Water-logged Uavionix Tail Beacon

[mshac]

Saw this during my pre-flight today. We've had some rain in the last week, but this thing looks like a fish tank!

Any suggestions?

I have no idea how long the warranty is on these things, buts that's pretty disappointing.

[mshac]

Well, its clear what caused it! The lower rudder cap was full of water! The drain hole had become clogged with dirt and debris. Both sides were clogged.

Uavionix sent me a canned email saying this will happen every time in certain aircraft designs because there is a hole in the back of the unit for baro.

They claim the unit is protected from water, but we shall see...

Lesson - CHECK YOUR LOWER RUDDER CAPS FOR BLOCKED DRAIN HOLES!

[Frank Benvin]

We had one of our 337's parked outside for a while on the wetcoast. Part of the preflight was to poke the drain holes and let the water out

[wslade2]

Yup. Every time I think they’re unblocked, they get blocked again. Don’t take them for granted or think just because you did them recently they’re ok.

[Joes]

Moisture:
The port in the unit where the wires come out is a pitot-static opening for the onboard Baro. This open port will always allow SOME moisture in the unit if you are operating in a humid area, and the electronics are covered with a conformal coating to protect against this. Obviously, the conformal coating on your tailBeacon failed to protect the circuitry. I did notice that there was visible water marks on the outside of the tailBeacon. This indicates that there is likely a large amount of water being directed at the portion of the tailBeacon that is inserted inside of the aircraft.

Some aircraft, merely by their design, channel water to the tailBeacon installation location and can cause more water onboarding than normal. To help combat this, we have seen some customers place a piece of fuel-tubing over the aluminum nipple where the wires exit the tailBeacon. Safety wire the fuel tubing to the nipple, and allow the tailBeacon wires to travel through the fuel tubing, but do NOT close off the air-supply through that open aluminum nipple. The fuel tubing can be looped or re-directed in a fashion that will help prevent water from traveling along the wires and into the tailBeacon.

You will never be able to eliminate humidity condensation, but your installation method can help prevent water channeling into the unit.

This is from Uavionix for installation of a replacement due to moisture in initial unit. Joe

[mshac]

uAvionix opened an RMA for me and had me return the unit to them. I'll update here what happens and what the costs are, if any.

Regarding the above post, they sent me the same email with the same photo and wording. Not sure if the tube would've helped or not, but I'll do that upon reinstallation. Certainly can't hurt!

And I'll start checking drain holes more frequently.

[Joes]

It is my understanding the moisture issues with the Uavionix tail beacon, is from water trailing down the wires into the unit. With a hole placed in the bottom of the tube loop and oriented downward, this should help the problem. As for the unit being submerged, that will call for other measures lol. Uavionix was great to work with and replaced my unit with a new one for 1/2 AMU. Joe

[mshac]

Originally Posted by Joes

It is my understanding the moisture issues with the Uavionix tail beacon, is from water trailing down the wires into the unit. With a hole placed in the bottom of the tube loop and oriented downward, this should help the problem. As for the unit being submerged, that will call for other measures lol. Uavionix was great to work with and replaced my unit with a new one for 1/2 AMU. Joe

The water doesn't exactly "trail down the wires" into the Tailbeacon. It simply enters the tailbeacon through the same hole that the wires go through. The hole is intentionally not sealed so the the baro sensor can get a reading.

That clear tube around the wires in the picture is not included in the install kit or mentioned in the instructions (at least wasn't when mine was installed). That is uAvionix's "suggestion" as to how one might keep this from happening again. In theory it could work, but if the lower rudder cap is 100% full of water like mine was, I'm not sure it would've made any difference.

[Joes]

I get it, the trailing of the water concept was from a conversation with Uavionix tech support. My personal concept on this was to use the tubing with a tee at midway length and silicone applied where the wires come in to the tube. Place a tube on the tee with a down turn at the top. Hope this helps, wasn't happy to have to replace after 2 years. Joe

[mshac]

Originally Posted by Joes

I get it, the trailing of the water concept was from a conversation with Uavionix tech support. My personal concept on this was to use the tubing with a tee at midway length and silicone applied where the wires come in to the tube. Place a tube on the tee with a down turn at the top. Hope this helps, wasn't happy to have to replace after 2 years. Joe

That sounds like the best we can do for now! I like the thinking.

If we keep our rudder cap drains unclogged it will never be an issue.

[mshac]

I wanted everyone to know that they totally took care of me and sold me a brand new unit for .4 AMU! I'm sold on uAvionix!

[mshac]

Installed and configured, The whole process took less than 30 minutes!