A helicopter ambulance crashed in a remote, mountainous area of northeastern Pennsylvania, killing the pilot, a flight nurse and two medical aides, authorities said.

The crash occurred Saturday night in state game lands about 120 miles northwest of Philadelphia and 45 miles west of Scranton, said Carolyn Corbett, a spokeswoman for Robert Packer Hospital in Sayre, Pa.Corbett said the four-member helicopter team had just dropped off a patient at the Geisinger Medical Center in Danville, Pa., about 7:30 p. m. and was returning to its base in Sayre when the aircraft lost radio contact with ground communications.

A signal was picked up from the crash site at 9:34 p.m., Corbett said, but rescuers didn't locate the crash site until 2 a.m. Sunday.