New details about the recent Duke LifeFlight helicopter crash emerge from a recently released National Transportation Safety Board preliminary report.

Two weeks ago, the helicopter crashed occurred at approximately 11:45 a.m. in Perquimans County in eastern North Carolina near the Amazon Wind Farm U.S. East complex. The recently released NTSB preliminary report included eye witness accounts from individuals who saw the flight right before it crashed.

"One witness reported that the helicopter was 'hovering' and 'not travelling forward' while it was a 'couple of hundred feet' above the wind turbine farm," the report noted. "Another witness reported hearing a 'popping noise.' He then observed the helicopter turn left, then right. It then descended quickly and appeared 'in control' with the rotors turning before he lost sight of it."

The report also noted that the helicopter, a Eurocopter Deutschland, was manufactured in 2011 and that the most recent 30-hour engine inspection was completed August 15.

In a joint letter to Duke students, faculty and staff, President Vincent Price and A. Eugene Washington, chancellor for health affairs and CEO of the Duke University Health System, wrote that they were "deeply saddened" by the news of the crash.

"The men and women of Duke LifeFlight put themselves at risk every day to save the lives of others, and the colleagues we lost in today’s terrible tragedy embodied Duke’s commitment to service and healing," they wrote. "Our thoughts are with their families, friends and colleagues."

A memorial service will be held Sept. 20, honoring the three Life Flight team members and the patient that died, in Duke Chapel. On board the flight were nurses Kris Harrison and Crystal Sollinger, pilot Jeff Burke and patient Mary Bartlett.