traffic systems (ex. TCAS, TAS)
  • Reduced separation between aircraft due to sharing of flight information between aircraft
  • Better predictability in departure and arrival times

    Ultimately, ADS-B will allow aircraft to fly at safe distances from each another.

Click Here to View the official FAA NextGen Final Rule released on 5/28/10.

You may also View an SEA Summary of the FAA NextGen Final Rule (NOTE: this information has been altered for summary purposes and should be used as Reference Only).
This is completely normal. The TT21, like most avionics units, needs to be setup and configured upon first use. The pilot’s guide and installation manual provided with the unit provides complete information for the setup and configuration process.

Although some manufacturers call out specific transponder antennas in their installation manuals, almost any transponder antenna can be used with any transponder. Various models are available based on the screw hole pattern desired and the speed & drag considerations based on the aircraft type.

For smaller general aviation aircraft, Southeast Aerospace recommends the stub type AV-22 or CI-101 antenna.



For medium to larger aircraft, Southeast Aerospace recommends the blade type CI-105 or AV-74 antenna.


Ultimately, it is the responsibility of the installer or installing agency to determine what antenna is suitable for the aircraft application.




Click here to find the answer.
While the TT21 is certified to TSO C166B, the TT21 is a Class 2 transponder and therefore does not meet the power output requirements for FAA transponder and ADS-B regulations. Currently, the FAA requirement for United States airspace is that ADS-B Out is in conjunction with a Class 1 transponder. Other ADS-B environments (ex. Europe and Australia) do not require a Class 1 transponder.

It is recommended that TT21 owners transition to the higher power, Class 1 TT22 to fully comply with the FAA ADS-B performance requirements.
The Mode S aircraft identification code is listed on AC Form 8050-3, Certificate of Aircraft Registration, as the International Civil Aviation Organization (ICAO) Aircraft Address Code. If the aircraft registration does not contain this information, aircraft owners with a Mode S transponder can obtain an aircraft identification code from the FAA Aircraft Registry in Oklahoma City, Oklahoma. This may be accomplished by writing to the following FAA address:

Federal Aviation Administration
Aircraft Registration Branch AFS-750
P.O. Box 25504
Oklahoma City, OK 73125-0504

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