Erosion Protection Coatings: Evidence of Structural Impact

This paper reports the results of a limited flight loads survey focusing on the increase in oscillatory loads caused by a degraded erosion protection coating. Load increase was on average between 10-20% leading to estimations of a significant reduction in fatigue lives. Lessons learned and various analytical studies are presented which emphasize the potential for erosion protection coatings to impact fatigue lives. The Aviation Engineering Directorate currently emphasizes the minimum requirement to performance flight test the coating in the worst authorized condition. An increase in power required of greater than 2% would require flight loads survey to demonstrate airworthiness.