Spragg clutches have failed and then worked perfectly afterwards. I know of at least two incidents of this on the Bell 212 / UH-1N.
Does anyone know of any statistics?
I also note it's not in any flight manuals as an emergency or abnormal procedure. Hmmmm.
You would think that someone would be educating pilots that if this happens they must write it up and submit it as an SDR, so that we can at least track statistics.