If you're flying a STAR and "cleared for the approach," how do you plan your descent to line up with the runway's vertical and lateral guideance? Here's what you should know...

Quick Review: Standard Terminal Arrival Routes

Standard Terminal Arrival Procedures (STARs) 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.

STARs Terminate In Different Ways

Let's take a closer look at the TEJAS 4 Arrival we just talked about. You'll notice that the STAR sends you in different directions based on the runway you're assigned. This is extremely important to keep in mind because failing to program the correct runway could result in you flying in a totally different direction. Depending on ATC-issued runway assignment during the TEJAS 4, you'll terminate the STAR at PRAYY or SKLER and "expect vectors to the final approach course."

Compare that to the QWENN 5 Arrival into Salt Lake City. At PLAGE (the final fix on the STAR) you're expected to "intercept the ISLC localizer and proceed inbound" when assigned Runway 34R. You'll then "expect an ILS/Visual approach" clearance from that point on.

For Runways 34L and 35, you'll just "expect radar vectors to the final approach course."

You're Flying The BRWNZ 3 Arrival Into Cleveland

Ok, let's set up a scenario that happens almost every day to pilots flying into the Cleveland Hopkins International Airport. You've been issued a "descend via" clearance on the BRWNZ 3 Arrival. Somewhere just past BRWNZ, the approach controller says "cleared for the ILS 24R." Prior to this point, the controller should've told you to expect Runway 24R, but that's not always the case. You program the ILS to Runway 24R with the LLROY transition (it's the last arrival fix setting you up for Runway 24R).

From this point on, the STAR is flown like normal. You're careful to notice the "1" depicted by QUUBE to cross between 7,000-6,000 feet, DEEKN at 6,000-5,000 feet, and LLROY at 210 knots at 5,000 feet. That's all normal. But things are just a little bit trickier past LLROY.

Transitioning To The ILS - When Can You Descend?

LLROY is both the last fix on the BRWNZ 3 Arrival and also an initial approach fix (IAF) on the ILS to Runway 24R. You've just crossed LLROY at the mandatory 5,000 feet and 210 knots. If you stay at that altitude until you intercept the ILS course, you'll be way too high to safely fly the approach. So when can you continue your descent?

Between LLROY and BORNY, the lowest segment altitude is 4,000 feet. It's clearly published on the chart. So, once you cross LLROY you're good to descend to 4,000 feet. Simple enough, right?

Here's where things get just a little more confusing. The next leg of the transition is from BORNY to SHERK, which aligns you with the final approach course of the ILS. Unlike the previous leg, there's no altitude written directly underneath the route.

When charts get over-saturated with information or condensed, you'll often find pointers that separately list the magnetic course, leg distance, and minimum altitude. In this case, the pointer shows a 3.2 mile long leg between BORNY and SHERK with a minimum altitude of 3,000 feet. In the fast-paced nature of a final approach, especially in a jet, it's easy to miss things like this because pointers look very similar to plenty of other markings on the approach plate.

If you were to miss this note and stay at 4,000 feet until SHERK, you'd still be way too high to intercept the ILS glideslope for Runway 24R.

Has This Happened To You?

Have you ever been cleared for the approach while you were still flying a STAR? Tell us about your experiences in the comments below.