Operational Control became an issue as a result of that NTSB report as I recall. Until that point...each base operated independently and provided monthly reports of operational statistics. No direct supervision of flight operations such as Dispatch oversight was done by the CP or DirOps from the Corporate Office. They issued Directives, SOP's, conducted Training and Checkrides, did the recruiting and other tasks but no daily close handed control or monitoring. If an accident occurred....they were notified by the customer generally.
The fact FAR Part 135 places the operational control burden on the CP/DirOps and the EMS Operators had been ignoring that for years did not bother the FAA for any number of reasons.
That is not the case now....as the FAA is requiring the Operators to comply fully with the 135 Requirements re Flight Tracking. I would suggest the issue also applies to Utility Helicopter Operators as well when their fleets are widely scattered and operating in remote areas far away from the Main Base/Main Office.
Applying the FAR's to helicopter operations can sometimes be very difficult even when the Operators are dedicated to doing the very best they can and a very bad situation if they are not so dedicated.
For a great bad example....think back to the Maryland State Police Bell 206 crash that went unnoticed for quite a long time despite being within minutes of takeoff and within just a mile or so of the point of departure.