§ 91.117 Aircraft speed.
(a) Unless otherwise authorized by the Administrator, no person may operate an aircraft below 10,000 feet MSL at an indicated airspeed of more than 250 knots (288 m.p.h.).
(b) Unless otherwise authorized or required by ATC, no person may operate an aircraft at or below 2,500 feet above the surface within 4 nautical miles of the primary airport of a Class C or Class D airspace area at an indicated airspeed of more than 200 knots (230 mph.). This paragraph (b) does not apply to any operations within a Class B airspace area. Such operations shall comply with paragraph (a) of this section.
(c) No person may operate an aircraft in the airspace underlying a Class B airspace area designated for an airport or in a VFR corridor designated through such a Class B airspace area, at an indicated airspeed of more than 200 knots (230 mph).
(d) If the minimum safe airspeed for any particular operation is greater than the maximum speed prescribed in this section, the aircraft may be operated at that minimum speed.
TRF 7/0204 ZDC FLIGHT RESTRICTIONS, WASHINGTON, DC
Size and location:
All airspace between 30 nm and 60 nmcentered on 385134N/0770211W or the DCA VOR/DME
Surface up to 17,999 ft
0100 local August 30 until further notice
Requirements for flight in the 30 nm-60 nm area:
Aircraft operations are restricted to an indicated airspeed of 230 knots or less
|All||Less than 10,000′ MSL||250 kts|
|Within 4 nautical miles of the primary airport of a Class C or Class D||Below 2,500′ AGL||200 kts|
|Class B||Below 10,000′ MSL||250 kts|
|Class B||Above 10,000′ MSL||Unlimited|
|Under Class B Shelf||All||200 kts|
|Class B VFR Corridor||All||200 kts|
|All airspace between 30 nm and 60 nmcentered on 385134N/0770211W or the DCA VOR/DME||Less than 10,000′ MSL||230 kts|
|Aircraft may operate at minimum safe speed—even if it is greater than the maximum in this section.|
|ATC may authorize speeds greater 200 kts in Class C and D.|
In FAR’s Explained, they note that an FAA Chief Counsel Opinion clarified that aircraft may exceed 250 kts above 10,000′ MSL in Class B airspace. I can’t find the opinion on-line.
There is a discussion on exceeding 250 kts limit is here. Basically, some aircraft, like 747’s must climb at greater than 250 kts clean. Also, some airports, DFW was mentioned, have been approved by the administrator to allow climb out at greater than 250 kts.