What is the maximum regulatory speed below 10,000 feet?

The maximum regulatory speed below 10,000 feet is indeed 250 knots. This speed limit is established by the Federal Aviation Administration (FAA) to enhance safety in congested airspace, where most commercial air traffic operates.

The rationale behind this regulation is to minimize the risk of wake turbulence and to ensure a manageable speed where pilots can maintain better control of their aircraft, especially during approaches and departures in busy terminal areas. The 250-knot speed limit applies to all aircraft operating below 10,000 feet unless otherwise specified by air traffic control.

While other higher speeds may be permissible in specific scenarios—such as during descent or cruise at higher altitudes or in less controlled environments—staying within the 250-knot limit is crucial for maintaining orderly and predictable aircraft behavior in lower airspace where traffic density is typically higher.