I found this article that refers to four crashes of S-61's that have involved
Input Clutch failures and reports a survivor said he heard unusual noises that when described could point to a possible Clutch Failure.
A Clutch failure would explain a Torque Split and maybe the use of an Emergency Throttle.
The article says Sikorsky changed the TBO for the Clutch Units by half....from 1,000 hours to 500 hours and put in place a requirement to change the units after 7,500 lifts while logging or hauling water buckets.
NTSB releases documents related to crash that killed seven Oregon firefighters | OregonLive.com
Another article that talks about the NTSB Report and the conflict between the NTSB and the FAA. One of the things the FAA did not do was provide the NTSB information contained in letters written to the FAA by two Carson Pilots which reported Carson may have been intentionally providing false weight data. The FAA did not release the information until a year after the crash and only after the NTSB had asked for documents from all interested parties.
http://wildfiretoday.com/2010/12/08/...icopter-crash/