FLC OF AN MLG FAILED TO COMPLY WITH ATC CLRNC WHEN THEY LEVELED OFF DURING DSCNT TO SLOW THE ACFT TO THE MAX PERMITTED SPD BELOW 10000 FT.

Narrative

DSNDING FOR APCH AT PORTLAND; MAINE; ZBW HAD CLRED US TO 11000 FT. DURING THE DSCNT PRIOR TO 11000 FT; WE WERE HANDED OFF TO PORTLAND APCH (119.75). APCH CLRED US TO 4000 FT. AT 10000 FT WE LEVELED OFF TO SLOW TO 250 KIAS BEFORE DSNDING TO 4000 FT. OUR AIRSPD PRIOR TO LEVEL OFF WAS 330 KIAS. AT THIS SPD IT WOULD TAKE US APPROX 7-8 MI TO SLOW TO 250 KIAS AT IDLE PWR. WHILE AT 10000 FT; APCH ASKED US IF WE KNEW THAT WE WERE CLRED TO 4000 FT. WE ACKNOWLEDGED AGAIN OUR CLRNC TO 4000 FT AND TOLD HIM WE WERE DECELERATING TO 250 KIAS. AGAIN HE ASKED US IF WE KNEW WE WERE CLRED TO 4000 FT. AGAIN I ACKNOWLEDGED AND TOLD HIM AS SOON AS WE SLOWED TO 250 KIAS; WE WOULD CONTINUE THE DSCNT. ALSO; DURING OUR DSCNT WE WERE TOLD ABOUT TFC AT A LOWER ALT HDG IN THE OPPOSITE DIRECTION. WE DID NOT SEE THE TFC; STATED THAT; AND WERE GIVEN A VECTOR TO AVOID. THIS HAD NO BEARING ON OUR AIRSPD REDUCTION. IT IS MY UNDERSTANDING THAT ACFT DSNDING BELOW 10000 FT; ARE ALLOWED AND EXPECTED TO LEVEL OFF AT 10000 FT UNTIL 250 KIAS THEN CONTINUE DSCNT. THIS CTLR DID NOT APPEAR TO KNOW THIS. IT MAY BE POSSIBLE WE WERE AT 10000 FT LONGER THAN HE WAS USED TO SEEING. I BELIEVE WE FOLLOWED THE FAR'S AND ARE NOT IN ERROR.