Updated: 08/13/2014 6:56 PM
Created: 08/13/2014 11:47 AM KAALtv.com
(ABC 6 News) -- The National Transportation Safety Board has released its report into a north Iowa helicopter crash that killed three medical workers.
On January 2, 2013, the Mercy Air Med helicopter was traveling to Emmetsburg to pick up a patient, when it crashed into a farm field near Ventura. All three people aboard the flight -- a pilot, nurse and paramedic -- were killed.
The NTSB report focuses on the weather conditions at the time of the crash. The report says witnesses and first responders reported mist, drizzle, freezing precipitation and icy roads.
Investigators said the helicopter wasn't certified for such conditions.
"The operator noted that the helicopter was equipped for instrument flight; however, it was not certified for flight under instrument flight rules," the report finds. "The helicopter was equipped with heated pitot and static ports; however, the rotor blades were not equipped with ice protection."
Instrumental flight rules, or IFL, are rules and regulations established by the FAA to govern flights when visual control of the aircraft is not safe.
Investigators will use the report to determine a probable cause of the crash.