Has anyone considered a possible manufacturing issue with the gears on this specific MGB batch
I'm sure a lot of people have - I certainly have.
A few years ago, in my previous company, a Bell-212 had a blade grip failure on a 1200 hour rotor head. Fortunately for the crew they were about 75 ft during the landing phase onshore, and 'got away with it,' though I think the underwear were written off! The point being that a vey old, established and proven design was the victim of poor manufacturing QA, and the head contained latent stresses which eventually resulted in the lower tang completely shearing accross its width.