Date: 201606
Local time of day: 1201-1800
Location: ORD.Tower, IL
Flight conditions: VMC
Light: Daylight
Aircraft: Large Transport; Low Wing; 2 Turbojet Eng
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Final Approach
Airspace: Class B ORD
ATC / advisory: Tower ORD
Second aircraft: Medium Large Transport; Low Wing; 2 Turbojet Eng
Reporter organization: Government
Reporter function: Local
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Situational Awareness; Communication Breakdown; Confusion
Second reporter function: Approach
Anomaly: ATC Issue All Types; Airspace Violation All Types; Conflict NMAC; Deviation / Discrepancy - Procedural Clearance
Detector: Automation Aircraft RA; Automation Aircraft TA; Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Flight Crew FLC complied w / Automation / Advisory; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Took Evasive Action
Contributing factors: Procedure; Airspace Structure; Chart Or Publication
Primary problem: Airspace Structure

Narrative: While working Local Control North; landing RWY9L on East Flow; I encountered a situation where Aircraft X was catching up to Aircraft Y that had been previously cleared to land. The separation between those 2 aircraft decreased to about 2 miles and I still was not talking to Aircraft X. While focused on that; a different aircraft; Aircraft Z called my frequency on about a 7 or 8 mile final; which would put them close to Schaumburg Airport. I advised Aircraft Z to 'continue' not realizing that he was about to inquire about the VFR target below them and about a mile in front of them. When they pointed out the target to me I exchanged a brief traffic call but Aircraft Z was already responding to an RA. I asked them to advise when they could continue the approach. The VFR target Mode C displayed 2200/2300 feet while Aircraft Z was level at 3000 feet. Aircraft Z said that their TCAS showed the VFR target only 300 feet below them and climbing. As this all was happening; I still had yet to rectify the two aircraft that were inside the FAF with reduced separation. Everyone continued and landed without incident. There is a chronic problem of C90 jamming arrivals on visual approaches and giving less than the adequate amount of spacing on final. What made this an even bigger issue was the fact that I was not talking to Aircraft X who was getting too close to Aircraft Y; so my focus was on working from the airport and out on my final. I don't know why Aircraft Z was on my frequency; outside of my airspace; without all conflicts being resolved in C90 airspace. I don't fault the TRACON too much regarding this because the airspace allows Runway 9L arrivals down to 3000 feet with VFR aircraft coming off of Schaumburg Airport directly below the 9L final. This is an airspace issue.C90 could do a better job of providing spacing on final that doesn't require the use of unsafe S-turns or rapid reductions/accelerations of airspeed. It seems that C90 believes that our 'Yes' in the visual separation box allows them to jam all of their arrivals and leaves it up to us to 'make it work'.


Second narrative: Aircraft Z was inbound to ORD from the northwest. Aircraft Z was cleared for the Visual Approach to runway 9L. A VFR aircraft departed Schaumburg airport and was in a climbing left turn to 2300 feet and headed west. Schaumburg is 8 miles west of ORD. The base of the Class B airspace is 1900 feet so the VFR was a Class B violator. The VFR passed within 700 feet vertically and .48 NM laterally from Aircraft Z. No traffic was issued. Aircraft Z switched to ORD tower before they were supposed to and advised ORD tower of the TCAS alert.I should be more aware of VFR traffic in the vicinity of Schaumburg airport.


Synopsis: A VFR aircraft climbed into ORD Class B without a clearance. An arriving aircraft reported a TCAS alert with the traffic.