What is the correct phraseology for issuing a clearance to an aircraft utilizing an airway above/below its route structure?

The correct phraseology for issuing a clearance to an aircraft utilizing an airway above or below its route structure is "Via the radials of Victor 9." This phraseology accurately communicates to the pilot that they should navigate using the specific radials associated with the Victor airway. It provides precise routing information that is essential for air traffic management and ensures that the aircraft follows the correct navigational path associated with the airway.

Using "Via the radials" indicates a clear understanding of how airways function, where aircraft can navigate using specific radial courses from a VOR (VHF Omnidirectional Radio Range) station. This is vital for maintaining safe separation from other aircraft that may be utilizing the same or adjacent airways.

The other phrases do not provide the same level of clarity. "Using Victor 9, proceed as filed" suggests following the filed route without indicating whether the route is over or under the airway or utilizing specific radials. "On the path of Victor 9, continue as planned" also lacks precise navigational instruction, which is necessary for air traffic control. "Cleared over Victor 9, descent requested" implies a clearance over the airway without detailing how to navigate it, which does not meet the standard phraseology for airway instructions