And a case where a blade bolt failed (luckily when parked in a hangar) also from 2012 thread titled R22 Rotor Seperation Florida:
helichoppers's , 14th Jan 2013 13:55
Bolt Failure
Just to throw something else in to the pot..
We had an R44 Raven II that fortunately whilst sat in the hangar and not flying suffered a Blade Bolt Failure!
We returned to the machine after it had sat for a weekend to find a thrust washer sitting on the hangar floor! The full horror then dawned as you looked up to see one of the main Blade bolts sticking out from the Hub. If this had failed in flight and not whilst sat with the full weight of the blade on the droop stop I am sure the bolt would have totally departed from the aircraft along with the blade etc and you can imagine the rest....
The bolt was sent to our local CAA for inspection who then sent it to the FAA via Robinson, the opinion in the end was that it was a one off caused by Hydrogen enbritellment of the bolt and was not considered to warrant further investigation. The bolt had a total time of 80 hours from new.
I appreciate this was on an R44 not an R22 but the bolts must go through a similar manufacturing process??
I can email pictures if you PM with an email address me as I cannot seem to get them to insert to this post.