When entering a FIR and tuning into Center, your first transmission should always be a “check-in”. This announces your presence on frequency and also serves as a request to continue following your flight plan. An approach request would be more appropriate if your destination is not served by an Approach controller and Center will be providing service all the way down.
In most cases you will not begin your TOD until you’re well inside of Center’s airspace so the check-in and “descent via” requests are separate. That said, following your check-in and radar contact you would then make a separate “descent via __” assuming you have a filed STAR complete with the green bracket.
Note: A separate “descent via” request is not required with Approach Control (even in the absence of Center). When your approach request is made, the response “continue as filed, expect __” serves as approval to continue your flight plan laterally and vertically
If you haven’t already, this Descent Tutorial shows the interactions between the pilot and ATC during the descent phase of the flight. Feel free to follow up with additional questions!
Got it, thanks. So the proper procedure is to simply check-in if one is already descending, and if there is no active approach frequency at the destination airfield, it is on the Center controller to ask us to “say approach request.”
I do have one follow-up on checking in during the descent phase, and perhaps I didn’t word my initial question #2 properly. The callout when a pilot checks-in is always “With you at XXk feet.” I sometimes hear “With you at XXk feet, descending via XXXXX arrival.” Which specific command results in the latter, and when is that appropriate versus the standard check-in?
If there is no approach frequency at your destination it is appropriate to make your approach request on initial contact. The Center will respond with “Continue as filed, expect __” (cleared to follow fpl laterally/vertically) or “Expect vectors for ___” (expect to be taken off of your filed route).
Not to worry if you’re unsure though! Simply check in and the Center controller can always ask for your request if needed.
Ah, I see! When you hear the attached, “via the XXX arrival” it is because they were previously approved to descend via the STAR, specifically in a situation where Center has handed off the descending aircraft to Approach. When Center issues that descent clearance it is attached to your flight progress strip on the ATC interface and also carries over on the initial call-up if check in is used again with a subsequent controller.