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You Were Cleared Direct To A Fix: When Can You 'Descend Via' On The STAR?

Can you begin descending before becoming established on the STAR arrival route? Here's what you need to know...

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Review: "Descending Via" The STAR

Before the scenario, let's review what you should know about Standard Terminal Arrival Procedures (STARs). Arrival procedures streamline inbound IFR traffic into defined routes. They usually start with a transition. On the TEJAS 4 Arrival below, there are several transitions, and one of them is the Corpus Christie VOR. On this particular arrival, all of the transition routes merge, and the aircraft join the same route at GMANN.

ATC organizes arriving traffic in three dimensions. They're managing altitude, lateral path, and airspeed to keep traffic separated. Arrivals help with all three.

According to NBAA, a descend via is "an abbreviated ATC clearance that requires compliance with a published procedure's lateral path and associated speed restrictions and provides a pilot-discretion descent to comply with published altitude restrictions until descending to the 'Bottom Altitude' published on the STAR."

Scenario: Direct To A STAR Fix

Approaching Chicago O'Hare from the Northwest at FL180 in a regional jet, you receive the following clearance:

"Bolmethod 123, cleared direct GURNN, descend via the MADII 4 Arrival."

View full MADII 4 STAR chart here.

On the STAR, you need to cross GURNN at or below FL180. You're already at FL180 roughly 20 miles from GURNN. The next fix, CHDRR, must be crossed at 14,000 feet MSL.

If you stay at your current altitude until you're established on the STAR, you'll have 10 miles to descend 4,000 feet from FL180 to 14,000 feet.

Chicago asks you to maintain best forward airspeed. So when can you start your descent?

Can You Descend Before Reaching GURNN?

The short answer: Yes, you can begin your descent right away to meet the crossing restrictions of the STAR.

In this case, you can begin your descent as soon as you receive the "descend via" clearance from ATC. Even though you're not established laterally on the arrival, ATC has assumed responsibility for obstacle separation as long as you remain above the MEAs. Without the ability to descend, meeting subsequent crossing restrictions might be impossible. Here's what a descend via clearance authorizes you to do (AIM 5-4-1a):

  • Descend at pilot's discretion to meet published restrictions and laterally navigate on a STAR.
  • When cleared to a waypoint depicted on a STAR, to descend from a previously assigned altitude at pilot's discretion to the altitude depicted at the waypoint.
  • Once established on the depicted arrival, to descend and to meet all published or assigned altitude and/or speed restrictions.
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If no altitude is depicted at the fix you've been cleared to along a STAR, ATC is required to assign you a crossing altitude. If you were cleared to FALLS (FAH) to "descend via" the MADII 4 arrival, the controller must issue you a crossing restriction at FAH (AIM 5-4-1a).

Have You Received A "Descent Via" Clearance Recently?

Tell us about a time you had trouble with a "descend via" clearance. Did it come too late for a safe descent? Did you understand where you may begin your descent? Tell us in the comments below.

Swayne Martin

Swayne is an editor at Boldmethod, certified flight instructor, and an Embraer 145 First Officer for a regional airline. He graduated as an aviation major from the University of North Dakota in 2018, holds a PIC Type Rating for Cessna Citation Jets (CE-525), and is a former pilot for Mokulele Airlines. He's the author of articles, quizzes and lists on Boldmethod every week. You can reach Swayne at swayne@boldmethod.com, and follow his flying adventures on his YouTube Channel.

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