Instrument rating · ACS IR.VI.B
Precision Approach
Precision approaches add vertical guidance: you follow the glideslope or glidepath down to a decision altitude.
Why this one matters
Precision approaches take you lowest, often to 200 feet above the runway. That leaves little room for an unstable approach or a late decision. Continuing below the DA without the runway clearly in sight, or chasing the needles near minimums, is how airplanes land short or hit obstacles. A stable final and a firm decision at the DA keep it safe.
Can’t miss
- •Precision approaches are ILS, GLS and PAR. LPV and LNAV/VNAV are approaches with vertical guidance (APV): also flown to a DA, but not precision, so for alternate planning they count as nonprecision (800-2).(Instrument Procedures Handbook (FAA-H-8083-16B), Approaches; AIM, Chapter 1 (navigation aids, GPS and WAAS))
- •The DA is a decision point, not a floor: if the required references aren’t distinctly visible, start the missed at the DA without leveling off. A brief dip below DA while the missed begins is expected.(14 CFR 91.175)
- •Set a descent rate as you intercept the glidepath: about 5 times your groundspeed for a 3° glideslope (90 knots ≈ 450 fpm).(Instrument Flying Handbook (FAA-H-8083-15B))
- •Localizer and glideslope get more sensitive as you get closer: small corrections, and no more than 3/4-scale deflection.(Instrument Procedures Handbook (FAA-H-8083-16B), Approaches)
- •Identify the localizer by its Morse code before relying on it; for LPV, confirm the LPV annunciation.(AIM, Chapter 1 (navigation aids, GPS and WAAS))
- •Adjust minimums for category, NOTAMs, inoperative aircraft or navigation equipment and visual aids (DA as well as visibility), using the Inoperative Components Table and chart notes. Glideslope out: use the localizer (LOC) line's MDA if the chart has one; if not, the approach can't be flown as published.(Terminal Procedures Publication, Inoperative Components or Visual Aids Table; IPH)
- •Checkride standard: from the FAF to DA, no more than 3/4-scale deflection of either needle, airspeed ±10 knots.(Instrument Rating ACS (FAA-S-ACS-8C), IR.VI.B.S12)
What you should know
Systems and indications K2 · K3
- An ILS has a localizer (lateral) and glideslope (vertical, usually 3°). The localizer is about four times as sensitive as a VOR; full deflection is a few degrees off course.(AIM, Chapter 1 (navigation aids, GPS and WAAS))
- RNAV (GPS) approaches with LPV or LNAV/VNAV minimums give vertical guidance from WAAS or baro-VNAV. Confirm the mode annunciation before the FAF.(AIM, Chapter 1 (navigation aids, GPS and WAAS))
- Identify the localizer by Morse code, check for flags, and watch for false glideslope indications above the published path; intercept from below.(AIM, Chapter 1 (navigation aids, GPS and WAAS))
- GPS can be affected by interference or jamming; ground-based aids can have outages. Check NOTAMs.(AIM, Chapter 1 (navigation aids, GPS and WAAS))
- Vertical-guidance limits: if an LPV downgrades to LNAV, fly the minimums the receiver now annunciates (the LNAV MDA) or go missed. Baro-VNAV has published temperature limits and needs a local altimeter setting.(AIM, Chapter 1 (navigation aids, GPS and WAAS))
The descent and minimums K1 · K4
- Plan the descent rate: groundspeed times 5 for a 3° path. A headwind lowers groundspeed and the rate needed.(Instrument Flying Handbook (FAA-H-8083-15B))
- Inoperative equipment (approach lights, for example) can raise the visibility minimum: look it up in the Inoperative Components Table at the front of the TPP, and check the chart notes, which can override it for that approach.(Terminal Procedures Publication, Inoperative Components or Visual Aids Table; IPH)
- Energy: fly a stable speed and configuration, with small pitch and power changes to hold the glideslope.(Instrument Procedures Handbook (FAA-H-8083-16B), Approaches)
At the decision altitude R7 · R5 · R6
- At the DA, the decision is made: continue only if you meet 91.175 (normal descent, flight visibility and a required visual reference); otherwise start the missed approach right away.(14 CFR 91.175)
- The approach-light rule is two steps. (1) With the approach lights as your only reference, you may descend no lower than 100 feet above the touchdown zone elevation (TDZE). (2) If the red terminating bars or red side-row bars are also distinctly visible and identifiable, the approach lights let you go below 100 feet. Work the number out from the chart before the approach: TDZE plus 100 feet is your floor on the altimeter.(14 CFR 91.175)
- Which lights have red bars: ALSF-1 has red terminating bars; ALSF-2 has red side-row bars in the inner 1,000 feet. MALSR, MALS and ODALS have none, so on those lights alone you never go below TDZE + 100; you need another listed reference (threshold, REIL, VASI, touchdown zone, runway, or their markings or lights) by then, or you go missed.(14 CFR 91.175; AIM, Chapter 2 (approach and runway lighting))
- The lights never cure the other conditions: all three in 91.175(c) must hold the whole way down: continuously in position for a normal descent with normal maneuvers, the required flight visibility, and a listed reference distinctly visible and identifiable, not just glimpsed. And 100 feet above TDZE is a floor on a continuous descent, not a second decision altitude: stay on the glidepath, and if you reach it with nothing beyond the white approach lights, go missed right then.(14 CFR 91.175)
- An unstable approach near minimums, such as full-scale deflection or a high sink rate, is a go-around.(Instrument Procedures Handbook (FAA-H-8083-16B), Approaches)
- Below DA with the references: a normal-rate descent on a stabilized visual path to the aiming point, and a normal landing in the touchdown zone. No diving or ducking under the glidepath.(Instrument Procedures Handbook (FAA-H-8083-16B), Approaches; Instrument Rating ACS (FAA-S-ACS-8C), IR.VI.B.S14-S15)
- The rest of the task: recognize inaccurate or inoperative instruments and say so; run the checklists; use the MFD for awareness; and manage the workload with SRM.(Instrument Rating ACS (FAA-S-ACS-8C), IR.VI.B.S5, S7, S16, S17)
Flying it: setup, automation and configuration R1 · R2 · R3 · R4
- Brief the chart before you need it: frequencies, final approach course, FAF altitude, minimums, the missed approach, and notes.(Instrument Procedures Handbook (FAA-H-8083-16B), Approaches)
- Tune, identify (Morse code) and confirm every navaid; for GPS, check the approach is loaded and the correct mode annunciates before the FAF.(AIM, Chapter 1 (navigation aids, GPS and WAAS))
- Know what the autopilot and navigator will do next, and be ready to hand-fly. Automation confusion on an approach is a known accident pattern.(Risk Management Handbook (FAA-H-8083-2A))
- Configure in stages, per the POH: approach configuration and speed by the FAF so the final segment needs only small changes; final flaps when landing is assured (when circling, not until you leave the MDA). Know the missed approach configuration too.(Your airplane's POH/AFM)
- Fly the procedure as published or as cleared. If you can’t comply with a clearance, say "unable".(AIM, Chapter 5, Section 4 (arrival and approach procedures))
On the flight
ACS standards
- Before the final approach segment: altitude ±100 feet, heading ±10°, airspeed ±10 knots, no more than 3/4-scale CDI deflection.(Instrument Rating ACS (FAA-S-ACS-8C), IR.VI.B.S9)
- From the FAF to DA, no more than 3/4-scale deflection of the vertical or lateral guidance, airspeed ±10 knots.(Instrument Rating ACS (FAA-S-ACS-8C), IR.VI.B.S12)
- Immediately initiate the missed approach at the DA when the required references aren’t unmistakably visible.(Instrument Rating ACS (FAA-S-ACS-8C), IR.VI.B.S13)
What your instructor is watching for
Your instructor watches whether you identify the localizer, set the descent rate at glideslope intercept, make small corrections, stay within 3/4 scale, and go missed promptly at DA.
Scenarios
Decide what you would do first, then see the worked answer.
Intercepting the glideslope from above, the needle shows centered at a much steeper descent than normal.
What could be happening? See the worked answer
A false glideslope. Intercept from below at the published altitude, and cross-check the altitude at the FAF.
AIM, Chapter 1 (navigation aids, GPS and WAAS)
Near DA the glideslope needle goes full scale up.
What do you do? See the worked answer
You’re well below the path: go missed. Full-scale deflection near minimums is unstable.
Instrument Procedures Handbook (FAA-H-8083-16B), Approaches
The approach lights are NOTAMed out of service.
What changes? See the worked answer
The visibility minimum usually goes up per the Inoperative Components Table; check the chart notes, which can override it, and adjust. You also lose the approach lights as a reference below DA.
Instrument Procedures Handbook (FAA-H-8083-16B), Approaches
Common mistakes
Chasing the needles.
Overcorrections grow as the needles get more sensitive.
Instead: Small, early corrections; hold a heading and descent rate.
Continuing below DA hoping to see the runway.
Below the protected path without references.
Instead: Decide at DA.
Not identifying the localizer.
Wrong or out-of-service signal.
Instead: Listen to the Morse ident.
Now train it
Say it out loud, hear it asked, and take the quick check in this lesson’s practice pack. It tracks your shaky spots.
Got it?
When it feels solid, practice precision approach out loud with our examiner.
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Teaching this? The instructor lesson plan →
Sources
- Instrument Procedures Handbook (FAA-H-8083-16B): Approaches
- Instrument Flying Handbook (FAA-H-8083-15B): Navigation systems; IFR flight
- Aeronautical Information Manual (AIM): Chapters 1, 2 and 5
- 14 CFR: 91.175, 97.3
- Instrument Rating ACS (FAA-S-ACS-8C): Area VI
- Terminal Procedures Publication (TPP): the current chart for each approach
Study aid, not FAA guidance. Regulations change; check the current text at eCFR and the ACS. Checked against current sources 2026-11-13.