EMB ERJ 170/175 ER/LR
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Communication Breakdown; Situational Awareness
Airspace Violation All Types; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Returned To Clearance
Airspace Structure; Human Factors
Level at 9;000 ft [and] 18-20 NM from [the] airport; we were cleared for the visual approach. FO (First Officer); PF (Pilot Flying); asked to activate vectors on approach. The final approach fix altitude was 7;000 ft. He initiated a descent to 7;000 ft. Bottom of Class B at that point was 8;000 ft. We descended below the Class B for a short period of time before re-entering to land. Misunderstanding by the FO of not descending below Class B when arrival airport is in Class B airspace. I didn't speak up even though something didn't seem right. Be more aware of lateral/vertical confines of Class B airspace when cleared for the visual approach.
EMB-175 Captain reported being unaware of the confines of Class B airspace resulting in an unauthorized entry.