Exploring the Corner Case Approach for a Pilot

Solar storm or poor signal quality can force a downgrade past minimums.

Max Trescott

Friday, August 28, 2026 at 08:00 AM ET

Verified

Edited By:

Travis Tingle

GA airplane approach point of view [Credit: FLYING Archive]

Key Takeaways:

LNAV/VNAV minimums are crucial when GPS signal quality is insufficient for LPV, even on LPV-equipped approaches, requiring pilots to actively monitor system annunciations for the authorized minimums.
Flying an LNAV/VNAV approach differs from LPV by using a magenta pentagon to indicate vertical guidance within a fixed ±75-foot window, rather than the angular, progressively more sensitive LPV guidance.
Factors such as solar storms or other signal quality issues can automatically downgrade an approach from LPV to LNAV/VNAV, underscoring the importance of pilot preparedness for these alternate minimums.

See a mistake? Contact us.

LNAV/VNAV minimums are a bit of a mystery to most U.S. pilots. That’s probably because they’re rarely encountered, except at the relatively few airports with RNAV (GPS) approaches that have LNAV/VNAV minimums but no LPV minimums.

However, as will be explained, I encountered them while flying an approach with LPV minimums when the satellite signal quality was insufficient to support LPV minimums.