What is the maximum airspeed in the airspace underlying class B airspace?

The maximum airspeed in the airspace underlying Class B airspace is 200 knots indicated airspeed. This regulation is in place to maintain safe operations in the vicinity of busy airports where Class B airspace is commonly found.

Class B airspace surrounds major airports and is associated with heavy traffic that includes a mix of commercial airliners and general aviation. Keeping the airspeed at or below 200 knots helps to ensure that pilots have adequate time and space to react to changes in traffic patterns, as well as to provide sufficient separation from larger, faster aircraft that are operating at higher altitudes within the Class B airspace.

The other speeds listed are not applicable to the area directly beneath Class B airspace. A speed of 120 knots may be a restriction for other airspace types, but it does not pertain to Class B. A speed of 250 knots is permissible above 10,000 feet MSL or outside of certain airspace but exceeds the restriction below Class B. Finally, 300 knots would be impractical and unsafe for operations beneath Class B airspace, considering the potential conflicts with traffic patterns and radar operations typical in those zones.