"...no person may operate an aircraft below 10,000 feet MSL at an indicated airspeed of more than 250 knots..."
...but not to worry, it would be OK with the FAA to do 280 knots at 5000 feet
AGL at places like mile-high Denver; 8,300' Bogota; 9,200' Quito; 13,300' La Paz...
