Date: 201911
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: B757 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
Airspace: Class B ZZZ
ATC / advisory: Ground ZZZ
Second aircraft: Airbus Industrie Undifferentiated or Other Model
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Human factors: Communication Breakdown
Second reporter function: Pilot Not Flying; First Officer
Anomaly: ATC Issue All Types; Conflict Ground Conflict; Critical; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Incursion Taxiway
Detector: Person Flight Crew
When detected: Taxi
Result: Flight Crew Took Evasive Action; Flight Crew Became Reoriented
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: Flight pushed back from [gate]. After engine start we started the after start checklist. During that time Aircraft Y called the Ramp Control for their push off of their gate. Ramp Controller asked us when we would be ready for taxi. Told them that we would 30 seconds was what we needed to complete the checklist. Nothing more was mentioned and we called for the taxi clearance. Clearance was given for us to taxi on the green line to [spot]. Taxied on the green line and made the transition to XX to proceed to [spot]. Aircraft Y was waiting to push back from [gate] and made mention to the Ramp Controller that it seemed to be a long 30 seconds. Ramp Controller did not respond until after we went past [gate] that Aircraft Y was cleared for pushback. We continued to [spot] where we were told to contact Ground. Ground Controller told us to taxi on Taxiway C and hold at C1. We were instructed to follow Aircraft Z; however; they were on Taxiway B. Making the turn on C; Aircraft Z was past C4 on Taxiway B. Another aircraft was on Taxiway B holding between C1 and Taxiway R. At C1 ground had us switch to Tower frequency and to continue on C. To us that meant we no longer had to hold at C1. As we started to continue to taxi on C my First Officer noticed Aircraft Z was turning from B to C via C1. I slammed on the brakes to prevent any incursion or incident. After Aircraft Z proceeded on Taxiway C we then continued to taxi behind them. No other problems were presented to us after that. I never heard any transmissions from ground control on what clearance was given to Aircraft Z. If we had we would have had a better understanding of what ground control wanted us to do. I believe ground control gave Aircraft Z a taxi clearance way before we got on the frequency.


Second narrative: Cleared from [spot] on the ramp to taxi east on Taxiway C to Runway XXR; hold short of C1. We held short of C1; then were told to continue; and follow Aircraft Z (who was on the parallel taxiway B; coming up from our right). We started moving again just as Aircraft Z turned left onto C1 to transition to taxiway C. He was taxiing really fast; made his turn onto C1 to transition; I prompted the Captain 3 times to stop; then put my feet on the brakes at about the same time he did I think. Aircraft Z went in front of us; we continued as well; completed the taxi and flight segment without further incident.The ATC command was confusing in that he told us to continue and follow Aircraft Z; this command cancels out the hold short for C1; and we just thought we would slot in behind Aircraft Z down at the end of the runway; again; we had NO idea he was transitioning at C1.I waited way too long to assist the Captain on the brakes. I have them under my feet too. Made for a jerky stop. I will get on them quicker next time. Having to run a taxi checklist with stuff that can be checked in 2 seconds at the gate is a bit of a distraction too; but I realize that is no excuse for my responsibility to get on the brakes.When I got home; I tried to listen to the exchange on [website] before I posted this report; and interestingly; that 2 minute segment has been deleted out of their archive.


Synopsis: Air carrier flight crew reported having to slam the brakes to avoid a collision on taxi out.