It was unclear whether Jerry Leonard, 63, died as a result of his heart condition or injuries received in the crash, said state police Sgt. Todd Ringle. An autopsy was planned.
Leonard was being flown from Huntingburg to an Evansville hospital when the helicopter crashed about 20 miles outside Evansville, Ringle said.
Ringle said the pilot of the Bell Jet Ranger helicopter "started to make a turn, and as he was doing so, he started to tumble." The cause of the crash was being investigated, he said.
Paramedic Robert Williams, 29, used a cell phone to call dispatchers, said Toni Chritton, a spokeswoman for Air Evac Lifeteam, which operates medical helicopters in 10 states.
It took more than an hour for rescuers in four helicopters to locate the downed aircraft in the hilly, remote area, amid darkness. Williams waved a flashlight to signal where to find them.
Williams and a nurse, Steve Ritchey, 30, underwent surgery in Evansville on Wednesday, Chritton said. The pilot, Richard Larock, was listed in stable condition at a hospital in Louisville, Ky.
By Kimberly Hefling