What is the speed limit below 10,000 feet ASL?

The speed limit below 10,000 feet Above Sea Level (ASL) is 250 KTS Indicated Air Speed (IAS). This regulation is in place to ensure safe and efficient operations in the terminal airspace, which is typically congested with traffic. By having a specific speed limit, operations can be more predictable, reducing the likelihood of collisions and helping with overall air traffic management.

Maintaining this speed limit aids air traffic controllers in managing aircraft spacing and sequencing, particularly during approach and departure phases when aircraft are closer together. This regulation also serves to reduce the noise impact on communities beneath flight paths, particularly in busy airport areas.

While higher speed limits may apply at greater altitudes, keeping aircraft below 10,000 feet at a maximum of 250 KTS is essential for safety and operational efficiency in both congested airspace and during the critical phases of approach and landing.