uAvinoix TailBeacon TSO

BillTIZ

BillTIZ

Final Approach
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Anyone having problems with the uAvionix TailBeacon TSO passing the FAA PAPR checks?

We received a letter from FAA in the summer of 2025 that our ADSB was failing. Prior to that we had good checks in the winter of 2024 and early spring 2025. Troubleshooting with uAvionix Support to check all wiring in the aircraft. Sensitivity to wiring connectors etc. In December 2025 uAvionix agreed to replace the unit. As it was over 4 yrs old, a very minor charge for the replacement unit.

Due to an engine change, we were not able to install and test the new unit until April 2026. Fails PAPR checks, multiple flights. Followed Tech Support ground test methods and it fails. They sent another unit for exchange. That one barely gets past the ground tests and fails airborne PAPR checks. They sent another. Company said they would install the last failed unit sent back by installing in an aircraft for testing. It supposedly passed their ground checks.

Now on 3rd "new" unit from the company, failing PAPR checks and takes for ever to get GPS lock on the ground. This is an L-19F/C-305F Bird Dog, 28V system.

Anyone else having issues with uAvionix TailBeacon TSO?
 
wilkersk

Thread 'uAvionics TailBeacon T/S experience?'

Looks like I'm gonna get sucked into the TailBeacon issue with my friend's PA28. It has a GTX327 transponder and a Transcal SSD120-(30)N encoder.

It took me awhile to understand what my friend was telling me, so I started by looking at the encoder. It works fine. But then he called the contact person (a local FSDO guy) and he sent my friend an email that showed a PAPR with baro alt failing 100%. And he also sent an excel file showing that it has failed every flight since the Tailbeacon was installed.

I've never installed or worked on the uAvionics ADS-B solutions. So, this is a new...

pilotsofamerica.com

uAvionix skyBeacon: A false sense of security?

Had lunch with a high school friend of mine a month ago. He’s been flying for some 45 years. Suggested I get ADSB so we could, along with some other folks, fly to areas inside of Mode C around the East Coast, where we all live. So, I picked up a uAvionix skyBeacon. That being the least...
pilotsofamerica.com pilotsofamerica.com
 
Is your tail beacon/light on the end of the tailcone close to ground. Or is it up on top of vertical stabilizer?
 
There have been other threads on problems. In some instances it was caused by inadequate sealing during installation, which allowed water intrusion into the circuitry. If you have swapped the unit several times, that is probably not the case, but who knows.
 
I had similar issues. There's a long thread here with details and how I eventually solved it. Search, and ye will find. Good luck!
 
Mikey52 said:
Is your tail beacon/light on the end of the tailcone close to ground. Or is it up on top of vertical stabilizer?
Click to expand...
The L-19/C-305 has the standard C-170 tail. The location is about 2+ft off the ground, Original unit worked fine for over 4yrs, eventually failed from water intrusion.
 
Lindberg said:
wilkersk

Thread 'uAvionics TailBeacon T/S experience?'

Looks like I'm gonna get sucked into the TailBeacon issue with my friend's PA28. It has a GTX327 transponder and a Transcal SSD120-(30)N encoder.

It took me awhile to understand what my friend was telling me, so I started by looking at the encoder. It works fine. But then he called the contact person (a local FSDO guy) and he sent my friend an email that showed a PAPR with baro alt failing 100%. And he also sent an excel file showing that it has failed every flight since the Tailbeacon was installed.

I've never installed or worked on the uAvionics ADS-B solutions. So, this is a new...

pilotsofamerica.com

uAvionix skyBeacon: A false sense of security?

Had lunch with a high school friend of mine a month ago. He’s been flying for some 45 years. Suggested I get ADSB so we could, along with some other folks, fly to areas inside of Mode C around the East Coast, where we all live. So, I picked up a uAvionix skyBeacon. That being the least...
pilotsofamerica.com pilotsofamerica.com
Click to expand...
the uAvionix Tailbeacon uses its own baro altitude. The sensor is internal and the "static port" is the end where the two power wires enter the unit. Don't block that off.
 
Is your PAPR failure due to GPS NIC/NAC dropouts, squawk code, baro?

If you've experienced this with multiple it seems like it might be something in your airplane. Most common issue is a bad ground. In some planes the the tail light was just grounded to the rudder, which grounds to the airframe only through the hinges. If that's your case run a new ground wire from the beacon to the airframe. Maybe your power wire has chafed somewhere and that's intermittently shorting?

I've also seen cases where a com radio has gone bad and starts jamming GPS.
 
compjtc said:
... I've also seen cases where a com radio has gone bad and starts jamming GPS.
Click to expand...
Some comm radios do this even when they are aren't going bad. No amplifier is perfect, every radio has some harmonic distortion. TailBeacon uses the GPS L1 frequency which is 1.575 GHz. Compared to comm frequencies, this ranges from the 11th to 14th harmonic of the comm frequency range of 118 to 135 MHz. The GPS signal is so weak that even low level distortion from a normally functioning comm radio can block it. To prevent this, one can install low-pass filters to the outputs of the comm radios.

Back when I was troubleshooting mine, Uavionix sent me a document titled "GPS Performance Troubleshooting", "UAV-1004106-001". It is marked "uAvionix Confidential" so I won't post it here, but I'll suggest @BillTIZ contact them and ask for it. It covers this and several other topics mentioned in this thread.
 
compjtc said:
If you've experienced this with multiple it seems like it might be something in your airplane. Most common issue is a bad ground. In some planes the the tail light was just grounded to the rudder, which grounds to the airframe only through the hinges. If that's your case run a new ground wire from the beacon to the airframe. ...
Click to expand...
I noticed this during my PA-28-161 installation of a tailBeacon. The tail light grounded through the hinge. I added a ground wire jumping the hinge and have never had an issue since the post installation sensitivity adjustment.
 
MRC01 said:
Some comm radios do this even when they are aren't going bad. No amplifier is perfect, every radio has some harmonic distortion. TailBeacon uses the GPS L1 frequency which is 1.575 GHz. Compared to comm frequencies, this ranges from the 11th to 14th harmonic of the comm frequency range of 118 to 135 MHz. The GPS signal is so weak that even low level distortion from a normally functioning comm radio can block it. To prevent this, one can install low-pass filters to the outputs of the comm radios.

Back when I was troubleshooting mine, Uavionix sent me a document titled "GPS Performance Troubleshooting", "UAV-1004106-001". It is marked "uAvionix Confidential" so I won't post it here, but I'll suggest @BillTIZ contact them and ask for it. It covers this and several other topics mentioned in this thread.
Click to expand...
thanks, I have that document. Does not make a difference if the unit does not get a GPS lock on battery power and no radios turned on.
 
Domenick said:
I noticed this during my PA-28-161 installation of a tailBeacon. The tail light grounded through the hinge. I added a ground wire jumping the hinge and have never had an issue since the post installation sensitivity adjustment.
Click to expand...
Thanks, after an extensive "text" discussion with their Tech yesterday. The next step is to move the ground from the horizontal stab under a fairing, to farther into the fueslage. I'll get to that next week.
 
BillTIZ said:
Thanks, after an extensive "text" discussion with their Tech yesterday. The next step is to move the ground from the horizontal stab under a fairing, to farther into the fueslage. I'll get to that next week.
Click to expand...
That didn't work. Now Tech Support is suggesting "dirty power", or a bad circuit breaker.
 
BillTIZ said:
That didn't work. Now Tech Support is suggesting "dirty power", or a bad circuit breaker.
Click to expand...
The tech is giving you 100% solid recommendations considering he's never seen your AC and is going by description. I go through the same process from GA AC to A350s. So many issues with chaffing/water/corrosion/bad connections/grounds and you'd think professional mechanics would know how to do it properly.

Ask any 135/121 MX about EWIS and see how many new curse words you learn.
 
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