General Description; Introduction; Equipment Description - Garmin GTX 33 Installation Manual

1 GENERAL DESCRIPTION

1.1 Introduction

This manual presents mechanical and electrical installation requirements for installing the various versions
of the Garmin GTX 33 Mode S Transponder. These versions include all GTX 33, GTX 33D, GTX 33H,
and GTX 33DH units with or without Extended Squitter Enabled; as part of a Garmin Integrated Flight
Deck. Throughout this manual, the term GTX 33 applies to all versions of the GTX 33 and GTX 33D
unless specifically stated otherwise.
The GTX 33 can also be incorporated as a remote mounted unit in installations with other compatible
control/display units such as the Garmin GNS 480 (CNX80), GTN 6XX/7XX, and GMX 200 (MX20)
Multifunction Display (MFD).

1.2 Equipment Description

The Garmin GTX 33 rack mounted Mode S Transponder is a radio transmitter and receiver that operates
on radar frequencies, receiving ground radar and TCAS interrogations at 1030 MHz and transmitting a
coded response of pulses on a frequency of 1090 MHz. The GTX 33 is equipped with IDENT capability
that activates the Special Position Identification (SPI) pulse for 18 seconds.
The GTX 33 replies to Mode A, Mode C and Mode S interrogation. Mode A replies consist of framing
pulses and any one of 4,096 codes, which differ in the position and number of pulses transmitted. Mode C
replies include framing pulses and encoded altitude.
The GTX 33 with Extended Squitter Enabled provides Automatic Dependent Surveillance-Broadcast
(ADS-B) technology that improves situational awareness and flight safety. With ADS-B capabilities,
position, velocity, and heading information are automatically transmitted to other aircraft and ground
stations. The current air traffic control system depends on the transmission of interrogations for pertinent
aircraft information at a slower update rate. ADS-B provides immediate surveillance of air-to-air traffic
and aircraft in remote or inhospitable areas not currently covered by radar.
Ground stations can interrogate Mode S Transponders individually using a 24-bit ICAO Mode S address,
which is unique to the particular aircraft. In addition, ground stations may interrogate a GTX 33 for its
Transponder data capability and the aircraft's Flight ID, which is the registration number or other call sign.
The GTX 33 makes the maximum airspeed capability (set during configuration setup) available to TCAS
systems on-board nearby aircraft to aid in the determination of TCAS advisories.
The unit features an altitude monitor and TIS traffic advisories. A voice or tone audio output announces
altitude and traffic alerts. The GDU Primary Flight Display screen displays the code, reply symbol and
mode of operation, depending on equipment connections and configuration selection. The GNS 480
(CNX80), GTN 6XX/7XX, and GMX 200 (MX20) MFD provide similar information with the addition of
pressure altitude.
The GTX 33 features multiple transmit/receive ARINC 429 and RS-232 data ports. The unit concentrates
data from three ARINC 429 inputs, gray code, RS-232 input data and discrete inputs to the high-speed
RS-232 data ports for display on the flight displays. Although multiple output capability is available, the
unit is designed to feed all outgoing data via RS-232 data ports. Two RS-232 data ports send and receive
data to/from the GIA 63(W) Integrated Avionics Units (IAU), GNS 480 (CNX80), GTN 6XX/7XX, or
GMX 200 (MX20) Multifunction Display.
190-00906-00 GTX 33 Installation Manual
Rev. F Page 1-1