Section 7
Columbia 400 (LC41-550FG)
Description of the Airplane and Systems
Initial Issue of Manual: November 10, 2004
RC050002
Latest Revision Level/Date: A/12-01-2004
7-127
ALT
–
Selects Mode A and Mode C. In ALT mode, the transponder replies to identification
and altitude interrogations as indicated by the Reply Symbol. Replies to altitude
interrogations include the standard pressure altitude received from an external altitude
source, which is not adjusted for barometric pressure. Any time the function ON or ALT is
selected, the transponder becomes an active part of the Air Traffic Control Radar Beacon
System (ATCRBS). The transponder also responds to interrogations from TCAS equipped
aircraft.
PICTURE OF THE GTX 327 TRANSPONDER
Figure 7 - 49
Code Selection Keys
–
Code selection is done with eight keys (0 – 7) providing 4096 active
identification codes. Pushing one of these keys begins the code selection sequence. The new
code is not activated until the fourth digit is entered. Pressing the CLR key moves the cursor
back to the previous digit. Pressing the CLR key when the cursor is on the first digit of the code,
or pressing the CRSR key during code entry, removes the cursor and cancels data entry, restoring
the previous code. You may press the CLR key up to five seconds after code entry is complete to
return the cursor to the fourth digit. The numbers 8 and 9 are not used for code entry, only for
entering a Count Down time, contrast and display brightness, and data selection in the
Configuration Mode.
Keys for Other GTX 327 Functions –
IDENT
– Pressing the IDENT key activates the Special Position Identification (SPI) Pulse
for 18 seconds, identifying your transponder return from others on the air traffic controller’s
screen. The word “IDENT” will appear in the upper left corner of the display while the
IDENT mode is active.
VFR
– Sets the transponder code to the pre-programmed VFR code selected in Configuration
Mode (this is set to 1200 at the factory). Pressing the VFR key again restores the previous
identification code.
FUNC
– Changes the page shown on the right side of the display. Display includes Pressure
Altitude, Flight Time, Count Up, and Count Down timers. In Configuration Mode, steps
through the configuration pages.
START/STOP
– Starts and stops the Count Up, Count Down, and Flight timers. In
Configuration Mode, steps through configuration pages in reverse.
CRSR
– Initiates starting time entry for the Count Down timer and cancels transponder code
entry. Selects changeable fields in Configuration Mode.
CLR
– Resets the Count Up, Count Down, and Flight timers. Cancels the previous keypress
during code selection and Count Down entry. Returns cursor to the fourth code digit within
five seconds after entry. Used in Configuration Mode.