Mode S Data Transmission

In addition to 4096 code and pressure altitude, the GTX 328 is capable of transmitting aircraft identification, transponder capability and maximum speed range. “Aircraft Identification” is commonly referred to as FLT ID (Flight Identification). The GTX 328 may be configured by the installer to allow the flight crew to enter FLT ID for each flight. An example is when air-carrier service requires changing the FLT ID.

The FLT ID may consist of the aircraft registration or a flight number as agreed upon with the local aviation authority. In either case, the FLT ID must be the same aircraft identification that appears in the flight plan to correlate the aircraft identification seen on ATC radar with the correct voice call sign for the aircraft. If no flight plan is filed with the aviation authority (as may be permitted by regulations), the FLT ID entered is the aircraft registration marking.

When flight crew entry of the FLT ID is not required, the installer configures the system to report the aircraft identification according to local aviation requirements. In this configuration, alteration of the FLT ID by the flight crew is not possible.

Entering a Flight ID Number

When configured for FLT ID PWR-UP ENTRY at installation, the flight crew must enter the Flight ID before the GTX 328 will operate. After the flight crew enters the correct Flight ID, the aircraft identification that is transmitted in response to ATC radar interrogations is properly correlated with the associated call sign for voice communication with the aircraft.

If the FLT ID PWR-UP ENTRY is required but does not appear at power up, contact a Garmin authorized service center for GTX 328 configuration.

No space is needed when entering Flight ID characters. When a Flight ID contains a space, the GTX 328 automatically removes the spaces upon completion of Flight ID entry.

At system power-up the FLT ID may appear with no number (as shown) or with the last FLT ID entered. The cursor covers the entire FLT ID field.

If the Flight ID appearing at turn-on is correct, press the CRSR Key to move the cursor to the “OK?” field. Press CRSR again to accept the FLT ID. The transponder then begins normal operation.

When no FLT ID appears or the FLT ID must be changed, press the number keys corresponding to the alphanumeric character entry. For example, to enter the letter “R” press the 5 Key four times.

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Garmin 328 manual Mode S Data Transmission, Entering a Flight ID Number