ACS Task IR.VI.D — Circling Approach (Procedures and ACS Tolerances)

What is a circling approach and when is one required?

A circling approach is an instrument approach procedure that does not end with a straight-in landing on the runway aligned with the final approach course — instead, you maneuver visually around the airport at or above circling MDA to align with a different runway. Per AIM 5-4-20, circling is required when the final approach course is aligned more than 30 degrees from the landing runway centerline, when the descent gradient to a straight-in landing would be excessive, or when wind or traffic requires landing on a runway other than the one the approach procedure serves.

The circling maneuver is flown entirely by visual reference — once you break out of the clouds and identify the airport environment, you maneuver using normal traffic-pattern judgment. The approach instrument chart provides the circling MDA and the required visibility, but the actual circling path is pilot-discretion. You must stay within the protected circling area for the terrain and obstacle clearance depicted on the plate to apply.

What is circling MDA and how does it differ from straight-in minimums?

Circling MDA is a minimum descent altitude published specifically for the visual maneuvering phase after the instrument segment ends. It is always at or higher than the straight-in MDA for the same approach, because the circling maneuver covers a larger area of terrain and obstacles around the entire airport — not just the terrain in the final approach path. Per 14 CFR 91.175(c), you may not descend below circling MDA until you have the required flight visibility and the required visual references distinctly in sight.

The circling MDA appears on the approach plate in the minimums section, labeled by aircraft category. Visibility minimums for circling are also category-specific and are always equal to or greater than straight-in minimums. ACS Task IR.VI.D holds you to +100/-0 feet on circling MDA — you may be up to 100 feet above, but you must never go below. This is the same altitude tolerance as for any other MDA during an ACS evaluation, but operationally it is higher-stakes because the terrain clearance margin during circling is designed around that exact altitude floor.

How are circling approach aircraft categories defined?

Aircraft approach categories are defined in 14 CFR 97.3 based on 1.3 times the aircraft's stall speed in the landing configuration (Vso) at maximum certificated landing weight, or the published Vref if specified.

Under 14 CFR 97.3, you may always operate at a higher category than your aircraft technically requires — but you must then use that category's minimums. You cannot fly at Category B speed and use Category A minimums.

What is the circling approach protected area and how have the radii changed?

The circling approach protected area is the region around the airport within which terrain and obstacle clearance is guaranteed at circling MDA. Per AIM 5-4-20, two different criteria exist and the applicable standard is shown on the approach plate itself.

Traditional (older plate) criteria use fixed radii measured from each runway threshold: 1.3 nm for Category A, 1.5 nm for Category B, 1.7 nm for Category C, and 2.3 nm for Category D. The protected area is formed by arcs of these radii centered on each runway threshold, connected by tangent lines.

Expanded (newer plate) criteria — developed by the FAA and published in updated TERPS guidance — use larger radii that vary by both aircraft category and airport elevation. These expanded radii provide more protected airspace during the circling maneuver, particularly at higher-elevation airports where true airspeed is greater for the same indicated airspeed. Approach plates published under the expanded criteria are annotated to indicate this; AIM 5-4-20 describes both sets of criteria and notes that pilots should check the applicable plate for which standard governs.

The practical implication: if you maneuver outside the protected circling area, the obstacle clearance guarantee no longer applies. Fly tight to the airport, keep turns coordinated, and treat the circling area boundary as a hard limit — especially at night or in reduced visibility.

What visual references are required, and what does the missed approach rule say?

Before descending below circling MDA, 14 CFR 91.175(c) requires that all three conditions be met simultaneously:

1. 1
   The aircraft is continuously in a position from which a descent to a landing on the intended runway can be made at a normal rate using normal maneuvers.
2. 2
   The flight visibility is not less than the visibility prescribed in the standard instrument approach procedure being used.
3. 3
   At least one of the visual references for the intended runway is distinctly visible and identifiable — including the approach light system (ALS), threshold, threshold markings, threshold lights, runway end identifier lights (REIL), visual glideslope indicator (VASI/PAPI), touchdown zone or its markings/lights, or the runway or runway lights.

The circling-specific missed approach rule in 14 CFR 91.175(e) is more demanding: you must execute an immediate missed approach whenever an identifiable part of the airport is not distinctly visible during the circling maneuver — unless the visibility loss is solely due to normal banking during the turn. This is a stricter standard than the straight-in missed approach trigger. Loss of visual contact during a circling maneuver at low altitude, in unfamiliar terrain, is one of the highest-risk moments in instrument flying.

When a circling missed approach is required, the published missed approach procedure is designed to be flown from the missed approach point of the straight-in segment. If you are circling and must go missed, the standard guidance is to turn toward the landing runway, climb to a safe altitude, and then intercept the published missed approach course — because the circling missed approach routing is not depicted on the plate and terrain clearance depends on this sequence.

What are "Circling NA" and night circling restrictions?

Some approach plates restrict circling for specific runways, directions, or conditions. These restrictions appear in the notes section and must be observed regardless of actual weather.

• Circling NA: The circling approach is not authorized in the indicated direction or to the indicated runway. This is typically due to obstacles or terrain in the circling area that cannot be cleared at the published MDA. You may not circle to that runway under any conditions.
• Circling NA at night: Circling is authorized in daytime VMC conditions but prohibited after sunset. Unlighted obstacles or insufficient airport lighting in the circling area makes the maneuver unsafe in darkness. The restriction appears as a note on the plate and applies regardless of whether you can see the airport.
• Sector restrictions: Some procedures restrict circling to specific sectors (e.g., "Circling south of Runway 18/36 NA") due to terrain on one side of the airport. You may circle on the unrestricted side but must not maneuver into the restricted sector.

Night circling is one of the most challenging tasks in instrument flying even when it is authorized. Depth perception and spatial orientation degrade significantly, airport perimeter lighting may be sparse, and unlighted terrain can be invisible. The DPE will probe your awareness of these limitations and your risk management strategy before authorizing a circling approach at night.

What does the DPE look for during IR.VI.D?

The DPE will pay particular attention to your altitude discipline during the circling maneuver — specifically, whether you allow the aircraft to drift below circling MDA during a bank or while maneuvering to align with the runway. Altitude loss below MDA during circling is an automatic unsatisfactory on Task IR.VI.D. The examiner also watches for whether you maintain visual contact throughout and whether your bank angles and turning radius keep you within the protected circling area.

Common errors on circling approaches

• Descending below circling MDA during the turn to final — the most common ACS failure point. Bank angle increases descent rate; trim and power must be actively managed throughout the maneuver.
• Losing visual contact with the airport environment while focused inside the cockpit or during a steep bank, then failing to execute the missed approach immediately as required by 14 CFR 91.175(e).
• Maneuvering outside the protected circling area — flying too wide a pattern or extending downwind too far — where terrain and obstacle clearance is no longer guaranteed by the published MDA.
• Using the wrong aircraft category minimums, particularly failing to apply higher-category minimums when flying at a speed that exceeds the lower category boundary.
• Incorrect missed approach execution during circling — turning the wrong direction, failing to climb promptly, or not intercepting the published missed approach course.
• Attempting a circling approach when the plate notes "Circling NA" or "Circling NA at night," or failing to recognize sector restrictions that prohibit maneuvering in a specific direction.

Frequently Asked Questions

Q: When is a circling approach required instead of a straight-in approach?

A circling approach is required when the final approach course is aligned more than 30 degrees off the runway centerline, when a straight-in MDA/DA would produce an excessive descent gradient, or when landing on a different runway than the one the approach is designed for. The procedure requires you to keep the airport environment in sight and maneuver visually at or above circling MDA.

Q: What are the ACS tolerances for a circling approach?

ACS Task IR.VI.D requires you to maintain circling MDA +100/-0 feet — you may not descend below MDA at any point during the circling maneuver. Airspeed must be kept within ±10 KIAS of the target. You must also maintain the required flight visibility and keep an identifiable portion of the airport environment in sight throughout the maneuver.

Q: What visual references are required before descending below MDA on a circling approach?

Under 14 CFR 91.175(c), you must have the required flight visibility and at least one of the listed runway environment references distinctly visible — such as approach lights, the threshold, touchdown zone markings, or the runway itself. For circling, 91.175(e) adds that a missed approach is required if an identifiable part of the airport is not distinctly visible during the maneuver.

Q: What is the difference between old and new circling approach area radii on approach plates?

Older plates used fixed radii from each runway threshold (1.3 nm for Cat A, 1.5 nm for Cat B, 1.7 nm for Cat C, 2.3 nm for Cat D). Newer plates published under the FAA's expanded criteria use larger radii that vary by aircraft category and airport elevation, providing greater protected airspace during the circling maneuver. AIM 5-4-20 describes both criteria; the plate itself indicates which standard applies.

Q: What happens if you lose visual contact with the airport during a circling maneuver?

Under 14 CFR 91.175(e), you must execute an immediate missed approach if an identifiable part of the airport is not distinctly visible during circling — unless the visibility loss is due to normal banking. The missed approach turn should be made toward the landing runway and then intercept the published missed approach course, since circling missed approach routing is not depicted on the plate.

Q: Are circling approaches permitted at night?

Circling approaches are permitted at night but carry significantly higher risk because airport lighting and terrain are harder to judge in darkness. Some approach procedures are annotated "Circling NA at night" when the circling area contains obstacles that are not adequately lit or are too close to provide a safe visual maneuvering margin. Always check the notes section of the approach plate.

Q: What does "Circling NA" mean on an approach plate?

"Circling NA" — or "Circling NA to Runway X" — means the circling approach is not authorized for that direction or to that runway. It may appear as an outright prohibition (e.g., due to obstacles or terrain in the circling area) or as a night-only restriction. You may not circle in a direction marked NA regardless of actual weather conditions.

Q: Can you fly a circling approach in a higher aircraft category than your aircraft requires?

Yes. Per 14 CFR 97.3, you may always use the minimums of a higher aircraft category than your actual approach speed requires. This gives you more protected airspace. However, you must then apply those higher-category minimums — you cannot use Cat A minimums while flying at a Cat B approach speed.

Sources

• FAA Instrument Rating ACS (FAA-S-ACS-8C Change 1)
• 14 CFR 91.175 — Takeoff and Landing Under IFR (Cornell LII)
• 14 CFR 97.3 — Symbols and Terms Used in Procedures (Cornell LII)
• AIM 5-4-20 — Circling Approaches
• FAA Instrument Procedures Handbook (FAA-H-8083-16B)
• FAA Instrument Flying Handbook (FAA-H-8083-15B)

This article was researched from FAA primary sources (ACS, FAR/AIM, Instrument Flying Handbook, Instrument Procedures Handbook) and citing current 14 CFR Part 91 and Part 97 — drafted by MockDPE. Last updated: May 2026. If you spot an inaccuracy, email corrections@mockdpe.org.