Date: 201311
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Aircraft: A320
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Taxi
ATC / advisory: Ramp ZZZ
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Human factors: Distraction
Second reporter function: Captain; Pilot Flying
Anomaly: Conflict Ground Conflict; Critical; Flight Deck / Cabin / Aircraft Event Illness / Injury; Ground Event / Encounter Vehicle
Detector: Person Flight Crew
When detected: Taxi
Result: Flight Crew Returned To Gate; Flight Crew Took Evasive Action; General Flight Cancelled / Delayed
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: This was our first flight of the day and the first leg of the trip. Preflight; pushback and start were completely normal and to SOP. Both engines were started and the Pre-taxi checklist was completed prior to starting to taxi. The weather was clear and all ramp areas were dry. There was a company 737 pushing at about the same time from an adjacent gate. When given taxi clearance from Ramp Tower; we were instructed to transition to the Charlie line for a west taxi to avoid the 737 taxing east. We began our taxi and I visually cleared the right side of our aircraft and verbalized clear 'right' to the Captain at least two times while we were moving toward the Charlie line. Once we were established west bound on the Charlie line I looked forward. The Captain was looking left to ensure we were going to be clear of the 737 taxiing east. In my peripheral vision; I detected movement to our right. I saw a baggage tug with three or four carts in tow traveling toward us from right to left perpendicular to our path at a high rate of speed. I yelled 'watch out' to the Captain. The Captain immediately applied full brakes and abruptly stopped the aircraft preventing a collision with the tug. The tug driver appeared to have been looking at a white sheet of paper while he was driving and the tug driver swerved right toward the west at the last second when he finally saw us. The tug driver continued south without stopping. Ramp Tower witnessed the incident and called us to ask if we got an identification number off the tug. I commented to Ramp Tower that we just had a close call with the tug and we thought the tug number was. About the same time; the Captain asked me to check on the flight attendants. We received a call from the Purser that a flight attendant who had been standing while doing her Cabin safety checks had been hurt. We asked if medical attention was needed and the Purser said yes. We told Ramp Tower we needed to return to the gate and to have the EMTs meet us at the gate. We coordinated with Operations to return to the Gate. It took several minutes to get ground personnel to park us and the jetway back to the aircraft. We blocked in approximately five to seven minutes after the incident. The EMTs arrived shortly thereafter. The Captain stepped back to the Cabin upon completion of the Parking checklist. He asked everyone to remain seated to allow the EMTs to attend to the [injured] Flight Attendant. The EMTs removed [the injured] Flight Attendant from the aircraft.


Second narrative: Pushback from gate was uneventful for a west taxi. Started both engines and completed all checklists prior to calling for our taxi clearance. One of our 737s had pushed from an adjacent gate and was set up to taxi east. When we called Ramp Tower for our taxi clearance; we were given 'taxi around the 737; taxi west on the Charlie line; contact Ground'. We were complying with those instructions and as I was looking left to ensure proper wing tip clearance from the 737; my First Officer yelled out to watch out for the fast moving baggage tractor towing four carts; coming from right to left. I looked up in time to see him zipping by while reading a paper. I had no option but to apply maximum braking on the aircraft to avoid the impact. He swerved away and continued on his merry way. Ramp Control saw it all happen and immediately asked us if we saw the vehicle number. [We thought we saw the vehicle number] but the paint was streaked and scraped quite a bit so we could not be certain of it. Ramp Control told us they were trying to track down this ramp serviceman right away and asked us if we needed any assistance.When I executed the rapid stop; our flight attendants were walking in the aisle performing their safety checks. We received a call from our Purser; letting us know that our 3rd Flight Attendant was down in the aisle and needed medical attention. We immediately let Ramp Control know that we would need to return to the gate and that we would need paramedics. Ramp Control was very helpful in getting us back to gate and sending medical help.Upon return to the gate; I asked for all of our passengers to remain seated while the paramedics tended to the [injured] Flight Attendant. After completing our Parking checklist I opened the cockpit door in time to see one of our passengers tending to the Flight Attendant. I assume she was a medical professional that was helping out. A Flight Attendant Supervisor came on board and fulfilled the requirement to have three flight attendants on board while FA was taken off by the paramedics. He also took her bags back to the domicile office after our replacement arrived. I also spoke with our other two flight attendants. One injured her back but chose to continue. The other reported that he was not injured and also chose to continue. I also called our Duty Manager and filled him in on what had happened.


Synopsis: A320 flight crew reports a near collision with a tug pulling carts during taxi from the gate. Hard braking is used and the tug driver swerves at the last second to avoid collision. A Flight Attendant is injured and the flight returns to the gate for medical assistance.