What is the maximum indicated airspeed for a reciprocating-engine airplane operating in the airspace underlying Class B airspace?

The correct maximum indicated airspeed for a reciprocating-engine airplane operating in the airspace underlying Class B airspace is 200 knots. This limit is in place to ensure safe operations in congested airspace, particularly around large airports where Class B airspace is often located.

When flying below Class B airspace, the restriction is imposed to minimize the risk of wake turbulence encounters and to enhance situational awareness for both the pilots of slower aircraft, such as those with reciprocating engines, and faster, jet-powered aircraft that may be operating in the vicinity. This speed limit helps maintain orderly traffic flow and allows for better integration of different aircraft types within the same airspace.

While lower speeds, like 180 knots, might seem safe, the established limit of 200 knots reflects the operational needs and characteristics of reciprocating-engine aircraft. It allows enough margin for performance without compromising safety in busy airspace environments.