No matter where you fly, there are numerous speed restrictions that you need to be aware of…
Flights Below 10,000 Feet MSL
According to FAR 91.117(a), unless otherwise authorized by the Administrator, no one can operate an aircraft below 10,000 feet MSL at an indicated airspeed exceeding 250 knots (288 mph).
If you’re flying a piston aircraft, this might not hold much significance for you. However, it’s a crucial aspect for turbine aircraft. Jets don’t slow down rapidly, and turbine pilots often need to level off at 10,000 feet to reduce airspeed before continuing their descent. This is quite common at 10,000 feet, and generally, pilots don’t have to notify ATC that they’re leveling to slow down.
Flights Above 10,000 Feet MSL
With limited exceptions, aircraft are not allowed to exceed Mach 1 over the United States (FAR 91.817). According to NASA, during the 1950s and into the 1960s, sonic booms were reverberating across the nation as the Air Force developed more and more Mach-1-breaking jets.
Between 1956 and 1968, there were 38,831 claims made against the Air Force (14,006 of which were approved) to cover losses due to sonic booms. The claims ranged from broken glass and cracked plaster to assertions of pets dying. Fortunately for you, unless you own a fighter jet, you probably don’t need to worry about violating this FAR.
Speed Restrictions in/Around Class B Airspace
There isn’t a specific speed restriction for operating in Class B airspace. If you’re below 10,000 feet, you need to abide by the standard speed restriction of 250 knots. However, if you’re in Class B at 10,000′ MSL or higher, you can fly at a speed faster than 250 knots (although ATC usually restricts aircraft speed for traffic flow and separation).
Most Class B airspace ends at 10,000′ MSL, so this isn’t a major concern. However, some Class B airspace extends higher, such as Denver’s Class B, which extends up to 12,000′ MSL.
According to 91.117(c), no person can operate an aircraft beneath Class B airspace or in a VFR corridor through Class B at an indicated airspeed exceeding 200 knots (230 mph). This is done to help segregate aircraft operating within Class B from those operating outside of Class B. Some aircraft flying below Class B may not be in contact with ATC, and the speed restriction of 200 knots provides ATC an additional buffer to move traffic out of the way in case of an airspace deviation.
Speed Restrictions in Class C/D Airspace
Unlike Class B, airports with Class C/D airspace have lower maximum speeds in the immediate vicinity of the airport. No person can operate an aircraft at an indicated airspeed exceeding 200 knots (230 mph) at or below 2,500 feet above the surface and within 4 nautical miles of the primary Class C or Class D airport.
Other Recommendations
The final rule is straightforward. If the minimum safe airspeed for a particular operation is greater than the maximum speed, the aircraft can be operated at that minimum speed (FAR 91.117(d)). It provides a clear fallback for pilots to ensure they aren’t being forced to exceed their operational limitations.
There are airspeed limits for different altitudes, classes of airspace, and aircraft limitations. Knowing the requirements will ensure that you never exceed a speed limit, regardless of the aircraft you’re flying.
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