Originally Posted by
DoubleD
The ORD 9 SID has a speed restriction posted in the upper right hand corner (Jepps) " SPEED: All turbojet departures in all directions: MAINTAIN 250 KT UNTIL ADVISED BY ATC"
I suspect the posted speed restriction in this specific SID is the reason for the letter.
The 250 is specific to the SID not to the U.S. Airspace.
Totally agree with Alder.
I think that we all agree that there is no regulation requiring advance clearance in the US for exceeding 250 below ten, (if required for weight) but ATC always appreciates advance notice for their planning purposes, and it may save you some unexpected vectors.
Joe