It’s getting more and more likely that regulations for medical helicopters will toughen after yet another accident that killed four people.

The helicopter was heading to a hospital when it struck a radio tower wire and crashed on October 14 in Aurora, IL, the Associated Press reported.

Killed in the wreck were a one-year-old patient, the pilot, a paramedic, and a nurse. Before this crash, at least 23 people had died this year in nine crashes involving medical choppers.

The National Transportation Safety Board indicated to the Associated Press that it was unlikely the helicopter had engine problems. Authorities have not determined whether the tower’s safety lights were on at the time of the collision.