uAvionics TailBeacon T/S experience?

[wilkersk]

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 piece of gear to me. I have the install manual and have downloaded the app. I'll be going through the config file and checking out the install tomorrow. It also looks like there may be a firmware update needed also.

Anyone have any suggestions other than just going the the install and configuration to see where it went wrong?

 

[Domenick]

tailBeacon is a tail mounted unit that contains a 978 MHz transmitter, power line transponder monitor, GPS/SBAS receiver, barometric pressure sensor and altitude encoder, and LED position light.

The above is from the installation manual. If the baro is failing 100% of the time, the issue may be the tailBeacon itself. I think a call/inquiry to uAvionix might shorten your troubleshooting.

I've had a tailBeacon since 2019. Has worked fine with my Narco AT150. It is important to have a good ground to the airframe. The most common adjustment from defaults during installation is a need to LOWER the transponder threshold setting. If I recall, the default setting is 42% and many need to go down to around 35% plus or minus. But I don't think this has anything to do with the barometer.

uAvionix has a number of troubleshooting docs on their website.

Please keep us informed.

 

[Racerx]

Call or email uavionix. I have a pa28 and had initial issues as well. You can't ground to the rudder as it's not part of the frame.

My issue was the nav lights were on "dim" instead of "bright".

Have your buddy email uavionix. They will call you back. Great to deal with.

 

[John Collins]

This is from the tailBeacon TSO IM:

6.2 Altitude Encoder with Continuous Calibration™ The integrated altitude encoder does not require connection to the aircraft static pressure system. Instead, tailBeacon benefits from being mounted in an ideal altitude sensing location, and contains Continuous Calibration™ technology. This patent pending technology automatically and continuously calibrates the integrated altitude encoder for correspondence with the aircraft transponder’s altitude encoder, allowing compliant operations in remote and challenging environments.

6.3 Power Line Transponder Monitor tailBeacon utilizes uAvionix’s Power Transcoder to ensure proper synchronization of data elements between Secondary Surveillance Radar (SSR) replies and ADS-B transmissions. These elements include Mode A squawk and IDENT status. In remote areas where you may not be interrogated by SSR, these data elements may at times be unavailable. The Power Transcoder additionally serves to provide Continuous Calibration™ data to the altitude encoder.

So the most likely suspect is the tailBeacon if you are experiencing a baro altitude failure.

 

[ktup-flyer]

Piece of crap. Go a different route.

 

[wilkersk]

I got to move the airplane outside today and powered it up. I got the app connected to the TailBeacon no problem. Tailbeacon "status" in the app is shown "OK". But, no pressure altitude is shown on the app. I tried adjusting the sensitivity threshold up and down. It made no difference. So, a call to uAvionics will be made first thing Monday morning.

 

[ElPaso Pilot]

When they work, they work. When they don’t, they are hard to debug.

The biggest issue I see is that they “sniff” the 12/24v power wire to the unit for signature noise of the transponder squawk.

This is a clever but non-robust detection method.

Mine worked well until my transponder crapped out and was replaced. After that, it no longer saw the signal on the power line. For many months, I didn’t notice, until I was put on the no service / no fly list by the FAA.

There is an internal calibration parameter that should have been checked by the shop after the transponder swap but wasn’t. Months of debug, test flights, and communication with the FAA I’m back and running just fine again.

Solution was to tweak the calibration parameter by a few digits and away we went.

Unfortunately, the service techs and I were all unfamiliar with the process.

 

[MRC01]

When they work, they work. When they don’t, they are hard to debug.

This ^

Earlier this year I was fighting similar issues and finally got them resolved. Here's the summary post of the thread with details:

uAvionix skyBeacon: A false sense of security?

Today my ADS-B Tailbeacon saga came to a successful conclusion. I have a clean PAPR from my flight this morning and the FAA inspector confirmed it is clean, case closed. In summary, what I did, since it may help others: Original Tailbeacon developed corrosion on its circuit board, after 2.5...

pilotsofamerica.com

 

[Wagondriver]

Throw it in the trash and save yourself the hassles of dealing with it. I wish I had done that, the next time it craps out I'm going to destroy so no one else can ever waste their time with it.

 

[GeorgeC]

The presence of a uAvionix transponder UAT in an aircraft ad conveys valuable information about the owner to the prospective buyer.

 

[asicer]

The presence of a uAvionix transponder in an aircraft ad conveys valuable information about the owner to the prospective buyer.

Careful there. The skyBeacon and tailBeacon are not transponders per se. The tailBeaconX is a transponder, however.

But the actual transponder that the *Beacon is paired with would tell me more about the owner than the uAvionix unit itself.

 

[TrueCourse]

I had the very same issue on a PA28 with a SkyBeacon (wing tip). The monitoring reports were hit or miss, than it got to where it wouldn’t pass the monitoring. After some troubleshooting it was suspected the unit was defective. Replaced under warranty (dealt directly with the manufacturer) and it worked after that. If it were me installing ADS-B, I would go with the full blown installation, not this technology.

 

[wilkersk]

Its fixed now. Got a good PAPR on it Saturday. Turns out the baro-alt sensor had failed due to water intrusion. uAvionix sent the owner a replacement for the fixed repair price since it was not under warranty.

uAvionix has had a service letter out on this failure due to improper installation on many of the early installs. The static port for the Tail Beacon is where the wires exit the module. You're supposed to install it with a length of tubing, forming a drip loop with a drain hole at the low point so moisture can't wick up the wires and into the module.

This was not done on the original install (wasn't me) on this aircraft. And, like many aircraft, the rudder top fairing that the TailBeacon attaches to is not rain proof.

 

[Ed Haywood]

That's an inherent issue with a design that puts sensitive electronics on the exterior of the aircraft, exposed to the elements instead of under a nice dry panel.

 

[MRC01]

I agree and speculated the same in the other thread. When new, mine worked flawlessly for a few years until developing corrosion on the circuit board. That wouldn't have happened if it were inside the airplane.

On the brighter side, uAvionix supported me through 6 weeks of troubleshooting and sent 2 warranty replacement units even though it was out of warranty, until we got it working again.

 

[asicer]

That's an inherent issue with a design that puts sensitive electronics on the exterior of the aircraft, exposed to the elements instead of under a nice dry panel.

When these things came out, my initial thought was "what a great way to get through the 2020 mandate crunch!" It surprises me that people regard this as a lifetime solution, especially when they're pairing it with transponders that went defunct decades ago.

 

[Ed Haywood]

Good company and I love to see innovation that results in affordable stuff. But not everyone can hit a homerun on every at-bat. I think they tried to be a bit too clever here.

Also, I think they need to be a bit more robust in their componentry. The D-Sub kit that came with my AV-30C was really low quality. The screw slots stripped if you looked at them sideways.

Still looking forward to installing my magnetometer.

 

[MRC01]

...
Also, I think they need to be a bit more robust in their componentry. The D-Sub kit that came with my AV-30C was really low quality. The screw slots stripped if you looked at them sideways.
Still looking forward to installing my magnetometer.

Same here. I pulled the vac system and installed dual AV-30C. The DG drift isn't any worse than a mechanical gyro, but it's no better either. And the built-in internal magnetometer makes it worse, not better. After years of flying with mechanical gyros I'm accustomed to adjusting the DG every 15 minutes or so, but even so I will probably install the AV-Mag at next annual since it's not too expensive.

 

[wilkersk]

... The D-Sub kit that came with my AV-30C was really low quality...

Agreed! I hate those cheap socket pins for the female Dsub connector from uAvionix. I replaced all those with proper pins and sockets.