Gtx 33 Mode S Transponder(S); Transponder Controls - Garmin G900X Pilot's Manual

4.4 GTX 33 MODE S TRANSPONDER(S)

The single or dual GTX 33 Mode S Transponders provide Mode A, Mode C, and Mode S interrogation and reply
capabilities. Selective addressing or Mode Select (Mode S) capability includes the following features:
• Level-2 reply data link capability to exchange information between aircraft and Air Traffic Control (ATC)
facilities
• Surveillance identifier capability
• Flight ID (Flight Identification) reporting – The Mode S Transponder reports aircraft identification as either the
aircraft registration or a unique Flight ID.
• Altitude reporting
• Airborne status determination
• Transponder capability reporting
• Mode S Enhanced Surveillance (EHS) requirements
• Acquisition squitter – Acquisition squitter, or short squitter, is the transponder 24-bit identification address.
The transmission is sent periodically, regardless of the presence of interrogations. The purpose of acquisition
squitter is to enable Mode S ground stations and aircraft equipped with a Traffic Avoidance System (TAS) to
recognize the presence of Mode S-equipped aircraft for selective interrogation.
• Extended squitter – Transmits the Automatic Dependent Surveillance-Broadcast (ADS-B) position, velocity, and
heading information periodically without requiring an interrogation.
The Hazard Avoidance Section provides more details on traffic avoidance systems.

TRANSPONDER CONTROLS

Transponder function is displayed on three levels of softkeys on the PFD: Top-level, Mode Selection, and
Code Selection. When the top-level XPDR Softkey is selected, the Mode Selection softkeys appear: XPDR1,
XPDR2, STBY, ON, ALT, VFR, CODE, IDENT, ADS-B TX, BACK.
When the CODE Softkey is pressed, the number softkeys appear: 0, 1, 2, 3, 4, 5, 6, 7, IDENT, BKSP,
BACK. The digits 8 and 9 are not used for code entry. Pressing the numbered softkeys in sequence enters
the transponder code. If an error is made, pressing the BKSP Softkey moves the code selection cursor to the
previous digit. Pressing the BKSP Softkey again moves the cursor to the next previous digit.
Pressing the BACK Softkey during code selection reverts to the Mode Selection Softkeys. Pressing the BACK
Softkey during mode selection reverts to the top-level softkeys.
The code can also be entered with the FMS Knob on either PFD. Code entry must be completed with either
the softkeys or the FMS Knob, but not a combination of both.
Pressing the IDENT Softkey while in Mode or Code Selection initiates the ident function and reverts to the
top-level softkeys.
After 45 seconds of transponder control inactivity, the system reverts back to the top-level softkeys.
190-00726-00 Rev. J
Garmin G900X Pilot's Guide
AUDIO PANEL AND CNS
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