Date: 201809
Local time of day: 1201-1800
Location: ORD.Airport, IL
Flight conditions: VMC
Light: Night
Aircraft: Regional Jet 200 ER/LR (CRJ200)
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Taxi
ATC / advisory: Ramp ORD
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; First Officer
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Confusion
Second reporter function: Captain; Ramp
Anomaly: Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown
Detector: Person Flight Crew
When detected: Taxi
Result: Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Contributing factors: Human Factors; Procedure
Primary problem: Human Factors

Narrative: Upon arrival to KORD we received ATC Ground instructions to taxi to the gate. From A Taxiway; I contacted ORD Ramp Control and we were instructed to enter on the Bravo-Line for taxi to the gate. It should be noted when we tuned to ramp frequency; the controller was arguing with several air crews. Once on the Bravo-Line; we stopped movement due to four 737's all pushed from their gates and stopped. Captain asked me to request transition to the Charlie-Line (on the West side; which was clear of any aircraft).In my transmission I stated 'Ramp; Aircraft X-- There are several planes stopped on the Bravo-Line. Can we transition to the Charlie-Line?' Ramp control quickly responded; 'You can't taxi to your gate from the Charlie-Line! Continue on Bravo-Line; just stay as tight as you can!' Both Captain and I interpreted this as instruction to taxi around the stopped aircraft in front of us; holding as tightly the Bravo-Line as possible. I immediately began to monitor the frequency listed for the Charlie-Line ramp control; but as that area was completely clear of traffic; we both assumed this was where we were told to taxi.We had proceeded past all of the parked aircraft (approximately 6-8 aircraft lengths) when Bravo-Line Ramp Control began shouting 'Aircraft X! WHAT ARE YOU DOING?? WHERE ARE YOU GOING?' I replied; 'We're continuing to taxi on Bravo-Line as tight as we can; Aircraft X.' Ramp again shouted; 'Aircraft X; WHAT YOU ARE DOING?? WHERE ARE YOU GOING??' At this point; Captain replied on frequency 'We're doing EXACTLY what you told us to do.' Ramp continued; 'Aircraft X; THIS IS TOTALLY NOT SAFE; TRANSITION TO THE CHARLIE LINE; HOLD SHORT [gate] CHARLIE!'We proceeded as instructed and were then given a phone number to call. After being held in place for a few minutes; we were given instructions to taxi to our gate. Once the flight was completed and the Shutdown Checklist completed; Captain called the number and spoke to; I believe; the Ramp Controller.It was unclear what exactly Ramp Control wanted us to do. The controller; based on his tone and arguing with other air crews; was having a stressful time. In hindsight; it is difficult for me to think both Captain and I would both misinterpret instructions that would have kept us stationary on the Bravo-Line. I would suggest 'pulling the tapes' from the evening in question and reviewing for how all parties can avoid such an event in the future.


Second narrative: After landing on [Runway] 27L in ORD; Ground asked us to proceed to our gate by taking Alpha Taxiway. We proceeded and were instructed by Ramp Control to follow the Bravo Line. As there were several aircraft pushed back blocking the Bravo Line; we asked permission to transition to the Charlie Line and continue taxi and were told no. Shortly afterward; Ramp told us to proceed and stay as close to the Bravo Line as possible. The First Officer and I interpreted this to mean to go around the aircraft that were pushed and stay close to the Bravo Line while we went by. As this put us in proximity to the Charlie Line; which was controlled by a different frequency; we put that frequency on Com 2 to monitor. The Charlie Line was clear and there were no obstructions ahead so we proceeded as we thought we were instructed. After we passed one aircraft; Ramp Control told us to stop; and transition back to the Bravo Line after the pushed aircraft began their taxi out. We complied with the instruction and continued to the gate without further incident. I called the Ramp Controller on the phone when we finished the Shutdown Checklist and he clarified his instruction to mean remain on the Bravo Line and pull up closer to the aircraft ahead. In hindsight; what he asked makes sense; but at the time his instruction seemed to us to bypass the aircraft ahead of us. I should have asked for a clarification to the instruction before moving the aircraft. Listening to the frequency; there were several other aircraft that seemed confused by his instructions as well.


Synopsis: CRJ-200 flight crew reported a ramp issue due to congestion and misunderstanding the Ramp Controller's instructions.