Conformal coatings are used to protect electronic circuitry from environmental conditions such as dust and moisture, that will interfere with the proper operation of Avionics equipment. This paper reveals the limitations of coatings ability to perform this task.
Difficulties with selecting the proper type of coating, application processes, integrity testing, durability, and detecting coating failures in the field are discussed. Because of undetected coating failures an increase in the number of No-Fault-Found units will occur.
The FAA Accident Investigation Office has issued a safety recommendation letter based on information contained in this paper.