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Window Condensation Can Cause Avionics Instrument Corrosion

August 2016

An aircraft charter company recently sent a Baker Audio Panel to our avionics instrument shop in Lincoln, Nebr., that was inop. We immediately sent a loaner back so the aircraft would not miss any flights. When the squawked unit was opened, Duncan Aviation avionics instrument technicians found it was full of corrosion in the back end.


On several make/model aircraft, the Baker Audio Panel sits directly below the windshield. And over time as condensation collects on the window, it has to drip somewhere. And that somewhere is directly on this unit below.

Although you cannot prevent corrosion, you can slow its growth by being aware of any moisture near avionics units. As condensation collects on the windshield, clean it off.

It is also a good idea to visual inspect the outside covers of the avionics units that sit under your aircraft’s windshield. If you see any evidence that water has been dripping on them, you can just about bet there will be evidence of corrosion on the inside. At your next scheduled maintenance, have these units sent to us for a thorough inspection and cleaning.

As for the unit above, we cleaned and repaired the circuit board and coated it with Humiseal for an extra barrier to the moisture.

Replacement Units On A Shelf

Don’t be fooled into thinking replacement avionics units sitting on a shelf are safe from corrosion just because they are not installed on an aircraft. Humidity is another cause of corrosion, especially if they are stored in coastal areas.

For more information on our repair capabilities, download the Avionics Instruments Information & Capabilities Facts Sheet or conduct an online search of our repair and overhaul capabilities.