Question from Victor, a Multi-Engine Instructor:
“You are at [FL250], cruising along, and ATC clears you to “Descend via STAR [xxxx].” As you begin the descent (at pilot’s discretion to save fuel), are you required to notify ATC that you are leaving [FL250] and if so, the target altitude on the STAR you are next going to? And if it is not required, does Center in general want you to do it as a courtesy/situational awareness to them, or will they view it as an unnecessary use of frequency?
“I thought it would be mandatory, since I thought that vacating an altitude was always a mandatory report to ATC. But others I have spoken with claim that ATC giving you the “descend via” clearance eliminates the requirement.”
It is mandatory to report vacating your cruising altitude under any circumstance, except when vacating intermediate altitudes on a STAR. What others may be misunderstanding is this. Once you have begun descending on a STAR, there is no need, and you really shouldn’t, report vacating each step down altitude on the STAR. Nor do you need to report your next level-off altitude on the STAR. When you acknowledge “Descend via” and the STAR’s identifier, you are telling ATC you’ll be complying with all of the restrictions on the STAR.
Your initial descent point is usually discretionary; and ATC wants to be notified when you start down. Once established on the STAR’s descent profile, ATC knows where you’ll be at any point on the path.
Just to be clear about all this, let’s look at an example. Let’s say you are cruising at FL250. Oakland Center says, “Descend via the Melon 6 Arrival.” You acknowledge this and maintain FL250 until reaching your top-of-descent point to begin the arrival. The first crossing restriction on the STAR is 15,000 feet, 80 DME from the next VORTAC. Your radio call to Oakland, as you begin your initial descent would be, “[Callsign], vacating FL250.” That’s it, nothing further. You don’t have to report your target altitude of 15,000 feet. You don’t have to report leaving 15,000 once past 80 DME. Just the initial report vacating FL250.
Here’s an extra, even though you didn’t ask about it. When descending on a STAR and checking in with a new controller as you pass 16,800 feet, your example transmission would be, “NORCAL Approach, [call sign], passing 16,800, on the Melon 6.”
Other questions or comments for me? Use the comments section below or write to me directly at Jeff@ATCcommunication.com.