Not every instrument approach gives you a glideslope to ride down. A large family of approaches guides you to the runway in the horizontal plane only, and leaves the descent to you, managed against altitudes and distances. These are the non-precision approaches, and learning how they differ from an ILS, and from the newer satellite approaches, is central to flying on instruments.
This is general educational information, not operational, legal, or regulatory advice. Rules differ by authority and change over time. Always verify against current official sources and follow your operator's approved procedures.
Lateral guidance, no glideslope
The defining feature of a non-precision approach is what it does not have: vertical guidance. It gives you a lateral track to the runway, but no electronic glidepath to follow down. Without that glidepath, you cannot fly a continuous guided descent to a decision height the way you can on an ILS. Instead you descend by reference to published altitudes and distances and level off at a minimum descent altitude (MDA), from which you look for the runway.
That single difference, lateral guidance only, ripples through everything else: the minima are higher, the descent is managed by the pilot rather than by a beam, and the missed approach is triggered by reaching a point rather than a height on a glideslope. The obstacle protection a procedure designer can guarantee is less tight without vertical guidance, which is exactly why the MDA sits higher than an ILS decision height to the same runway.
The family of non-precision approaches
Non-precision approaches are named after the navigation aid that supplies their lateral guidance, and the common members are:
- the VOR approach, tracking radials from a VOR;
- the NDB approach, the oldest and least precise, tracking bearings to or from a non-directional beacon;
- the localiser-only (LOC) approach, an ILS used without its glideslope, so the localiser keeps you aligned but you descend to an MDA;
- the RNAV (GNSS) approach flown to LNAV minima, where satellite navigation supplies a lateral track but no vertical guidance.
They feel different to fly, an NDB needle wanders where an RNAV track is rock-steady, but they share the same skeleton: a final approach fix, a lateral track, step-down altitudes, an MDA, and a missed approach point. Learn that skeleton once and every non-precision approach is a variation on it.
The middle ground: APV
Between the non-precision approaches and the precision ILS sits a third group, approaches with vertical guidance (APV). These do provide a glidepath, but not to the full precision-approach standard. The two you will meet are the RNAV approach flown to LNAV/VNAV minima, which builds a glidepath from barometric vertical guidance, and the LPV approach, which builds one from satellite augmentation. Because they give vertical guidance, APV approaches are flown to a decision altitude, like a precision approach, and they often deliver lower minima than a plain non-precision approach to the same runway. The modern hierarchy, then, runs precision (ILS, GLS), APV (LNAV/VNAV, LPV), and non-precision (LNAV, VOR, NDB, LOC), in roughly descending order of how low they let you go.
MDA, not DA
The minimum on a non-precision approach is a minimum descent altitude, and it behaves differently from the decision altitude on a precision approach, a distinction big enough to have its own guide. The short version is that an MDA is an altitude you must not descend below unless you have the required visual reference to continue, so you level off at it and fly along it until you either see the runway or reach the missed approach point. A decision altitude, by contrast, is a height at which you decide, accepting that the aircraft will dip slightly below it as the go-around is initiated. The non-precision MDA is a hard floor; the precision DA is a decision gate.
Flying it: the descent profile
Historically, pilots flew non-precision approaches by dive-and-drive: descend promptly to the MDA after the final approach fix, then fly level at the MDA until the runway appeared or the missed approach point arrived. The problem is the long, low level segment near the ground, a classic setup for controlled flight into terrain. The modern, safer technique is the continuous descent final approach (CDFA), flying the final segment as a single steady descent with no level-off, which our guide to stabilised approaches and CDFA covers in full. Even without a glideslope, a calculated descent rate against distance lets you approximate a stable 3-degree path down to the MDA.
The missed approach point
Because there is no glideslope to tell you when you have run out of approach, a non-precision approach defines its missed approach point (MAPt) explicitly, by a fix, a DME distance, or a time from the final approach fix at a given groundspeed. Reach the MAPt without the required visual reference and you must go around. The timing method is the one that catches people out: it depends on groundspeed, so a strong headwind or tailwind changes the time to the MAPt, and you compute it for the conditions rather than using a single memorised figure.
Circling from a non-precision approach
A non-precision approach does not always line you up with the runway you will land on. Where the final approach track is offset from the runway, or where you need a different runway from the one the procedure serves, the approach can end in a circling manoeuvre: you break off the instrument approach at the circling minima and fly a visual circuit at low level to position for the landing runway. Circling has its own, usually higher, minimum descent altitude and a defined area within which obstacle clearance is guaranteed, and you must keep the runway environment in sight throughout. It is a demanding piece of flying, a low-level visual manoeuvre in marginal weather, which is why many operators restrict or avoid it and why its minima are conservative. The point for this guide is that the non-precision approach gets you down to a visual position, and the circling minima, not the straight-in minima, govern when an offset or different-runway landing is allowed.
A worked example
You are cleared for a VOR approach. Crossing the final approach fix, you start down, descending by reference to the published altitudes and any step-down fixes, aiming for a steady continuous descent rather than dropping straight to the floor. You level off, if you have not yet seen the runway, at the minimum descent altitude, and you fly along it.
You also started a timer at the final approach fix, because this approach defines its missed approach point by time from the fix at your groundspeed. As the clock reaches the computed time, you arrive at the missed approach point. If by then you have the runway environment in sight and can land, you continue; if not, you fly the missed approach, because the MDA is a floor you will not go below without the runway in sight, and the MAPt is the end of the approach.
Now run the same runway as an LPV approach instead. Now you have vertical guidance, so you fly a continuous glidepath down to a decision altitude, typically lower than the VOR approach's MDA, and decide there. Same runway, but the APV approach gives you a glidepath and a lower minimum, where the non-precision VOR approach gives you a level segment and a higher one.
Common pitfalls
- Expecting a glideslope. A non-precision approach has none; you manage the descent yourself to an MDA.
- Confusing the MDA with a DA. The MDA is a hard floor you do not descend below without the runway in sight; the DA is a decision gate.
- Diving to the MDA and driving. The long level segment is a CFIT risk; a continuous descent is safer.
- Using a fixed time to the missed approach point. Timing to the MAPt depends on groundspeed, so compute it for the wind on the day.
- Assuming all RNAV approaches are the same. LNAV is non-precision; LNAV/VNAV and LPV are APV with vertical guidance and lower minima.
In Pilot EFB
Pilot EFB is a study and planning companion for instrument approaches, helping you tell the precision, APV and non-precision families apart and read what each chart is asking of you, alongside the approach plate and the rest of your offline-first briefing. It does not fly the approach, compute your descent, or set your minima, and the procedure you fly comes from the current chart and your approved minima. Pilot EFB is not a certified Electronic Flight Bag, so treat it as a study and planning aid and fly the approach from your official source of record.