Medical plane's voice recorder likely wasn't working for years before Philadelphia crash

The cockpit voice recorder was not working on a medical transport plane that killed seven people when it plummeted into a Philadelphia neighborhood in January and likely had not been functioning for several years, the National Transportation Safety Board said in a preliminary report Thursday. The NTSB also confirmed Thursday that the crew made no distress calls to air traffic control. A ground warning system that may contain flight data memory is still being evaluated by the manufacturer, the agency said.