Date: 201811
Local time of day: 1801-2400
Location: CLT.Tower, NC
Flight conditions: VMC
Light: Daylight
Aircraft: B737 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Landing
Airspace: Class B CLT
ATC / advisory: Tower CLT
Second aircraft: B737 Undifferentiated or Other Model
Reporter organization: Government
Reporter function: Local
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Situational Awareness; Time Pressure
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Air Traffic Control Separated Traffic; Flight Crew Executed Go Around / Missed Approach; General Flight Cancelled / Delayed
Contributing factors: Procedure; Airspace Structure; Human Factors
Primary problem: Procedure

Narrative: Air Carrier X was cleared to land upon completing a Visual Approach. When Air Carrier X was on approximately a 4 mile final; Air Carrier Y who was holding short of the runway was issued clearance for takeoff. When Air Carrier X was approximately 2.5 mile final I instructed Air Carrier Y to expedite takeoff roll; however the aircraft was extremely slow on takeoff roll. I considered cancelling Air Carrier Y's takeoff clearance and exiting the aircraft onto the taxiway however there was a Heavy Aircraft on Ground frequency that I would need to coordinate with to stop and hold short of the taxiway so that I could exit Air Carrier Y. On approximately .75 mile final; I cancelled the approach clearance; issued a climb to 4000 feet and instructed Air Carrier X when able fly heading 270. Air Carrier X flew runway heading for approximately 2 miles to midfield before beginning his turn while Air Carrier Y was rolling and rotating approximately .75 miles ahead. The Tower radar depicted Air Carrier X out of 2;100 feet climbing however I did not see the turn to 270 beginning so I instructed Air Carrier Y to maintain 2;000 until I could turn him to diverging heading and climb.When I observed Air Carrier X had turned; I issued the climb instructions to Air Carrier Y proximally 3 miles north west of the airport. Air Carrier Y was issued a turn to heading 360 and issued climb instructions to 8;000 feet. I provided visual separation to both aircraft and both aircraft were on frequency. I was instructed that the issuance of 2;000 as an altitude to maintain inside the surface area violated the MVA (Minimum Vectoring Altitude) of 2;300 feet. However; the altitude to maintain was issued inside the Class B Surface Area. The altitude complied with Minimum Safe altitudes of 1;000 above congested areas and there were no carats of depicted obstacles within 3 miles of the route of flight. The climb allowed the aircraft to top the 2;300 foot MVA that is depicted outside of the Class B surface area 7 miles to the north.Clarify if the MVA applies inside the Class B surface area or if the surface area of a Class Bravo has been tapered to the ground and any altitude can be issued as long as it is in compliance with the minimum safe altitude and obstacle obstructions.




Synopsis: A Tower Controller reported assigning a go around 2;000 feet in a 2;300 foot Minimum vectoring Altitude area.