Aurora, Illinois – A medical helicopter transporting a girl to Chicago Hospital crashed on Thursday, killing two crew members, a nurse and the patient, a 1 year old girl.

The helicopter, which was on its way to the Children’s Memorial Hospital in Chicago, inbound from Valley West Hospital in Sandwich, 50 miles to the west, crashed a few minutes before midnight, according to Aurora police spokesperson Sergeant Robb Wallers. According to Wallers, the helicopter’s blades may have clipped a guy wire from a 750 foot radio tower before crashing into the Chicago suburb.

The helicopter, a Bell 222, belonged to Air Angels Inc., a critical care transport company based at Clow Airport in West Chicago that provides critical care transport services. Air angels CEO Jim Adams reported to press that the helicopter’s crew included the pilot, a nurse and a paramedic, all employed by the company. He would not disclose their names.

Children's Memorial Hospital spokeswoman Julie Pesch, said to press that the girl, who was being transported to hospital for epileptic seizures, was on route to the Chicago hospital due to Central DuPage Hospital in Winfield, which was 20 miles closer to Sandwich, reporting having no room for her.

The crash site was a field in east Aurora, close to a residential area. Nobody on the ground was hurt.

National Transportation Safety Board investigators are at the scene, according to Wallers, and Aurora’s Assistant Fire Chief John Lehman reported engineers evaluating the structural integrity of the radio tower that allegedly had its guy wire clipped in the accident.

This is not the first crash involving Air Angels helicopters. In January 2003, one of their choppers crashed, killing the pilot. Investigations proved the cause of the accident was pilot error and bad weather. There was also another crash in 2007, caused by mechanical failure, but in which there were no injuries.