ACS Task IR.VI.A — Nonprecision Approach (VOR, LOC, RNAV)

What is ACS Task IR.VI.A?

ACS Task IR.VI.A is the nonprecision approach task in Area of Operation VI of the FAA Instrument Rating ACS (FAA-S-ACS-8C). It covers approaches that provide lateral course guidance but no electronic vertical guidance — VOR, LOC, RNAV (LNAV), and NDB approaches. Every instrument rating checkride includes at least one nonprecision approach, and many DPEs assign two to evaluate consistency across different navaid types.

The DPE evaluates three dimensions: knowledge (can you explain the procedure?), risk management (can you identify decision points and hazards?), and skill (can you fly the tolerances?). All three must be satisfactory for a passing grade.

What nonprecision approach types does the ACS cover?

The ACS evaluates four nonprecision approach types, each using a different navaid for lateral guidance but all sharing the same MDA-based descent structure.

Note that an RNAV approach plate may also publish LPV or LNAV+V lines. LPV uses a glidepath and a DA — that is an approach with vertical guidance (APV), evaluated under ACS Task IR.VI.B. LNAV+V provides an advisory glidepath but still uses an MDA; it remains a nonprecision approach for ACS purposes.

What is MDA and how does it differ from DA?

14 CFR 1.1 defines MDA as "the lowest altitude specified in an instrument approach procedure, expressed in feet above mean sea level, to which descent is authorized on final approach or during circle-to-land maneuvering until the pilot sees the required visual references for the heliport or runway of intended landing." On a nonprecision approach, you descend to MDA and then maintain it — you do not continue descending past MDA unless you have the required visual references and can make a normal landing.

A Decision Altitude (DA), used on precision and APV approaches, is fundamentally different: you make the land/miss decision at DA and do not level off. The level segment at MDA is the defining structural difference between nonprecision and precision approaches, and the DPE will probe your understanding of it.

What are stepdown fixes and how do they affect the descent?

Stepdown fixes are intermediate altitude constraints published between the FAF and the MAP on some nonprecision approaches. They exist because an obstacle within the approach segment prevents a single uninterrupted descent to MDA. You must reach each stepdown fix at or above its published crossing altitude before continuing the descent to the next fix or to MDA.

Missing a stepdown fix — descending to MDA before the fix is crossed — is a procedural error that violates the published approach procedure and may place the aircraft below obstacle clearance. The DPE expects you to brief stepdown fixes during the approach briefing and confirm each crossing altitude as you fly the procedure.

What is the visual descent point (VDP)?

The VDP is a defined point on the final approach segment from which a normal 3-degree descent from MDA will reach the runway touchdown zone. It is depicted on approach charts as a "V" symbol on the profile view and is calculated for straight-in approaches where the charted MDA allows a normal-rate descent. Not every nonprecision approach has a published VDP — its absence typically indicates that obstacles or a high MDA preclude a stabilized descent to the touchdown zone from that point.

The VDP serves as a practical decision gate: if you arrive at the VDP still in IMC without the required visual references, a landing from MDA will likely be unstabilized. Flying to the MAP and executing the missed approach is the correct response. The Instrument Procedures Handbook (FAA-H-8083-16B) discusses the VDP as part of the continuous descent final approach (CDFA) technique in Chapter 4.

What is the missed approach point (MAP) on a nonprecision approach?

The MAP is the latest point at which the missed approach procedure must be initiated if the required visual references have not been established. 14 CFR 91.175(e) requires pilots to "immediately execute an appropriate missed approach procedure" upon arrival at the MAP if the conditions in 91.175(c) are not met.

On nonprecision approaches, the MAP is identified by:

• A timing fix — elapsed time from FAF at a specified groundspeed (VOR, NDB, LOC without DME)
• A DME distance — a specific DME reading from the navaid
• A waypoint — the final waypoint in the RNAV sequence
• A navaid passage — crossing a VOR station or NDB on the inbound course

Unlike a DA on a precision approach, the MAP is not altitude-based. You reach the MAP when the fix, distance, or time is met — regardless of where you are in your descent to MDA.

What visual references are required to descend below MDA?

Under 14 CFR 91.175(c), three conditions must all be met before you may descend below MDA:

1. 1
   Position. 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 of descent using normal maneuvers.
2. 2
   Flight visibility. Flight visibility is not less than the visibility prescribed in the approach procedure being used.
3. 3
   Visual references. At least one of the following is distinctly visible and identifiable: the approach light system (with a restriction — approach lights alone authorize descent only to 100 feet above the TDZE; red terminating bars or red side row bars must also be visible to continue lower), the threshold, threshold markings, threshold lights, REIL, visual glideslope indicator (VASI/PAPI), touchdown zone or touchdown zone markings, touchdown zone lights, the runway, runway markings, or runway lights.

All three conditions must exist simultaneously. Approach lights alone authorize descent no lower than 100 feet above the touchdown zone elevation (TDZE). This specific restriction is one of the most frequently tested 91.175 details on the oral portion of the checkride.

What are the ACS skill tolerances for IR.VI.A?

The FAA Instrument Rating ACS (FAA-S-ACS-8C) sets three primary performance tolerances for the nonprecision approach skill elements:

The altitude tolerance is asymmetric by design: going below MDA without visual references violates 14 CFR 91.175(c) and is an automatic unsatisfactory. Going more than 100 ft above MDA during the level segment (e.g., leveling at 1,700 ft MSL when MDA is 1,500 ft) is also a tolerance bust — you are not flying the published procedure.

What is the continuous descent final approach (CDFA) technique?

CDFA is a technique endorsed by the Instrument Procedures Handbook (FAA-H-8083-16B) in which you fly a constant-angle descent from the FAF to a point just above MDA — rather than leveling at MDA and flying level until the MAP (the traditional "dive-and-drive" technique). If visual references are not established by the VDP or MAP, you transition directly into the missed approach without ever actually leveling at MDA.

CDFA produces a stabilized approach profile consistent with a normal landing descent, reducing controlled-flight-into-terrain (CFIT) risk. Most modern DPEs expect CDFA execution. If you use dive-and-drive, expect a follow-up question about why and what the risk management considerations are.

What does the DPE look for on IR.VI.A?

DPEs evaluate IR.VI.A across the entire approach sequence — from the approach briefing through either the landing or missed approach initiation. Key observation points:

• Approach briefing. Did you brief the procedure name, navaid frequency and identification, final approach course, FAF, stepdown fixes, MDA, MAP identification method, missed approach procedure, and required visual references? An incomplete briefing is the first mark against you.
• Navaid setup. Is the frequency tuned, identified (Morse), and crosschecked before the FAF? CDI source set correctly for RNAV vs. VOR?
• Stepdown fix compliance. Did you reach each fix at or above the published crossing altitude? The DPE notes every altitude constraint crossing.
• Final approach track. CDI deflection within 3/4 scale throughout final. Heading corrections proportionate and timely, not overcorrected.
• MDA level-off. Leveling precisely within +100/-0 ft of MDA without floating above for extended periods or busting through the floor.
• MAP identification and action. Positive identification of the MAP before arrival. Missed approach initiated at or before the MAP if visual references are not established.
• Risk management articulation. During the oral or debrief, can you explain what could go wrong (CFIT, missed MAP, MDA bust) and how you mitigate each?

What are the most common errors on a nonprecision approach?

• MDA bust (below). Descending below MDA without the required visual references established — the most disqualifying single error. Cause: task saturation, rushed approach, poor MDA callout discipline.
• Missing or late MAP. Continuing past the MAP in IMC without initiating the missed approach. Cause: misidentifying the MAP type (time vs. DME vs. waypoint) or fixation on achieving visual contact.
• Skipping stepdown fixes. Descending to MDA before crossing an intermediate stepdown fix. Cause: inadequate approach briefing or not cross-checking altitude against chart.
• Floating well above MDA. Leveling 300–500 ft above MDA due to an early level-off. Cause: premature power reduction or confusion about which altitude line applies.
• Dive-and-drive with no awareness of CDFA. Not a hard failure, but demonstrates incomplete knowledge of current best practices in approach technique.
• Navaid not identified. Flying a VOR or LOC approach without listening to and confirming the Morse code identifier. The DPE may ask "how do you know that localizer is actually operational?" immediately post-approach.

Frequently Asked Questions

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