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

Attributes
ACN	1699741
Time
Date	201911
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Flight Plan	IFR
Aircraft 2
Make Model Name	Airbus Industrie Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Flight Plan	IFR
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument
Experience	Flight Crew Last 90 Days 159 Flight Crew Total 2663 Flight Crew Type 2663
Person 2
Function	Pilot Not Flying First Officer
Qualification	Flight Crew Multiengine Flight Crew Instrument Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	ATC Issue All Types Conflict Ground Conflict Critical Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Ground Incursion Taxiway

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 right. 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.

Original NASA ASRS Text

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

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.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.