reverse. reporter: this man was driving his family and says he barely missed the aircraft. this is absolutely a miracle from the lord. reporter: a miracle, witnesses say, behind a church. an absolutely miracle, no debris, no wires down, hit no trees. reporter: the chopper had been flying to the philadelphia hospital carrying two nurses, the patient and an infant. all four were able to escape the mangled wreckage, even before emergency crews survived, but witnesses say they could see the chopper was in trouble. we looked up and saw how low it was. reporter: the chopper first took off from maryland around 10:30 tuesday morning. minutes later, it landed with no apparent problems, about 20 miles away in central pennsylvania before taking off again. it was about 40 minutes into that next flight when tracking data shows the aircraft dropping altitude. that s when authorities believe the pilot noticed a problem. what the pilot was able to do