What is the maximum speed for aircraft below 2,500 feet AGL and within 4 NM of Class C or D airspace?

The maximum speed for aircraft operating below 2,500 feet AGL (Above Ground Level) and within 4 nautical miles of Class C or D airspace is indeed 200 knots. This speed limitation is part of the regulations intended to ensure safe operations in the vicinity of busy airports, where air traffic is more concentrated. By keeping speeds at or below 200 knots, pilots can better manage their aircraft's performance and response to air traffic control instructions, which are crucial in these zones often characterized by high-density traffic and potential for complexity in flight patterns.

Class C and D airspace indicates more stringent requirements due to surrounding traffic density, and enforcing a maximum speed helps in maintaining safety and situational awareness for both pilots and air traffic controllers. Other speed limits, such as 180 knots or 250 knots, apply under different conditions or altitudes but do not pertain specifically to this scenario involving Class C and D airspace.