Commercial Fixed Wing
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 100; Flight Crew Type 100
Communication Breakdown
Conflict Ground Conflict; Critical
Flight Crew Took Evasive Action
Procedure; Human Factors
We were given a taxi clearance of Runway 20C via T5 S7; cross 31/13.  While entering 31/13; the FO called out Stop Stop Stop!  We used maximum braking and came to an abrupt stop narrowly avoiding a single engine small aircraft taxiing at high speed from right to left.  Ground apologized saying they weren't talking to the small aircraft.  Flight then progressed without incident to destination.
We were given a taxi clearance to Runway 20C via T5; S7 cross 13/31. While attempting to cross 13/31; I looked to my right and saw a single engine small aircraft taxiing down Runway 13/31 with a converging path to our aircraft. I called out; 'Stop; Stop; Stop!!' to the Captain; who then brought our aircraft to an abrupt stop in order to avoid collision with the small aircraft. The small aircraft continued to taxi in front of us; right to left without slowing. We stayed put until Ground then again gave us clearance to cross 13/31 S5; T7 to 20C. Ground also apologized to us and said they were not talking to the small aircraft.There was an obvious miscommunication between the small aircraft and Ground; as Ground said; they were not talking to the small aircraft; and the small aircraft stated they had clearance to turn left onto Runway 13/31.
Air carrier flight crew reported a ground conflict with a small aircraft during taxiout at BNA airport.  Reportedly; ATC was not communicating with the small aircraft.