Approaches
AIM 5-4 / IFH Ch 9–10 / IPH Ch 4 • ILS, GPS/WAAS, Non-Precision, Minimums, Missed
Approaches: The Heart of the IFR Checkride
You must demonstrate precision, non-precision, and circling approaches. Know your minimums cold, brief the approach before you fly it, and treat DA/MDA as a hard decision point — failing to go missed when required is a checkride bust. (FAA-S-ACS-8C)
Key Takeaways
- A precision approach (ILS, PAR, GLS) gives both lateral AND vertical guidance and uses a Decision Altitude — Cat I ILS is 200 ft AGL, ½ SM / RVR 2400.
- Intercept the localizer first, then the glideslope from BELOW — never dive to catch the glideslope from above.
- A localizer-only or back-course approach has no glideslope, so it's non-precision — MDA and timing from the FAF.
- Back-course reverse sensing: set the OBS to the front-course inbound heading and fly away from the needle (unless your HSI corrects it).
Precision Approach Definition
- Provides both lateral AND vertical guidance to the runway
- Examples: ILS, PAR (Precision Approach Radar), GLS (GBAS Landing System)
- Uses Decision Altitude (DA) or Decision Height (DH) — a go/no-go point
- At DA: if required visual references are NOT in sight, execute missed approach immediately
- Standard Cat I ILS: DA 200 ft AGL, visibility ½ SM or RVR 2400
AIM 5-4-5
ILS Components & Design
- Localizer: Lateral guidance — provides course alignment with the runway centerline
- Glide Slope (GS): Vertical guidance — typically 3° descent angle to the runway threshold
- Outer Marker (OM): Identifies FAF/GS intercept point — blue light, dashes in Morse "—"
- Middle Marker (MM): Near DA — amber light, alternating dots/dashes
- Course sensitivity: LOC is ~4× more sensitive than VOR (5° vs 20° course width) — small corrections only on final
IFH Fig 9-34
IFH Ch. 9 / AIM 1-1-9
Flying the ILS
- Intercept localizer first, then intercept glideslope from below — never dive to catch GS from above
- Set power for descent: Know your aircraft's descent power setting (typically ~1,800-2,100 RPM)
- Glideslope descent rate: Approximately 5 × groundspeed (e.g., 90 kts GS ≈ 450 FPM descent)
- Small corrections: 1–2° heading changes and ±50 FPM adjustments — avoid chasing needles
- At DA: If runway environment in sight → land; if NOT → immediate missed approach, no hesitation
IFH Ch. 9
Localizer-Only (LOC) Approaches
- Same lateral guidance as ILS but WITHOUT glideslope — it's a non-precision approach
- Uses MDA (not DA) — descend, level off at MDA, fly to MAP
- Timing from FAF to MAP is required (no glideslope to define missed approach point)
- Minimums are higher than full ILS — typically 400-600 ft AGL
- Can happen when glideslope is out of service — NOTAMed as "ILS GS OTS, LOC approach available"
AIM 5-4-5 / IFH Ch. 9
Localizer Back Course (LOC BC)
- Uses the back side of the localizer signal — approach from the opposite end of the runway
- REVERSE SENSING: If your HSI is set to the front course inbound heading, the CDI reverses
- Solution: Set the OBS to the front course inbound heading and fly AWAY from the needle
- Some HSIs eliminate reverse sensing — know your equipment before you fly this approach
- No glideslope — it's always a non-precision approach with MDA
IFH Ch. 9 / IPH Ch. 4
ILS Approach Segments
- Feeder route: Transition from en-route to IAF (Initial Approach Fix)
- Initial: IAF to IF (Intermediate Fix) — alignment and altitude setup
- Intermediate: IF to FAF/glideslope intercept — final configuration
- Final: FAF to MAP (Missed Approach Point) — precision tracking required
- Missed approach: MAP to the holding fix — follow published procedure exactly
IFH Ch. 10
Key Takeaways
- GPS approach hierarchy: LPV (best, DA to 200 ft) > LNAV/VNAV (DA) > LP / LNAV (MDA, lateral only).
- LNAV+V is the trap — the +V is ADVISORY vertical guidance only, so it's still non-precision and uses MDA, not DA.
- LPV needs a current WAAS database and gives ILS-like ±0.3 NM final sensitivity with no ground equipment.
- Going missed: press OBS/SUSP to un-suspend so the GPS sequences to the missed approach fix.
GPS Approach Types Overview
- LPV: Localizer Performance with Vertical guidance — best GPS approach, similar to Cat I ILS
- LNAV/VNAV: Lateral Nav + Vertical Nav — uses baro-VNAV or WAAS, DA minimums
- LP: Localizer Performance — lateral only (like LOC approach), uses MDA, rare
- LNAV: Lateral Navigation only — basic GPS non-precision approach, MDA minimums
- LNAV+V: LNAV with advisory vertical guidance — still a non-precision approach using MDA
AIM 5-4-5
LPV Approaches (Best Available)
- Requires WAAS-capable GPS receiver with current database
- Decision Altitude as low as 200 ft (equivalent to Cat I ILS)
- CDI sensitivity narrows to ±0.3 NM on final — localizer-equivalent precision
- No ground-based equipment needed — works at airports without an ILS
- Technically an APV (Approach with Vertical Guidance), but operationally similar to ILS
AIM 5-4-5 / AIM 1-1-18
LNAV+V: Know the Trap
- The "+V" is ADVISORY vertical guidance ONLY — it is NOT a precision approach
- Minimums are MDA, not DA — you must fly dive-and-drive or CDFA to MDA
- Do NOT treat the glidepath as precision guidance — it may not provide obstacle clearance below MDA
- DPE gotcha: Students often assume +V makes it a precision approach — it does NOT
- If WAAS is available, the GPS may automatically offer LPV — always verify which minimums to use
AIM 5-4-5
GPS SUSPEND & WAAS Concepts
- SUSPEND mode: GPS stops automatic waypoint sequencing at the MAP — used for missed approach
- When going missed: Press OBS/SUSP to unsuspend so GPS sequences to the missed approach fix
- WAAS integrity: WAAS provides differential corrections — if WAAS lost, the GPS may downgrade to LNAV only
- Check the annunciator: "LPV" means full WAAS; "LNAV/VNAV" or "LNAV" means reduced capability
- Database currency: GPS database must be current for IFR operations — expired = not legal for approaches
AIM 1-1-18 / AC 90-108
Key Takeaways
- Non-precision approaches (VOR, NDB, LOC, LNAV, LP) give lateral guidance only and use an MDA you may not descend below without §91.175 visual references.
- Prefer CDFA — a continuous, stabilized descent to MDA — over dive-and-drive, and treat the MDA like a DA.
- Circle when the final course is >30° off the runway; stay within the category circling radius and turn toward the runway if you go missed.
- The VDP marks where a normal descent to landing can begin — past it without the runway in sight, a stabilized landing is unlikely.
Non-Precision Approach Basics
- Provides lateral guidance ONLY — no electronic vertical guidance
- Examples: VOR, NDB, LOC (localizer without glideslope), LNAV, LP
- Uses Minimum Descent Altitude (MDA) — NOT a Decision Altitude
- Pilot descends to MDA and levels off until visual contact or missed approach point
- Cannot descend below MDA without required visual references per §91.175
AIM 5-4-5
VOR Approaches
- Use VOR facility for lateral course guidance — tune and identify the VOR
- VOR on-airport: MAP is typically station passage (CDI flip)
- VOR off-airport: MAP may be a DME distance, timed from FAF, or a GPS waypoint
- GPS overlay: Using GPS for situational awareness on a VOR approach — still uses VOR minimums
- VOR approach sensitivity: ±10° full-scale deflection — much less precise than LOC or GPS on final
IFH Ch. 9 / IPH Ch. 4
Dive-and-Drive vs. CDFA
- Dive-and-drive: Descend to MDA, level off, fly to MAP — traditional method
- CDFA (Continuous Descent Final Approach): Constant-rate descent similar to precision approach
- CDFA is safer — stabilized approach, less level flight at low altitude
- FAA encourages CDFA technique on non-precision approaches
- With CDFA: treat the MDA like a DA — if no runway environment at MDA, go missed
AIM 5-4-5
Circling Approaches
- Used when landing runway not aligned with final approach course (>30° offset)
- Higher minimums than straight-in — based on aircraft approach category
- Category A (<91 kts): 1.3 NM radius, Cat B (91-120 kts): 1.5 NM radius
- Must remain within the circling area — protected airspace for obstacle clearance
- If runway environment lost during circling, execute missed approach toward the landing runway
- DPE test: You may be asked to circle during a checkride — know the procedure cold
AIM 5-4-20
Visual Descent Point (VDP)
- A defined point on a non-precision approach from which a normal descent to landing can begin
- Shown as a bold "V" on the profile view — not all approaches have one
- If you reach the MAP without having reached the VDP, the approach may not be practical to land from
- VDP is for planning only — it does not replace MDA restrictions or required visual references
- Calculate VDP: (MDA HAT ÷ 300) = distance from runway in NM at normal 3° glidepath
AIM 5-4-5 / IPH Ch. 4
Key Takeaways
- Brief the approach before flying it: type/minimums, frequencies, final course, altitudes (FAF, DA/MDA, stepdowns), missed approach, and MAP timing.
- Chart layout reads top-down: heading → plan view → profile view → minimums (by aircraft category), plus the notes for the "T" / "A" symbols.
- NoPT means skip the procedure turn from that transition; a HILPT is a hold used as the course reversal.
- Aircraft approach category is set by 1.3 × Vso — fly a faster category and you use that category's higher minimums.
Approach Chart Briefing (The "Must-Brief" Items)
- Type of approach: ILS, LOC, VOR, RNAV (GPS) — and which minimums you'll use
- Frequencies: Nav aid, tower/CTAF, missed approach comm
- Final approach course: Inbound heading to fly
- Altitudes: FAF altitude, glideslope intercept, stepdown fixes, DA/MDA
- Missed approach procedure: Initial action, route, holding fix, holding entry
- Timing: MAP timing (for non-precision) — calculate based on groundspeed
ACS VI / IPH Ch. 4
Approach Chart Sections
- Heading section (top): Approach name, airport, nav frequencies, notes, MSA circle
- Plan view (middle): Bird's-eye view of the approach — course, fixes, altitudes, holding patterns
- Profile view (bottom-left): Side view of descent profile — FAF, stepdowns, DA/MDA, missed approach point
- Minimums section (bottom-right): DA/MDA, visibility, by aircraft category (A, B, C, D)
- Notes: Check for "T" (non-standard takeoff), "A" (non-standard alternate), and other limitations
IPH Ch. 4
Procedure Turns & HILPT
- Procedure turn (PT): 45°/180° or 80°/260° course reversal to establish inbound on the final approach course
- Remain within specified distance from the PT fix (typically 10 NM)
- HILPT (Hold In Lieu of Procedure Turn): A holding pattern at the IAF used as a course reversal
- NoPT: "NoPT" on the chart means you don't do the procedure turn from that transition — go straight in
- Barbed arrow shows PT side — always remain on the maneuvering side of the final approach course
AIM 5-4-9 / IPH Ch. 4
TAAs (Terminal Arrival Areas)
- RNAV approach feature: Pie-shaped sectors around the IAFs that define arrival altitudes
- Three sectors: Straight-in, Left Base, Right Base — each with a minimum altitude
- No procedure turn needed when arriving from within a TAA sector
- GPS automatically activates the appropriate sector based on your position
- Simplifies the approach setup — fly to the appropriate IAF at the TAA altitude, then proceed inbound
IPH Ch. 4 / AIM 5-4-5
Aircraft Approach Categories
- Based on 1.3 × Vs0 — stall speed in the landing configuration at maximum gross LANDING weight
- An aircraft fits in exactly one category — see the speed table below
- Your category determines which minimums line to use — a faster category means higher minimums
- The trap: if you maneuver ABOVE your category's upper speed limit, you must use the minimums for the higher category. A Cat A airplane circling at more than 90 knots uses Cat B circling minimums
| Cat | Speed | Typical |
|---|---|---|
| A | Below 91 kt | Most single-engine trainers |
| B | 91 to 120 kt | High-performance singles, light twins |
| C | 121 to 140 kt | Turboprops, business jets |
| D | 141 to 165 kt | Larger jets |
| E | 166 kt or more | Certain military types |
Speed is 1.3 × Vs0 at max gross landing weight. Ranges are half-open — 120 kt is still Cat B, 121 kt is Cat C.
14 CFR §97.3 / IPH Ch. 4
Key Takeaways
- §91.175 lists the visual references required to descend below DA/MDA — with the approach lights alone (no red bars) you may go to 100 ft above TDZE.
- DA/DH is a precision/APV decision point (MSL/AGL); MDA/HAT is the non-precision floor.
- When listed components are inoperative, apply the single greatest visibility increase from the inop-components table — not cumulative.
- Set personal minimums above published, and be ready to articulate the philosophy to a DPE.
Required Visual References (§91.175)
- Approach light system (ALS) — with ALS only (no red terminating bars): descend to 100 ft above TDZE max
- Threshold or threshold markings or threshold lights
- Runway end identifier lights (REIL)
- Visual approach slope indicator (VASI/PAPI)
- Touchdown zone, TDZ markings, or TDZ lights
- Runway or runway markings or runway lights
14 CFR §91.175(c)(3)
Reading Minimums on Approach Charts
- DA/DH: Decision Altitude (MSL) / Decision Height (AGL above TDZE)
- MDA/HAT: Minimum Descent Altitude (MSL) / Height Above Touchdown (AGL)
- Visibility: Statute miles or RVR (in hundreds of feet) — e.g., RVR 24 = 2400 ft
- Inoperative components table: If certain lights/equipment are out, minimums increase
- Non-standard alternate minimums shown with "A" in an inverted triangle
AIM 5-4-5
Inoperative Components & Adjustments
- If approach lights, MALSR, or SSALR are out: Visibility increases per inop components table
- VASI/PAPI inop on a visual or circling approach: Does not change published minimums
- Medium-intensity approach lights (MALS/MALSF): Visibility may increase when inop
- If multiple components are inop: Apply the greatest single adjustment, not cumulative
- Always check inoperative component table on the approach chart — it's there for a reason
AIM 5-4-5 / IPH Ch. 4
Personal Minimums
- Add a margin above published minimums — especially as a new instrument pilot
- Consider: recent IFR experience, approach type familiarity, weather trend, and aircraft capability
- Example: "My personal minimums are 500/2 for any approach until I have 50 hours actual IMC"
- DPE perspective: Applicants should be able to articulate their personal minimums philosophy
- Adjust based on fatigue, unfamiliar airport, single-pilot vs. crew, day vs. night
AC 60-22
Key Takeaways
- Fly the airplane first: full power, pitch to climb, THEN the published route — climb straight ahead until the published turn altitude unless an immediate turn is charted.
- Go missed at DA (no visual references) or at the MAP (runway not in sight); failing to is a checkride bust — it's a decision point, not an advisory.
- Never descend below DA/MDA once you've decided to go missed.
- On a circling missed, turn toward the landing runway first, then fly the published missed approach.
Missed Approach Procedure
- Step 1: Apply full power and establish a climb attitude (FLY THE AIRPLANE FIRST)
- Step 2: Follow the published missed approach instructions (climb, then turn unless specified)
- Step 3: Notify ATC: "[callsign] missed approach"
- Step 4: Clean up the aircraft (flaps, gear as appropriate)
- Step 5: Proceed to the missed approach holding fix and hold or follow ATC instructions
IFH Ch. 10
When to Execute a Missed Approach
- At DA/DH on a precision approach if required visual references are NOT in sight
- At MAP on a non-precision approach if runway environment is NOT visible
- Anytime during the approach if the approach becomes unstabilized
- If ATC instructs you to go missed
- If you lose sight of the runway environment after descending below DA/MDA
- If the runway is obstructed (vehicle, aircraft, wildlife)
14 CFR §91.175
Missed Approach Gotchas (DPE Favorites)
- Never descend below DA/MDA after deciding to go missed — immediate climb
- A climbing turn should NOT begin until reaching the published altitude unless specified
- Know the missed approach holding fix, entry, and expect-further-clearance time
- Failing to go missed at DA is a checkride bust — it is a decision point, not an advisory
- Circling missed approach: Turn toward the landing runway, then follow published missed approach
FAA-S-ACS-8C
Memory Items for Approaches
- In-range (WIRE): Weather/ATIS, Instruments (altimeter set), Radios (approach/tower freq), Essentials (brief the approach)
- IAF (BCCGUMPS): Brief, Course set, CDI source, Gas (fullest tank), Undercarriage, Mixture, Props, Switches (lights)
- FAF: Time/Gear/Power/Tower — start timer, gear down, set descent power, contact tower if not already
- Go-around: Full power, pitch up, flaps adjust, positive rate → gear up, climb to assigned altitude
- These memory items ensure nothing is missed during the high-workload approach phase
IFH Ch. 9 / PFC TCO
Go Deeper
Question about minimums, an LPV vs LNAV+V call, or a missed approach? Ask Kit for a CFI-level explanation.
“Explain the difference between LPV, LNAV/VNAV, and LNAV+V minimums”
Training aid only — verify all data against your POH and current FAA publications.