Updated October 2026
An ILS approach gives you a localizer for left-right guidance and a glideslope, normally 3 degrees, for vertical guidance down to a decision altitude, as low as 200 feet on a Category I ILS. RNAV (GPS) approaches do the same job from satellites, and with WAAS the LPV line reaches the same 200-foot floor at qualifying airports.
Every approach chart you will ever brief belongs to one of a few families. Below are those families, the four lines of minimums on an RNAV (GPS) chart, what WAAS adds, how to read a plate, circling, and the approaches we fly from Van Nuys.
Book A Discovery Flight — $229 Book A Free Consultation Call (818) 330-1318
Precision, Vertical Guidance And Non-Precision Approaches
AIM 5-4-5 sorts approaches by what the needles give you. A precision approach provides course and glidepath guidance built to the ICAO precision standard; the AIM's examples are PAR, ILS and GLS. An approach with vertical guidance, an APV, also has a glidepath but is not built to that standard, and LPV and LNAV/VNAV both belong here. A non-precision approach gives course guidance only, as on a VOR, an NDB or an LNAV line.
The type sets the bottom of the approach. With a glidepath you fly down to a decision altitude, DA, and decide there: land or go missed. Without one you descend to a minimum descent altitude, MDA, and level off until you have what 14 CFR 91.175 requires to go lower or you reach the missed approach point.
| Class | Guidance | Minimum | Examples |
|---|---|---|---|
| Precision approach | Course and glidepath to ICAO precision standards | Decision altitude | ILS, PAR, GLS |
| Approach with vertical guidance | Course and glidepath, not to precision standards | Decision altitude | LPV, LNAV/VNAV, LDA with glidepath |
| Non-precision approach | Course only | Minimum descent altitude | VOR, NDB, localizer, LNAV, LP |
The checkride uses a simpler line. The Instrument Rating ACS defines a precision approach, for the test, as one flown to a published decision altitude with approved vertical guidance. So an LPV approach satisfies the precision approach Task even though the AIM files it as an APV.
The ILS: Localizer, Glideslope, Markers And Categories
The localizer is the left-right half. AIM 1-1-9 says its course is tailored so that full deflection either side equals 700 feet at the runway threshold, which is why the needle gets so sensitive in the last mile. It is usable to 18 nautical miles within 10 degrees of the course and 10 miles out to 35 degrees. A localizer also radiates a back course along the opposite end, but you use it only when a back course procedure is published and ATC authorizes it.
The glideslope is the vertical half, normally 3 degrees above horizontal and 1.4 degrees thick, usable to about 10 miles. Intercept it from below. The AIM warns that false courses and reverse sensing occur at angles well above the real path, so a needle that comes alive far too high is lying to you.
Marker beacons are fading out. The outer marker identifies the final approach fix for the non-precision version of the approach. A compass locator, DME, a VOR or NDB fix or a GPS fix can substitute for it, as 14 CFR 91.175(k) allows. The middle marker, about 3,500 feet from the threshold, is no longer operationally required.
| Category | Decision Height | Visibility (RVR) |
|---|---|---|
| Category I | 200 ft | 2,400 ft, or 1,800 ft with touchdown zone and centerline lights, or with autopilot, flight director or HUD |
| Category II | 100 ft | 1,200 ft |
| Category IIIa | Below 100 ft, or none | Not less than 700 ft |
| Category IIIb | Below 50 ft, or none | Less than 700 ft but not less than 150 ft |
| Category IIIc | None | No RVR limit |
Training airplanes fly Category I. Categories II and III need special authorization for the crew and the aircraft. One more AIM detail matters on a marine-layer morning. ATC protects the ILS critical areas around the antennas when the ceiling is below 800 feet or visibility under 2 miles, because a vehicle or airplane inside one can bend the signal.
Localizer-Only, LDA And The Lettered Approaches
Take the glideslope away and an ILS becomes a localizer approach, a non-precision procedure flown to an MDA. Many charts are titled "ILS or LOC" for exactly that reason, with both lines in the minimums box. An LDA is a localizer-type course that is not aligned with the runway, and Van Nuys has one, the LDA-C.
The title tells you more than people notice. Under AIM 5-4-5, a letter instead of a runway number, as in VOR-A, means the approach has circling minimums only. When there is more than one approach of the same type to the same runway, they get letters from the end of the alphabet: ILS Z, then ILS Y. Van Nuys has both an ILS Y and an ILS Z to Runway 16R, so the name is the first thing you check when you are cleared.
RNAV (GPS) Approaches: LPV, LNAV/VNAV, LP And LNAV
An RNAV (GPS) chart can carry several lines of minimums, and your equipment decides which one you may fly. AIM 5-4-5 defines them.
| Line | Guidance | Minimum | Equipment |
|---|---|---|---|
| LPV | Lateral and vertical from WAAS, flown like a Category I ILS | DA | WAAS receiver approved for LPV, with the flight manual saying so; baro-VNAV not authorized |
| LNAV/VNAV | Lateral and vertical, with larger integrity limits than LPV | DA | Approach-approved baro-VNAV, or WAAS |
| LP | Lateral only, with angular, localizer-like guidance from WAAS | MDA | WAAS equipment approved for LP |
| LNAV | Lateral only | MDA | Any GPS approved for approaches |
LP needs a word of its own. The FAA publishes LP where obstacles or terrain prevent an LPV, and the AIM says LP minimums are never published on the same procedure as LPV or LNAV/VNAV. It is not a fallback mode for a failed LPV. If WAAS vertical guidance goes away on an LPV approach, you fly the LNAV line.
The receiver changes as you get close. Within 2 nautical miles of the final approach waypoint, the approach mode becomes active and the CDI and integrity monitoring tighten from 1 mile to 0.3 mile full scale. If the receiver flags an integrity problem before the final approach waypoint, do not complete the approach. If it flags one after, climb and fly the missed. A negative W symbol on the chart marks places where WAAS vertical outages may happen daily without any NOTAM, so plan on LNAV or circling minimums there.
What WAAS Is And Why It Gives You LPV Minimums
WAAS, the wide area augmentation system, is the U.S. satellite-based augmentation system for GPS. The FAA describes it in four steps. Precisely surveyed wide-area reference stations across the country receive the GPS signals and measure their errors. Master stations turn that into a correction message every second. Uplink stations send the message to payloads on geostationary satellites, which rebroadcast it on a GPS-like signal. Your receiver applies it.
The result, in the FAA's words, is position accuracy of a few meters across the airspace system, and a warning within six seconds if the system is sending misleading information. That integrity is what lets an approach come down to ILS-like minimums. The FAA says an LPV can go as low as 200 feet at qualifying airports. Its count in November 2025 was 4,219 LPV procedures at 2,035 airports, 1,273 of them airports with no ILS at all, plus 759 LP procedures.
Whether you can use any of it depends on the box in the panel. A WAAS receiver approved for LPV, and a flight manual supplement that says so, are what put that line within reach. Check both before you brief an LPV, and if in doubt, brief LNAV.
Reading An Approach Plate: Briefing Strip To Missed Approach
The FAA chart is laid out in the order you brief it. Work through it the same way every time, out loud if you are training.
| Part Of The Chart | What You Check |
|---|---|
| Title | The exact procedure name, printed top and bottom: ILS Y or ILS Z, RNAV or VOR |
| Briefing strip | Frequencies in the order you will use them, the final course, and the notes that restrict the approach |
| Plan view | The route from where you are, the fixes, any hold, and the minimum sector altitude circle |
| Profile view | Altitudes at each fix, the final approach fix, the glideslope or glidepath, and the missed approach point |
| Minimums | The line your equipment supports, by approach category: DA or MDA, height above touchdown, visibility |
| Airport sketch | Touchdown zone elevation, runway length and the approach lights you expect to see |
| Missed approach | The first climb, the first turn and the hold you are going to, briefed before you start down |
The minimum sector altitude is an emergency altitude, not a target, and our guide to minimum sector altitude reads one step by step. What you must see before leaving DA or MDA is on our FAR 91.175 page. The missed approach starts at DA or the missed approach point, not after a second look. Under 91.175(e) it is immediate once the requirements are not met.
Circling And Straight-In Minimums
A straight-in approach lines you up with a runway. A circling approach brings you to the airport and leaves you to maneuver visually to land, either because no runway is aligned with the final course or because the wind wants a different runway. Circling minimums are higher, and they rise with speed.
Speed is sorted into approach categories under 14 CFR 97.3, using VREF or, without one, 1.3 times the landing-configuration stall speed at maximum landing weight. Category A is below 91 knots, B from 91 to below 121, C from 121 to below 141, D from 141 to below 166, and E above that. Our Piper Warrior's landing-configuration stall speed is 44 KIAS, so 1.3 times that is about 57 knots, comfortably inside Category A.
While circling, you stay at or above the MDA until you can descend normally to the runway. If you lose sight of an identifiable part of the airport, 91.175(e)(2) says go missed, unless the airplane's own bank is hiding it. On the checkride the ACS holds you to MDA +100/−0 and no more than 30 degrees of bank. At Van Nuys this is not a classroom topic, because three of the field's five approaches are circling-only.
Approaches You Will Fly From Van Nuys: The ILS 16R, The Lettered Procedures And The Practice Airports
Van Nuys publishes five approaches on the October 2026 charts. Two are the ILS Y and ILS Z to Runway 16R, which is 8,001 feet long with approach lights. The LDA-C, VOR-A and VOR-B are all circling procedures. None of them is an RNAV (GPS) approach, so for GPS and LPV work we fly a few minutes to the neighbors.
| Airport | Published Approaches | What It Teaches |
|---|---|---|
| Van Nuys (KVNY) | ILS Y RWY 16R, ILS Z RWY 16R, LDA-C, VOR-A, VOR-B | The ILS to a busy runway, and circling-only procedures |
| Whiteman (KWHP), 6 mi NE | RNAV (GPS) RWY 12, VOR-A | A short RNAV approach next to home |
| Camarillo (KCMA), about 30 NM W | RNAV (GPS) RWY 08, RNAV (GPS) Y RWY 26, RNAV (GPS) Z RWY 26, VOR RWY 26 | A WAAS approach with an LPV line, plus a VOR approach |
| Oxnard (KOXR) | ILS or LOC RWY 25, RNAV (GPS) RWY 07, RNAV (GPS) RWY 25, VOR RWY 25 | A coastal ILS for marine-layer mornings |
That spread is useful twice. The long IFR cross-country in 14 CFR 61.65(d) needs an approach at each airport and three different kinds of approach, and an ILS, an RNAV and a VOR are all within a short flight. The checkride asks for the same variety. From late spring into summer the marine layer often turns the coastal approaches into the real thing, with Van Nuys clear enough to come home to.
If the IFR system itself is new, start with IFR explained. We brief and fly these first in the Redbird MCX full-motion simulator, then in the airplane. Our instrument rating is $11,700 with 20 hours in the airplane and 20 in the simulator, and the flight school cost guide puts it beside the private and commercial numbers.
Related Reading
- Instrument flying skills, the scan, chart reading and holds behind every approach.
- VOR navigation explained, radials, CDI versus HSI and DME for VOR approaches.
- FAR 91.175 explained, what you must see to leave DA or MDA.
- Minimum sector altitude, the circle in the plan view and what it protects.
- Instrument rating checkride guide, the approaches the examiner will ask you to fly.
- Instrument rating in Los Angeles, the course, the price and the marine layer.
Instrument Approach FAQ
What Is The Difference Between An ILS And An LPV Approach?
An ILS uses a localizer and glideslope transmitted from beside the runway. An LPV uses GPS corrected by WAAS. Both are flown to a decision altitude, and both can go as low as 200 feet, but the AIM classes the ILS as a precision approach and the LPV as an approach with vertical guidance.
What Does LPV Stand For?
Localizer performance with vertical guidance. It is the lowest line on most RNAV (GPS) charts and needs a WAAS receiver approved for LPV; the FAA counted 4,219 LPV procedures in November 2025.
What Is WAAS In Aviation?
The wide area augmentation system. Ground reference stations measure GPS errors, master stations build a correction message every second, and geostationary satellites broadcast it, giving receivers position accuracy of a few meters.
Is An LPV Approach A Precision Approach?
The AIM calls it an approach with vertical guidance, not a precision approach. For the instrument checkride, though, the ACS treats any approach to a published DA with approved vertical guidance as a precision approach, so an LPV counts.
What Is A Localizer Approach?
An ILS without the glideslope. You get the same sensitive left-right guidance, 700 feet full scale at the threshold, but descend to an MDA as on any non-precision approach.
What Is Precision Approach Radar?
PAR is a radar landing aid that shows a controller your range, azimuth and elevation on final, out to 10 miles, so the controller can talk you down. The AIM lists it as a precision approach; none of the airports we train at publishes one.
How Low Can You Go On A Category I ILS?
A decision height of 200 feet with 2,400 feet RVR, or 1,800 feet RVR with touchdown zone and centerline lights or an autopilot, flight director or HUD. Below that, 91.175 still requires the visual references to continue.
Fly The ILS To Runway 16R With An Instructor
Approach charts make sense once you have flown one with the needles alive. If you already hold a private certificate, book a free consultation and we will look at your logbook against the instrument rating requirements. Not started yet? A 60-minute discovery flight from Van Nuys is $229 in a Piper Warrior, flown by you from the left seat and credited in full if you enroll within 24 hours.
Book A Discovery Flight — $229 Book A Free Consultation Call (818) 330-1318
