[DoubleC]

The technical limit laterally from structures is 2000 feet, up to 1000 feet.

Now for those arrival/approach procedures I imagine you need more than just 2000 feet since many times aircraft are flying in the clouds or in “instrument meteorogicial conditions” (meaning they can’t see outside very well if at all), so there’s got to be some swath of airspace that has to be clear for the procedures to remain.