Cabin & Cabin Systems

AS350 & H125
GTX330 (mode S) Garmin™ Transponder
SB number : AS350-34-30-02 (R1)
Applicable to version(s) : B2, B3
Installation of GARMIN transponder GTX 330 mode "S" wether as a replacement for GTX 327 mode "C" or not.
This equipment provides information to the air traffic control services.
The GTX 330 uses the mode "S" in addition to modes "A" and "C" (existing on GTX 327).
The GARMIN transponder GTX 330 is a radio transceiver which uses radar frequencies. The transponder receives interrogations from a ground radar or an onboard collision avoidance system or TCAS (Traffic Alert and Collision Avoidance System) on 1,030 MHz and transmits its response by encoded pulses on the 1,090 MHz frequency. The GTX 330 device supports the IDENT function which allows SPI pulses (Special Position Identification) to be activated for 18 seconds. The GTX 330 transponder responds interrogations from the ATC radar beacon system or ATCRBS (Air Traffic Control Radar Beacon System) mode "A", mode "C" and mode "S".

The GARMIN GTX 330 transponder upgrade provides for:
- individual identification and location of the helicopter by a ground radar equipped with an interrogator (mode "A"),
- associated with an encoding altimeter, transmission of helicopter altitude (mode "C"),
- transmission of a specific identify code (mode "S"). The three data: location, identification and altitude are displayed on the air traffic controller’s screen.
This equipment may be required within the frame of helicopter use under JAR-OPS3 during offshore flight, for example.
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+2.15 kg


4 day(s)


  • Requirement set by the European mandate for mode S level 2 surveillance.
  • Complying with ICAO annex 6 Part III and EASA Part CAT (EU Regulation n°965/2012).
  • Transmission of a specific identity code (mode "S").


Not Applicable.

Avionic, Electrical 25 Hour(s)
Airframe, Systems 10 Hour(s)

ADDITIONAL INFORMATION : This upgrade corresponds to MOD OP3294 and drawing 350A826428.01.

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1 Helicopter with Honeywell Block, PRE MOD 073274, PRE MOD OP3184, PRE MOD 073273 This is my configuration
2 PRE MOD 073274, POST MOD OP3184, PRE MOD 073273, Helicopter with Honeywell Block This is my configuration
3 POST MOD OP3184, POST MOD 073273, POST MOD 073274, PRE MOD 074280, Helicopter with SMS Block This is my configuration
4 POST MOD OP3184, POST MOD 074280, Helicopter with Muli-Block This is my configuration

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