Date: 202201
Local time of day: 1801-2400
Location: ORD.Airport, IL
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
ATC / advisory: Ground ORD
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Human factors: Workload; Troubleshooting; Time Pressure; Situational Awareness; Human-Machine Interface; Distraction; Confusion; Communication Breakdown
Second reporter function: Pilot Not Flying; Captain
Anomaly: Deviation / Discrepancy - Procedural Clearance; Ground Event / Encounter Weather / Turbulence; Ground Incursion Runway
Detector: Person Air Traffic Control; Person Flight Crew
When detected: Taxi
Result: Air Traffic Control Issued Advisory / Alert; Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: ATC Equipment / Nav Facility / Buildings; Chart Or Publication; Human Factors; Weather
Primary problem: Ambiguous

Narrative: Leaving the CDF (Central Deice Facility) we were given taxi instructions of Zulu; Golf; cross [Runway] 4L; hold short of [Taxiway] TT for a [Runway] 27L departure.  There was light snowfall at the time and local Tower had just turned the airport around to a west flow. As we left the CDF; Taxiway Zulu remained unplowed. We were able to use the blue taxiway edge post lights as guidance.  At that time; those lights were the only means of navigating that taxiway. Any and all pavement markings were indiscernible. The taxi was slow and methodical due to the conditions. It was very dark over on that side of the airport and difficult to see. As soon as we noticed we were slightly north of the [Taxiway] Golf intersection; we stopped the aircraft. At no time did we encroach onto [Runway] 27L/9R as the runway edge lights provided us guidance. ATC immediately queried us as to our position and asked if we were over the hold short line. As there was no way to tell by looking at the airport environment due to the snowfall; we used the AMM (Airport Moving Map) in our Jeppesen Charts which we both had already in use. The chart shows the hold short line well south of the [Taxiway] Golf intersection. According to the chart we had absolutely passed it; but we would have anyway if we had turned right onto [Taxiway] Golf to make our way to the [Taxiway] TT intersection. There was no way to see where the actual markings were on the concrete. While we did taxi slightly past the [Taxiway] Golf intersection due to the conditions and focusing on centerline discipline; I cannot tell you if we actually passed the hold short line that I assume is painted correctly on the ground. There were no lights flashing to denote the hold short line either. Also; there are 10 intersections to that runway; the AMM only shows 4 hold short lines. We were given instructions to taxi across [Runway] 9R and given a number to call. Eventually after taxiing to the active; we took off with no further issues. We landed in ZZZ and after the debrief with O'Hare ATC; we explained our situation. They had indicated to us that our position was not visible to them and the ground radar at that location was not always accurate. After our event; several other pilots voiced concern to Tower about the conditions and that is when they directed the plows to that area of the airport. This was conveyed to us by ATC directly when we called after we landed in ZZZ.  While I understand it is a new runway; there should be hold short lines depicted at every intersection accurately in our charts; including the low-vis charts. I have attached the most updated AMM screenshot of that taxiway intersection for [Runway] 9R.Weather was the main factor compounded by the errors in the Jeppesen charts.Having the CDF located on the west side of the airport with a west flow; plowing should take place before aircraft start movement on taxi routes to the departure runways. Also; Jeppesen needs to correct their charts.


Second narrative: Taxiing out of Central Deicing Facility. Airport changed from East to West flow. Taxi clearance was [Taxiway] Z right on [Taxiway] G; cross [Runway] 4L to for [Runway] 27L [Taxiway] TT departure. Taxiway Z was not plowed and G Taxiway was obscured by snow. Just missed Taxiway G and stopped at the same time Tower told us to stop. He asked if we had passed the hold short line and we said yes because you have to cross hold short line for [Runway] 09R in order to make the right turn on [Taxiway] G. Snow prevented seeing any taxiway markings. We never encroached on [Runway] 9R/ 27L. We were eventually cleared to cross [Runway] 9R/27L taxi E to [Taxiway] TT for takeoff.  We were given a phone number to call ORD Tower which I did after arriving in ZZZ. Tower personnel asked if at any time did we encroach the edge of the runway. We did not. The Tower said that later aircraft complained about the snow and plows were dispatched to clear the taxiways we had used. He also stated that it is difficult for the Tower to see us on Taxiway Z approaching [Taxiway] G.Taxiways that had not been plowed were the biggest factor. Runway change from when we started deicing to when we finished deicing. Snowy conditions. Please see attachment.More timely snow removal would have helped immensely. If you look at the Taxiway Diagram; you must pass the hold short line for [Runway] 9R in order to turn onto Taxiway G. The hold short line is too far from the runway and there are no 'wig wag' lights to identify the hold short line.  Suggest that the hold short lines be relocated north of Taxiway G.


Synopsis: Air carrier flight crew reported a possible runway incursion at ORD airport. While taxiing on a snow covered taxiway and no lights indicating a hold short position; the incursion may have taken place. The pilots reported the Jeppesen airport chart does not show an accurate location for hold short lines.