Deadly Display Potential in the Cockpit

It's common misconception, but +V advisory glide slope isn't same as LPV glide path.

Max Trescott

Friday, June 26, 2026 at 08:00 AM ET

Verified

Edited By:

Travis Tingle

Level at MDA and don’t go lower until you can see the runway environment. [Credit: FlySto]

Key Takeaways:

Advisory glide slopes (+V) on non-precision RNAV approaches provide obstacle protection only down to the Minimum Descent Altitude (MDA), unlike LPV paths which are protected down to a Decision Altitude (DA), despite looking similar on a PFD.
A fatal accident demonstrated the danger of pilots misunderstanding that autopilots will continue descent past MDA when coupled to an advisory glide slope, and that it's unsafe to follow this path below MDA as obstacle protection ends.
Pilots must manually level off at the MDA on non-precision approaches with advisory glide slopes and only descend further when strict visual requirements (FAR 91.175(c)) are met, recognizing subtle chart warnings about potential terrain below MDA.

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Flying an RNAV (GPS) approach with a +V advisory glide slope looks and feels exactly like flying a glide path to LPV minimums. But while an LPV path is obstacle-protected down to a decision altitude (DA), a +V glide slope can run you through a mountain after you descend below the minimum descent altitude (MDA). Yet in both situations, the PFD display will look almost identical.

A recent fatal accident involving a 2024 Epic E1000 at Steamboat Springs, Colorado, highlights this issue. The E1000 is a capable six-place turboprop equipped with the latest NXi version of the Garmin G1000. While it’s early in the National Transportation Safety Board’s investigation, already much is known about what happened from ADS-B data.