https://www.bbc.com/news/world-us-canada-51332546
Island Express Helicopters was restricted to flying under what are known as visual flight rules, meaning pilots must be able to see clearly outside the aircraft in daylight, Keith Holloway, a National Transportation Safety Board (NTSB) spokesman, told the Reuters news agency.
I'm not sure I understand what they mean by this. Do commercial operators in the US require a specific license (or training?) for their instrument-rated pilots to fly in IFR conditions?