Hello Marcel,
One of the more common issues on ACCs are cracks in fan blades, failures of fan blade hardware, and fan blade failure. These have been issues primarily on the windward sides of ACC. High wind and wind gusts can be the root cause. I have photos of broken fan blades and cracked fan blades. As stated by the prior respondent, a minor crack can be cosmetic and can occur in the resin rich portion of the blade. However most larger cracks can be significant and you should consider blade replacement. Some fan suppliers have blades that are matched pairs so that replacement should be done as pairs. Galebreaker has provided perimeter mounted wind screens that reduce the stress on fan blades and provides trouble free operation. Our first install was in 1998 in Belgium. Since then we have installed our screens on 50 + ACCs and they can be cofigured to reduce performance deficiencies. You can contact me at gmirsky@galebreaker.com
