It was a "miracle" that none of the four people aboard, including an infant patient, suffered life-threatening injuries, Upper Darby Police Superintendent Timothy M. Bernhardt said.
Rescue crews rushed to the wreckage by the Drexel Hill United Methodist Church in Upper Darby at about 1 p.m. and helped get the pilot, two crew members and the two-month-old infant out of the aircraft, Bernhardt said at a press conference.
The infant was taken to a hospital as authorities worked to notify the child's family, Bernhardt said.
"The pilot is a hero and it really boils down to that," said aviation expert and former Navy pilot John Gagliano, who also holds the FAA's highest pilot rating.
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He says when an aircraft begins to go down, it's up to the pilot and their training.
"The first thing they do is figure out what the problem is and then you need to see if there's a checklist to deal with it. And most times there is a checklist to deal with it," said Gagliano.
He also says given where it went down in Drexel Hill, near power lines and church, there likely wasn't much time to react.
"You can make that logical jump and you can infer that they didn't have much time to deal with whatever emergency they were dealing with," said Gagliano.
Emma Gray, an Upper Darby High School senior, was traveling in a Lyft vehicle when she heard the crash nearby.
"We heard this big boom. All of a sudden there was a bunch of glass and flaming debris on the road. Then there was a helicopter and part of it was on fire," she recalled.
Gray said she and her Lyft driver got out to help.
"These guys started coming out of it and they're like, 'Someone come help us, there's someone trapped underneath.' They were like, 'here take this,' to my Lyft driver, and it was a baby," recalled Gray.
Gray said she did her best to calm the pilot.
"I was able to kneel down beside him and say like, 'Hey man, I called 911, help is in the way," said Gray.
A fire official said the helicopter had about an hour's worth of fuel left at the time of the crash, and crews took steps to keep leaking fuel from contaminating groundwater.
The Federal Aviation Administration said the aircraft was a Eurocopter EC135 medical helicopter and that the agency was investigating, along with the National Transportation Safety Board.
A spokesman for Air Methods, the air medical emergency transport service that owns the helicopter, said it was part of the LifeNet program based in Hagerstown, Maryland. Federal agencies were investigating.
"Our team will cooperate fully with their efforts to assess the cause of this unfortunate accident," said Air Methods spokesman Doug Flanders.