A very interesting story of a fellow who made a very wise decision.
If your helicopter has a sudden change in background noise or vibrations, it is time to find a parking place and figure out what is going wrong.
Of real interest in the story is the comment the Ground Crew heard the "Bang" too.
http://www.rotor.org/Portals/1/ROTOR/Story/Nosie.html
https://www.rotor.com/Publications/R...rentIssue.aspx