Date: 201904
Local time of day: 1201-1800
Location: MDW.Airport, IL
Flight conditions: Marginal
Weather elements / visibility: Snow
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 91
Flight plan: IFR
Mission: Passenger
Flight phase: Final Approach
Airspace: Class B MDW
ATC / advisory: Tower MDW
Second aircraft: Any Unknown or Unlisted Aircraft Manufacturer
Reporter organization: Government
Reporter function: Local
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Situational Awareness; Confusion; Distraction
Anomaly: ATC Issue All Types; Aircraft Equipment Problem Less Severe; Conflict Ground Conflict; Critical; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Detector: Person Air Traffic Control
Result: Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Flight Crew Executed Go Around / Missed Approach
Contributing factors: Aircraft; Airport; Weather; Staffing; Human Factors; Company Policy
Primary problem: Aircraft

Narrative: While working a Local Control position; [I was] landing and preparing for departures during a snow event. [I was] on [a] 25 minute break and not getting a contractually mandated lunch break between 4-6 hours; on my 5th time on a position; Aircraft X was on ILS approach to the center runway. The RVR's were around 1;600 feet; RCC (Runway Condition) codes 333; strong crosswind (030@20G25) component and information to pass along to each arrival. Aircraft checking in were given long transmissions of information and most were reading back most of the information or had questions. While Aircraft X [was] 6 to 7 miles in trail [and] Aircraft X was reading back a landing clearance; two breaks in the radio transmission happened. The other Local Control position yelled out that the left runway was clear!! I looked at the radar and as the tag was dropping off the radar a tag appeared heading to the left runway on short final.I sent Aircraft X around and as it was climbing; it went over multiple aircraft waiting for departure on the left runway. I let the crew of Aircraft X regain control of the aircraft and then asked the reason for the side step. They replied that they had lost instruments short final and the autopilot disengaged. I am not sure when the aircraft went around or if it went around on its own. I saw the tag go over many airplanes and when it tagged back up on the radar it was at 1;100 feet indicated. I believe this could have been a tragic event had the other Local Controller not seen his safety logic hold short bars on the runway and me telling the aircraft to go around. There were two heavies that were in between the runways and those were also in close proximity to the aircraft.Multiple times; the Supervisors were made known of the DECREASED RVR's and did nothing about certifying for Cat II or Cat III operations. I don't know if this aircraft could even had attempted an approach with these minimums; but obviously the aircraft did not stay on the ILS. We were on 25 minute breaks and the limited crew were exhausted from the snow event. In the South Tower there were two controllers who could have been brought up to the Main Tower to help with the break situations. The Supervisors said they had tried to get permission to close the South Tower which wasn't going to be used and upper management said no. This facility is in a severely unsafe culture of getting by. This near miss should not go unnoticed. The break situations and not having a lunch made situational awareness down and it's in my opinion that it was due to the great work by the other Local Controller and myself that saved us from a major disaster.




Synopsis: MDW Local Tower Controller reported issuing an aircraft a go-around because they were lined up with the wrong runway which had traffic on it.