What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

GARMIN GTX 335: TRANSPONDER FAILED

P

pdrecker

I'm New Here
Hi all,

I have a GARMIN GTX 335 with integrated GPS and GARMIN GAE12. The GPS and the GAE12 are working fine. The transponder is not working at all.

Directly after power-on I got the following message: "TRANSPONDER FAILED"

Pressing the buttons "ALT", "SBY", "VFR" has no effect.

Under "MESSAGES" there is only the following entry:

"1090ES ADS-B OUT FAILED"

An aviation engineer successfully checked the antenna (RAMI AV-74) and the antenna cable. He also reviewed the wiring. Unfortunately he did not found an error.

The GTX335 device was also tested outside the airplane with another antenna and another power source. The failure still exists.

hardware p/n and versions:

XPDR: p/n 006-B1607-09, version 2.12
GPS: p/n 006-B1827-00, version 6.0
ALT: p/n 3T6005914

pin assignment (P3251):

Code: 
PIN 21: VAC 14V
PIN 42: VAC 14V
PIN 20: AIRCRAFT GROUND
PIN 41: AIRCRAFT GROUND
PIN 9: RS232-OUT (Moving-Map: SKYMAP)
PIN 31: RS232-IN (Moving-Map: SKYMAP)
PIN 52: RS232-GND (Moving-Map: SKYMAP)
PIN 44: USB-VBUS
PIN 2: USB-DATA-Hi
PIN 24: USB-DATA-LO
PIN 45: USB-GND
PIN 43: CONFIG-POWER (GAE12)
PIN 23: CONFIG-GND (GAE12)
PIN 22: CONFIG-DATA (GAE12)
PIN 1: CONFIG-CLOCK (GAE12)
PIN 25: OAT-IN (DAVTRON C307PS)
PIN 3: OAT-OUT (DAVTRON C307PS)

configuration:

Code: 
INTF
    RS232
        CH1
            INPUT: XPDR FMT 1
            OUTPUT: XPDR FMT 1
        CH2
            INPUT: XPDR FMT 1
            OUTPUT: XPDR FMT 1
        CH3
            INPUT: OFF
            INPUT: OFF
    A429 IN
        CH1
            FORMAT: OFF
            SPEED: N/A
        CH2
            FORMAT: OFF
            SPEED: N/A
    A429 OUTPUT: OFF
    DESTRETE IN
    PIN NONE
    FUNC AUD MUTE
AUD
    AUDIO OUTPUT: XPDR
    VOICE: MALE
    VOLUME: 50
    TEST AUDIO: NONE
    ALTITUDE ALERT: OFF
    TIMER EXPIRED ALRT: OFF
    TRAFFIC ALERT: MESSAGE
ADSB
    ACFT CATGRY: LIGHT
    ACFT MAX A/S: <= 150 kt
    ACFT STALL METHOD: DEFAULT
    ACFT STALL SPEED: N/A
    AIRCRAFT LENGTH <= 15mt
    AIRCRAFT WIDTH: <= 23mt
    1090ES OUT CONTROL: DISABLED
    UAT OUT RMT CONTROL; N/A
    1090ES IN CAPABLE: NO
    UAT In CAPABLE: NO
    AIRCRAFT TAIL NUMBER
        ADDRESS: HEX / 3D42EA
    ALLOW PILOT TO EDIT FLT ID: NO
    DEEFAULT FLT ID: ENTRY DEXPA
    FLT ID PREFIX: NONE N/A
SENSOR
    UAT SENSOR INSTALLED: YES
    ALTITUDE SOURCE 1: ALT ENC
    ALTITUDE SOURCE 2: NONE
    GPS 1 SRC: INTRNL
    LAT OFST: UNK
    INTGRTY: AUTO
    LON OFST: UNK
    GPS 2 SRC: NONE
    LAT OFST: N/A
    INTGRTY: N/A
    LON OFST: N/A
    INTERNAL ALT ENCODER INSTALLED
        INSTALLED: YES
        CEILING: 13500
        TEST POINTS: 3
    INTERNAL ALT ENCODER ADJUSTMENT
        TEST ALT: NONE
        CORRECTION: N/A
        MEASURED: ---- ft
DISP
    DISPLAY BACKLIGHT: PHOTOCELL
    MINIMUM LEVEL: 0
    KEYPAD BACKLIGHT: PHOTOCELL
    MINIMUM LEVEL: 0
    PHOTOCELL TRANSITION: 25
        SLOPE: 50
        OFFSET: 50
    LIGHTING BUS INPUT VLTG: 14 VDC
        SLOPE: 50
        OFFSET: 50
    DEFAULT BACKLIGHT OFFSET: 0
    DEFAULT CONTRAST OFFSET: 0
UNIT
    ALTITUDE UNITS: FEET
    TEMPERATURE UNITS: CELCIUS
    INSTALLED ID: 1
    VFR ID: 7000
    ALTITUDE ALERT DEVIATION: 250 ft
    RESTORE PAGES ON POWER-UP: YES
    FLASH MESSAGE INDICATOR: YES
    EHS: DISABLED
    
DIAG
    DISCRETE INPUT STATE
        TIS-A: NC
        STANDBY: NC
        SQUAT: NC
        ALT DATA: NC
    GPS
        SRC 1: LAT 54,43?
        SRC 2: OFF

Has anyone an idea?

Thank you!

Pascal
 
Did you set in the internal altitude offsets for the three (?) altitudes?

They default to zero, not to any useful number.
 
Do you mean "SENSORS / INTERNAL ALT ENCODER ADJUSTMENT"?

I did not change the values! I'm in office right now but I think that the values are zero (default).

Reading the TSO I found the following under "INTERNAL ALT ENCODER ADJUSTMENT":

Code: 
Sets the GAE module altitude to match the primary altitude display.

Should I determine these 3 values by a flight-test? QNH for the primary altitude display 1013,25?
 
same here...

pdrecker said:
"1090ES ADS-B OUT FAILED"
Click to expand...

Actually we have the same problem with our 335. We were told to check if there is 5V on the back of the rack at the GPS antenna cable connector. Ours didn't do anything! We have send it back but no word on what the issue is.
 
pdrecker said:
Do you mean "SENSORS / INTERNAL ALT ENCODER ADJUSTMENT"?

I did not change the values! I'm in office right now but I think that the values are zero (default).

Reading the TSO I found the following under "INTERNAL ALT ENCODER ADJUSTMENT":

Code: 
Sets the GAE module altitude to match the primary altitude display.

Should I determine these 3 values by a flight-test? QNH for the primary altitude display 1013,25?
Click to expand...

This adjustment is supposed to be done by an avionics shop that has a pitot-static test box available to verify the encoder is adjusted/working properly and matches the aircrafts altimeter.
(in the USA this a required test when installing a new altitude encoder or altimeter, it also must be checked every 2 years when performing an IFR cert)

For new certifications or if the encoder or altimeter has been replaced, a Data Correspondence Check must be accomplished to ensure the altitude data transmitted to ATC corresponds to within 125 feet of the altimeter normally used to maintain flight altitude per CFR 91.217
 
Last edited:
pdrecker said:
Do you mean "SENSORS / INTERNAL ALT ENCODER ADJUSTMENT"?

I did not change the values! I'm in office right now but I think that the values are zero (default).

Reading the TSO I found the following under "INTERNAL ALT ENCODER ADJUSTMENT":

Code: 
Sets the GAE module altitude to match the primary altitude display.

Should I determine these 3 values by a flight-test? QNH for the primary altitude display 1013,25?
Click to expand...

I set mine to zero (correction - I think I set them to the actual altitudes) and then had the avionics shop check them.

There was no change...:) The encoder was pretty much spot on.
 
Last edited:
Walt said:
This adjustment is supposed to be done by an avionics shop that has a pitot-static test box available to verify the encoder is adjusted/working properly and matches the aircrafts altimeter.
Click to expand...

Thanks. If the transponder is working the gtx 335 will be calibrated by an avionics shop.

Only for testing I set the 3 values to 1. The result is the same: TRANSPONDER FAILED

Which value for "ALTITUDE SOURCE 2" is correct if I like to use only the Garmin GAE12 altitude encoder?

Code: 
ALTITUDE SOURCE 2 = "NONE" or "ALT ENC"

Reading "Table C-3 Altitude Sources" of the TSO I believe that "NONE" is correct.
 
GTX Install Tool solved the problem

The problem is now solved.

It was no hardware and no wiring problem! The configuration was not complete.

We configured every parameter directly on the GTX335. Although the GTX3X5 has a separated "configuration module" all information is stored at the device.

If the airplane registration is directly configured on the GTX335 it does not update the "configuration module". This is also true for a brand-new module.

If the airplane registration is not configured on the configuration module the described error appears:

TRANSPONDER FAILED

@Garmin: Please change the error message to "airplane registration is missing in configuration module" or something like that!

SOLUTION: Connect the GTX3X5 to a Windows PC via USB and start the program "Garmin G3X5 Install Tool". After setting the airplane registration with this program the transponder is working fine.
 
You must log in or register to reply here.
Back
Top