General Description; Introduction; Equipment Description - Garmin GTX327 Installation Manual

1

GENERAL DESCRIPTION

1.1

Introduction

This manual presents the mechanical, and electrical installation requirements for the GTX 327 Digital
Display Mode A/C Transponder. After installation of the GTX 327, FAA Form 337 must be completed
by an appropriately certificated agency and ATC transponder tests required by 14 CFR, Part 91.413 must
be completed to return the aircraft to service.
1.2

Equipment Description

The Garmin GTX 327 is a panel-mounted transponder with the addition of altitude reporting and timing
functions. The transponder is a radio transmitter and receiver that operates on radar frequencies,
receiving ground radar or TCAS interrogations at 1030 MHz and transmitting a coded response of pulses
to ground-based radar on a frequency of 1090 MHz.
As with other Mode A/Mode C transponders, the GTX 327 replies with any one of 4,096 codes, which
differ in the position and number of pulses transmitted. By replying to ground transmissions or TCAS
interrogations, the GTX 327 enables ATC to display aircraft identification, altitude and groundspeed on
ATC radar screens or TCAS traffic indicators. The GTX 327 is equipped with IDENT capability that
activates the Special Position Identification (SPI) pulse for 18 seconds.
The GTX 327 is configured with all key controls. The layout of the front panel keys and displays
segregates the transponder's primary functions from the secondary timing functions. The unit can be
configured so the aircraft avionics master bus can turn the unit on.
The GTX 327 can also be incorporated in installations with other compatible control/display units such as
the Garmin GNS 480 (CNX80).
Provision is made for unit software upgrade by means of RS-232 data transfer through rear connector
pins. The installation of an optional connector is highly recommended. If the optional connector is
placed in the aircraft, transponder removal and reinstallation for software upgrade is not required. The
software can be changed while the unit is still mounted inside the aircraft.
The GTX 327 lens is coated with a special anti-reflective coating, which
is very sensitive to skin oils, waxes and abrasive cleaners. CLEANERS
CONTAINING AMMONIA WILL HARM THE ANTI-REFLECTIVE
COATING. It is very important to clean the lens using a clean, lint free
cloth and an eyeglass lens cleaner that is specified as safe for
anti-reflective coatings.
GTX 327 Installation Manual
190-00187-02
CAUTION
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Revision K