The TT21 is a two part transponder system, which includes an integrated altitude encoder. In design and technology the TT21 is identical to the TT22; the only difference is that the transmitted output power of the TT21 is lower, qualifying the unit as a Class 2 transponder. Class 2 transponders may be used on aircraft cruising slower than 175 knots, and operating below 15,000 feet, IFR or VFR.
The front panel controller is smaller than a standard instrument, and the remote transponder is not much bigger than a pack of cards. The TT21 can fit into the smallest of aircraft – and yet it is fully certified and compliant with all the transponder requirements.
The TT21 can be mounted in a standard 57 mm (2 1/4 inch) instrument hole, or where space is really tight, in a compact mounting just 42 mm high.
The TT21 is TSO approved for fitting to European and FAA registered aircraft.
Box includes installation kit.