Date: 201201
Local time of day: 1801-2400
Location: ORD.Airport, IL
Flight conditions: VMC
Aircraft: B737-800
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Descent
Airspace: Class B ORD
ATC / advisory: TRACON C90
Aircraft component: FMS/FMC
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Human-Machine Interface; Confusion; Communication Breakdown
Second reporter function: Pilot Flying; First Officer
Anomaly: ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented
Contributing factors: Procedure; Human Factors; Chart Or Publication
Primary problem: Ambiguous

Narrative: Arriving ORD terminal area via filed BULLZ2 arrival; a relatively new procedure; issued less than a month prior. Approach cleared us 'direct KRENA; cross KRENA at 10;000 and 310 KTS'. The Controller then said [to us]; 'Runway 28; 'North flow;' or 'North traffic'.' We didn't ask the Controller what routing he wanted at that point. We input all that into the FMS; and descended to make the crossing restriction. When Runway 28 is loaded into the FMS; it also changes the arrival routing after the SOOLU Intersection; that published routing is south of the airport. We looked at the routing; but didn't realize that Approach might want us to do something different until the aircraft behind us began to ask Approach to clarify the routing. Approach told the aircraft behind us to fly to KURKK; VULCN; etc.; all points on the north side of the field; and published for Runways 27L; 27R; 22R; etc.Based on this overheard conversation; we realized we might be on the wrong track; and manually put KURKK into the FMS; but it was behind us. At this point Approach gave us a 090 vector; which puts us on a 'Northside'--or right hand--downwind and descended us to 4;000. We continued to set up for the approach (a visual) and subsequent landing on Runway 28. Approach never asked us about our routing; so I still don't really know what was expected of us. After we got to the gate; and deplaned the passengers; we looked at the BULLZ2 arrival; and there is no mention of 'North flow'; and confirmed that once Runway 28 is put into the FMS; it changes the arrival after SOOLU Intersection. This arrival is new for the crews and for ORD Approach. Over the years; late night arrivals from the west; to Runway 28 have been primarily on the north side of the airport; and it seems that ORD Approach is continuing to use that route. But with the new arrival procedure; crews need to know what routing to use; and that in this scenario; they will have to manually input all the north side points into the FMS; as it will auto-load the southern points.

Callback: The reporter advised he had discussed the event with his union safety representative who; in turn; contacted and conferred with ORD Approach Control. The reporter reported that the event took place on the first day of utilization of the new procedure and that the 'north flow' terminology had been quickly determined to be inappropriate and revised terminology is being developed. He also advised that the need for 'phraseology inconsistent with the charted procedure' is the result of late night closures of the other westbound runways; thus requiring that all arrivals from the west be directed to Runway 28. They (ATC) are aware that terminology 'consistent' with the Chart is 'inconsistent' with and inappropriate for use under those conditions.The reporter also commented that he was aware that his suggestion to NOTAM or Bulletin directives for flight crews to manually enter fixes was inconsistent with his airline's SOP which precludes manual entries in the terminal area.

Second narrative: ...we were told by Chicago Approach to 'Expect Runway 28; North Flow'. At that point; the Captain and I discussed what this terminology might mean; since there is nothing specified on the arrival procedure. We concluded we should expect vectors to the north of ORD for a right base to the ILS 28. I inserted Runway 28; BLUTO transition; verified the points and ensured LNAV was selected. I did not; however review the points on the STAR relative to the magenta line after inserting the runway as I probably should have. The rest of the arrival and approach was conducted using radar vectors and existing ILS Runway 28 FMS approach points.Currently; our FMS database does not include the Bullz2 arrival diversion points; or a way to differentiate between 'North flow' and 'South flow' except by using runway assignments in the FMS. Additionally; there is no verbiage on the STAR delineating between 'north flow' and 'south flow'; except by runway. I suggest an immediate NOTAM and a company bulletin regarding the database and advising crews to manually insert FMS points into the computer when runways are closed.


Synopsis: Confusion regarding a newly issued revision to the BULLZ STAR to ORD and Approach Control's use of the phrase '...North flow or North traffic' to Runway 28 may have resulted in a track deviation for a B737-800 flight crew.