Old fan blades
 

For those still running the 216 or 235 with an old fan. The steel in the blades cracks from fatigue and age. I found a broken blade on mine last week. When I inspected the blade 6 years ago, it looked good.

What I learned is they are now repopping the fan. Price from the vendors is about $30, and worth every penny. Fit is very good. With this part now available, I would replace an old blade as a precaution. If one breaks, it ain't pretty.