GTN 625/635/650 TSO Installation Manual
Page 6-29
190-01004-02
Rev. C
AIR/GROUND LOGIC
Select the source for the air/ground logic.
Selection
Description
Auto Airborne Off
The transponder will not automatically transition to operate mode when it
senses the aircraft is airborne.
Squat Switch
The transponder is connected to a squat switch to determine airborne state.
GPS Data
The transponder is using GPS data to determine the airborne state.
Altitude Data
The transponder is using an altitude source to determine the airborne state.
SQUAT SWITCH SENSE
The squat switch sense field may be set to either High or Low. If the air/ground logic field is set to squat
switch, the squat switch sense field is used to define the state of the squat switch input. If the squat sense
field is set to High, then when the squat switch input is high, the aircraft is considered to be on the
ground. If the squat sense field is set to low, then when the squat switch input is low, the aircraft is
considered to be on the ground.
MAX AIRSPEED (GTX 33 ONLY)
Select the maximum true airspeed for the aircraft. The default is
<= 150 KTS.
Selection
Description
<= 75 KTS
Max aircraft operating speeds less than or equal to 75 knots TAS.
<= 150 KTS
Max aircraft operating speeds less than or equal to 150 knots TAS.
<=300 KTS
Max aircraft operating speeds less than or equal to 300 knots TAS.
<=600 KTS
Max aircraft operating speeds less than or equal to 600 knots TAS.
<=1200 KTS
Max aircraft operating speeds less than or equal to 1200 knots TAS.
>1200 KTS
Max aircraft operating speeds greater than 1200 knots TAS.
UNKNOWN
Max aircraft speed is unknown.
ADDRESS TYPE (GTX 33 ONLY)
Select the method of entry of the aircraft address.
Selection
Description
US Tail
For future use. Invalid Selection. Do not select US Tail. Address can only be
entered in hexadecimal code format.
HEX ID
Allows technician to enter the aircraft registration number in hexadecimal
code format. This is the only valid selection.
ADDRESS (GTX 33 ONLY)
Enter the Aircraft Address. Enter the aircraft registration number in hexadecimal code format. The Octal
code for the Mode S Address is an 8-digit number that can be found on the aircraft registration certificate
or by visiting www.faa.gov and entering the N-number of the aircraft into the N-number inquiry section
of the website. Convert the Octal Mode S Address into hexadecimal format and enter the hex ID of the
aircraft. If the ‗Flight ID‘ is configured to SAME AS TAIL, ensure that the correct tail number appears in
the Flight ID field.
NOTE
The Octal Mode S Address can be converted to hexadecimal format with the use of a
scientific calculator. Microsoft Windows calculator can be used by selecting ‗scientific‘
view and then by entering the octal code. With ‗Oct‘ selected on the calculator, enter the
Octal Mode S Address. Change the selection to ‗Hex‘, as shown in Figure 6-35, and
enter the displayed Hex code into the address field on the GTN.
