What is the permissible indicated airspeed below 10,000 feet ASL unless otherwise authorized?

The permissible indicated airspeed below 10,000 feet Above Sea Level (ASL), unless otherwise authorized, is 250 knots. This regulation is primarily established to promote safety and reduce noise in areas near airports and populated regions. The limitation helps to minimize the risk of high-speed operations close to the ground, which can lead to increased noise pollution as well as greater potential for accidents due to less reaction time in crowded airspaces.

Understanding this regulation is crucial for pilots, as it not only affects their operational procedures but also ensures compliance with air traffic control instructions and contributes to overall safety in the national airspace system. Other indicated airspeeds mentioned are not the established maximums below this altitude and generally apply to different altitude bands or operational circumstances.