Predicting Service Life of Aircraft Coatings in Various Environments

Abstract There is a great need for a method of evaluating aircraft coating systems and predicting their performance under a variety of service conditions. This paper describes an accelerated simulated service test and a procedure for using the test results to predict the time to initial breakdown of the coating and the optimium time for complete repaint of aircraft operating in various environments. The predictive coating degradation procedure involves a statistical analysis which is based on reliability theory. Multiple coated panels are subjected to an environmental spectrum which includes the major degradation factors encountered by aircraft coating systems; exposure to ultraviolet radiation, heat, high humidity, salt water, and deformation at sub-zero temperatures. A FORTRAN program was developed which uses the results of the environmental test to (1) predict the service life of different coating systems in an average environment or (2) the service life of a specific coating system in a variety of environments.