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RNAV (GPS) Approaches for Pilots: Flying the LNAV Line Like a Pro

RNAV (GPS) approaches are the everyday IFR workhorse now—available at thousands of airports, usually straightforward to load, and often your best option when an ILS isn’t available. But within RNAV approaches, the LNAV minima line is the one pilots most often misunderstand, because it can look “modern” while still behaving like a classic non precision approach.


This post is a pilot-focused guide to LNAV: what it is, how to brief it, how to fly it smoothly, and the common traps.



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What “LNAV” Means on an RNAV Approach

LNAV stands for Lateral Navigation. On an RNAV (GPS) approach, LNAV provides:

  • Approved lateral guidance (the magenta line) to the runway environment, but

  • No approved vertical guidance to minimums


That means LNAV is normally flown to an MDA, not a DA. You manage the descent using:

  • Published step-down fixes, and/or

  • A constant descent technique (when appropriate and allowed), using advisory guidance if available


LNAV vs LP, LNAV/VNAV, and LPV (Quick Pilot Context)

On the same RNAV approach plate you might see multiple minima lines:

  • LNAV: lateral only, MDA

  • LP: lateral only with tighter sensitivity near runway, MDA

  • LNAV/VNAV: lateral + approved vertical guidance, DA

  • LPV: localizer-like lateral + approved vertical guidance, DA


Pilot takeaway: If you’re flying LNAV, treat it like a non precision approach even though it’s RNAV.


How LNAV Is Structured: FAF, Step-Downs, and the MAP

FAF (Final Approach Fix)

Most LNAV procedures have a published FAF (often labeled with the “Maltese cross” on charts). At the FAF you’re usually cleared to begin the final descent—but only within published altitude constraints.


Step-down fixes

Some LNAV approaches include step-down fixes on final. If they do:

  • You must not descend below each published altitude until past the fix

  • These are obstacle-clearance-critical on LNAV


MAP (Missed Approach Point)

For LNAV, the MAP is often defined by:

  • A specific waypoint (common on RNAV), or

  • Distance (less common now), or

  • Timing (rare on RNAV compared to VOR/NDB days)


Pilot takeaway: Know exactly how you’re identifying the MAP, because LNAV is MDA-based and the MAP is where “continue or missed” becomes real.


The Big Pilot Technique Issue: Avoiding “Dive and Drive”

Because LNAV is typically an MDA, pilots sometimes fly it like this:

  1. Descend aggressively after the FAF

  2. Level at MDA early

  3. Fly level hoping the runway appears


That works, but it can increase workload, destabilize the approach, and tempt people to cheat below MDA.


Better technique: CDFA mindset (when appropriate)

A constant descent final approach (CDFA) technique often produces a more stable LNAV:

  • Plan a steady descent rate from the FAF that brings you to MDA near the MAP

  • Respect all step-down fix altitudes on the way down

  • If you reach MDA early, level off and hold it—no “sneaking down”


Pilot takeaway: LNAV can be flown smoothly and stabilized if you plan the descent instead of reacting to it.


Advisory Glidepath (“+V”): Helpful, but Not Vertical Guidance

Many WAAS GPS units provide an advisory glidepath on LNAV approaches (often displayed as “+V” or a glidepath indicator). This can help you fly a stable descent.


But here’s the key:

  • Advisory glidepath is not approved vertical guidance

  • It does not convert the LNAV MDA into a DA

  • You still must comply with step-down fixes and LNAV MDA rules


Pilot takeaway: Use “+V” as a tool, not as permission.


LNAV Briefing Flow (Pilot Practical)

A good LNAV brief can be quick but specific:

  1. Approach and runway

  2. RNAV (GPS) RWY XX, expected landing runway, winds and runway length

  3. Equipment/annunciation

  4. Confirm approach loaded correctly and GPS integrity/RAIM/WAAS status as required by your system

  5. Confirm you’re actually on LNAV minima (not expecting LPV)

  6. Courses and altitudes

  7. Final approach course

  8. FAF altitude

  9. Any step-down fixes

  10. MDA and required visibility

  11. Descent plan

  12. “CDFA-style descent to arrive at MDA near the MAP”

  13. Target descent rate and power settings if you use standardized numbers

  14. MAP and missed approach

  15. Identify the MAP waypoint

  16. Missed approach first step: climb, heading/course, and altitude


Flying LNAV Well: Practical Tips

1) Configure early

LNAV doesn’t forgive last-second configuration changes. Have:

  • Gear and first flaps early (aircraft dependent)

  • Final landing configuration planned before the MAP


2) Make small lateral corrections

RNAV tracks precisely, and it’s easy to overcorrect. Smooth inputs win.


3) Cross-check with raw data/monitoring

Even with RNAV, back up your picture:

  • Cross-check headings, distances, and altitude constraints

  • Ensure waypoint sequencing is correct

  • Confirm you’re on the correct leg (especially if given vectors or a late clearance)


4) Treat MDA like a hard floor

  • Level at MDA promptly if you reach it early

  • Don’t descend below without required visual references

  • If you don’t have what you need at the MAP, execute the missed


5) Don’t stretch the approach past the MAP

The protected segment ends at the MAP for LNAV. If you’re not in a position to land, go missed—don’t “drift” beyond it hoping it appears.


Common LNAV Traps

  • Briefing LPV but getting LNAV: Your box can downgrade. If it’s LNAV, you fly LNAV minima.

  • Ignoring step-down fixes: A big risk on LNAV procedures with multiple altitude constraints.

  • Misusing advisory glidepath: Treating “+V” like a real glidepath can lead to premature descent or missed constraints.

  • High/fast at the FAF: LNAV is workload-heavy if you’re unstable early.

  • Late missed approach decision: Don’t delay past the MAP.


Bottom Line

LNAV on an RNAV approach is modern lateral guidance with classic non precision rules. Fly it with a disciplined brief, a planned descent (CDFA mindset), strict step-down compliance, and a hard respect for MDA and the MAP.



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