What is the speed limit below 10,000 feet?

The speed limit below 10,000 feet is set at 250 knots indicated airspeed (KTS). This regulation is primarily designed to promote safety in the National Airspace System (NAS) by minimizing the speed of aircraft operating in an area dense with air traffic and lower altitudes. At lower altitudes, the likelihood of encounters with other aircraft is higher, both visually and in terms of airspace management. Limiting speed to 250 KTS helps to ensure pilots have adequate time to react to other traffic and maintain safe operational parameters while managing approach and departure angles.

While there are specific situations where exceptions apply, such as during procedures associated with departure or approach where different speed limits may be authorized by air traffic control, the general guideline remains 250 KTS under 10,000 feet. This speed limit balances operational efficiency with safety considerations in high-traffic airspace.