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B737-900 first officer reported that a misunderstood taxi clearance resulted in a critical ground conflict.
| Attributes | |
| ACN | 1729576 |
| Time | |
| Date | 202002 |
| Local Time Of Day | 1201-1800 |
| Place | |
| Locale Reference | ORD.Airport |
| State Reference | IL |
| Aircraft 1 | |
| Make Model Name | B737-900 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Taxi |
| Flight Plan | IFR |
| Aircraft 2 | |
| Make Model Name | Embraer Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Taxi |
| Flight Plan | IFR |
| Person 1 | |
| Function | First Officer Pilot Not Flying |
| Qualification | Flight Crew Instrument Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine |
| Events | |
| Anomaly | Conflict Ground Conflict Critical Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Ground Incursion Taxiway |
Narrative:
During taxi out from chicago from [gate] short of a; we were cleared by ground to taxi to '28R at N5 via A3; N2; north.' I wrote down and acknowledge the clearance as I understood it and the captain began a right turn on a commenting that A3 was 'way up there.' I agreed and stated they must be putting us in line. Just then; as we were passing A13; ground called and said we missed A13 and to use A12; N2; north and to follow the rj. I replied with the new clearance and stated that he had cleared us via A3; not A13. We did not see an rj; but as we turned left onto A12; we did see an embraer on B moving from right to left. I told the captain to stop because the embraer was moving fast and I thought the embraer was the aircraft ground wanted us to follow. The captain immediately applied the brakes and we shuddered to a stop just short of B. Ground then called and said 'aircraft X; keep it moving and follow the rj on N2.' we both now saw the rj on N2; but the embraer was moving too fast on B; and we were concerned with wingtip clearance from the embraer so the captain did not continue the taxi. The embraer passed in front of us with an unknown close wingtip to nose clearance (best guess was 10 ft.). There was another embraer following the embraer and ground stated 'aircraft Y; let aircraft X out.' we proceeded to the runway in front of the second embraer as cleared and switched to tower once holding short of runway 28R/N5. The rest of the takeoff was uneventful.cause:mis-stated and/or misunderstood initial clearance to A3 vice A13. In addition; it was dusk and we could not see any rjs. I thought ground meant the embraer; so we played it safe and stopped. The embraer passed us uncomfortably close at a fast taxi speed.after further review of the taxi chart it was obvious that we couldn't connect to N2 from A3. I should have verified the route better on the taxi chart and drawn a line. That would have led me to verify the route with the ground controller.
Original NASA ASRS Text
Title: B737-900 First Officer reported that a misunderstood taxi clearance resulted in a critical ground conflict.
Narrative: During taxi out from Chicago from [gate] short of A; we were cleared by Ground to taxi to '28R at N5 via A3; N2; N.' I wrote down and acknowledge the clearance as I understood it and the Captain began a right turn on A commenting that A3 was 'way up there.' I agreed and stated they must be putting us in line. Just then; as we were passing A13; Ground called and said we missed A13 and to use A12; N2; N and to follow the RJ. I replied with the new clearance and stated that he had cleared us via A3; not A13. We did not see an RJ; but as we turned left onto A12; we did see an Embraer on B moving from right to left. I told the Captain to stop because the Embraer was moving fast and I thought the Embraer was the aircraft Ground wanted us to follow. The Captain immediately applied the brakes and we shuddered to a stop just short of B. Ground then called and said 'Aircraft X; keep it moving and follow the RJ on N2.' We both now saw the RJ on N2; but the Embraer was moving too fast on B; and we were concerned with wingtip clearance from the Embraer so the Captain did not continue the taxi. The Embraer passed in front of us with an unknown close wingtip to nose clearance (best guess was 10 ft.). There was another Embraer following the Embraer and Ground stated 'Aircraft Y; let Aircraft X out.' We proceeded to the runway in front of the second Embraer as cleared and switched to Tower once holding short of Runway 28R/N5. The rest of the takeoff was uneventful.Cause:Mis-stated and/or misunderstood initial clearance to A3 vice A13. In addition; it was dusk and we could not see any RJs. I thought Ground meant the Embraer; so we played it safe and stopped. The Embraer passed us uncomfortably close at a fast taxi speed.After further review of the taxi chart it was obvious that we couldn't connect to N2 from A3. I should have verified the route better on the taxi chart and drawn a line. That would have led me to verify the route with the Ground Controller.
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.