AURORA, Ill. – Kirstin Blockinger spent much of her short life in and out of hospitals, fighting severe seizures.

It was on her way to get more lifesaving treatments that the 1-year-old died – not in a hospital, but in a helicopter that crashed and burned on its way a Chicago hospital more equipped to handle her disorder than one near her small town.

Kirstin and three others were killed when the Air Angels helicopter carrying her to Children’s Memorial Hospital late Wednesday clipped a radio tower wire and went down in a suburban field minutes before midnight, authorities said. Federal authorities Thursday said they were investigating whether the tower’s lights were on at the time of the crash – the sixth fatal one involving medical helicopters in the U.S. this year, according to federal data.

Press Writer Deanna Bellandi, Karen Hawkins, Megan Reichgott, Lindsey Tanner, Sophia Tareen, and Michael Tarm contributed to this report.