Offshore heli's flying over my head & house here in Norway, accident in 2016 happening just a few minutes flighttime from my garden (instant gearbox failure\lock up, rotor detached and flew away, went down like a brick >
picture >
picture), have found interest in reading reports, great (& dramatic) source of tech knowledge, details and insight.
This f.ex, the story of a few bad studs...
"At 0945:05, the flight data recorder (FDR) registered that the main gearbox (MGB) oil pressure started decreasing from its normal range.."
http://www.hse.gov.uk/aboutus/meetings/iacs/oiac/wig/110211/cougar-crash-investigation-report-110211.pdf