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 RNAV (GPS) approaches appear identical to LPV glide paths on PFDs but only offer obstacle protection down to the Minimum Descent Altitude (MDA), not below it.
A recent fatal accident highlighted the danger of pilots continuing to descend below the MDA while coupled to an advisory glide slope, as autopilots will not automatically level off at the MDA.
Pilots must adhere to FAR 91.175(c) for descending below the MDA, requiring specific visual references, and should recognize subtle chart clues that indicate potential obstacles in the visual segment below the 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.