The ILS Circle-to-Land: Using Your Glideslope to Fly Circling Minimums

The ILS circle-to-land is a fully authorized instrument procedure that many pilots overlook or misunderstand. If circling minimums appear on the approach plate, you can circle - regardless of whether the underlying approach is precision or non-precision. The ILS glideslope actually gives you a meaningful advantage during the descent to circling minimums compared to a VOR or RNAV approach without vertical guidance.

Can You Really Circle Off an ILS Approach?

Yes. FAR 91.175 governs instrument approach procedures and landing minimums. It requires that you not descend below the circling minimum descent altitude (MDA) unless you have the required flight visibility and the runway environment in sight. The regulation does not restrict circling to non-precision approaches.

Most published ILS approaches in the United States include circling minimums directly on the plate - typically in a column labeled “Circling” within the minimums section. If those numbers are there, you’re authorized to use them.

How Does the Procedure Actually Work?

Fly the ILS normally - intercept the localizer, capture the glideslope, configure the aircraft, and track both needles toward the airport. The key difference from a straight-in is that you don’t fly all the way to the ILS decision altitude.

The ILS decision altitude is typically around 200 feet above touchdown zone elevation - a precision minimum designed for a straight-in landing on that specific runway. The circling MDA is always higher, because it accounts for terrain and obstacles in every direction you might be heading during the visual maneuvering phase.

As you descend the glideslope, you’ll reach the circling MDA before you reach the ILS decision altitude. At that point, level off, hold that altitude, and look outside.

Why Is the ILS Better Than a VOR for Getting to Circling Minimums?

On a VOR or RNAV approach without vertical guidance, descending to MDA involves managing step-down fixes, checking distance measuring equipment, and confirming altitude against the plate at each point. That’s sustained heads-down work arriving right at the moment you need to transition to visual maneuvering.

The ILS glideslope handles all of that vertical guidance automatically. One needle. A smooth, continuous, stabilized path. No step-down fixes, no timing, no DME cross-checks. When the glideslope delivers you to circling MDA, you arrive with more mental bandwidth available - better positioned, mentally and physically, to begin the visual maneuvering phase.

That’s a genuine operational advantage, and one reason to choose an ILS circle over a VOR circle when both options exist at the same airport.

What Do You Need Before Maneuvering?

Two conditions must be met at circling MDA before you can continue:

1. Required flight visibility. Circling minimums carry their own visibility requirement, separate from and higher than the ILS straight-in visibility. Check the circling column specifically.

2. Runway environment in sight. This means the runway itself, runway lights, approach lights, threshold markings, or any combination of visual references that lets you determine your position relative to the landing runway and conduct a normal approach.

If either condition isn’t met at circling MDA, execute the missed approach. No waiting, no descending further hoping the ceiling lifts.

How Do You Stay Within the Protected Area?

The FAA defines the circling protected area by a radius from each runway threshold, based on aircraft approach category:

• Category A (under 91 knots): 1.3 nautical miles
• Category B (91–120 knots): 1.5 nautical miles
• Category C (121–140 knots): 1.7 nautical miles
• Category D (141–165 knots): 2.3 nautical miles

Obstacles within those radii have been evaluated for the published circling minimums. Stay inside the protected area and obstacle clearance is assured at your circling MDA. Outside it, that assurance is gone.

Your aircraft category is determined by 1.3 times your stall speed at maximum certified landing weight in the landing configuration. Don’t fly Category A minimums if your approach speed puts you in Category B.

What Are the Most Common Mistakes on Circling Approaches?

Losing visual reference and continuing anyway. The accident record on circling approaches highlights this repeatedly. FAR 91.175 uses the word “immediately.” If you lose visual reference with the runway environment during the circle, you execute the missed approach immediately - not after waiting to see if the runway reappears. That discipline has saved lives. The absence of it has ended them.

Excessive bank angle on the turn to final. If the geometry gets wide and a pilot tries to tighten the turn, the result is a steep bank at low altitude in marginal visibility with airspeed decaying. This is one of the most dangerous situations in instrument flying. Keep bank angles moderate throughout the circle. If the geometry doesn’t set up a normal landing, go missed and reposition.

Not briefing the missed approach before starting down. The missed approach from the circling phase doesn’t begin at a fixed point on the ground - it starts wherever you are when you lose visual reference or decide to go missed. The FAA’s general guidance: initiate a climbing turn toward the approach end of the ILS runway, then follow the published missed approach procedure from there. If you’re on the opposite side of the airport when you go missed, you need to know which direction to turn before that moment arrives. Brief it before passing the final approach fix.

What About Night Circling?

Some approach plates restrict night circling to specific runways or prohibit it entirely where runway lighting is inadequate. Read the approach notes before planning a night circle - those restrictions exist for documented reasons.

Even at well-lit airports, night circling is a meaningfully different task. Depth perception degrades. Your sense of terrain clearance is reduced. Visual cues that help you judge position in the pattern - tree lines, ramps, taxiway layouts - are harder to read. Night circling is legal and sometimes the right call, but it raises the floor on acceptable conditions.

Before You Commit to an ILS Circle

A few things to confirm before beginning the approach:

• Circling minimums must be published on the plate. Some approaches are designated straight-in only. If circling minimums don’t appear, circling is not authorized regardless of the underlying approach type.
• Check conditions against circling minimums, not ILS minimums. They are two different numbers, and the circling MDA will be higher.
• Know your aircraft category. Don’t fly Category A minimums if your approach speed puts you in Category B.
• Consider whether circling is necessary at all. If the same airport offers a different instrument approach with a straight-in option to the preferred runway, use it. The ILS circle is a valid procedure - not a required one when a better option exists.

If circling approaches aren’t part of your recent practice, work through the procedure with a CFI before flying it in actual conditions. Simulate the level-off at circling MDA, fly the visual maneuvering, and practice the missed approach from multiple points in the circle. Using the ILS as your starting point for that practice gives you a stabilized descent - which is exactly the advantage the procedure is designed to provide.

Key Takeaways

• If circling minimums are published on the ILS plate, circling is authorized - FAR 91.175 does not restrict circles to non-precision approaches.
• The ILS glideslope delivers you to circling MDA in a more stabilized, lower-workload state than a VOR or RNAV approach, making it operationally advantageous for circling.
• You must have the required visibility and the runway environment in sight at circling MDA before beginning visual maneuvering.
• The protected area radius ranges from 1.3 to 2.3 nautical miles depending on aircraft category - obstacle clearance is only assured inside that boundary.
• If you lose visual reference during the circle, go missed immediately. It is not a judgment call.