When I crashed my shuttle I took off everything that I thought was re-usable and all the shafts and spindles etc looked fine. I couldn't see any bend or anything, but when they are placed on a nice smooth surface you can definitely see the bends in them. Dismantle the head and place the main shaft and spindle on a really shiny surface, if you roll your fingers over them you can feel the bends and also see it. You will probably hear a more of a wobbling sound when it is rolled along rather than a constant tune.

This is just how I check to see things are ok, others may do it differently. I think you can even get tools to check these things. The feathering spindle is the shorter thinner one that goes through the flybar head and connects to the blade grips. I think it's got threaded ends, but I can't remember.

James

edit: Of course it's got threaded ends. Who was I kidding. I never had my heli with me and couldn't think. Otherwise the blades would fly off!