The National Transportation Safety Board is taking a deeper dive into its investigation following a near-miss incident at JFK airport.
Federal safety experts are looking into why an American Airlines 777 crossed an active runway without clearance last month.
The maneuver forced a Delta 737 to abort its takeoff to avoid collision on the ground as the aircraft passed within 1,400 feet of each other.
The NTSB has issued subpoenas for the testimony of the American Airlines pilots involved.