Light Transport; Low Wing; 2 Turboprop Eng
Air Traffic Control Fully Certified
Situational Awareness; Confusion; Human-Machine Interface
ATC Issue All Types; Airspace Violation All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued New Clearance
Airspace Structure; Human Factors
We recently had a change in airspace and procedures with C90 climbing departures northbound to 15;000 (it used to be 13;000). I had an overflight that was at 16;000; he asked to descend to 12;000 as soon as he was clear of C90 airspace. There was aircraft departing ORD that were also traffic for him. Once aircraft was clear of C90 and departing traffic; I descended him to 12;000 without thinking about the fact that I was over Milwaukee Approach airspace who owns up to 13;000. I was more concerned with missing the new C90 airspace. All the airspace below us was uniform when it was at 13;000. The change in procedures took my attention away from Milwaukee Approach airspace. Nothing happened from the incident other than I descended into somebody else's airspace with no appreq. I have worked this airspace very little since the change in airspace and procedures.
ZAU Controller descended aircraft into Milwaukee airspace after the traffic cleared the lateral confines of C90 airspace. Reporter cited confusion following a recent airspace change.