This is interesting about the freewheel on 206's
https://www.casa.gov.au/sites/defaul...separation.pdf
1. Effectivity All Bell 206 Jet Ranger and Long Ranger series helicopters. 2. Purpose Alert operators, pilots and maintainers to critical freewheel unit lubrication issues in order to reduce the possibility of torsional main rotor mast yielding and in-flight separation of the main rotor head from the mast. 3. Background Defect report investigations into continuing failures of main transmission freewheel units in Australia and a near fatal incident in Canada demonstrate that a malfunctioning freewheel causes varying degrees of main rotor mast failure, ranging from torsional yield to complete separation of the rotor head from the main rotor mast.
In a 206, the transmission is not directly connected to the t/r driveshaft - it runs through the freewheeling unit and then the engine.
So a freewheel failure/snatch could have caused the TRDshaft to distort stressing the tail boom as well as trashing the MRGB.