NTSB investigators traveled in support of this investigation and used data obtained from various sources to prepare this aircraft accident report. The NTSB's full report is available at http://www.ntsb.gov/investigations/AccidentReports/Pages/AccidentReports.aspx. The Aircraft Accident Report number is NTSB/AAR-20/01. On January 29, 2019, about 0650 eastern standard time, a single-engine, turbine-powered Bell 407 helicopter, N191SF, being operated as a helicopter air ambulance (HAA) flight, collided with forested terrain about 4 miles northeast of Zaleski, Ohio. The certificated commercial pilot, flight nurse, and flight paramedic died, and the helicopter was destroyed. The helicopter was registered to and operated by Viking Aviation, LLC, doing business as Survival Flight Inc., under Title 14 Code of Federal Regulations Part 135. Company flight-following procedures were in effect for the visual flight rules (VFR) flight, which departed Mount Carmel Hospital, Grove City, Ohio, about 0628 and was destined for Holzer Meigs Emergency Department, Pomeroy, Ohio, about 69 nautical miles southeast, to pick up a patient. Night visual meteorological conditions existed at the departure location, but available weather information indicated that snow showers and areas of instrument meteorological conditions (IMC) existed along the route of flight.