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
