190-00709-05 Rev. D
Garmin G1000 Pilot’s Guide for the Socata TBM 850/900
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AUDIO PANEL AND CNS
4.5 GTX 33/33D MODE S TRANSPONDERS
The GTX 33 Mode S Transponder and GTX 33D Diversity Mode S Transponder provide Mode A, Mode C, and
Mode S interrogation and reply capabilities. Diversity incorporates antennas mounted on the top and bottom of
the aircraft for dependable operation while maneuvering. Selective addressing or Mode Select (Mode S) capability
includes the following features:
• Level-2 reply data link capability (used to exchange information between aircraft and 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.
The Hazard Avoidance Section provides more details on traffic avoidance systems.